Here, in part 2, we extend this to include 1 keV electron irradiation at 20 K of several stoichiometric mixing ratios of CO2 : NH3 ices followed by thermal processing. We demonstrate that not all stoichiometric mixing ratios of CO2 : NH3 ice form the same products. Not only did the 4 : 1 ratio form a different residue after thermal processing, but O3 was observed after electron irradiation at 20 K, which was not observed in the other ratios. For the other ratios, the residue formed from a thermal reaction similar to the work shown in Part 1. However, conversion of ammonium carbamate to carbamic acid was hindered due to electron irradiation at 20 K. Our results demonstrate the need to systematically investigate stoichiometric mixing ratios to better characterise the chemical and physical properties of interstellar ice analogues to further our understanding of the routes of molecular synthesis under different astrochemical conditions.Many experimental parameters determine the chemical and physical properties of interstellar ice analogues, each of which may influence the molecular synthesis that occurs in such ices. In part 1, James  2 : NH3 ice mixtures determines the electron irradiation products at 20 K and the composition of residue material formed after thermal processing.The stoichiometric mixing ratio of CO For example, the NH3-rich CO2 : NH3 mixtures  formed higher amounts of residue material where more NH3 crystallite grain boundaries existed, suggesting that structural diffusion of reactants may be linked to enhanced reactivity of this system.Interstellar ice analogue experiments play an important role in understanding molecular synthesis in the interstellar medium (ISM), and systematic investigations into the experimental parameters can provide a wealth of information. In James 2 : NH3 ices to include 1 keV electron irradiation at 20 K followed by thermal processing. Non-thermal processing due to electrons is thought to occur in the ISM due to the interaction of cosmic rays with solids releasing secondary electrons.2 Electron irradiation of CO2 : NH3 ice analogues has been previously studied3,4 as well as other methods of non-thermal processing such as UV photons5 and ions.6 These previous studies are summarised in 4][H2NCO2]) and carbamic acid (H2NCOOH) were reported as UV processing products at 10 K, ammonium carbamate was reported as a product for 9–20 eV electron irradiation at 10 K and carbamic acid as a product for 144 keV S9+ ion processing at 16 K. We note that ammonium carbamate, or both ammonium carbamate and carbamic acid, were identified as the thermal products in previous non-irradiated studies.1,3,5–12 In addition to ammonium carbamate and/or carbamic acid CO,4,5 OCN−,4,5 N2O  studies of CO2 : NH3 mixtures deposited at 20 K and then irradiated with 1 keV electrons at 20 K, and subsequent thermal processing. Henceforth ices processed in this way are referred to as e-irradiated. Mid-IR spectra of CO2 : NH3 mixtures with differing ratios of 4 : 1, 2 : 1, 1 : 1, 1 : 2, 1 : 5 & 1 : 10 are complemented by a VUV spectroscopic study of mixtures with ratios of 4 : 1, 2 : 1 & 1 : 3. The results presented in RJ20, which were also thermally processed, but not irradiated with electrons, are used as a set of control experiments to make direct comparisons and, therefore, investigate the effect of electron irradiation on the chemical and physical properties of the ice mixtures. The astrophysical implications of this study combined with that of RJ20 will be presented in a further publication.In this paper, we present the results of CO2−9 mbar and a base temperature of 20 K. CO2  and NH3  were premixed in the gas line prior to deposition and deposited onto a cooled substrate . After deposition, the ice samples were irradiated with 1 keV electrons using a Kimball Physics FRA-2X1-5549 electron gun with a current of 10 μA. Electron irradiation was conducted at set intervals, cumulating in a total electron irradiation time of 30 min or a total fluence of 3.37 × 1016 e− cm−2, and spectroscopic measurements were taken after each interval. The acquisition time for each mid-IR spectrum was approximately 2 min. After electron irradiation, the ices in the mid-IR study were allowed to rest for ∼1 h. For the VUV spectrum, the acquisition time is dependent on the step size used: for spectra below 110 K, this corresponded to ∼1 h, and for temperatures at or above 120 K, this corresponded to ∼10 min. The ice samples were then thermally processed to set temperatures and held at this temperature while spectroscopic measurements were taken.Both the mid-IR and VUV experiments were performed using The Open University Portable Astrochemistry Chamber (PAC). This was the same experimental system used in RJ20, using a Nicolet Nexus 670 FTIR spectrometer with an external MCT detector for mid-IR measurements and the AU-UV beamline on ASTRID2  to record the VUV spectra. A more detailed description can be found in Section 2 of RJ20 and Section S1.1 of the ESI for RJ20. Physical vapour deposition of the ices was conducted at a base pressure of low 102 : NH3 mixtures were calculated in the same way as described in the ESI of RJ20. Deposition rates were between 0.8–1.9 nm s−1 for both mid-IR and VUV spectroscopic studies. The average film thickness for the mid-IR study was 437 nm. Thinner films for the VUV measurements were required to prevent saturation of the absorption peaks, and the average film thickness was 204 nm for the VUV study. The spectra of the mixtures were normalised to a specific thickness when compared, 400 nm for the mid-IR samples and 200 nm for the VUV samples, and indicated in the figure captions. The individual sample thickness and normalisation factors are given in Table S1 in the ESI.†The film thickness and ratios of the CO13All mid-IR and VUV spectra are freely available on the Open Research Data Online (ORDO) Repository.2.114 The CASINO program requires inputs of the electron energy, the angle of the electron beam with respect to the sample, the composition, and density of the sample. A weighted density was used for the CO2 : NH3 mixtures which was calculated using the density of pure CO2 (1.11 g cm−3) and pure NH3 (0.74 g cm−3)15 and specific values are given in Table S2 of the ESI.To negate any substrate effects which may occur during electron irradiation the ice samples were grown to a thickness larger than the electron penetration depth. The penetration depths of the 1 keV electrons within the ice samples were estimated using the CASINO (monte CArlo SImulation of electroN trajectory in sOlids) program.33.12 : NH3 mixtures were deposited at 20 K: 4 : 1, 2 : 1, 1 : 1, 1 : 2, 1 : 5 & 1 : 10. These ratios are similar to the ratios used in the mid-IR study of RJ20 , with slight differences arising due to practical difficulties during gas mixing prior to deposition. In this study, the 4 : 1 ratio is comparable to the RJ20 3 : 1 ratio, and the 1 : 2 & 1 : 5 ratios are comparable to the RJ20 1 : 3 ratio.The following CO2 bonding environment. For the NH3-rich 1 : 10 mixture, CO2 was essentially a defect within the NH3 ice and existed in the form of isolated CO2 molecules. For the NH3-rich 1 : 5 mixture CO2 complexed to NH3 to form a CO2 : NH3 molecular complex as well as existing as isolated CO2 molecules. Within the other ratios  CO2 was in the form of CO2 dimers, CO2 : NH3 molecular complexes and isolated CO2. For a detailed characterisation of the CO2 : NH3 mixtures deposited at 20 K, see Section 3.1 of RJ20.Deposition spectra are shown in Section 2.1, Fig. S2.1 of the ESI,3.22 : NH3 mixtures were irradiated with 1 keV electrons at discrete intervals cumulating in a total fluence of 3.37 × 1016 e− cm−2. 2 : NH3 mixture in a 1 : 1 ratio after set intervals of 1 keV electron irradiation. Mid-IR spectra of the irradiated ices in other ratios can be found in Section S2.2, Fig. S4 to S7 of the ESI.2 and pure NH3 are shown in Fig. S2 and S3 of the ESI,After deposition at 20 K, the CO2 : NH3 mixture as shown in 2 absorption bands decreased throughout electron irradiation. Within the O–H/N–H stretching region, between 3550–2900 cm−1 , CO (2140 cm−1) and HCN (2092 cm−1). Several broad features also appeared between 1750–1250 cm−1: broad shoulders on both sides of the NH3 ν2 absorption band, and broad features centred around 1485 cm−1 and 1343 cm−1.Irradiation with 1 keV electrons induced several changes within the 1 : 1 CO900 cm−1 , an over−1 were not present in all ratios and are discussed further in Section 3.2.1. The new absorption features which were present also varied in position. The ratio-dependent formation of CO and OCN− are discussed in Section 3.2.2.Differences between the stoichiometric ratios were observed, and the positions at which new features formed are listed in 3.2.1−1 for all ratios after irradiation with 1 keV electrons after a total fluence of 3.37 × 1016 e− cm−2. The new absorption features formed are dependent on the stoichiometric ratios of the initial CO2 : NH3 mixtures. For example, on the blue wing of the NH3 ν4 absorption band one distinct absorption feature was identified in the 4 : 1 ratio at 1715 cm−1. For the 2 : 1, 1 : 1 & 1 : 2 ratios, the absorption feature on the blue wing of the NH3 ν4 absorption band was broad with two shoulder features. On the red wing of the NH3 ν4 absorption band, two distinct absorption features were observed near 1583 and 1550 cm−1 but only in the NH3-rich mixtures. Broad, asymmetric features were observed in the NH3-rich mixtures at ∼1505 cm−1 shifting to ∼1480 cm−1 in the other mixtures. Absorption features at ∼1380 cm−1 were observed for the NH3-rich mixtures. Broad absorption bands were observed for all ratios, except for the 4 : 1 ratio, near 1340 cm−1. An absorption feature was observed near ∼1300 cm−1 for all ratios except the 1 : 10 ratio.3-rich mixtures had additional absorption features at ∼1583 cm−1, ∼1550 cm−1, and ∼1380 cm−1 which could either indicate a more complex product, additional products or both.Absolute band assignments of these irradiation features are very difficult without theoretical calculations and are beyond the focus of this paper. Broadly, the overall profile of the mixtures shown in 3.2.2− was dependent on the initial mixing ratio as shown in −. CO forms from the direct dissociation of CO2 due to electron irradiation, and the amount of CO in the CO2 : NH3 ratios is in proportion to the concentration of CO2 within the mixtures. The 4 : 1 ratio had the highest amount of CO, and the 1 : 10 ratio had the lowest amount of CO. The formation of OCN− occurs via several steps, first requiring CO formation.4,5 The highest amount of OCN− formed was in the 1 : 5 ratio followed by, in descending order, the 1 : 2, 1 : 10, 1 : 1 & 2 : 1 ratios. While the amount of OCN− seems to depend on the concentration of NH3, the 1 : 10 does not fit this trend. This suggests that the formation of OCN− depends on an N-bearing intermediate but requires a minimum amount of CO, of which there is not enough in the 1 : 10 mixture. No detectable amounts of OCN− were observed in the 4 : 1 ratio. The position of the OCN− peak is also ratio-dependent, blueshifting as the concentration of NH3 decreases in the mixing ratios.The formation CO and OCN3.32 : NH3 mixtures were thermally processed and analysed at discrete temperatures until desorption. 2 : NH3 mixture in a 1 : 1 ratio. Mid-IR spectra of the other ratios can be found in Section S2.3 of the ESI.2 and pure NH3 ices are given for reference in Fig. S8 and S9 of the ESI,After 1 keV electron irradiation at 20 K, the CO2 : NH3 mixtures as shown in 2 : NH3 mixture in RJ20, segregation of the homogeneous mixtures was identified through blue shifts in the CO2 vibrational modes towards pure CO2 wavenumbers between 60–70 K , but the electrons are estimated to only penetrate to a depth of 17% of the thickness of the ice. Although sputtering will reduce the ice thickness, the majority of the mixtures were still mainly composed of CO2 and NH3, as evidenced through the strong absorption bands of CO2 and NH3 observed after e-irradiation shown in 2 : NH3 mixtures was, therefore, likely to be the same as the non-irradiated ices in RJ20. Similar to RJ20, ammonium carbamate was identified via the COO− asymmetric and symmetric stretches, and carbamic acid via the C–O and CO stretches.In addition to e-irradiation induced reaction at 20 K from 1 keV electrons, a thermally induced reaction was observed for all CO2 : NH3 ratios. Ammonium carbamate and carbamic acid were identified in the residue spectra at 150 K and 200 K for all mixtures except the 4 : 1 ratio. Among these ratios, the 1 : 5 ratio had the highest amount of residue material, followed by the 1 : 2 and 1 : 1 ratios, with the 1 : 10 and 2 : 1 ratios forming the least amount of residue. Ammonium carbamate to carbamic acid conversion was observed between 150–200 K in all mixtures except the 4 : 1 ratio.− asymmetric and symmetric stretches suggesting that little to no ammonium carbamate formed, the overall residue spectral profile is different from the other ratios. Focussing on the region between 1900–800 cm−1, at 150 K, the 4 : 1 residue spectra has broad absorption peaks centred around 1470 cm−1 and 1368 cm−1 and a much weaker absorption peak at 1262 cm−1. Thermal processing to 200 K redshifts the broad peaks observed at 150 K to 1448 cm−1 and 1332 cm−1 and the weaker absorption peak to 1257 cm−1. The appearance of the absorption peak at 1612 cm−1 suggests thermal conversion occurred between 150 K and 200 K. While it is clear that the 4 : 1 residue was different from the other ratios, identification of this residue is not possible without further experimental and computational investigations.From O and C–O stretches at ∼1707 cm-1 and ∼1327 cm−1, respectively. However, very little thermal conversion of ammonium carbamate to carbamic acid was observed in the e-irradiated 1 : 10 ratio. Additionally, OCN− was observed at 150 K and 200 K for the e-irradiated 1 : 10 residue. The e-irradiated residues at 150 K and 200 K were much more intense compared to the non-irradiated residues of RJ20, indicating the formation of higher amounts of residue material.2-rich ratios formed lower amounts of residue material compared to the NH3-rich ratios. This was attributed to the different bonding environment of CO2 within the different CO2 : NH3 mixtures. CO2 dimers, which formed mainly in the CO2-rich and 1 : 1 mixtures, desorbed at lower temperatures compared to isolated CO2 within an NH3 matrix and CO2 : NH3 complexes found largely in NH3-rich mixtures. As discussed in Section 3.3, e-irradiation of the CO2 : NH3 mixtures appeared to elevate the desorption temperatures of CO2 and NH3 increasing the probability for a thermal reaction to occur before desorption of CO2 and NH3. Also, the residence of CO may play a part, with CO desorption delayed to higher temperatures in the 1 : 1 & 1 : 2 and 2 : 1 & 1 : 5 mixtures.Electron irradiation at 20 K clearly influences the thermal reactivity of the 2 : 1 & 1 : 1 ratios. In the non-irradiated study of RJ20 the 1 : 1 and CO44.12 ice and pure NH3 ice deposited at 20 K and irradiated with 1 keV electrons at discrete intervals to a total fluence of 3.37 × 1016 e− cm−2 are shown in 2 and NH3 ices in The VUV spectra of pure CO2 at 20 K with 1 keV electrons at discrete intervals. The formation of CO was observed by the appearance of an absorption band centred around 147 nm, which had intense vibrational structure, and was due to the A1Π ← X1Σ+ transition.23–25 We tentatively assign the observation of O3 to the broad absorption peak centred around 258 nm, which is known as the Hartley band.26,27 We note that this broad absorption peak may also be ascribed to the Cameron band of CO28 or a combination of both the Hartley band of O3 and the Cameron band of CO. However, interpretation of our e-irradiated CO2 : NH3 mixtures in Section 4.3, suggests that this band was more likely due to the presence of O3. After electron irradiation at 20 K pure CO2 was thermally processed, and VUV spectra were acquired at discrete temperatures until desorption. VUV spectra of the thermal processing of e-irradiated CO2 ice is shown in 3 in 1Π ← X1Σ+ transition disappeared between 80–90 K, as did the absorption band of the Hartley band of O3 with CO2 desorbing around 100 K.3 ice at 20 K with 1 keV electrons at discrete intervals. A new absorption feature centred around 150 nm was observed after an irradiation fluence of 1.12 × 1016 e− cm−2. The intensity of the NH3 absorption peaks decreased significantly throughout electron irradiation. Due to the relatively strong VUV absorption cross-section of NH3 compared to CO2,24 a thinner ice sample was required to prevent saturation of the absorption peaks. The estimated electron penetration depth of the NH3 ice was 54% compared to the CO2 ice which was at 23%. After electron irradiation at 20 K, pure NH3 was thermally processed, and spectra were acquired at discrete temperatures until desorption. VUV spectra of the thermal processing of e-irradiated NH3 ice is shown in 2H4). Previous studies identify hydrazine as a product of non-thermal processing  of pure NH3 , having the highest relative decrease.Similar to the mid-IR spectra, the VUV spectra showed changes after electron irradiation. CO formed in all ratios, and was observed 3, rather than the Cameron band of CO. If the peak was due to the Cameron band of CO, we would expect to see it in the 2 : 1 ratio where relatively large amounts of CO were still observed. The formation of O3 was not observed in the mid-IR spectra due to the intense absorption peak of the ν2 absorption band of NH3 obscuring the O3 ν3 absorption peak at 1038 cm−1.In addition, the 4 : 1 ratio had a broad absorption peak centred around 258 nm. We believe this absorption peak is due to the Hartley band of O4.42 : NH3 mixtures were thermally processed and VUV spectra were measured at discrete temperatures until desorption. After electron irradiation at 20 K the CO1Π ← X1Σ+ electronic transition between 80–90 K corroborating the mid-IR results shown in Section 3.3 and consistent with the CO2 desorption temperature in pure irradiated CO2 ice. The Hartley band of O3 also disappeared at the same temperature as CO, indicating O3 desorption. The absorption band due to the  electronic transition of NH3 also decreased significantly between 80–90 K and an absorption band centred around 205 nm also formed at this temperature, indicating a thermal reaction, which continued to increase in intensity until 150 K.For the 4 : 1 ratio, the VUV spectra changed quite significantly between 80–90 K. Desorption of CO was marked by the disappearance of the intense vibrational structure on the absorption band due to the A1Π ← X1Σ+ electronic transition disappeared between 110–120 K for the 2 : 1 ratio and 120–150 K for the 1 : 3 ratio, corroborating the mid-IR results presented in Section 3.3. The absorption band due to the  electronic transition of NH3 gradually decreased throughout thermal processing until 150 K where it disappeared for the 2 : 1 ratio. For the 1 : 3 ratio, the absorption band due to the  electronic transition of NH3 had mostly disappeared after electron irradiation at 20 K before thermal processing. At 150 K, an absorption peak was observed centred around 145 nm in the 2 : 1 & 1 : 3 ratios had vibrational structure. At 200 K, the vibrational structure disappeared in the 2 : 1 ratio but remained in the 1 : 3 ratio. This vibrational structure was not associated with CO, which had desorbed between 110–150 K.The thermal processing of the VUV spectra for the 2 : 1 and 1 : 3 ratios did not change as significantly as the 4 : 1 ratio. The vibrational structure on the absorption band of CO due to the A3 was observed via the formation of a Wannier–Mott exciton peak at 194 nm in the 1 : 3 ratio when thermally processed to 90 K. However, no Wannier–Mott exciton was observed in the e-irradiated 1 : 3 ratio. The Wannier–Mott exciton peak intensity is associated with the presence of many NH3 crystallite grain boundaries . Due to electron irradiation, about 42% of the 1 : 3 ratio ice sample was processed, which reduced the number of pure NH3 crystallite grain boundaries in the non-irradiated part of the sample, and hence there was no observation of the NH3 Wannier–Mott exciton peak.In RJ20, a phase change of NH4.5Ammonium carbamate and carbamic acid were identified at 150 K and 200 K for all mid-IR ratios except the 4 : 1 ratio, which exhibited a different residue spectrum . Fig. 152 : NH3 residues at 150 K and 200 K of the non-irradiated study of RJ20 and the e-irradiated mixtures in this study. In agreement with the mid-IR residue spectra comparison :cp is the constant of proportionality of the processed  ice sample and cd is the constant of proportionality of the ice sample at 20 K.Similar to RJ20 we present the Rayleigh scattering tails as a fractional change in the constant of proportionality of the processed ice relative to the constant of proportionality at deposition (Δc after 1 keV electron irradiation for pure NH3 (0 : 1) and the CO2 : NH3 mixtures . The scattering tails for pure CO2 were outside the Rayleigh scattering regime. In c values after 1 keV electron irradiation to a total fluence of 3.37 × 1016 e− cm−2. For all CO2 : NH3 ratios and pure NH3 the Δc value was significantly higher after electron irradiation compared to before deposition. Molecular dissociation and the formation of new products due to electron irradiation of the samples appeared to disrupt the ice structure. These VUV scattering results provide direct evidence that as well as inducing chemical changes, electron irradiation also caused macroscopic changes in ice structure and morphology. A significant decrease in the Δc value at 90 K, for the 4 : 1 ratio, and to a lesser extent the 2 : 1, corresponded to the combined desorption of CO and CO2, consequently leading to rearrangement within the ice. The 1 : 3 had the least amount of CO2 and CO and their desorption appeared to have little effect on the Δc value. The Δc value of pure NH3 also remained relatively constant throughout thermal processing after electron irradiation at 20 K.52 : NH3 ice mixtures can have on the molecular synthesis induced by electron irradiation and subsequent thermal processing.We set out with the aim of demonstrating the impact that the different chemical and physical properties of a range of stoichiometric CO2 : NH3 ices below 16 K, we observed the formation of CO and OCN− after 1 keV electron irradiation at 20 K.4–6 Bertin et al. did not observe CO or OCN− after 9–20 eV electron irradiation at 30 K and noted that if CO had formed, it would have desorbed at their working temperature of 30 K. Given that OCN− requires the formation of CO, this would explain the lack of OCN−.4,5 For the other products reported in previous studies, i.e. ammonium carbamate, ammonium formate, carbamic acid, NH+4 and N2O, most of their identifying functional groups are within the 3500–2800 cm−1 or 1800–1250 cm−1 regions where significant overlap occurs with the strong NH3 absorption bands. We find it difficult to make absolute assignments of the IR absorption peaks within these two regions. Overlap from the intense NH3 absorption bands, similar functional groups present within molecules (e.g. ammonium carbamate and ammonium formate), and matrix-isolation effects due to the different stoichiometric ratios of CO2 : NH3 mixtures are all contributing factors. As such, we do not identify molecules within this region at e-irradiation temperatures.In agreement with three out of four previous studies on the non-thermal processing of CO3, not observed in the other ratios. O3 formation in pure CO2 is a multi-step process which is summarised below:2 : NH3 mixtures, the only source of O atoms comes from the CO2 and therefore it is not surprising that O3 was formed in CO2 : NH3 mixture with the highest amount of CO2. However, compared to the O3 absorption peak in the pure CO2 ice, the O3 absorption peak in the 4 : 1 ratio is much weaker, indicating a lower amount of O3 formed in the 4 : 1 ratio compared to the pure CO2 ice. Apart from there being fewer O atoms available due to less CO2, other reactions occurring due to the presence of NH3 and its e-irradiated products in the mixtures will reduce the amount O atoms available for O3 formation. It appears that for the other CO2 : NH3 mixtures, O-containing molecules like OCN− are formed either preferentially over O3 during e-irradiation or deplete the available O-atoms before O3 can form.Our e-irradiation of stoichiometric ratios revealed that the 4 : 1 ratio formed O3, which was otherwise obscured by the intense ν2 absorption band of NH3 in the mid-IR study. Other than the identification of CO, OCN− and O3, no identification of products due to e-irradiation was made. Mid-IR spectra obtained for the stoichiometric mixing ratios of CO2 : NH3 indicated a ratio-dependence on products formed from e-irradiation with NH3-rich mixtures showing more complex spectra within the region between 1800–1200 cm−1.Our VUV spectroscopic study was particularly useful for observing the formation of O2 : NH3 residue results with the residue of Jheeta et al., who also used 1 keV electrons to irradiate their 1 : 1 CO2 : NH3 mixture albeit at a slightly higher temperature of 30 K, showed good agreement.4 While Jheeta et al. only identified ammonium carbamate, an absorption peak at ∼1700 cm−1 is indicative of a CO stretch suggesting that carbamic acid was also present. Our 1 : 1 results were also in agreement with the 1 : 1 residues of Bossa et al.5 and Bertin et al.3 who identified ammonium carbamate and carbamic acid within their residue material. No comparison was made with Lv et al.6 as they did not thermally process their irradiated CO2 : NH3 mixtures.Comparison of our 1 : 1 CO2 : NH3 mixtures, presented in RJ20, we were able to further elucidate the impact of electron irradiation. Excluding the 4 : 1 ratio, all of the other e-irradiated CO2 : NH3 ratios formed a similar residue to the non-irradiated residues in RJ20. This suggests that the e-irradiated residues, apart from the 4 : 1 residue, are comprised of products mainly induced by the thermal reaction occurring at approximately 80–90 K. However, higher amounts of residue material formed in the e-irradiated CO2 : NH3 mixtures compared to the non-irradiated mixtures of RJ20. We believe this was due to the refractory layer formed from electron irradiation at 20 K, which consequently elevated the desorption temperature of CO2, thus allowing more time for a thermal reaction to occur. This corresponds to the practices within the literature which use more refractory molecules as ‘plugs’ to prevent the desorption of more volatile molecules.21,22By combining our e-irradiated results with our non-irradiated thermal study of CO2 : NH3 mixtures upon thermal processing between 150–200 K. For example, the non-irradiated CO2 : NH3 2 : 1, 1 : 1, 1 : 3 & 1 : 10 mixtures showed an increase in the CO and C–O stretch in 2 : NH3 mixtures. Ammonium carbamate appears to be stabilised by the products in the e-irradiated mixtures. At 150 K and 200 K, the e-irradiated product of OCN− is present, which we suggest stabilises the ammonium carbamate, thus preventing decomposition to carbamic acid at higher temperatures.We also observed that less conversion of ammonium carbamate to carbamic acid occurred in the e-irradiated CO2 : NH3 ice mixtures due toelectron irradiation.The Rayleigh scattering tails obtained from VUV spectra gave direct evidence of physical changes within the CO62 : NH3 ices and subsequent thermal processing using mid-IR and VUV spectroscopy. Our work is the first time that a study has focussed on the non-thermal processing of stoichiometric mixing ratios of CO2 : NH3 ices. We show that the small e-irradiation products of CO and OCN− are strongly dependent on the initial mixing ratio of CO2 and NH3, with no observable OCN− formed in the 4 : 1 ratio. However, the 4 : 1 ratio did form O3 after e-irradiation at 20 K which was not observed in the other CO2 : NH3 mixtures. We also show that the CO2-rich, e-irradiated 4 : 1 CO2 : NH3 ratio formed a markedly different residue upon thermal processing compared to the other ratios. The other ratios formed similar residues between themselves and similar residues to their thermal processing counterpart residues from RJ20. However, ammonium carbamate to carbamic acid conversion was arrested in the e-irradiated residues. The astrophysical implications of these results, along with the results of RJ20, will be discussed in a forthcoming paper.We systematically investigated the effect of the stoichiometric mixing ratio on 1 keV e-irradiated COThere are no conflicts to declare.RA-011-D1RA05600J-s001


The authors wish to make the following changes to their paper .Original:To be replaced with:Explanation for the correction:−9 cm2∙min−1 from 10−8 cm2∙min−1.We observed an error in the calculations of the vanadium (IV) diffusion values; as a result of this, the order of magnitude of these values has been corrected to 10Original:−8 cm2∙min−1), while commercial Nafion® NR212 suffered the highest V(IV) diffusion ((744 ± 9) × 10−8 cm2∙min−1),V(IV) diffusion through the composite PP-PBI membrane was found to be the lowest ((14 ± 1) × 10To be replaced with:−9 cm2∙min−1), while commercial Nafion® NR212 suffered the highest V(IV) diffusion ((744 ± 9) × 10−9 cm2∙min−1).V(IV) diffusion through the composite PP-PBI membrane was found to be the lowest ((14 ± 1) × 10Explanation for the correction:−9 cm2∙min−1 from 10−8 cm2∙min−1.We observed an error in the calculations of the vanadium (IV) diffusion values; as a result of this, the order of magnitude of these values has been corrected to 10Original:dryw) was obtained after drying it under vacuum at 55 °C for 22 h. The weight measurement was carried out in a closed vial to limit the uptake of moisture from the air. Then, the weight of the membrane in the wet state (wetw) was determined after immersion for 2 days in deionized water or in 1.6 M vanadium in 2 M H2SO4 and 0.05 M H3PO4 electrolyte , followed by the removal of droplets on the surface with a tissue. In this case, the wet weight was measured in a vial to reduce the evaporation of water from the membrane. Lastly, water and electrolyte uptake of pristine m-PBI and of commercial membranes NR212 and FAP-450 was calculated according to Equation (1).The dry weight of the membrane (To be replaced with:drym) was obtained after drying it under vacuum at 55 °C for 22 h. The weight measurement was carried out in a closed vial to limit the uptake of moisture from the air. Then, the weight of the membrane in the wet state (wetm) was determined after immersion for 2 days in deionized water or in 1.6 M vanadium in 2 M H2SO4 and 0.05 M H3PO4 electrolyte , followed by the removal of droplets on the surface with a tissue. In this case, the wet weight was measured in a vial to reduce the evaporation of water from the membrane. Lastly, water and electrolyte uptake of pristine m-PBI and of commercial membranes NR212 and FAP-450 was calculated according to Equation (1).The dry weight of the membrane (Explanation for the correction:m).The change described above has been made to be in line with the commonly used scientific unit of mass  with 2.5 mL of solution from the MgSOTo be replaced with:4 flask. Each time, the measured solution was transferred back to the MgSO4 flask to avoid significant volume changes.The measurements were carried out by filling two quartz cuvettes  with 2.5 mL of solution from the MgSOExplanation for the correction:4 flask and not the VOSO4 flask.The correction described above has been made as the measured solutions were transferred back into the MgSOOriginal:w) was calculated according to Equation (4). In Equation (4), iw and fw are the initial and final weight, respectively.Lastly, the change in weight (∆To be replaced with:m) was calculated according to Equation (4). In Equation (4), im and fm are the initial and final weight, respectively.Lastly, the change in weight (∆Explanation for the correction:m).The change described above has been made to be in line with the commonly used scientific unit of mass , theoreticalQ is the theoretical charge, n is the number of moles, F is the Faraday constant , and z is the charge.Efficiencies and discharge capacity are calculated according to Equations (5)–(8). In Equations (5)–(7), To be replaced with: chQ and disQ are the charges for the discharge and the charge process, while ch and dis are the average voltages during charge and discharge, respectively. In Equation (8), theoreticalQ is the theoretical charge, n is the number of moles, F is the Faraday constant , and z is the number of electrons associated with the electrochemical reaction.Efficiencies and discharge capacity are calculated according to Equations (5)–(8). In Equations (5)–(7), Explanation for the correction:V). Furthermore, the description of this symbol was corrected to the average voltage instead of volume, which was a typing mistake. The last change was made to provide a clearer description of the symbol z as “charge” did not provide the desired clarity.The changes described above were made to avoid confusion between the average voltages in the cell  as compared to the commercial Nafion® NR212 and Fumasep® FAP-450, (744 ± 9) × 10−8 and (351 ± 1) × 10−8 cm2∙min−1, respectively. This asymmetric composite membrane showed the lowest V(IV) diffusivity ((14 ± 1) × 10To be replaced with:−9 cm2∙min−1) as compared to the commercial Nafion® NR212 and Fumasep® FAP-450, (744 ± 9) × 10−9 and (351 ± 1) × 10−9 cm2∙min−1, respectively. This asymmetric composite membrane showed the lowest V(IV) diffusivity ((14 ± 1) × 10Explanation for the correction:−9 cm2∙min−1 from 10−8 cm2∙min−1.We observed an error in the calculations of the vanadium (IV) diffusion values; as a result of this, the order of magnitude of these values has been corrected to 10The authors apologize for any inconvenience caused and state that the scientific conclusions are unaffected. This correction was approved by the Academic Editor. The original publication has also been updated.


Here, we demonstrate how the proton resonances of a group of thienopyridazines (with known anticancer properties), can be amplified using the para‐hydrogen . Pseudo‐singlet state approaches were deployed to extend magnetic state lifetimes. Proof of principle spectral‐spatial images were acquired across a range of field strengths (7T‐9.4T MRI).Thienopyridazine isomers, including a 1H‐NMR signal enhancements of −10,130‐fold at 9.4T (~33% polarization) were achieved on thienopyridazine , using SABRE under optimal mixing/field transfer conditions. 1H T1 lifetimes for the thienopyridazines were ~18‐50 s. Long‐lived state approaches extended the magnetic lifetime of target proton sites in TP from an average of 25‐40 seconds. Enhanced in vitro imaging  of target TP was demonstrated.Here, we demonstrate the power of SABRE to deliver a fast and cost‐effective route to hyperpolarization of important chemical motifs of anticancer agents. The SABRE approach outlined here lays the foundations for realizing continuous flow, hyperpolarized tracking of drug delivery/pathways. PHIP‐side arm hydrogenation (SAH) expands on this route by releasing the final molecular probe via hydrolysis.In vivo metabolic images using PHIP‐SAH hyperpolarized [1‐13C]pyruvate permit monitoring of altered cardiac metabolism.Although next generation d‐DNP polarizers using cryo‐coolingp‐H2 induced polarization can also be implemented without changing the chemical identity of the agent (substrate) of interest. This is achieved via signal amplification by reversible exchange (SABRE)p‐H2 and the target substrate  ligand.1H NMR signals associated with up to 60% magnetic state purity to be recorded.e Figure . When p‐s Figure . A suita1H SABRE hyperpolarization efficiency  for a family of synthesized thienopyridazine (TP) isomers (IMes)] in methanol‐pH2 gas and mixed to start the polarization exchange either (1) manually (simply through vigorous shaking) for 10 s (method 1); or (2) via an automated polarizer (method 2). Polarization transfer was implemented at ~60 G for 1H in the fringe field of the NMR spectrometerSamples were exposed to 3 bar(g) MR signal detection was completed using a BBI probe on 400 MHz or 500 MHz spectrometers . Polarization levels were assessed using a pulse acquire sequence (90° flip angle), with a receiver gain of 1.p‐H2 was a custom‐made p‐H2 rig.p‐H2 for method 2 was a FDGS‐Alliance  hydrogen generator linked to a Bruker p‐H2 generator.In method 1, the source of p‐H2 addition (nitrogen gas shuttles solutions from the solenoid where SABRE takes place to the NMR detector).p‐H2 bubbling time, mixing field, time to transfer, etc.) and timing, which is controlled within the pulse sequence.Method 2 allowed for efficient delivery of the sample into the detector following d]P. [IrCl(COD)(IMes)],d22‐1,3‐bis‐imidazol‐2‐ylidene)] ([IrCl(COD)(d22‐IMes)])d22‐1,3‐bis‐4,5‐dihydroimidazol‐2‐ylidene)] [IrCl(COD)(d22‐SIMes)]Six catalyst precursors were tested with TP achieved using [IrCl(COD)(IMes)] (method 1) is shown in Figure d]P resonances in [Ir(H)2(IMes)3] and free substrate peaks are observed with enhancement. A signal enhancement of −2150 ± 67 was determined for H7 of the free substrate, (~6.9% ± 0.2% polarization) after SABRE. The highest signal enhancement found for a bound TP peak was −1576 ± 50, on the signal at 9.3 ppm. Similar results were collected for the remaining TP isomers, with TP proving to give the greatest signal improvements as summarized in Figure A typical SABRE hyperpolarized 3.21 values were measured for all proton sites in each of the four TP isomers . The individual proton T1 values for H2 and H3 were 28 and 18 s, respectively. The creation of a short‐lived singlet state is therefore indicated, with a signal lifetime of only ~1.7 times that of the average T1 because of the small couplings to proton sites H4 and H7.Summed integral areas for both H2 and H3 resonances were fitted to Equation  assumingLLS values and T1 values were measured with and without the SABRE catalyst. The presence of the catalyst reduces signal lifetimes dramatically  approach.Previous studies on many hetero‐aromatic substrates have identified an optimum polarization transfer field (PTF) of around 65 G for a Figure  show thad]P. Figure d]P (Supporting Information section 3).It has been demonstrated that SABRE signal enhancement levels are affected by the molar ratio of the substrate to catalyst.d]P. [IrCl(COD)(IMes)]d22‐IMes)]d22‐SIMes)]d22‐SIMes)] ultimately resulted in the best performance with the signal enhancement levels of H7 within TP of −3142‐fold ± 58  of pressure, it becomes the limiting factor for enhancement as eventually all of it is converted to H2.d]P and [IrCl(COD)(d22‐SIMes)], changing only the pressure of the p‐H2 introduced into the standard 5 mm J. Young tube to 4 bar(g) and 5 bar(g) with a constant exposure (shake) time of 10 seconds. The results should, therefore, reflect the increase in p‐H2 incorporation rate into the SABRE catalyst. The results shown in Figure p‐H2 pressure leads to a corresponding increase in SABRE enhancement. An increase in signal enhancement with p‐H2 pressure is independent of the proton site . An increase from 3 bar(g) to 5 bar(g) results in a 20% gain in signal enhancement across the substrate. It must be noted that the use of higher gas pressures is not practical for routine use without increasingly specialized apparatus. One can hypothesize that if equipment allowed an increase in the pressure beyond 5 bar(g) there would be a corresponding increase in enhancement before a plateau at a given pressure, at which point relaxation effects would dominate.Because d]P) resulted in a further increase in H7 signal enhancement to −5240‐fold at 9.4T (17% polarization), through reduction of spin dilution to these co‐ligands. Furthermore, when shaking in the somewhat variable stray field of the magnet was replaced by shaking in a purpose built 60 G handheld magnet arrayThe presence of a fully deuterated co‐ligand  compared to the 1:4 ratio (41.75). The blurring observed in both Figure 1H resonances within the TP molecule.RARE imaging studies on optimally hyperpolarized TP molecule a chemical shift‐based sequence was used. A 20:1 TP sample was prepared with [IrCl(COD)(IMes)]. The J. Young’s tube was placed within a falcon tube containing water/agar to aid automated shimming and to mimic the water resonance that would be present in in vivo conditions. Subsequent spectra‐spatial data, captured using centric encoded CSI (74 s), is shown in Figure Although direct high‐resolution imaging of the proton resonances is permitted by 1H sites is the relatively small bandwidth of possible resonances (~20 ppm). This permits the application of EPSI as a faster method of spectroscopic imaging for all resonances. A complementary EPSI experiment was also completed on the same sample. Total EPSI scan time was 6 s and the sequence parameters resulted in a 4‐fold increase in spatial resolution over the CSI equivalent . A direct comparison between resulting CSI and EPSI acquisitions for detection of hyperpolarized TP was made  is adjacent to the carbon of the fused rings and, therefore, sterically hindered when approaching the catalyst.Four thienopyridazines isomers were hyperpolarized using the SABRE technique. All isomers achieved high levels of SABRE hyperpolarization signal enhancements over thermal conditions. TP the highest signal enhancement −2150 ± 67 was measured for H7 on the free substrate. In the same spectrum, a bound peak was measured with an enhancement of −1576 ± 50 at 9.3 ppm. Moving this “bound” polarization into solution will maximize SABRE polarization levels. SIMes is known to have a faster rate of ligand exchange compared with its unsaturated analog.In agreement with previous studies, catalyst optimization remains substrate specific.p‐H2 pressure represents a simple route to increasing polarization.Although it is difficult to establish ideal polarization conditions for specific substrates without completing optimization studies, some general trends are apparent. The relation between signal enhancement and d]P). This is driven by less efficient mixing with pH2, and exposure to the air as samples are shuttled to the detector. Further research is required to optimize this system to achieve at least the levels of polarization reached using the manual method. Data here support use of specifically designed magnetic shakers tuned to a specific polarization transfer field (~60 G) to further optimize polarization transfer.When considering SABRE translation to the clinic an automatic polarizer would be necessary to achieve consistent polarization levels. Polarization via an automated system in this study was lower than the standard manual shaking . This is consistent with less spin dilution and reduced dipole‐dipole relaxation respectively because of the presence of deuterium. Here, use of a fully deuterated TP co‐ligand in a 1:3:1 catalyst to co‐ligand to substrate ratio afforded higher signal enhancements (66% increase). The co‐ligand does not receive polarization itself and, therefore, reduces spin dilution to give higher polarization levels on the 1H‐sites of the protio substrate trans to hydride in the active SABRE catalyst.Deuteration of both the catalyst and substrate are also clear routes to increased polarization  is a limiting factor. Furthermore, these levels of polarization were achieved in a methanol‐d4 solvent, which is toxic and not suitable for subsequent in vivo injection  showed an extension in magnetic lifetime in the proton pair of interest (between H2 and H3 from T1 of 18 and 28 s to TLLS of 40 s). A 40‐s magnetic lifetime is in‐line with 13C d‐DNP polarized pyruvate and therefore supports clinical detection feasibility.d]P, this could be counterproductive because H7 already has a T1 lifetime of 49 s (longer than the long‐lived lifetime on the H2/H3 resonances). In fact, deuterating H2, H3, and H4 in an effort to increase the T1 of H7 (without the use of LLS strategies) would be more sensible in this case. Unfortunately, synthetic attempts were unsuccessful.A long‐lived singlet state pulse sequence was applied to the target thienopyridazines. The regioisomer  yielded a TLLS value of over 100 s highlighting how effective LLS can be.Interestingly, elsewhere we tested 3,6‐substituted pyridazines, representing simpler systems (containing only one proton pair).4.31H RARE imaging approach. One of the advantages of hyperpolarizing protons is that one can use the abundant water signal on a phantom to easily optimize the power settings for the transmit coil using standard approaches. This means setting the accurate pulse power for a π pulse is possible and rapid spin echo measurements can be completed. Unfortunately, RARE approaches do not easily encode chemical shift information and resultant images exhibit chemical shift artefacts.High hyperpolarized signal intensities were observed with a single shot 1H water signal were detected (even when said background protons were saturated with the fast RF pulsing regimes applied to overcome hyperpolarization T1 decay). Volumes would need to be scaled up for detection in humans and might affect polarization levels.To overcome chemical shift artefacts, MRSI can be used. Both CSI and EPSI techniques allow chemical shift information to be mapped spatially. It is noted that using a more spectroscopic imaging approach, hyperpolarized signals of up to 40% of the background in vivo where field shimming is compromised) and therefore would be somewhat detrimental.In both cases, RF suppression of the water pool could be used to ease the detection of the hyperpolarized signal. Such approaches are standard in thermal based MRS, but successful implementation takes time, requires a localized voxel shimming approach, and uses high flip angle pulses.2). Long scan times are a problem when considering a hyperpolarized agent with a relatively short T1. To overcome this limitation centric  encoding schemes should always be used.2), albeit at the slight expense of spectral resolution and potential N/2 Nyquist ghosting. The reduction in spectral resolution is not a major problem for 1H MRS as the spectral width is narrow (20 ppm). This would not be true for X nuclei, such as 13C, where the spectral width required for metabolic mapping is much wider (~200 ppm).d]P peak identification. This can be manually corrected when the peaks arise in spatially distinct areas, but in vivo this would not be the case and more sophisticated correction methods would have to be implemented.When considering hyperpolarized MR imaging, overall scan time and image resolution are very important considerations. CSI, as applied here, has a long >1‐minute scan time, with low in plane spatial resolution  not suitable for biomedical use. Although methods to address this should be the primary focus of future research, it is noted that the deuteration of the actual ligand/drug (to enhance target polarization) could alter biological activity and should be investigated.Although SABRE has proven to deliver high levels of polarizationp‐H2d6 and D2O.1 relaxation values were found to decrease relative to those in methanol.1 values will extend as they return to their original values. Preliminary experiments using the catalyst‐separated CASH‐SABREd]P using a D2O saline bolus. A hyperpolarized signal was observed in the aqueous layer, albeit under acidic conditions (pH 1.5), with a −940‐fold signal enhancement (3% polarization for H7) compared to the corresponding methanol‐d4 value of make −3142‐fold (9.8% polarization). Hence, the biphasic route appears to be effective for delivering biocompatible SABRE, but alternatives using water‐soluble catalysts,Direct SABRE polarization in water would be ideal, however both the metal catalyst [IrCl(COD)(IMes)] and 2H bonds) may lead to known kinetic isotope effectsin vivo that the pharmo‐kinetic parameters of 4,6‐d2‐nicotinamide (one of the earlier SABRE hyperpolarization targets) are similar to protio‐nicotinamide. Because this target substrate was tolerated and deemed safe for administration,The present study also uses deuterated TP motifs as co‐ligands to concentrate spin hyperpolarization on the protio version. One would expect similar deuteration of the potential drug scaffolds may be required for this reason. Selective deuteration  one could target 15N instead. d‐DNP hyperpolarization studies already take advantage of its broader chemical shift range, and longer T1 lifetimes.15N labeled version of TP is possible.Once biocompatibility is achieved, initial chemical shift resolved NMR studies investigating hepatic metabolism 1 lifetimes. We hypothesize that such alterations in chemical structure and/or conformation would result in chemical shift changes of similar magnitude to that observed when the TP ligand binds to the SABRE catalyst .Chemically active substituent groups attached to the TP backbone (to form a suitable drug), or direct TP binding to target enzymes , could shorten Tt Figure . Mandal 51H SABRE hyperpolarization of 33% (H7) recorded for TP. Unlike alternative hyperpolarization methods, SABRE provides a simple, rapid, reversible, and inexpensive route, capable of polarizing a wide range of molecules containing NMR active nuclei . Targeting 1H as the probe nucleus (as opposed to 13C or 15N) is beneficial because it (1) has the highest gyromagnetic ratio of all nuclei and, therefore, high NMR sensitivity; (2) has a 99.98% natural abundance (negating the need for expensive/complicated synthetic pathways to generate the agents); and (3) can be used with existing clinical 1H MRI systems without the need for expensive hetero‐nuclei RF coils/system upgrades. We have shown how this low‐cost hyperpolarization technique can be combined with MRS techniques available on all standard MRI scanners. These early‐stage developments form a solid springboard for continued research and eventual clinical application of this technology for hyperpolarized drug tracking/chemotherapy.In summary, a family of thienopyridazines, with known anticancer properties, have been successfully studied with FIGURE S1 Structure of d4‐thienopyridazineFIGURE S2 Polarization transfer field plot for TP at 298 k using the automated polarizer. PTF plots for each resonance show a Gaussian distribution and give a single maximum at 60.9 ± 0.5 GFIGURE S3 Polarization transfer field plot for TP at 298 k using the automated polarizer. PTF plots for each resonance show a Gaussian fit and give three maxima at peak 1 = 13.30 ± 4.48 G, peak 2 = 65.37 ± 0.60 G, and peak 3 = 109.778± 0.13 GFIGURE S4 Polarization transfer field plot for TP at 298 K using the automated polarizer. PTF plots for each resonance show a Gaussian fit and give three maxima at peak 1 = 13.64 ± 1.06, peak 2 = 60.81 ± 0.62, and peak 3 = 109.36 ± 0.81983FIGURE S5 Hyperpolarized spectra for TP achieved at 0G (blue) and 60 G (black). Positive magnitudes for H7 and H3 and negative magnitudes for H6 and H2 at 0 G (blue). Negative magnitudes for all resonances at 60 G (black)FIGURE S6 Effect on signal enhancement values when changing substrate to catalyst ratios. The substrate used was TP and the catalyst [IrCl(COD)(IMes)] forming the active catalyst [Ir(H)2(IMes)3]Cl. The solvent used was methanol‐d4 and measurements were made on a 400 MHz spectrometer at 298K. (A) Signal enhancements values measured per individual proton with 4, 6, and 8 eq. of TP to 1 equivalent of catalyst [IrCl(COD)(IMes)]. (B) Normalized signal enhancement values per proton showing a linear decrease of enhancement with increased number of substrate equivalentsClick here for additional data file.


In contrast to all reported complexes of this type, the transition metal atoms possess twofold coordination only, hence the complex as a whole does not exhibit significant steric shielding or further linkage of the metal atoms. This is reflected in a high flexibility, as confirmed by slight deviations from a tetrahedral coordination of the Sb atom in the crystal and soft vibrational modes. An alternative pyramidal conformer, observed for a related arsenic compound with terminal phosphine ligands, is apparently disfavored owing to electron correlation effects. The compound is formed in a reaction that in another solvent or at other reactant concentrations yields salts of ternary cluster anions. By a combined experimental and theoretical study of different reaction conditions and previously unidentified side‐products, we provide insight into multimetallic cluster synthesis reactions.The anion of [K(crypt‐222)] 4]3− formed in a reaction of (Sn2Sb2)2− with [AuMePPh3] that affords multimetallic clusters for other reactant ratios. A central Sb atom bridges four free‐standing {AuMe} units, which is unprecedented for main group metal complexes. Comprehensive DFT investigations explained the stability of the tetrahedral structure relative to a pyramidal one found in related molecules and shed light on the reaction space of said multimetallic species.[Sb(AuMe) The cluster molecules are either protected by organic groups, as in [Aux [K(crypt‐222)]2(Sn2Sb2)⋅en with y [AuMePPh3] were reported to yield [K(crypt‐222)]3[(Sn2Sb2)2Au] (A)[x:y=2:1) or [K(crypt‐222)]4[(Sn5Sb3Au)2]⋅2 py (B)x:y=1:2) , yet the underlying reactions are only poorly understood. The formation of the anion in A, [{(Sn2Sb2)2−}2Au+]3−, at first glance shows no sign of redox chemistry in comparison with the reactants. However, the anion in B, [{(Sn5Sb3)3−Au+}2]4−, is overall oxidized relative to the (Sn2Sb2)2− anion—and in both cases, the gold complex apparently released not only the PPh3 groups, but also the (CH3)− ligands. For this, it is very obvious that side reactions take place that have not yet been elucidated.In this context, reactions of )2Au] (A)19, 202(Sn2Sb2)⋅en and [AuMePPh3] from 2:1 or 1:1 to 1:2.2, and also searched for side‐products that are likely to form. This way, we obtained [K(crypt‐222)]3[Sb(AuMe)4]⋅py (1), the anion of which represents a very uncommon metal complex. Being based on an {SbAu4} core, thus inverse to the {AuSb4} core mentioned above, it is a very rare example of a heavy pnictogen atom being surrounded by free‐standing transition metal complex fragments.We were interested to understand these reactions better and therefore changed the ratio of the reactants [K(crypt‐222)]1, report the electronic structure of the anion in comparison with related compounds, and comment on its formation reaction as opposed to the formation of the anionic clusters in A and B.Herein, we present the synthesis and crystal structure of 1 is obtained from a reaction of 80 mg (0.058 mmol) of [K(crypt‐222)]2(Sn2Sb2)⋅en with 60 mg (0.125 mmol) of [AuMePPh3] in 3 mL of pyridine at room temperature. After stirring for 3 hours, filtration and layering with 3 mL of THF, the mixture is stored at 5 °C for four weeks. Crystals of 1 form in ≈16 % yield. Scheme 1, A , and B, respectively. Noteworthy, other synthetic approaches to 1 starting out from K3Sb failed to work so far.Compound 1 crystallizes in the monoclinic space group P21/c with four formula units in the unit cell. Figure 1 and the anion in it in the crystal, as determined by means of single‐crystal X‐ray diffraction.Compound 1, a central μ4‐Sb atom possesses an idealized tetrahedral environment by the linearly coordinated Au atoms of four {AuMe} complex fragments. However, the Au–Sb1–Au angles actually indicate a certain degree of distortion. Quantum chemical calculations (see below) rationalize that this is due soft vibrational modes, and thus a high flexibility of the molecule as a whole that adopts a shape that fits best to the cation environment.In the anion of 4‐bridge to four free‐standing transition metal complex fragments that do not exhibit any further linkage of central and attached metal atoms, or among the attached metals atoms in cluster architectures. For Sb as the central atom, this was reported for two complexes only, [Sb{Fe(CO)4}4]3− 3PPh3}4]+,3 ligands, respectively. Beyond this background, the formation and crystallization of compound 1, with little steric shielding, is even more remarkable.Indeed, only very few compounds have been described to date, in which a heavy (thus large) pnictogen atom acts as a μ1, we carried out DFT calculations . It is thus reasonable to assume that the Sb–Au bonds possesses a similar polarity as the C–H bonds. Correspondingly, the LMOs representing Sb–Au and Au–C bonds  mainly comprises contributions of 5p and 6p atomic orbitals (AOs) from Sb and Au atoms, respectively. Further bonding orbitals are 9t2, mainly composed of 5p (Sb) and 5d (Au), 8a1, mainly composed of 6p (Au) and 2p (C), and 7a1, mainly composed of 5d (Au) and 2p (C). A minor contribution from 6p (Au) is also observed for 7a1, which mainly represents the Sb 5s AO though. Hence, with the 5dz2AO of the Au atoms acting as an “extension bar” without changing the phase of the wave function, the overall situation is thus reminiscent of the CH4 molecule itself or the isoelectronic (NH4)+, which is in agreement with the anion's relative stability that at least suffices for its formation and crystallization as the ionic compound 1.While the overall dipole moment of the molecule is zero owing to its perfect 4} unit occur at wavenumbers below 200 cm−1. Symmetric and asymmetric stretching modes of the complex are calculated between 450 and 470 cm−1. All higher‐energy modes are assigned to vibrations of the ‐CH3 groups. The findings confirm the structural flexibility of the molecule mentioned above, and they also suggest that both the Sb–Au bonds and the Au–C bonds are readily broken. This is reflected by the ESI(−) mass spectrum of a fresh solution of single‐crystals of compound 1 . The most  prominent signal originates from Au− , with a less intensive signal stemming from (AuMe)− , while the heterometallic complex is only reflected in two fragments, [Sb(AuCH3)2]−  and [{K(crypt‐222)}{SbAu4(CH3)2}]− . The latter are observed with lower relative abundances than the obvious decomposition product Sb7− . These findings reflect that the Sb–Au bonds in 1 are free‐standing and unsupported by any further interactions. Hence, although the bonds are shorter (2.5923(9)–2.6080(10) Å) and thus virtually stronger than those of the reported complexes [((o‐(Ph2P)C6H4)2(o‐Ph2PO)C6H4)SbAuCl]2+ (2.627 Å),3)4]+ (2.656–2.658 Å),o‐(Ph2P)C6H4)2SbCl2AuCl] (2.7086 Å),2(Ph2Sb)Au] (2.762 Å),Calculation of the vibrational modes  indicate that deformations of the {SbAu3)4]+ , were studied by DFT and ab initio calculations.3)4]+ to adopt Td symmetry,4)+ cation itself, and the experimentally found structure of the heavier homologue [As(AuPPh3)4]+,Cv4 symmetry 4]+ or [Sb(AuPH3)4]+ should adopt Td or Cv4 symmetries, respectively.Some years ago, a series of related, yet cationic, complexes [Pn4]3−, we repeated these calculations and compared the results with the series of cluster homologous to the anion in 1 at DFT level (TPSS/dhf‐TZVP), MP2 level  methyl group causes the structure of 1 to be tetrahedral. For the central atom being N, the pyramidal structure shows an imaginary mode. Distortion along this mode lowers the symmetry to Cv2, and subsequent optimization results in the tetrahedral structure. This compound is thus not shown in Figure As this prediction obviously does not hold for the tetrahedral anion in all valence electrons, and not just a dispersive interaction between the d electrons of the Au atoms. This becomes clear when comparing the Au–Pn–Au angle in the pyramidal structure for three different calculations, exemplarily discussed here for [Sb(AuPH3)4)]+: at HF level, it amounts to 115.2°, at MP2 level to 103.3°. In a third calculation we correlated only the Au(d) orbitals which are energetically reasonably well separated from the other orbitals, see Table S11. This yields four d orbitals per Au atom, the fifth is involved in the bonds to the neighbors. In this way, one gets 114.5°, which is very close to the HF result. If there had been a notable difference, this had indicated that the electrons in the four d orbitals located at the Au atom had undergone dispersive interactions. As this is not the case, the result shows that dispersive interactions of Au(d) electrons (often denoted as “aurophilic”) are not structure‐determining here. We finally note that the tetrahedral and the pyramidal structures are separated by energy barriers that are estimated to be in the range of 32 kJ mol−1 ([Bi(AuPH3)4]+) to 45 kJ mol−1 ([Sb(AuMe)4]3−) higher than the tetrahedral structure  of the reactive solutions, by detection of CH4 gas using gas chromatography‐mass spectrometry (GCMS), and by detection of H2 gas with the Pd/MoO3 method. In addition, quantum chemical calculations of corresponding reaction energies (Tables S12 and S13) suggested that the given reaction schemes are plausible.As mentioned above, the formation of the anions in compounds eactions.19, 201, thus in an ≈1:2 ratio of the reactants, the precipitate was confirmed to contain  Sb and Sn metal . We could additionally show by 31P‐NMR spectroscopy that PPh3 is released under conditions that lead to the formation of all products . The formation of [AuMe2]− 4  under the same conditions (in pyridine). The formation and release of H2 gas  was indeed only detected for the 1:2 reactant ratio in pyridine (leading to the formation of 1 or B), while no H2 is released for the 2:1 ratio in en (leading to the formation of A)—in agreement with the reaction schemes shown above.In agreement with the experimental findings, metallic precipitates are observed in most of the reactions; for the formation reaction yielding compound −1. Yet the numbers indicate that most of the reactions are overall favorable and that the assumption of a key reactive role of the solvent in such processes seems to be plausible.The calculated reaction energies are to be taken with a grain of salt, as (a) for reactions that indicate the formation of metals, the  values of the atomization energies needed to be taken into consideration, and as (b) calculation of gas phase species instead of crystalline compounds neglects the beneficial lattice energy, which might overcompensate small energy differences, such as ±40 kJ mol3[Sb(AuMe)4]⋅py (1) comprises a central Sb atom serving as a μ4‐bridge to four free‐standing {AuMe} units. It is thus a rare example of complexes based on an {SbM4} unit without further linkage of the transition metal M atoms or further bridging of the Sb and M atoms. Comprehensive quantum chemical studies showed that electron correlation effects stabilize this labile tetrahedral structure, while a related species with Pn=As and PPh3 ligands, instead of methyl substituents, was reported to adopt a pyramidal shape. A combination of experimental and quantum chemical investigations served to suggest possible reaction schemes that yield three different anions, and to rationalize that their occurrence is mainly controlled by the ratio of the used reactants, (Sn2Sb2)2− and [AuMePPh3], and the solvent. Although mechanistic details cannot be gained from these complex reaction systems‐since kinetic studies and reasonable in situ monitoring fail owing to the lack of key spectroscopic handles and due to the difficulties in drawing conclusions from time‐dependent mass spectra‐we were able to shed some light on the still widely unexplored landscape of multimetallic cluster synthesis and on the nature of the uncommon compounds isolated from it. We are confident that this knowledge can be transferred to the synthesis of many similar systems in the future.In summary, we reported a new product in the reaction space of an Sn–Sb‐based binary Zintl anion and an Au complex yielding multimetallic products. The anion of the title compound [K(crypt‐222)]The authors declare no conflict of interest.As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re‐organized for online delivery, but are not copy‐edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors.Supporting InformationClick here for additional data file.Supporting InformationClick here for additional data file.Supporting InformationClick here for additional data file.


In this paper, an anion‐rich electrode material, NiS2, and its composite with Ni‐based carbon nanotubes (NiS2/NCNTs) are explored as the cathode materials for Mg‐ion batteries. These NiS2/NCNTs with excellent Mg2+ storage property is synthesized by a simple in situ growth of NiS2 nanoparticles on NCNTs. NiS2 with both a large regular cavity structure and abundant sulfur‐sulfur (S—S) bonds with high electronegativity can provide a large number of active sites and unobstructed transport paths for the insertion–disinsertion of Mg2+. With the aid of 3D NCNTs skeleton as the transport channel of the electron, the NiS2/NCNTs exhibit a high capacity of 244.5 mAh g−1 at 50 mA g−1 and an outstanding rate performance (94.7 mAh g−1 at 1000 mA g−1). It achieves capacitance retention of 58% after 2000 cycles at 200 mA g−1. Through theoretical density functional theory (DFT) calculations and a series of systematic ex situ characterizations, the magnesiation/demagnesiation mechanisms of NiS2 and NiS2/NCNTs and are elucidated for fundamental understanding.Magnesium (Mg)‐ion batteries with low cost and good safety characteristics has attracted a great deal of attention recently. However, the high polarity and the slow diffusion of Mg 2/NCNTs fabricated by the in situ anchoring of NiS2 on the surface of Ni‐based CNTs integrates the advantages of the strongly electronegative S—S bonds and the large regular 1D cavities of NiS2 and the 3D conductive skeleton of NCNTs to achieve excellent Mg2+ storage properties.NiS However, Li will eventually be in short supply, leading to a questionable sustainability, and the formation of Li dendrites during the battery charge/discharge can pose several safety issues. Therefore, there is a need to replace Li with low‐cost and safe metal anodes. Due to the unique diagonal rule of the periodic table, Mg and Li have similar chemical properties. It is worth mentioning that Mg is abundant in the earth's crust, ≈104 times more than Li. Moreover, Mg is much less active than Li, which can dramatically improve the safety manufacture and performance of the batteries. Unfortunately, there are currently the limited promising cathode materials for Mg2+ storage. When Mg2+ with high charge density are intercalated into the crystalline structure of the host material, the surrounding electrostatic field of the host lattice can be changed dramatically, leading to high diffusion energy barriers of Mg2+, resulting in a difficult Mg‐intercalation process, and the high volume change of cathode material during cycling processes can also leads to a rapid capacity decay. Therefore, choosing a suitable cathode host electrode material with optimum structural design is the key to solving the problem of Mg‐ion batteries.Electrochemical energy devices including batteries and supercapacitors water electrolyze to produce hydrogen with high performance can promote the large‐scale storage of electricity energy generated from the sustainable green energy sources such as solar, wind, waterfall, geothermal, etc.2, 3 it is obvious that Li/Na‐S batteries have higher theoretical specific capacities, suggesting that the increase of non‐metallic elements in electrode materials is conducive to the increase of theoretical specific capacity, and can attribute to the formation of anions of those non‐metallic elements. These anions can provide more reversible redox active sites for embedding active metal ions. Therefore, the anion‐rich electrode materials have received much attention recently. For example, Nazar et al. reported layered anion‐rich TiS2 as a promising positive electrode intercalation material for Mg‐ion batteries, providing the stabilized capacity of 115 mAh g−1 in a Mg‐ion full cell and Jin et al. prepared VS2 nanoflowers with highly reversible discharge capacity (245 mAh g−1 at 100 mA g−1). These materials showed a 2D laminar crystal structure with wide crystal plane spacing for the transport of Mg2+ within the crystal and provided space for the electrode deformation of the material during the insertion of Mg2+. These studies have not only demonstrated the obvious advantages of anion‐rich electrode materials for the storage of Mg2+, but also suggested the design of regular pore structures for the transportation of Mg2+ as a general strategy to improve the rate performance and cycle life of Mg‐ion batteries. Among anion‐rich transition metal compounds, the crystal structure of NiS2 possesses both the highly electronegative S—S bonds and the abundant regular 1D pore structure similar to metal–organic frameworks. The former can generate attraction with Mg2+ to facilitate the embedding of Mg2+; the latter displays a much larger pore diameter than that of Mg2+ and can act as the directional transport channels of Mg2+. Compared with the 2D layer structure, the single transport direction of Mg2+ can ensure more efficient transport of Mg2+. These features endow NiS2 with a great potentiality in Mg‐ion batteries. To our knowledge, there are no reports of NiS2 being used as a cathode material for Mg‐ion batteries.Based on Li/Na‐ion batteries and Li/Na‐S batteries research progress,17 it 2 has been developed as a candidate for cathode material in Mg‐ion batteries, which has rarely been reported in the literature to our best knowledge. However, this anion‐rich NiS2 has poor electronic conductivity, which is demonstrated by the kinetic slowness of NiS2 as a conversion‐type cathode material for Li‐ion batteries. In general, the combination of electrode material with high conductivity carbon‐based material is considered to be an effective strategy to improve its conductivity. According to recent studies, the related composite methods can be divided into carbon coating technology and in situ growth technology on the surface of carbon material. Carbon coating technology can not only improve the electrical conductivity of electrode materials, but also limit the deformation of electrode materials due to its mechanical strength, thus improving the utilization rate and cycle life of the electrode. However, the coating of carbon on the electrode material can reduce the contact area between electrode material and the electrolyte, resulting in a large concentration polarization. Although the in situ growth technology on the surface of carbon material can improve the conductivity of the electrode material without weakening the contact area between electrolyte and the electrode material, the structural collapse caused by the structural deformation of the electrode material cannot be improved. Therefore, to obtain NiS2 with high Mg2+ storage performance, it is necessary to further optimize these two composite technologies. It is well known that the irreversible structural deformation and the large difference in the ratio of internal and external deformation of electrode material are the main factors leading to the structural collapse of electrode materials. The nanoscale construction of electrode material is recognized to be effective in shortening the ionic and electronic transport paths and multiplying the active sites, thus weakening the irreversible deformation caused by the polarization phenomenon, and significantly improving the deformation uniformity of the electrode material by improving the utilization rate. Therefore, the simultaneous nanoscale construction of NiS2 and its in situ growth on the surface of highly conductive carbon material is expected to assemble the outstanding Mg2+ storage material.In our research, NiSatteries.25 In 2 it is explored as the active material, which is anchored on the surface of the nickel (Ni)‐based carbon nanotubes to produce the NiS2/NCNTs for Mg‐ion batteries. The large cavity structure of NiS2 allows Mg2+ to shuttle freely, and the magnesiation/demagnesiation processes are found to involve the dissociation/formation of S−S bonds. The addition of NCNTs promotes charge transfer kinetics and improves the structural stability of the composite. Impressively, electrochemical characterization demonstrates a discharge capacity of 244.5 mAh g−1 at 50 mA g−1 and also excellent multiplier performance of 94.7 mAh g−1 at 1000 mA g−1. The assembled battery can be cycled more than 2000 cycles at 200 mA g−1. This work presents a high‐performance NiS2 and NiS2/NCNTs for Mg‐ion batteries cathodes and enables the in situ growth of NiS2 on NCNTs, which is important for the design of micro and nanostructures for Mg cathodes and the improvement of Mg storage performance.In this work, of the anion‐rich NiS2Figure 2 nanoparticles on NCNTs. Ni2+ , and the sharp and robust diffraction peaks indicate high crystallinity. The X‐ray diffraction peak located at 27.2°, 31.5°, 35.3°, 38.8°, 45.1°, 53.3°, 58.5°, 61.0°, and 89.7°, can be attributed to the (111), (200), (210), (211), (220), (311), (023), (321), and (511) crystal planes, respectively. No heterochromatic peaks of NiO and NiS are observed in the XRD images, indicating the high purity of the synthesized NiS2. Because of the composition of NCNTs, a prominent diffraction peak can be observed at 26°, confirming the formation of NiS2/NCNTs nanocomposite. According to the standard card of NiS2, the crystal structure of NiS2 is shown in Figure 2 is a common cubic of pyrite structure. One Ni atom is connected to six S atoms. An S—S bond links two S atoms. It is noteworthy that the smallest pitch between adjacent atoms in the NiS2 lattice structure is measured to be 2.47 Å and the beneficial 1D cavity structure of NiS2 can donate the directional transmission path of Mg2+ (1.4 Å). Mg2+ can shuttle freely in the NiS2 crystal structure, make a possibility for NiS2 to store Mg2+. The corresponding simulated XRD pattern  and Ni 2p1/2 (870–884 eV). Two peaks at 853.8 and 871.2 eV are attributed to Ni2+, with two satellite peaks located at 861.9 and 880.1 eV, respectively. The Ni 2p peak of NiS2 alone is shown in Figure 2+ of NiS2/NCNTs is much lower than NiS2, possibly owing to the NCNTs entangled on the surface. Due to the in situ growth of NiS2 on NCNTs and the 3D network structure formed by the interwoven NCNTs, most of NiS2 is coated in the 3D network structure of NCNTs, which reduces the possibility of NiS2 being oxidized to a certain extent. In addition, NCNTs also contain a certain amount of nickel ions, which can also affect their diffraction peaks. Figure 1/2, 2p3/2), and the peak value of 168.4 eV can be attributed to the Ni—S bond. The acceptable spectrum of C 1s is shown in Figure  These Ni—S bonds and C—O bonds can immobilize cations . These chemical bonds could keep the whole structure stable when Mg2+ is detached and embedded.The X‐ray photoelectron spectroscopy (XPS) was used to analyze the surface of the prepared NiSectively.44 The2/NCNTs in Figure 2 nanoparticles grown in situ on NCNTs. The diameters of NiS2 nanoparticles are ≈20–80 nm. The large specific surface area of the nanoscale particles can provide more active sites for the electrochemical reaction. The cohesive network structure and fluffy structure of NCNTs also facilitate the penetration of electrolytes. Figure 2 nanoparticles attached to single NCNTs, and the dense arrangement of NiS2 nanoparticles almost covering the entire NCNTs, indicating that NCNTs and NiS2 nanoparticles are well composited. The microstructure of the samples was further characterized by transmission electron microscope (TEM)  image in Figure 2, respectively. In addition, the lattice fringe of NCNTs can also be seen. The resolved lattice fringe with the spacing of 0.35 nm can be assigned to (002) lattice planes of NCNTs, further confirming the excellent combination of NiS2 and NCNTs. According to the relevant selected‐area electron diffraction (SAED) image . A typical FESEM image of NiSreaction.49 The) Figure . It can e Figure , the cle2 alone is 18.9:8.5. Obviously, the atomic ratio of S and Ni in NiS2/NCNTs composite is lower than that in NiS2 due to the influence of NCNTs. Elements mapping image  test Figure , the atoe Figure  reveals Figure 2/NCNTs electrode show a voltage window of 0.1–2.1 V and a scan rate of 0.2 mV s−1. According to the test, in the initial five circles of the CV curves, all the CV curves exhibit a similar shape, indicating the high degree of reversibility of electrochemical reactions. During charging, the oxidation peak appears at 1.8 and 2.0 V, at 1.8 V, Ni is oxidized to NiS or Ni3S4, and at 2.0 V, NiS or Ni3S4 is further oxidized to NiS2. Due to the insertion and extraction of Mg2+ and the increase of cycles, the oxidation peaks are more obvious, which means the growth of reactivity and storage capacity of Mg2+. During the discharge process, a reduction peak appearing at 1.2 V could be attributed to the decomposition of electrolytes to form a solid‐electrolyte interface film. It is also that Mg is reduced MgS, a prominent reduction peak center at 1.1 V, which can be ascribed that NiS2 begins to transform into MgSX‐NiS2−X due to the insertion of Mg2+. With increasing the number of cycles, the reduction peaks at 1.1 V almost overlap, signifying that the NiS2/NCNTs electrode has excellent reversibility and stability. The CV curves of NiS2 and NiS2/NCNTs at 0.2 mV s−1 scanning rate are compared, as shown in Figure 2 electrode are slightly higher than those of the NiS2/NCNTs electrode. In Figure 2/NCNTs electrode, the initial discharge capacity of the battery reaches 84.95 mAh g−1 at 50 mA g−1. However, the discharge capacity of the second cycle decreases to 20.14 mAh g−1 significantly, which is due to the activation of the electrode for conversion‐type materials, maybe ascribe to the irreversible trapping of Mg2+ too. Such an activation process is very common for conversion‐type materials. After 30 cycles of activation, the battery reached the maximum discharge capacity and started the rate cycles . The peak of the Ni—S bond is 169.7 eV when pristine. During the discharge process from pristine to 0.02 V, the Ni—S bond shifts to the low binding energies and shifts back to the initial value with charging to 2.0 V. The reversible shift in binding energy indicates that the anion S is involved in redox reaction. One peak located at 162.7 eV corresponds to 2p3/2, while the other peak at 161.6 eV corresponds to 2p1/2. During the discharge process, two peaks of 2p1/2 and 2p3/2 gradually diminish, and at 0.02 V in the discharge state, the two peaks are almost zero, indicating that the peak value decreases due to the attraction of S2− during Mg2+ insertion. As charging proceeds, the two peaks rise slowly with charging voltage, showing excellent reversibility. At the same time, Mg 1s peak enhances/fades upon discharge/charge  and the scan rate (ν) measured in the CV curve allows a qualitative analysis of the extent of the capacitive effect:The CV curves with different scan rates of 0.2, 0.4, 0.6, 0.8, and 1.0 mV ss Figure 5a of dif They can be determined from the slope of the log i versus log ν plot. The slopes of log ν–log i plots are 0.25 and 0.71, respectively. Besides, the peak current gradually enhances with increasing the scan rate. The results reveal that the storage mechanism of Mg2+ has excellent non‐diffusion limits because of NCNTs covered by NiS2 nanoparticles. As seen from the FESEM images, this unique structure exposes many active sites for charge storage, suggesting that the non‐diffusion limit current in the NiS2/NCNTs electrode is important. By using the formula, the capacitive contribution ratio can be ascribed to the equation:Where a and b both are constant. The value of b is between 0.5 and 1.0. The b value of 0.5 indicates a total diffusion‐controlled behavior, whereas 1.0 represents a capacitive process.65 The1vk, and the insertion type capacity is 2ν1/2k. The non‐diffusion limiting current is obtained by calculating the 1vk value of the red region in Figure −1, the capacitance contribution rate is 30%, 38%, 42%, 46%, and 49%, respectively. The quantified results  measurements . Benefited from the electrical conductivity of NCNTs and the fact that NCNTs reduce the volume change of the material during cycling, NiS2/NCNTs exhibits excellent long cycle performance (58% capacity retention after 2000 cycles). This research explores new Mg storage materials and offers a promising option for developing cathode materials for Mg‐ion batteries.In summary, inspired by anion‐rich NiS42 sample was synthesized using a typical solvothermal method. Nickel nitrate hexahydrate 2·6H2O), sodium thiosulfate , and absolute alcohol  were added in 30 mL Teflon‐lined autoclave under magnetic stirring until all the solids were dissolved completely. The autoclave was heated for 36 h at 150 °C, then this autoclave was cooled down to room temperature naturally, to obtain a black precipitation, which was then separated by centrifugation and washed six to seven times with distilled water and absolute ethanol, dried overnight in a vacuum oven at 80 °C, to obtain the target NiS2 particle sample.The NiS2/NCNTs, Ni‐Based carbon nanotubes (NCNTs) (30 mg), nickel nitrate hexahydrate 2·6H2O), sodium thiosulfate , and absolute alcohol  were added in 30 mL Teflon‐lined autoclave under magnetic stirring until all the solids were dissolved completely. The followed procedure for heat‐treatment and collection of NiS2/NCNTs sample was the same as that of the NiS2 sample described above.For synthesis of NiSα radiation from 10° to 90° at a scanning rate of 10° min−1. Fourier‐transform infrared (FTIR) spectra of the nanostructures were recorded with a Thermo Fisher Nicolet iS50 FTIR, which had a scan range of 4000 to 400 cm−1. XPS was performed using an X‐ray photoelectron spectroscopy  with Al Kα X‐rays as the excitation source.The morphology and elemental composition of the samples were analyzed by FESEM . The nanostructures of the resulting samples were recorded using a TEM . The composition of elements was analyzed by energy dispersive spectroscopy (EDS) under a 20 V electron beam. The crystal structure of the as‐prepared materials was recorded on X‐ray diffraction  with Cu‐K2 or NiS2/NCNTs with acetylene black and polyvinylidene fluoride (PVDF) binder at a ratio of 8:1:1 on copper foil collector. Coin‐type battery cells (CR2032) were assembled in an Ar‐filled glove box with water and oxygen contents below 0.1 ppm. The cells contained Mg foil anode polished by SiC sandpaper and cleaned before use. All phenyl complex/tetrahydrofuran solution (APC) as the electrolyte and glass microfiber filter  as the separator. Electrochemical measurements  were performed on the electrochemical workstation (brilliance chi660e). The galvanostatic discharge–charge performances were recorded by the XinWei multichannel battery test system using the voltage range of 0.1–2.1 V.The cathodic working electrodes were fabricated by coating NiS−5 eV and 0.02 eV Å−1, respectively.The spin‐unrestricted density functional theory (DFT) calculations were performed by the Vienna Ab initio Simulation Package (VASP) with the GGA‐PBE exchange–correction functional. The E‐cut was set to be 400 eV, and the 5 × 5 × 5 Monkhorst‐Pack k‐point grid was adopted to sample the Brillouin zone. The convergence criteria for energy and force were set to be 10The authors declare no conflict of interest.Supporting informationClick here for additional data file.


ROC5 and ROC8, regulating rice leaf rolling have been cloned and functionally analysed. However, the molecular mechanism by which these genes modulate leaf‐rolling remains largely elusive. In this study, we demonstrated the transcription activation activity of both ROC8 and ROC5. Overexpressing ROC8 caused adaxially rolled leaves due to decreased number and size of bulliform cells, whereas knockout of ROC8 induced abaxially rolled leaves due to increased number and size of bulliform cells. ROC8 and ROC5 each could form homodimer, but ROC8 interacted preferably with ROC5 to forms a heterodimer. Importantly, we showed that the ROC8‐ROC5 heterodimer rather than the homodimer of ROC8 or ROC5 was functional as neither overexpressing ROC8 in the ROC5 mutant nor overexpressing ROC5 in the ROC8‐knockout line could rescue the mutant phenotype. This was further partially supported by the identification of a large number of common differentially expressed genes in single and double mutants of roc8 and roc5. ROC8 and ROC5 were functionally additive as the phenotype of abaxially rolled leaves was stronger in the roc5roc8 double mutant than in their single mutants. Our results provide evidence for the role of dimerization of ROC members in regulating leaf rolling of rice.Moderately rolled leaf is one of the target traits of the ideal plant architecture in rice breeding. Many genes, including homeodomain leucine zipper IV transcription factors  Oryza sativa L.), the staple food for more than half of the world's population. As an ideal trait to achieve the goal of higher yield, moderate leaf rolling in rice is helpful to delay leaf senescence, keep leaf erect to increase the light‐receiving space, and enhance the light quantity and intensity at the base of rice plants in the field  to ROC9  showing abaxial leaf rolling thanks to increased number and size of bulliform cells. Overexpressing ROC5 resulted in leaf rolling in the opposite direction, that is, adaxial rolling, due to decreased number and size of bulliform cells  genes encode a class of homeobox transcription factors  were constructed and subsequently analysed in yeast. The results showed that the yeast strains transformed with the region comprising amino acids 1‐710 (F), 71‐710 (P4), or 71‐200 (P8) grew well on the SD/‐Trp/‐His/‐Ade medium, suggesting that the full‐length ROC8 and the M region of ROC8 had transcriptional activation activity Figure . We alsoet al., et al., Plant HD‐ZIP IV family members may function via homodimers in planta  and knockout  transgenic lines, we compared their bulliform cells abutting the large vascular and those between the two small vascular bundles, using leaf cross sections. We found that, compared with Kitaake, the overexpression lines contained less and smaller bulliform cells, while in contrast, the knockout lines contained more and bigger bulliform cells  and the GAL4 activation domain (AD) construct containing ROC5 could grow in the SD medium (‐LTHA), but the strains co‐transformed with other ROC8 regions did not survive Figure , indicatGiven that the same regions were involved in the interaction between ROC8 and ROC5 , the eYFP signal was very strong in the nucleus. However, in the presence of ROC8, the interaction between ROC5‐nYFP and ROC5‐cYFP became weaker as indicated by the weaker eYFP signal Figure , was co‐ROC8 gene in the oul1 mutant and generated five independent T0 positive transgenic lines that all exhibited abaxially rolled leaves. Two independent lines, oul1oe8‐1 and oul1oe8‐2, were selected for detailed phenotyping. Compared to the oul1 mutant, both oul1oe8‐1 and oul1oe8‐2 had similar overall plant morphology and abaxial‐rolling indexes  of oul1, let alone induce adaxially rolled leaf as observed in the ROC8 overexpression lines with the Kitaake background  mutant. Differentially expressed genes (DEGs) between each mutant and its corresponding wild type were first identified and the DEGs were then compared to identify those shared by the three mutants. Compared with Kitaake, the double mutant crispr5&8‐1 had 3377 and 3632 up‐regulated and down‐regulated genes, respectively  analysis of these 269 genes revealed that approximately two‐thirds of them were significantly enriched with genes involved in metabolic process and cellular process  nor overexpression of ROC5 in the roc8 mutant line crispr8‐6 could rescue the mutant phenotype of abaxial rolling leaf , it is evident that majority of these shared DEGs are related to metabolic process and cellular process , and transgenic plants related to these two accessions. All plants were grown in a greenhouse at the Jiangsu Academy of Agricultural Sciences, Nanjing, China. Leaf adaxial/abaxial‐rolling index was measured as previously described  according to the manufacturer's instructions. Each RNA sample was extracted from a pool of tissues collected from at least three individuals. For each sample, 1 μg of total RNA was reverse transcribed to cDNA using a reverse transcription kit . qRT‐PCR was performed using a SYBR Premix Ex TaqTM kit (TaKaRa) on an ABI prism 7500 Real‐Time PCR System. The rice ubiquitin gene (Os03g0234200) was used as a reference gene with the primer pair Ubq. All primer sequences are listed in Table For analysis of the expression levels of ROC8 and ROC5 was individually fused to the AD in the pGADT7 vector. The constructs were transformed into the yeast strain AH109 according to the manufacturer's instructions. The growth state of each transformant was examined on the SD/‐Trp‐His/‐Ade medium for the transcription activation activity assay, and on the SD/‐Trp/‐Leu/‐His/‐Ade medium for the protein interaction analysis. All the primer pairs used in amplifying the corresponding fragments are listed in Table Fragments including different domains of ROC8, i.e., amino acids 1‐710 (F), 1‐200 (P1), 1‐70 (P2), 18‐70 (P3), 71‐710 (P4), 201‐710 (P5), 201‐435 (P6), 436‐710 (P7), and 71‐200 (P8) were PCR‐amplified and fused to the GAL4 binding domain in the pGBKT7 vector. Similar constructs were made for ROC5 using fragments including amino acids 1‐804 (F), 1‐308 (X1), 1‐153 (X2), 97‐153 (X3), 154‐804 (X4), 309‐804 (X5), 309‐544 (X6), 545‐804 (X7), 154‐308 (X8), 97‐308 (X9), and 154‐544 (X10). For both proteins, the PGBKT7 vector without fused fragment was used as control. In addition, the full‐length coding sequence of ROC8 and ROC5 were cloned into the binary BiFC vectors p2YN and p2YC to generated ROC8‐nYFP, ROC8‐cYFP, ROC5‐nYFP, and ROC5‐cYFP constructs, respectively. The coding sequences of ROC8 and ROC5 were also cloned into the pCAMBIA1305‐YFP vector (generated by insertion of a 35S promoter and an YFP expression cassette into the pCAMBIA1305 vector) to generate the ROC8‐YFP and ROC5‐YFP constructs, respectively, which were used as the positive controls. The fragments encoding amino acids 201‐435 (P6) of ROC8 and amino acids 545‐804 (X7) of ROC5 were cloned into the pCAMBIA1305‐35S vector (generated by deletion of the YFP expression cassette from the pCAMBIA1305‐YFP vector) to generate the 35S:P6 and 35S:X7 constructs, respectively.The coding sequences of Agrobacterium tumefaciens strain EHA105 carrying the BiFC construct was co‐infiltrated into N. benthamiana leaves with the p19 strain and the nuclear marker, D53‐mCherry fusion protein  to generate the ROC8‐GFP construct. Subsequently, the plasmid was introduced into the Agrobacterium tumefaciens strain EHA105 and used to infect the calli of Kitaake. The ROC8‐GFP construct was also used in Co‐IP assays.For overexpression of ROC8, a 20‐bp sequence specific to ROC8 was synthesized and cloned into the entry vector pOs‐sgRNA, and then cloned into the gateway destination vector pOs‐Cas9. The resulting plasmid was introduced into Kitaake. Positive lines were confirmed by PCR followed by sequencing.To generate knockout lines of ROC8 in the oul1 mutant, the full‐length CDS of ROC8 was amplified and then cloned into the pCAMBIA2300‐Actin1‐ocs vector to generate the 2300‐ROC8 construct. Subsequently, the plasmid was introduced into the oul1 mutant.For overexpression of ROC5 in the ROC8‐knockout line crispr8‐6, the full‐length CDS of ROC5 was amplified and then cloned into the pCAMBIA2300‐Actin1‐ocs vector to generate the 2300‐ROC5 construct. Subsequently, the plasmid was introduced into the mutant line crispr8‐6.For overexpression of roc5roc8 double mutants, a 20‐bp sequence specific for ROC5 or ROC8 was synthesized and cloned into the entry vector pOsU3 and pOsU6a to generate the pOsU3‐ROC5 and pOsU6a‐ROC8 constructs, respectively. Then, pOsU3‐ROC5 and pOsU6a‐ROC8 were simultaneously cloned into the gateway destination vector pOs‐Cas9. The resulting plasmid was introduced into Kitaake. Positive lines were confirmed by PCR followed by sequencing. The primers and the 20‐bp sequences used in constructing these vectors are listed in Table To generate ROC5 was amplified and then cloned into the pCAMBIA1305‐GFP vector to generate the ROC5‐GFP construct. The full‐length CDS of ROC8 was cloned into the pCAMBIA1300‐221‐Flag vector (generated by insertion of a 35S promoter and a Flag tag into the pCAMBIA1300 vector) to generate the ROC8‐Flag construct. The full‐length CDS of ROC5 was fused with His‐tags and then cloned into the pCAMBIA1305‐35S vector to generate the ROC5‐His construct.The full‐length CDS of et al., Protoplasts isolated from wild‐type plants were transfected with desired plasmids and incubated overnight. Co‐IP assay was conducted as previously described  for RNA quantification and qualification, library construction, and transcriptome sequencing. Expression of genes was calculated using StringTie  and polymerized. Sections (8 μm) were cut and stained with filtered 1% toluidine blue before microscopic examination (Leica DM5000B) and photographing.The number of typical bulliform cells and the adjacent epidermal cells between the two small vascular bundles and those abutting the large vascular bundles were all counted. Four leaves were counted for each line, with each leaf counted only once.ROC5 (LOC_Os02g45250.1) is available in the MSU Rice Genome Annotation Project Database. ROC8 (XM_015786612.2/Os06t0208100‐01) is available in the NCBI/Rice Annotation Project (RAP) Database and Resource.The authors have submitted a patent application based on the results reported in this paper.Y. X., Q‐H. Z. and J. Y. designed the research; Y. X., W. K., F. W., J. W., Y. T., W. L., Z. C., F. F. and Y. J. performed the research; and Y. X. and Q‐H. Z. wrote the paper.Figure S1 Characterization of ROC8 transcript and protein.Figure S2 Yeast two‐hybrid assay of the protein truncations without transcriptional activation activity.Figure S3ROC8 overexpression and knockout analyses.Figure S4 qRT‐PCR analysis of ROC8 expression in the third leaf of the wild type Kitaake and three independent ROC8‐knockout lines crispr8‐6, crispr8‐7, and crispr8‐8.Figure S5 qRT‐PCR analysis of ROC5 and ROC8.Figure S6 Yeast two‐hybrid assay.Figure S7 Characterization of roc5roc8 double mutants generated by Crispr/Cas9‐mediated gene editing.Figure S8 A proposed working model for ROC‐mediated regulation of leaf rolling.Table S1 Sequencing results of the T0roc5roc8 double mutant lines generated by gene editing.Table S2 Differentially expressed genes associated with lignin biosynthetic process, cell wall and vacuole formation, and water stress in leaves.Table S3 List of primers used in this study.Click here for additional data file.Data S1 Genes differentially expressed between the double mutant line crispr5&8‐1 and Kitaake.Click here for additional data file.Data S2 Genes differentially expressed between the single mutant line crispr8‐6 and Kitaake.Click here for additional data file.Data S3 Genes differentially expressed between the oul1 mutant and Nipponbare.Click here for additional data file.Data S4 Differentially expressed genes shared among the double mutant line crispr5&8‐1, the single mutant line crispr8‐6, and oul1.Click here for additional data file.


KIR2DL5A*0010104 differs from that of KIR2DL5A*0010101 with eight single intronic nucleotide changes.The novel allele  Among these receptors are the killer‐cell immunoglobulin‐like receptors (KIR) that have major histocompatibility complex (MHC) I molecules serving as their ligands. KIR2DL5 is a two‐domain receptor variant and is presumed to have inhibitory functions based on the fact that it has immunoreceptor tyrosine‐based inhibitory motifs (ITIMs) on its cytoplasmic tail.KIR2DL5A*0010104 by the World Health Organization (WHO) Committee for factors of the HLA System, Subcommittee for Killer‐cell Immunoglobulin‐like Receptors. This new allele was isolated from the DNA of Zimbabwean donors using previously described high‐resolution long‐range sequencing techniques.Described here is the identification of a novel KIR2DL5A subtype officially named KIR2DL5A*0010104 were compared with that of KIR2DL5A*0010101 and we found eight intronic single nucleotide polymorphisms four of which occurred in intron 2 as illustrated in Table KIR2DL5A*0010104 have been deposited into GenBank with the Accession number MG004194 and IPD‐KIR database,Full‐length nucleotide sequences of 2DL5A*0010104 has been officially assigned by the WHO Nomenclature Committee in October 2019. This follows the agreed policy that, subject to the conditions stated in the most recent Nomenclature Report,The name The authors have declared no conflicting interests.2