To quantify the influence of beam optics asymmetric distribution on dose.X‐direction while keeping consistent in the Y‐direction. The dosimetric comparisons in dose deviation, γ‐index analysis, lateral penumbra, and flatness were evaluated.Nine reference cubic targets and corresponding plans with modulation widths (M) of 3, 6, and 9 cm and with center depths (CDs) of 6, 12, and 24 cm were generated by the treatment planning system (TPS). The Monte Carlo code FLUKA was used for simulating the dose distribution from the aforementioned original plans and the dose perturbation by varying ±5%, ±15%, ±20%, ±25%, and ±40% in spot full width half maximum to the γ‐index passing rate was 80.6% with criteria of 2%–2 mm by a +40% variation in M3CD6. For the M9CD24 with a −40% variation, the maximum 1D dose deviations were 5.6% and 15.7% in the high‐dose region and the edge of the radiation field, respectively. The maximum deviations of penumbra and flatness were 3.4 mm and 11.4%, respectively.The largest 3D absolute mean deviation was 15.0% ± 20.9% (mean ± standard deviation) in M3CD6, whereas with the variation from −15% to +20%, the values were below 5% for all cube plans. The lowest 2D The scenario of beam optics asymmetric showed relatively slight influence on the global dose distribution but severely affected dose on the edge of the radiation field. For scanning carbon‐ion therapy facilities, beam spot lateral profile settings in TPS base data should be properly handled when beam optics asymmetry variation is over 15%. Carbon‐ion beams possess smaller spot sizes and steeper dose gradients, reducing the absorbed dose to organs‐at‐risk consequently.The spot‐related commissioning and QA parameters for proton beams were recommended in AAPM TG224.X‐direction due to the horizontal extraction process in Heidelberg Ion Therapy Facility . In Heavy Ion Medical Accelerator in Chiba , Furukawa et al.X‐ and Y‐direction were assumed to be completely concordant. A similar beam spot setting was applied in RayStation  during the commissioning of a proton facility.Compared to proton beams, the more substantial magnetic rigidity of carbon‐ion beams leads to more difficulties in the construction of the gantry and the commission of the magnets.3) and ignored the impact of the target depth. Moreover, taking flatness as the only parameter for analysis might be insufficient. To the best of our knowledge, most literature reported research on spot size variation, but few for the beam optics asymmetry and its characteristics in both spot scanning proton and carbon‐ion beams. Meanwhile, as far as our clinical experience and the extensive literature, check of beam optics asymmetry was not included in the acceptance test procedures of carbon beam facilities.Y‐direction while changing the spot size in the X‐direction. The dose distribution of original plans, as well as the plans with various spot sizes in the X‐direction, were simulated by using FLUKA. 3D absolute mean point‐to‐point dose deviation, γ‐index analysis for 2D dose distribution, 1D flatness, and penumbra were analyzed. Consequently, the asymmetric relevance of beam optics impact on the quality of scanning carbon‐ion beam dose distribution was discussed.Klodowska et al.22.13 cube located at 6‐cm depth in a water phantom.Cubic targets with different range modulation were modeled in Syngo TPS . Three cubes with different dimensions  were generated to make a thorough inquiry into the effect of beam optics asymmetry on dose distributions under the various sizes of tumors. The cube centers were placed in a water phantom at different locations . The character M represents the modulation width of the cube, whereas the character “CD” represents the center depth. For example, M3CD6 represents a 3 × 3 × 3‐cmThe plans were generated by Syngo TPS. The absorbed dose calculation algorithm of Syngo TPS is based on the pencil beam algorithm. The lateral profile distribution is modeled as a two‐dimensional symmetric Gaussian, and the double‐Gaussian scattering model describes lateral fluence distribution.2.2−5 eV, and the transport threshold of other particles was set at 100 keV.In this study, the Monte Carlo code FLUKA  was chosen as a simulation software because of its widespread usage and its accuracy in the simulation of particle beam radiotherapy.In‐line with the previous work of Sheng et al.,2.3X‐direction, whereas it was consistent in the Y‐direction.The DICOM RTplans of nine cubes derived from TPS were converted to FLUKA source files. The original beam optics parameters from the RTplans were imported to FLUKA, and the dose distributions of the original plan simulated from FLUKA were utilized as references. FWHM variations  were applied to the 2.4DevD (%) was the absolute mean point‐to‐point dose deviation, d and dref were the perturbed and reference doses, respectively, i was the corresponding scoring point, and N was the total points of the scoring region.Absolute mean point‐to‐point dose deviation was chosen to analyze the 3D dose distributions. The dose region higher than 10% of the maximum dose was selected to calculate the 3D dose deviations by using the following formulaγ‐index analysis tool  was chosen to analyze the 2D dose distribution in the X–Y plane of the target center. The parameters of the γ analysis were as follows: 2%–2 mm, the negligible threshold dose was 10% and the normalization of γ analysis was performed on the global dose maximum.X‐direction of the target center were also compared.The X‐axis of the X–Y plane at the target center were also analyzed.DLPmax and DLPmin are the maximum and minimum absorbed dose, respectively.In addition, lateral penumbra and 1D flatness along the In the following sections, the high‐dose region was defined as the area where the absorbed dose exceeded 90% of the prescribed dose, whereas the area between the high‐dose region and the 80% of the prescribed dose was defined as the edge of the radiation field.33.1X‐direction, the 3D dose deviation was 15.0% ± 20.9%  in M3CD6, and 3.4% ± 9.0% in M9CD24. With the variation from −15% to +20%, 3D dose deviations were below 5% for all cube plans.The 3D absolute mean point‐to‐point dose deviations are shown in Table γ‐index passing rates (γ‐PRs) of the nine different cubes with criteria of 2%–2 mm were shown in Table γ‐PRs, similar to the results of 3D dose deviations, the best and worst cube groups were M9CD24 and M3CD6, respectively. With an increase of 40% on the spot size in the X‐direction in M3CD6, the γ‐PR was 80.6%, whereas all γ‐PRs could achieve 90.0% with the criteria of 2%–2 mm when the spot size in the X‐direction varies within ±30%.The X‐direction at the target center slice of the best (cube M9CD24) and worst (cube M3CD6) match situations are shown in Figure 1D relative dose profile and dose deviation in the 3.2The flatness deviations relative to the reference were shown in graphs a–c of Figure 4X‐direction). The impact of beam optics asymmetric distribution in scanning CIRT was evaluated. Apart from 3D dose comparison, we conducted a further analysis of the 1D flatness and penumbra and aimed to obtain the influence precisely for the beam optics asymmetry in CIRT.This study performed Monte Carlo simulations to simulate the beam optics variation in a single direction . We have simulated and compared the corresponding beam quality of the worst scenario. The 3D absolute mean dose deviation never exceeded 5% and the 2D γ‐PRs were never below 99% with criteria of 2%–2 mm. The deviation of flatness and lateral penumbra were within tolerance for all the cubic targets  directions of the pencil beam propagation was not evaluated. The worst case scenario of spot shape variation could happen when the spots are rotated by 45° with the carbon gantry. This requires further investigation.One limitation of this study is that the covariance between the orthogonal  and TPS (dots) IDDs for carbon‐ion beam energies of 88.65, 171.59, 234.05, 285.35, 351.41, and 430.12 MeV/uFigure S2 Sample of the TPS and FLUKA spot sizes in the X‐direction for six energies and three positions around the isocenterFigure S3 1D dose profile comparison between the MC simulation (line) and TPS (dot) for M6CD12Figure S4 Relative dose (left axis) and dose deviation (right axis) on different positions in the cube M9CD24 (a) and the cube M3CD6 (b)Table S1 The results of 3D absolute mean dose deviation, 2D γ‐PRs (2%–2 mm), the deviation of 1D flatness and lateral penumbra with spot sizes variation of +10% in the X‐direction and −10% in the Y‐directionClick here for additional data file.Supplementary MaterialsClick here for additional data file.


Combined scanning probe microscopy investigations complemented by theoretical calculations reveal how the substrate selection drives different reaction mechanisms. On Ag(111) the dissociation of bromine atoms at room temperature triggers the homocoupling of tetraazapentacene units together with the binding of silver adatoms to the nitrogen atoms of the monomers giving rise to a N‐containing conjugated coordination polymer (P1). Subsequently, P1 undergoes ladderization at 200 °C, affording a pyrrolopyrrole‐bridged conjugated polymer (P2). On Au(111) the formation of the intermediate polymer P1 is not observed and, instead, after annealing at 100 °C, the conjugated ladder polymer P2 is obtained, revealing the crucial role of metal adatoms on Ag(111) as compared to Au(111). Finally, on Ag(100) the loss of :CBr2 groups affords the formation of tetraazapentacene monomers, which coexist with polymer P1. Our results contribute to introduce protocols for the synthesis of N‐containing conjugated polymers, illustrating the selective role of the metallic support in the underlying reaction mechanisms.On‐surface synthesis has recently emerged as a powerful strategy to design conjugated polymers previously precluded in conventional solution chemistry. Here, an N‐containing pentacene‐based precursor (tetraazapentacene) is ex‐professo synthesized endowed with terminal dibromomethylene (:CBr 2 groups is synthesized to steer unprecedented on‐surface polymerizations. On Ag(111) an intermediate conjugated coordination polymer (P1) is detected, which evolves towards a conjugated ladder polymer P2 upon annealing. Counterintuitively, on Au(111) P2 is found at a much lower annealing temperature, without the observation of P1, thus highlighting the decisive role of the substrate.A tetraazapentacene precursor endowed with =CBr For instance, the recent synthesis of several members of the acene family or acene‐based 1D polymers supported on metal substrates has supposed a great progress in this field in view of their unique electronic, magnetic, and optical properties, with potential applications in organic (opto)electronics and spintronics. Among the existing strategies to tune their remarkable properties, heteroatom substitution allows to tailor the topology of the π‐conjugation by replacing CH groups from the carbon skeleton by N, B, P, or S atoms. In particular, in the case of N‐containing acenes, so called azaacenes or N‐heteroacenes, it has been demonstrated that N‐doping is an efficient strategy to engineer their electronic bandgap and/or to induce an open‐shell character in their ground state.During the last decade, on‐surface synthesis has emerged as a powerful and successful strategy toward the synthesis of carbon‐based nanomaterials such as nanographenes (NGs)2, 3π‐conjugated systems on surfaces, the fabrication of low dimensional coordinative metal–organic nanoarchitectures based on metal ions and π‐conjugated ligands has been extensively explored. Herein, the on‐surface chemistry toolbox of π–d systems, achieved by direct deposition of molecular ligands that coordinate with substrate adatoms or by codeposition of different metals and ligands, leading to the hybridization of the d‐orbitals of transition metals and frontier orbitals of conjugated ligands, has been extensively investigated.Contemporarily to the progress made in the synthesis of explored.28 HerMost of the works related to on‐surface synthesis have been realized on noble metal substrates in order to steer desired chemical reactions by exploiting the catalytic role of the metallic support. Hereby, the selection of the substrate is crucial for the evolution of the reaction and, actually, the same precursor can give rise to different reaction pathways and products on distinct metals. Therefore, the reaction mechanisms involved in an on‐surface reaction depends on the choice of both the surface and the organic precursor.32‐containing pentacene‐based (tetraazapentacene) precursor, termed 4Br4AzaPn, which is endowed with dibromomethylene groups (:CBr2) to steer dehalogenation and homocoupling at a first stage, and ladderization at a second one, upon thermal annealing on gold or silver substrates.In this work, we present a comprehensive study based on scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS), and noncontact atomic force microscopy (nc‐AFM), complemented by density functional theory (DFT), to unveil the role of the metal substrate in the formation of new conjugated polymers, revealing substrate‐selective synthetic pathways toward novel reaction products. With this aim, we employ a Ncond one,34 upo4Br4AzaPn on Ag(111) at room temperature (RT) gives rise to the formation of a 1D polymer constituted by central ethynylene bridges and peripheral N‐Ag‐N links (product P1), thus affording both π–π and π–d conjugation pathways. Subsequent annealing at 200 °C results in an unprecedented pyrrolopyrrole N‐containing conjugated ladder polymer (P2) through a novel reaction pathway .Notably, following the same strategy on Au111), we only observe intact precursors at RT, while once thermal annealing surpasses 100 °C, the formation of the conjugated ladder polymer 11, we onP1, 4Br4AzaPn was deposited onto a pristine Ag(100) substrate at RT, giving rise to the formation of oligomers of P1 and tetraazapentacene monomers (P3) after the cleavage of both :CBr2 groups  onto a pristine Ag(111) held at RT leads to the spontaneous formation of 1D linear polymers, as illustrated in the chemical sketch and the STM and nc‐AFM images shown in Figure‐containing pentacene units, which is expressed as an enhanced contrast at their central positions, characteristic of a triple bond, as displayed in Figure Sublimation of  being chelated by the nitrogen atoms of adjacent tetraazapentacene units , displaying both π–π and π–d conjugation pathways and featuring a low bandgap.Next, we have investigated the electronic properties of P1 on Ag(111) , via an unprecedented ladderization reaction, as shown in Figure Further annealing at 150 °C does not lead to any significant modification in the polymer structure of 2.24Br4AzaPn was sublimed on top of a pristine Au(111) surface held at RT. After sublimation, we observe the intact precursor on the surface, as shown in Figure 2 moieties and the formation of polymer P2  surface and the silver adatoms, we deposited the precursor on two additional substrates, namely Au(111) and Ag(100), and inspected the reaction products. First, 11 surfacP2 was elucidated by nc‐AFM measurements, revealing the non‐planarity of the polymer  with the substrate held at RT, which results in the formation of two different products . To understand the reaction mechanisms toward the synthesis of P1 and P2 and the crucial role of the surface, we have performed DFT calculations of the reaction pathways on Ag(111) and Au(111).Considering the different behaviors on Ag(111) and Au(111) it is of interest to understand how the reaction mechanisms differ between the surfaces. In particular, getting knowledge about how important the Ag adatoms are for the formation of ethynylene‐bridged polymer FigureOne hypothesis is that the different reaction products are a result of different activation energies for making ethynylene and pyrrolopyrrole links on the two surfaces. In S2 to S3) of 1.04 eV is lower than without adatoms (1.25 eV). However, removing the adatoms, necessary to enable the reaction, is highly endothermic, providing a plausible explanation why the ethynylene polymer is stabilized on Ag(111): the temperature needs to be increased such that the entropy of the adatom is sufficient to make coordination to the polymer less favorable compared to diffusing over the surface. Including the entropy of Ag adatoms would in fact have a two‐fold impact, both making the reaction more kinetically accessible and thermodynamically favorable. If considering the free energy of the reaction, for each step where an adatom is removed we would need to add a term − TΔSAg, where ΔSAg is the entropy difference of a free Ag adatom and an Ag atom coordinated to the polymer., i.e., the term needs to be added for states S1 and TS2 which have one Ag atom less than the initial state S0, while for states S2, TS3, and S3 there are two adatoms less than S0, and − 2TΔSAg has to be added to account for the entropy of the adatoms. The effect of including the entropy is demonstrated in the Figures  has been included in the energy profile. By doing so, the overall reaction becomes thermodynamically favorable. While estimating the full free energy pathway is not computationally feasible, the results give a qualitative understanding why a relatively high energy is required for the ladderization on Ag(111).In Figure 3‐containing conjugated polymers by the reaction of a 4Br4AzaPn precursor sublimed on distinct noble metal supports, namely Ag(111), Au(111) and Ag(100), revealing the influence of the surface in directing the reaction pathways and the obtained products.We have carried out a comprehensive study toward the synthesis of Nπ‐conjugated and N‐Ag‐N coordinated tetraazapentacene units (P1). Subsequent annealing to 200 °C reveals the formation of an unprecedented conjugated ladder polymer (P2), with tetraazapentacene units fused to pyrrolopyrrole bridges.On Ag(111), we report the on‐surface synthesis of a CCP based on P1 being detected. Such different behavior between Ag(111) and Au(111) is attributed to the role of silver adatoms and their affinity to the tetraazapentacene moieties.Conversely and counterintuitively, on Au(111) the reaction of the precursor gives rise to the pyrrolopyrrole polymer already at 100 °C, half the temperature required for the Ag(111) case and without the intermediate 4Br4AzaPn precursor with the substrate is manifested and the formation of both isolated P3 monomers and P1 polymers is observed.Finally, on Ag(100) the influence of a higher interaction of the Our study opens new avenues for engineering unique conjugated polymers on distinct metallic supports, while shedding light into the critical role of specific metallic surfaces in driving reaction pathways. Altogether, our findings will contribute to the development of the fields of on‐surface synthesis and polymer materials science in a controlled manner.4−10 mbar) hosting a commercial low‐temperature microscope with STM/AFM capabilities from ScientaOmicron and located at IMDEA Nanoscience .Experiments were performed in a custom‐designed ultrahigh vacuum system (base pressure below 4 × 10+ sputtering (E = 1 keV) and subsequent annealing to 740 K for 10 min. All STM images shown were taken in constant current mode, unless otherwise noted, with electrochemically etched tungsten tips, at a sample temperature of 4.3 K (LakeShore). Scanning parameters are specified in each figure caption. Molecular precursor 4Br4AzaPn was thermally deposited (Kentax TCE‐BSC) onto the desired clean substate held at RT with a typical deposition rate of 0.1 Å min−1 (sublimation temperature of 165 °C), controlled by a quartz micro balance (LewVac). After deposition of 4Br4AzaPn, the sample was either inspected by scanning probe microscopy or postannealed at indicated temperatures.The metal substrates were prepared by repeated cycles of Ar The tip was a posteriori functionalized by a controlled adsorption of a single CO molecule at the tip apex from a previously CO‐dosed surface. The functionalized tip enables the imaging of the intramolecular structure of organic molecules. The sensor was driven at its resonance frequency (≈26 kHz for Qplus) with a constant amplitude of ≈60 pm. The shift in the resonance frequency of the sensor  was recorded in a constant‐height mode (ScientaOmicron Matrix electronics and MFLI PLL by Zurich Instruments for ScienaOmicron). The STM and nc‐AFM images were analyzed using WSxM.Noncontact AFM measurements were performed with a tungsten tip attached to a Qplus tuning fork sensor (ScientaOmicron).40 The using the projector‐augmented wave method to describe ion–core interaction, together with a plane wave basis expanded to a kinetic energy cutoff of 400 eV. Exchange‐correlation were described by the van der Waals density functional (vdW‐DF), in the recent form by Hamada, denoted by rev‐vdW‐DF2, which has shown to accurately describe molecular adsorption on gold and silver surfaces. The Ag(111) and Au(111) surfaces were represented by four layered slabs. For the calculations of the monomer adsorption as well as the coupling between two monomers a p(8 × 8) surface unit cell together with a 4 × 4 k‐point sampling for Ag(111) and a 8 × 8 k‐point sampling for Au(111). The relatively large k‐point sampling was needed due to the strong interaction between dehalogenated monomer and the surfaces. For the calculations of oligomers with four and six monomers units, we a p(8 × 13) and a (8 × 18) unit cell, respectively. Γ‐point only k‐point sampling was sufficient in these cases. The Ag(100) surfaces were also represented by four layered slabs. For isolated molecules, a p(8 × 6) unit cell together with a 3 × 3 k‐point was used, while for the P3 polymers we used a p(8 × 4) surface unit cell (four surface atoms per two molecules in the direction of the polymer) together with a 3 × 6 k‐point sampling. Transition states of reactions were found using a combination of the climbing image nudge elastic band (CI‐NEB) and Dimer methods, where CI‐NEB was used to provide an initial guess of a transition state, to be refined by the Dimer method. All structures  were geometrically optimized until the residual forces on all atoms, except those of the bottom two layers of the slab, were smaller than 0.01 eV Å−1. STM simulations were performed for the freestanding networks within the framework of the Tersoff–Hamann approximation as implemented by Lorente and Persson.Periodic density functional theory calculations were performed with the VASP code,43 usiP2 in the gas phase, without and with hydrogenation of the nitrogen atoms of the pyrazine moieties, using the FHI‐AIMS package and the hybrid exchange–correlation functional B3LYP[47]. Systems were allowed to relax until the remaining atomic forces reached below 10–2 eV Å−1. In all calculations and for all atomic species, the default light basis sets were used.Complementary theoretical calculations were performed to simulate the conformation of polymer S package54 andThe authors declare no conflict of interest.Supporting InformationClick here for additional data file.


The covalent attachment of molecular photosensitizers (PS) to polyoxometalates (POMs) opens new pathways to PS‐POM dyads for light‐driven charge‐transfer and charge‐storage. Here, we report a synthetic route for the covalent linkage of BODIPY‐dyes to Anderson‐type polyoxomolybdates by using CLICK chemistry . Photophysical properties of the dyad were investigated by combined experimental and theoretical methods and highlight the role of both sub‐components for the charge‐separation properties. The study demonstrates how CLICK chemistry can be used for the versatile linkage of organic functional units to molecular metal oxide clusters. Covalent functionalization of Anderson‐polyoxometalates with BODIPY light‐absorbers using CLICK chemistry is reported. The resulting photosensitizer‐polyoxometalate dyads are characterized by photophysical and theoretical methods, highlighting the electronic interactions between the sub‐components, and their possible application in visible light‐driven chemistry. Covalently linked organic‐inorganic hybrid molecules are important multi‐functional materials for nanostructure design, catalysis, and sustainable energy.1, 2 TIn molecular materials chemistry, polyoxometalates (POMs) have emerged as ideal candidates for the design of organic‐inorganic hybrids. POMs are molecular metal oxide anions based on early transition metals such as Mo, V, and W.3+, Co3+, Mn3+) of the Anderson anion can be used to tune the light‐driven hydrogen evolution of these systems. Further, detailed time‐resolved optical spectroscopy and spectro‐electrochemistry demonstrated the charge‐separation pathwaysRecently, organo‐functionalized POMs have attracted immense interest in the fields of energy conversion and storage.16, 172 reduction,In particular, the use of noble‐metal‐free photosensitizers such as BODIPY and its derivatives30, 311 with two alkyne‐functionalized BODIPY 2 to give a covalent BODIPY‐Anderson‐dyad 3. This concept is based on earlier studies by Oms, Dessapt, Mialane and co‐workers, who demonstrated that CLICK‐chemistry can be used to access these types of dyads.Taking inspiration from these studies, we here report a CLICK‐chemistry based system which enables the covalent linkage of an azide‐functionalized Anderson type polyoxometalate Here, we report the first example of a bis‐BODIPY‐Anderson‐POM hybrid, together with experimental and theoretical insights into the photophysical properties of the system.3 was synthesized as follows: the literature‐known bis‐azide‐functionalized Anderson‐POM, (nBu4N)3[MnMo6O18((OCH2)3C3H3N4O)2] 1,2)4 ⋅ 5H2O as CLICK catalyst and sodium ascorbate as reducing agent 3[MnMo6O28C56H60B2F4N12] 3 was obtained in yields of 82 % (based on 1). The identity and purity of 3 was confirmed by elemental analysis, 1H  and 19F NMR spectroscopy , electrospray ionization mass spectrometry  and matrix‐assisted laser desorption/ionization mass spectrometry . No copper catalyst residues were observed in the solid samples of 3, based on energy dispersive X‐Ray (EDX) analysis . FTIR spectroscopy  is absent in 3, while a prominent triazole band at 1680 cm−1 is observed, indicating the successful formation of the triazole‐linked species.The BODIPY‐POM hybrid o6O18(OCH3C3H3N4O)1, 2 and 3 was performed to assess accessible redox transitions in these species. As shown in Figure 1 shows two redox transitions, assigned to the MnIII/II couple , and one MoVI/V couple , respectively.2 shows one quasi‐reversible process (III/III’) at Em=−1.58 V. In the dyad 3, the three processes are retained with virtually no potential changes, i. e. Em=0.33 V (I/I’), Em=−1.18 V (II/II’), and Em=−1.57 V (III/III’).Cyclovoltammetric (CV) analysis of 3 at the molecular level, quantum chemical simulations were performed at the density and time‐dependent density functional (DFT and TDDFT) levels of theory. Initially, the nature of the electronic ground state was evaluated, i. e. with respect to the configuration of the manganese(III) centre of the POM. In case of MnIII with a formal 3d4 configuration two configurations are conceivable – either a closed shell singlet, or an (opened shell) triplet species. In the first case, the closed shell singlet species features a formal MnIII electronic configuration of (3dxy)2, (3dxz)2, (3dyz)0, (3dx2‐y2)0, (3dz2)0 with one vacant t2g orbital, for example the dyz orbital. In the second case, the triplet species exhibits two unpaired electrons in the t2g level, yielding the following configuration of the manganese(III): (3dxy)2, (3dxz)1, (3dyz)1, (3dx2‐y2)0, (3dz2)0, as illustrated by the spin density shown in Figure 3, DFT simulations performed at the PBE0/def2‐SVP[To evaluate the electronic structure of the BODIPY‐POM dyad /def2‐SVP40, 4113 and T14 (at 422 nm or ∼2.9 eV) in Figure 13 and T14), the energetic position of charge‐separated states associated to the photoreduction of the POM, in particular of the central manganese from MnIII to MnII, are of potential interest in the scope of photocatalytic applications. Based on the electronic ground configuration of MnIII, both semi‐occupied dMn‐orbitals (dxz and dyz) can act as electron acceptor sites – as evident from the low‐lying doubly degenerate metal‐centered excited states in 3 . Therefore, four quasi‐degenerate charge‐separated states of BODIPY.+‐POM.− character  and 3  in MeCN showed no changes of the absorption or emission wavelength maximum, indicating that under the experimental conditions used, no aggregation‐induced spectral changes are observed.The photophysical properties of 2 Figure . In the 1 / BODIPY 2 and the covalent hybrid 3, emission quenching studies were performed at different concentrations of 2 , and at different equivalents (1‐10 μM and 10–100 μM) of POM 1 . The corresponding Stern‐Volmer plots  despite the fact that calculations show that the entire system (including the POM) is in a triplet state due to unpaired electrons on the Mn ion. However, the optical properties of the dyads upon visible excitation can be discussed based on isolated BODIPY centers, i. e. photosensitizers which are electronically only very weakly coupled to the POM fragment of the dyads. Hence, for the sake of readability, the following section will adopt the nomenclature used in literature for isolated BODIPY fluorophores.Femtosecond transient absorption (TA) spectroscopy was performed to study the excited‐state properties of 2 and 3 initially display identical spectral features  excited state.[2 and 3 . As predicted by the performed TDDFT simulations, the four quasi‐degenerate charge‐separated states, i. e. T126, T127, T128 and T129 in Figure Upon excitation in the blue edge of BODIPY's ππ* absorption band at 475 nm, the fs TA spectra of ed state.48, 492 and 3, two time‐constants were used to fit the fs TA data. The first component  indicates an increase of the signal amplitude of the ESA, GSB and SE, and is attributed to the vibrational cooling of the initially excited ππ* state. The magnitude of this time constant is in good agreement with the literature for the vibrational relaxation (10–20 ps) of the first excited ππ* (S1) state of BODIPY chromophores.[3, τ2=1193 ps (i. e. k=8.4×108 s−1) shows a slightly faster decay of the ππ* state than the parent chromophore 2 . This is consistent with the reduced fluorescence quantum yield of 3 (QY=0.20) compared to 2 (QY=0.48).For quantitative analysis of the fs TA results, decay‐associated spectra (DAS)50, 512 and 3 is not complete within the experimentally accessible range of delay times, nanosecond transient absorption spectroscopy was performed. Due to the very strong fluorescence of 2 and 3 between 500 and 700 nm, the ns transient absorption spectra were only recorded between 370 and 460 nm. In order to show the contribution from the fluorescence emission, time‐resolved emission spectra (between 500 and 600 nm) were recorded as well. Figure 3. From 10 to 40 ns, the ESA intensity at 420 nm decreases and undergoes a fast red shift to ca. 430 nm .[1 state decays to the ground state with a time constant of 240 ns in aerated acetonitrile . Very similar spectral evolution and kinetics were observed for 2 .Since the decay of the fs TA signal in nt only).47, 531→T1 and T1→S0, are reflected in the kinetics of the transient absorption signal at 420 nm . The generation of a triplet state in 3 was further confirmed by the significantly prolonged lifetime in de‐aerated acetonitrile: τns2=30 μs  being detected, in agreement with the theoretical simulations which predict the charge‐separated states above 4.5 eV. Instead, a BODIPY localized T1 state is observed , suggesting a high energetic level (>1.68 eV) of the BODIPY.+‐POM.− state. Thus, we conclude that upon excitation of 3, BODIPY‐to‐POM electron transfer does not occur in a pure acetonitrile solution. Instead, a slightly faster intersystem crossing may take place, which (slightly) shortens the lifetime of the BODIPY S1 state. This is possibly due to the POM unit present in 3.Thus, at a longer time regime, the presence of POM in d Figure . The quaA novel Anderson‐polyoxomolybdate dyad covalently functionalized with two BODIPY groups is reported. Covalent attachment is possible by using a straight‐forward CLICK chemistry approach. Photophysical and electrochemical properties of the novel compound were investigated. According to these investigations, the dyad retains the unique photophysical properties of BODIPY, showing its promise as a photosensitizer in solar energy conversion processes. Future studies will include variation of the central metal to access a library of compounds based on this structural motif, which will allow modification of redox potentials for improved light‐induced electron transfer. Furthermore, modifications on the BODIPY moiety  will be performed to fine‐tune spectroscopic and photo‐/electrochemical properties, and to enable stable anchoring, for example on photoelectrode surfaces.Synthetic, analytical, spectroscopic, and computational details are given in the Supporting Information.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.


A tailored multiscale computational protocol based on Molecular Dynamics simulations and DFT investigations revealed an oxidative addition/reductive elimination process of the supramolecular catalyst [8PhenMe6)ICu within the phenanthroyl‐containing calix[8]arene derivative 1,5‐‐2,3,4,6,7,8‐hexamethyl‐ In a combined theoretical and experimental study, we report how calix[8]arene encapsulation enhances the catalytic activity for C−N coupling of an Earth‐abundant Cu‐phenanthroline catalyst by prevention of deactivation through dimerization and by promotion of product release. C−N bond formation is a reaction with a large demand, as amine derivatives are essential building blocks for multiple biologically active molecules,In recent years, computational chemistry has played a fundamental role in the development of new catalysts by uncovering reaction mechanisms and rationalizing reactivity and selectivity.As Earth‐abundant systems such as those with copper are prone to dimerization and other deactivation patterns, including oxidation from Cu(I) to Cu(II), recent efforts to incorporate it as catalytic center have resorted to bioinspired supramolecular catalysis.p‐tert‐butylcalix[8]arene (8C) is an outstanding option for supramolecular catalysis.arenes.In this context, calix[n]arenes (n=4–8) represent a group of cavitands that has been used as hosts for different metal centers including copper, aimed at emulating enzymatic catalysis.]arene C8 is an ou]arene C8 is an ou]arene C8 is an ouCu(Phen)(μ‐I)]2 ‐p‐tert‐butylcalix[8]arene (8PhenC)8Phen)ICu, an atom transfer mechanism with charged species, or an oxidative addition/reductive elimination sequence . These mechanistic possibilities have been investigated with computational methods, as well as experiments, with varying results.15, 16In this context, the computational modelling of supramolecular systems including large calixarenes is not straightforward due to their intrinsic flexibility and hence, conformational diversity.8C cavitand significantly increases the C−N coupling activity of a Cu‐phenanthroyl‐derived catalyst, with CuI as an inexpensive and abundant metal source to assemble the supramolecular pre‐catalyst arene, Scheme 8PhenMe6)ICu(μ‐I)]2. Our modelling approach is based on enhanced sampling techniques and quantum chemical investigations, while computational results are validated and complemented by extensive experimental characterization and activity studies.Thus, we describe how encapsulation within a macrocyclic 8PhenMe6C, the hydroxy groups from the parent 8PhenC were substituted by methoxy groups, which do not participate in acid‐base equilibria under the basic conditions required for catalytic C−N coupling.8PhenC was achieved with a slight excess of MeI after deprotonation with NaH in anhydrous THF. The 1H NMR spectrum of 8PhenMe6C does not display signals beyond δ 8.50 ppm, which are associated with hydroxy groups in calix[8]arenes  and 3.30 ppm  attest to the −OMe substitution. The methoxy groups are labelled as MeOint, for those facing inside the calixarene, and MeOext, for those outside, based on the shielding or deshielding caused by the aromatic groups. Full NMR spectroscopic analysis of 8PhenMe6C is presented in the Electronic Supporting Information , including COSY NMR that allowed the assignment of signals corresponding to the methylene bridges of the cavitand CH2C8 at δ 3.49 ppm ), 3.59 ), 3.98 ), and 4.34 ), while the methylene connector to the phenanthroyl moiety was detected at 4.27 ppm . Assignment of the signals was facilitated by Variable Temperature (VT) 1H NMR spectroscopy . The aromatic signals corresponding to the phenanthroyl moiety are well resolved at high temperature, being clearly identified at δ 8.06 and 7.55 ppm. The signals corresponding to the cavitand phenolic framework (ArC8) were observed from δ 7.55 to 6.65 ppm. The IR spectrum of the new cavitand in Figure S5 does not show bands above 3315 cm−1 that may be assigned to νO‐H, further supporting the complete methylation of the hydroxy groups. Positive‐ion Fast Atom Bombardment Mass Spectrometry (FAB+ MS) in Figure S6 shows an intense peak at m/z=1586, assigned to the protonated molecular ion [8PhenMe6HC]+. Finally, addition of CuI to an equimolar amount of 8PhenMe6C in toluene suspension resulted in pre‐catalyst [8PhenMe6)ICu(C].In the new cavitand 8PhenMe6)ICu. The compound exhibits a symmetry plane as the free cavitand 8PhenMe6C, based on the three tert‐butyl signals in a 1 : 1 : 2 ratio, and the four doublets corresponding to the calix[8]arene methylene bridges CH2C8 at δ 3.75 ), 3.81 ), 4.18 ), and 4.21 ) observed at 393 K. The monomeric nature of  is EPR‐silent as expected for a diamagnetic Cu(I) d10 species ICu species. [Cu(Phen)(μ‐I)]2 appears to be protected towards oxidation due to its dimeric nature;2 was employed as reference (OTf−=trifluoromethanesulfonate), see spectra in Figure Characterization of  discriminates substrate by size: A significantly better performance was achieved for the production of diphenylamine (product a) when bromobenzene (PhBr) was used, rather than iodobenzene (PhI). Although iodide acts as a better leaving group that facilitates the potentially rate‐limiting oxidative addition step (vide infra),8Phen)XCu.a with PhBr ICu(C] afforded only 50 % of product a (entry 4 in Table 8PhenC in the presence of the strong base KOtBu. Although a reasonable amount of a was obtained (50 %), collateral formation of homocoupling products of aryl halide  and aniline  were observed in low (7–12 %) yields. The formation of b is a commonly observed secondary catalytic path in Cu(I)‐based systems,tBu can also promote biaryl coupling reactions.c has been associated with Cu(I) complexes in the presence of an oxidant.8PhenC does not seem to protect the Cu(I) center towards oxidation to Cu(II) by adventitious oxygen as its methylated counterpart 8PhenMe6C. Thus, aniline oxidation to generate c may occur at the Cu(II) center, regenerating Cu(I). Acid‐base equilibria also affect the catalytic performance, since deprotonation of the hydroxy groups of 8PhenC is likely favored over that of aniline (even when coordinated to Cu(I)) necessary for C−N coupling. The presence of Cu(II) in the 8PhenC system was confirmed by EPR analysis as mentioned above, with approximately 20 % of + was detected by Direct Analysis in Real Time (DART) MS at m/z=479 . Halogen ligands tend to favor Cu−X−Cu  bridge formation that limit the availability of the Cu(I) centers for catalytic reactions,Phen in Figure S11 that affords a value of rH=2.38 Å vs that of [Cu(Phen)(μ‐I)]2 in Figure S12 that is more than double at rH=7.25 Å, consistent with a dimeric formulation. These experimental findings are in line with quantum chemical calculations, where dimerization yielding a Cu−X−Cu structural motif was energetically favored .To evaluate the influence of the cavity on catalytic performance, we compared the 2Phen(OAr) that also features the bidentate phenanthroline fragment, we hypothesized that the bulky substituents akin to those in 8PhenMe6C may inhibit the dimerization observed with Phen (for DART MS of 2Phen(OAr) see Figure S13, for 1H NMR characterization of 2)]2[Cu(Phen(OAr) (rH=10.56 A) is about twice that of the free ligand 2Phen(OAr) (rH=5.65 A). Furthermore FAB+ MS attests to the presence of the redistribution product 2)2]++ is likely due to equilibration with [2)2Cu(Phen(OAr)]+, and the absence of the confined space provided by the cavity in 8PhenMe6C. The combined observations indicate that such cavity is necessary to obtain high yields of the C−N coupling products, likely by increasing the local concentration of substrates during the catalytic process. This would allow more efficient interactions of the substrates with the Cu(I) center. We also tested C−N coupling with substoichiometric quantities of CuI (10 % mol) in the absence of ligands ICuICu. The overall results evidence the good catalytic performance of [8PhenMe6)ICuICuICuICuI] (μ‐I)]2 . Indeed, dispersion‐corrected density functional theory (DFT) investigations in implicit toluene  predicted relative electronic and free energies to thermodynamically favor dimerization with ΔE=−71 kJ mol−1 and ΔG298=−39 kJ mol−1 I] as model system is ideally suited to gain mechanistic insights prior to tackling the full‐fledged catalyst [8PhenMe6)ICuI] (denoted as 1) is depicted in Figure 1 to afford 2 in an exergonic reaction . This adduct formation is monotonously downhill and hence diffusion controlled. For such processes, typical free energy barriers are about 20 kJ mol−1 – a value we assumed for 1‐2TS.2 shows π‐π stacking of the phenyl ring of the aniline and the phenanthroyl moiety, at a distance of 3.5 Å . In the next step, deprotonation of coordinated aniline via 2‐3TS  occurs, for which we estimated a free energy barrier of approximately 25 kJ mol−1 . As a result, the negatively charged intermediate 3 is formed, with an additional stability of ΔG298=−120 kJ mol−1 and ΔE=−147 kJ mol−1. The aniline phenyl ring moves closer to the phenanthroyl fragment at 3.3 Å, while the rest of the structure remains largely unchanged . For the subsequent dissociation of iodide, we estimate a free energy barrier for 3‐4TS of 14 kJ/mol  to yield intermediate 4 with ΔG298=−110 kJ mol−1 and ΔE=−116 kJ mol−1. Here, Cu regains a trigonal planar geometry . Alternatively, 4 can be accessed by iodide dissociation from 2, resulting in 2 a , which would be followed by coordination of aniline to give 3 a , and finally deprotonation. This alternative pathway can be ruled out based on the highly unfavorable energetic profile, which results in relative free energies of ΔG298=274 and 160 kJ mol−1 for 2 a and 3 a, respectively. Approach of the phenyl bromide to 4 proceeds via 4‐5TS. Once again, this step presents a monotonous decrease in electronic energy. We assumed diffusion control and – in the absence of the calixarene cavity – estimated a barrier of ΔG≠ ≈20 kJ mol−1 (4‐5TS).A schematic reaction mechanism for the C−N bond formation between aniline and bromobenzene mediated by . Apart from dimerization as a deactivation pathway, strong interactions between [Cu(Phen)Br] and the product may also result in loss of activity or complete deactivation of the catalyst.The calculated rate determining step or state, according to Kozuch and Shaik's energy span model,Cu(Phen)I] catalyst predicted the reaction barriers of all alternative mechanisms to be higher.Although other mechanisms, such as single electron transfer (SET) or atom transfer are discussed in the literature,8PhenMe6C in chloroform to explore the potential energy surface. Although the experiments were conducted in toluene, deviations were found to be small  and computational costs were significantly lower. To also investigate the corresponding Cu(I) complex and selected reaction intermediates as well as transition states, force field parameters had to be generated prior to simulation. After the simulation runs, obtained trajectories were clustered to yield a few representative and structurally diverse conformers. The initial structures thus generated were re‐optimized with DFT .To estimate the effect of confinement on the reaction mechanism, we investigated the supramolecular catalysts and its intermediates by developing a multiscale approach workflow . Due to the flexibility of macrocyclic ligands, enhanced sampling methods were necessary to capture their conformational diversity. In addition, simulation in the full condensed phase, that is, in explicit solvation, was required to retain the cavity. Therefore, we performed accelerated Molecular Dynamics (MD) simulations of the ligand Cu(Phen)I], as shown in Figure calix2, calix, 5calix4 and calix8 the relative stabilities differ by less than 15 kJ mol−1. Notable differences are found for calix3, calix6, and calix7. While the deviation of 54 kJ mol−1 between the small model and the supramolecular structure of calix3 arises potentially due to insufficient sampling, the higher relative energy of calix6 can be attributed to the very bulky nature of the intermediate, which occupies the calixarene cavity in its entirety, forcing the cage into unfavorable conformations. In addition to these intermediates, we also converged transition‐states for the oxidative addition  and reductive elimination  steps, respectively. Although the predicted barriers are somewhat higher than in the molecular case, this should not be overemphasized because we did not run MD simulations on these structures. Consequently, we were unable to predict the lowest conformation properly and the reported numbers can be considered as upper bounds to the true TS barriers. Moving forward in the reaction, the release in energy from calix6 towards calix7, at −255 kJ mol−1 is similar to that of the transition from 6 to 7, at −239 kJ mol−1. A structural difference that can be remarked between 7 and calix7 is that the hydrogen bond between the amine and the bromine is no longer present. Instead, it has been replaced by a hydrogen bond to a calixarene oxygen atom, thus weakening the product‐catalyst interaction. Consequently, the release of product from the calixarene cavity is facilitated, with calix8 being only 18 kJ mol−1 higher in energy than the previous intermediate, compared to 60 kJ mol−1 for 8. As these are electronic energies only, thermal and entropic corrections will make this step exergonic.Overall, investigation of the supramolecular system as a whole revealed a similar energetic profile as , and determined the origin of this increase in catalytic activity. The supramolecular catalyst achieves C−N coupling reactions in toluene with low loadings featuring Earth‐abundant copper. The system offers a chemical environment that is inert to basic conditions, while also favoring interaction of the metal center with the substrates. Based on the experimental and theoretical results, the catalytic process is kinetically limited by the oxidative addition of the haloarene, and by the steric restrictions imposed by the macrocycle suggesting that a 1,5‐phenanthroline bridge is vital for catalysis. Computational studies further revealed that prevention of catalyst aggregation, activation of intermediates as well as facilitation of product release fuels C−N coupling activity in comparison to the molecular analogue. +. Elemental analysis for C108H134N2O8 ⋅ H2O ⋅ CHCl3, found: C, 75.87; H, 8.00; N, 1.62; requires: C, 75.88, H, 7.86, N, 1.43.8PhenMe6)I]Synthesis of  and [Cu(Phen)I]2, except that the catalyst loadings corresponded to 10 % mol for the latter two complexes.8PhenMe6)ICu. We first studied the C−N coupling mechanism with monomeric [Cu(Phen)I] (1) as the catalyst, before assessing the flexibility of the macrocyclic ligand and studying the supramolecular system.A multiscale modelling protocol was designed to describe the supramolecular catalyst [Quantum chemical studies of [Cu(Phen)I]. The initial geometry for 1 was constructed using Gaussview 6.0.16.C1 symmetry using the BP86E (PBE0/def2‐TZVP/D3/COSMO//PBE0/def2‐SVP/D3/‐COSMO) or relative free energies ΔGarene/Cs8PhenMe6C were generated using Amber's Generalized Force Field (GAFF),To obtain adequate sampling of the catalyst, we performed twelve 1μs aMD simulations, followed by a hierarchical clustering to obtain a structurally diverse ensemble .50, 51calix1 and 6calix, to assess how the flexibility of the cavity changes upon Cu coordination. Therefore, a parametrization of the metal ion at the center of the molecule was required. MCPB.pyIn addition, we simulated the assembled supramolecular structures To investigate the flexibility of the calixarene units, a dihedral analysis was used, to characterize the rotations between each calixarene unit. Dihedral angles were assigned between the planes of each of the six‐membered rings of the calixarene units, as changes in these angles accurately describe the movements within the calixarene ring. Using the X‐entropy scriptAssembly of supramolecular catalyst for DFT investigations. Once the [Cu(Phen)I] (1) structure pathway investigation was completed, the next step was to study the effects of the confinement by the calix[8]arene on the energetic landscape. To this end, a fitting of the reaction intermediates back into the 8C ring was necessary. Cluster representatives of the molecular dynamics simulations were selected using a hierarchical clustering algorithm. The cluster representative with the largest population of the aMD simulation of structure calix1 was chosen as the starting point for a fitting of all QM optimized structures. The fitting process was automated using a python script via PyMOL,Structural parameter measurements and visualizations were done with PyMOL.8PhenMe6C and the supramolecular system [8PhenMe6)ICu should be addressed to the authors.Supporting InformationClick here for additional data file.


Single‐crystal X‐ray analysis revealed a highly symmetric hollow cube‐octahedral arrangement of the gold atoms, resembling gold bulk structure. Quantum‐chemical calculations illustrated the cluster can be described as a 20‐electron superatom. Optical properties of the compound have shown molecular‐like behavior.Metalloid gold clusters have unique properties with respect to size and structure and are key intermediates in studying transitions between molecular compounds and the bulk phase of the respective metal. In the following, the synthesis of the all‐phosphine protected metalloid cluster Au 20 cluster was synthesized by a wet chemistry approach, solely stabilized by phosphine ligands. The presented superatom cluster possesses a high symmetrical structure and an oxidation state of the gold atoms of ±0.A theoretically long‐studied Au I or AuIII precursor like (PPh3)AuCl or HAuCl4 respectively.Since the first synthesis of gold nanoparticles within the purple of CassiusnRm 2 or ligands like PPh3), which are actually often named “metal clusters” or “metal nanoclusters” or “monolayer protected metal clusters”, are ideal model compounds to illuminate the transition area from molecular compounds to bulk materials.Nanoclusters and nanoparticles represent an intermediate state between molecular gold compounds and the bulk phase. Within this size regime, these systems exhibit a manifold of different structures that resemble the elemental gold fcc‐lattice as well as novel polyhedral structures.The precise structures of metalloid clusters can be determined by single‐crystal X‐ray structure analysis, which can also aid to study the transition from molecular to metallic compounds.11, 1211(PPh3)7(SCN)3102(p‐MBA)44279(SPh‐tBu)84.Since the first crystallographic characterized metalloid gold cluster Au20 cluster that was extensively studied, by theoretical calculations,20 cluster built solely from gold atoms in the oxidation state ±0 none was successful to date.22 cluster Au22L6 ‐octane),3Au2PPh3, generated by the reduction of (PPh3)AuI with NaC10H8.3(CO)12 or Ir4(CO)12 are known.Gold clusters built from gold atoms in the oxidation state of ±0 are almost exclusively found in the gas phase, generated for example by laser vaporization.20(tBu3P)8 solely stabilized by phosphine ligands and exhibiting a high symmetry structure, closely related to bulk gold fcc‐structure. Quantum chemical calculations along with transient absorption measurements give deeper insights into the cluster and corroborate the unusual oxidation state of the gold atoms within this cluster.In the following we report the synthesis and structural characterization of an all‐gold‐0 superatomic cluster compound AutBu3PAuCl with NaBH4 in ethanol. The synthetic protocol resembles the previously published Au32‐syntheses,20(tBu3P)81 suitable for single crystal X‐ray analysis. The derived structure is displayed in figure The title compound is generated by reduction of 20(tBu3P)81 crystallizes in the space group R3‾, with z=3. Within the asymmetric unit 4 gold atoms are present. The cluster possesses Oh‐symmetry, showing the high symmetry of the compound. It consists of a central hollow cuboctahedron motif formed by 12 gold atoms surrounded by 8 gold atoms, each bound to a tBu3P‐group capping each of the eight triangular faces of the cuboctahedron. The three gold atoms of the triangular faces along with the capping gold atom forming tetrahedrons with all angles being at 60° while angles of the hexagons within the cuboctahedron are 120°.The title compound Au2211‐centaur polyhedra, thus not showing bulk gold features. The gold core within 1 has a cubic structure with an edge length of 0.51 nm. The whole compound, including the phosphine ligands, can be approximated as a sphere with a diameter of about 1.9 nm, measured from the outermost hydrogen atoms.The structure of the core resembles the face centered cubic (fcc) packing of gold atoms in elemental bulk, solely deviating in the missing central gold atom. The high symmetric and fcc‐like structure of this compound distinguishes this cluster from the sole other example of an all gold‐0 metalloid cluster Au20 deviates from the tetrahedral arrangement of the gold atoms predicted by theoretical calculations and proven for gas phase clusters. The stabilizing phosphines may be held accountable for this alternation, as predicted by Häkkinen in 2016.Furthermore, the structure of Au27920 core in 1 is zero, being thus one of only two known metalloid gold cluster compounds exhibiting the same oxidation state as the element.Due to the high symmetry of the cluster all Au−Au bonds are of equal length of 272 pm which is contracted compared to the Au−Au distances of 288 pm found in bulk gold. Comparable gold bond lengths are more likely to be found in smaller gold clusters7/2 at 84.14 eV. This signal is similar to literature values of elemental gold, which range from 84 eV to 84.07 eV.7/2 orbitals of small gold clusters Au9(PPh3)8(NO3)3 (85.2 eV) and Au11(PPh3)8I3 (84.7 eV), where the oxidation state of the gold atoms is ≠0.To rule out potential adsorbates, such as protons, and therefore a charge of the cluster molecule, HR‐ESI‐MS measurements were conducted . The measurement shows the cluster as double charged cation without any additional adsorbates which substantiates the oxidation state of the gold atoms of ±0. To further support this, XPS measurements were performed . The measurements yield a signal for the gold 4fHowever, there will be a certain electronic effect i.e., charge effect of the phosphine ligands on the gold atoms, which explains the small shift of energy compared to elemental gold.1, we performed ab‐initio simulations on the molecular structure of the title compound at the PBE/TZP level, including relativistic effects using Amsterdam Density Functional (ADF) software.To investigate the electronic effect of the ligand on the individual gold atoms in 1 to examine its possible molecular‐like behavior, i.e., superatom character. Previous studies have illustrated gold nanoparticles less than 2 nm behave molecule‐like instead of bulk‐like.21P61D102S2, a magic number within the spherical jellium model.1, we see a different arrangement of molecular orbitals 12Cl8, have shown that cluster symmetry plays a key role in the electronic structure of a given system and is instrumental in gaining a complete view of superatom behaviour.[We studied the electronic structure of gure 1.32nBu3P12C1 reveals several peaks in the UV and Vis spectral range . The simulated spectrum is red‐shifted from the experimental spectrum, which has been observed in other comparison of gold molecule‐like clusters.3 b and 3 c), typical for inorganic  cluster compounds with prevailing molecular character,Figure 3 c and 3 e), i.e., when going from inter‐ to intraband excitation according to theory (see above). This implies rather efficient internal conversion processes within the time resolution of the experiment, i.e., within 80 fs or faster.Interestingly, this situation does not change considerably when increasing the pump power by more than 1.3 eV to an excitation wavelength of 317 nm  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.


The optimum proportion of MnO2/MXene–Ti3C2 composites and MnO2 was used as a cathode material for magnesium batteries to carry out the electrochemical performance test. The results showed that the charge–discharge capacity of the MnO2/MXene–Ti3C2 composite was up to 105 mA h g−1, much higher than that of MnO2 (64 mA h g−1), and meanwhile it had good rate performance. At the same time, this also opened up the application of MXene–Ti3C2, a new two-dimensional material, in the field of battery electrode materials.In this paper, MnO 2/MXene–Ti3C2 composites with different molar ratios were successfully prepared by a one-step hydro-thermal method, and the optimum proportion was confirmed by XRD and SEM comparative analysis.In this paper, MnO Among them, lithium-ion batteries are widely used because of their high energy density and mature technology, but they have the problems of high cost and poor safety.4,5 Magnesium and lithium are located in a diagonal position in the periodic table, and have similar ionic radii and chemical properties. Compared with lithium metal (180.5 °C), the melting point of magnesium (648.8 °C) is much higher, and its activity is poorer. So, it is easy to process and also safer. Moreover, magnesium ions can carry two charges. Although the mass specific capacity (2205 mA h g−1) is not as high as lithium metal (3862 mA h g−1), it is still considerable.6–9 At the same time, China is rich in magnesium resources, ranking first in the world, and the price is low and it's easy to obtain.10–12 So, magnesium ion batteries have attracted much attention from researchers around the world.With the rapid development of social economy, increasing consumption of fossil energy and escalating environmental pollution, it is extremely urgent to find clean, environmentally friendly, efficient and sustainable energy sources.13,14 Some researchers have also used the first principle to do research about the stability on electrode materials for magnesium batteries.15 The calculation and experiment of large shared database connection can greatly help to narrow some of the current experimental and technical gaps, as well as predict the path-independent characteristics, and help to fundamentally understand the path-independent performance in multiple space-time scales.Based on advanced theoretical algorithms, modeling, simulation, and computer technology, the reasonable design of materials, batteries, devices and batteries in the field of lithium ion batteries is gradually being realized.16–18 When discharging, the metal magnesium of the negative electrode dissolves out and forms the magnesium ion. It reaches the positive electrode through a series of processes such as dissolution, adsorption and transfer of electrolyte, and then it is embedded in the cathode materials. When charging, the magnesium ions embedded in the cathode material are detached and reach the negative electrode under the action of external electric field, and then they are deposited again to form the metal magnesium.19–22Magnesium ion battery is mainly composed of three parts: compound cathode which can reversibly imbed–detach magnesium ion, metal magnesium and its alloy's negative electrode, and electrolyte.23–25 MnO2 is a kind of electrode material with high theoretical specific capacity, low cost and easy availability, which has been widely used as battery electrode material, but its poor conductivity and stability limit the application of MnO2 as electrode material.26–28 Therefore, many researchers have improved the electrochemical performance of MnO2 by improving MnO2's nanostructure or combining MnO2 with some conductive materials.29–32At present, the studies on magnesium ion batteries at home and abroad mainly focus on cathode materials and electrolytes, which are all still in the preliminary stage. Cathode material is the key factor which restricts the development of magnesium ion battery, and some domestic and overseas scholars are trying to find and develop new cathode materials.n+1XnTx , of which is an early transition metal, X is carbon or nitrogen, and Tx represents O2−, OH−, F− and other surfaces functional group, MXene has been widely used in various fields.33–35 MXene is mainly obtained by selectively etching a fixed atomic layer in the MAX phase of the precursor. MAX phase is the general term of a class of ternary layered compounds, which have a uniform chemical formula Mn+1AXn . Common chemical etchants are hydrofluoric acid or a mixture of hydrochloric acid and lithium fluoride.36–38 MXene is a new type of two-dimensional layered material, which has the following advantages as electrode material: (1) good electrical conductivity, which is conducive to the electron transmission; (2) large specific surface area, which can provide more storage sites; (3) layered structure, which is conducive to the rapid diffusion of electrolyte ions between layers, providing excellent rate performance; (4) high density of magnesium metal, which makes the volume specific capacity high; (5) adjustable surface chemical structure, which means different MXene can provide different working potential windows.39–43 So far Ti3C2Tx is the most studied MXene. It has been successfully used as electrode material for supercapacitors, sodium-ion batteries and lithium-ion batteries.44–46 Among them, Ti3C2Tx as electrode material for lithium ion battery is the most widely studied. Some researchers have also prepared some Ti3C2Tx matrix composites for lithium batteries and shows excellent capacity and rate performance.47,48 Moreover, MXene has excellent optical, mechanical and thermal stability properties, and has a wide range of applications in the fields of electromagnetic shielding, water treatment, gas, biosensor and photo electrochemistry catalyze.49,50MXene is a new type of transition metal carbide, carbonitride and nitride  with two-dimensional graphene-like structure. The general formula of MXene is M2 nanoparticles on the surface of MXene–Ti3C2 material with high specific surface areas and high electrical conductivity by hydro-thermal method in this article, and its electrochemical performance was tested as the cathode for magnesium batteries.According to the advantages of MXene-a new type of material, we deposited MnO2.2.1Firstly, 145.29 mg of potassium permanganate was weighed and placed into the beaker; added 50 mL distilled water, stirred it for 30 minutes to fully dissolve. Then the solution was transferred to the hydro-thermal reactor and reacted at 150 °C for 20 h. After the reaction is over, take out the hydro-thermal reactor and cool it to room temperature. After cooling, the samples were centrifugally washed with alcohol and water alternately for 6–8 times. After that the samples were transferred to the beaker and dried in vacuum for 24 h at 60 °C, then it became the manganese dioxide.2.23AlC2 2 g and lithium fluoride were respectively accurately weighed; 40 mL of hydrochloric acid  was weighed using a measuring cylinder and was poured slowly into a beaker. Added 2 g of lithium fluoride and stirred it for 60 minutes; added 2 g of Ti3AlC2 slowly into the mixed solution; then magnetically stirred it at room temperature (25 °C) for 24 h at a speed of 200 rpm; repeated washing it ultrasonically centrifugally with deoxidized water until the pH value reaches 6; dried the sediment in vacuum at 120 °C for standby use, and this is the MXene–Ti3C2.Firstly, 2 g of Ti2.33C2Tx was weighed and placed in the beaker; added 50 mL distilled water, ultrasonically stirred it for 30 minutes; 145.29 mg of potassium permanganate with the mole ratio of 1 : 1 was weighed and fully mixed for 30 min. Then poured the stirred solution into the hydrothermal reactor, and set the temperature at 150 °C and the time at 20 h. After the reaction is over, the reaction still was taken out and cooled to room temperature. After cooling, the resulting solution was centrifuged to get the underlayer sediment; the sediment was washed with absolute ethyl alcohol and distilled water alternately for 6–8 times. The washed sample was put into the beaker and dried in a vacuum drying box at 60 °C for 24 h to obtain MnO2/MXene–Ti3C2 composites.Firstly, 40 mg of Ti2/MXene–Ti3C2 composites with molar ratios of 1 : 2, 1 : 1 and 2 : 1, the mass of KMnO4 was maintained the same, and different mass of MXene–Ti3C2 mixtures were weighed respectively for reaction, which was consistent with the above-mentioned process.When preparing MnO3.3.12 and MnO2/MXene–Ti3C2 nanocomposites with different molar ratios. It can be seen from the figure that there are obvious diffraction peaks in MnO2 sample at 2θ of 12.77°, 24.78°, 36.55° and 66°, corresponding to (003), (006), (012) and (110) crystal planes of the δ-MnO2 standard card (JCPDS 01-086-0666) respectively.51–53 No other phase substances were detected in the spectrums, indicating that the layered δ-MnO2 is successfully prepared. From the XRD diffraction spectrums of MXene–Ti3C2, by comparing and analyzing the standard cards of precursor Ti3AlC2 in other papers, it can be seen that when 2θ was 9.0°, 16.21°, 18.32°, 34.26°, 52.88° and 60.81°, it was corresponding to the crystal planes of (002), (004), (006), (0010), (0012) and (110) respectively, these are the characteristic diffraction peaks of MXene–Ti3C2, which are consistent with other reports.54,55 In the XRD spectrums of MnO2/MXene–Ti3C2 composites with molar ratio of 1 : 2, the characteristic diffraction peaks of MnO2 and MXene–Ti3C2 appeared, which indicated that MnO2 was successfully loaded on the MXene–Ti3C2, MnO2/MXene–Ti3C2 composites are successfully prepared. But there is a main peak at 26.5° which illustrates that MXene–Ti3C2 is easy to be oxidized to form TiO2 in the hydro-thermal reaction. Moreover, the characteristic diffraction peaks of MXene–Ti3C2 were obviously weakened after adding MnO2. In the XRD spectrums of MnO2/MXene–Ti3C2 composites with molar ratio of 1 : 1 and 2 : 1, the characteristic diffraction peaks of MnO2 appeared, but the characteristic diffraction peaks of MXene–Ti3C2 gradually weakened and disappeared, showing that MnO2 nanoparticles can inhibit the recrystallization of two-dimensional MXene–Ti3C2 lamellae in MnO2/MXene–Ti3C2 composites, and the larger the proportion, the more obvious the effect.3C2 has a layered structure similar to the organ, and the nanosheet of MXene–Ti3C2 are tightly bonded together, so the large specific surface area of MXene–Ti3C2 can not be fully utilized. 2. It can be seen that MnO2 is formed by overlapping and agglomeration of nanosheet layers into three-dimensional flower bract shape. The interspace of nanosheet layers is large which forms abundant pore structures.56–592/MXene–Ti3C2 nanocomposites with molar ratio of 1 : 2, from which we can see that MnO2 is evenly distributed between the nanosheet layers and the interspace of MXene–Ti3C2. At the same time, there are some irregular nanoparticles on the surface and between layers of MXene–Ti3C2, which consistent with the XRD analysis above. So MXene–Ti3C2 is easy to be oxidized to form TiO2 in the hydro-thermal reaction. Because MXene–Ti3C2 is obtained by removing A by etching MAX through HF, some surface functional groups will be produced during etching and some defects may occur at the edge of MXene–Ti3C2 lamellae. These defects and active sites provided by surface functional groups create conditions for the uniform distribution of MnO2. 2/MXene–Ti3C2 nanocomposites with molar ratio of 1 : 1 at different multiples. From 2 nanospheres and some agglomerated TiO2 particles are closely accumulated on MXene–Ti3C2 lamellae, wrapping MXene–Ti3C2 sheet lamellae, and the structure of MXene–Ti3C2 can hardly be seen. As can be seen in 3C2 lamellae surfaces are densely packed with spherical MnO2, which seriously hinders the effect of MXene–Ti3C2. 2/MXene–Ti3C2 nanocomposites with molar ratio of 2 : 1. In the picture we cannot see any MXene–Ti3C2 substance. There were all nano MnO2 with flower sphere shape. The flower spheres are tightly packed together, forming a honeycomb three-dimensional structure. In conclusion, when the molar ratio of MnO2 to MXene–Ti3C2 is 1 : 2, they are evenly combined. With the increase of molar ratio, the MXene–Ti3C2 substance decreases and disappears gradually. The increase of MnO2 inhibits the recrystallization of MXene–Ti3C2.3.23C2 as cathode material for magnesium batteries is 18 mA h g−1 at 50 mA g−1 current density, which is low. This is consistent with other literature reports. The first discharge capacity of MnO2 at 50 mA g−1 current density is only 64 mA h g−1, which is reduced to 45 mA h g−1 after 100 cycles. When 1 : 2 MnO2/MXene–Ti3C2 composite is used as cathode material of magnesium battery, the first discharge capacity is 105 mA h g−1, which is much higher than that of other manganese dioxide matrix composites. And after 100 cycles, the discharge capacity is 58 mA h g−1, the cycling performance is better than that of Mn2. After adding the MXene–Ti3C2, the capacity of the composite material is greatly improved, which is due to the addition of MXene–Ti3C2 which has large specific surface area and high electrical conductivity, providing more storage sites for the entry and exit of magnesium ions during the working of magnesium batteries, and shortening the transport path of magnesium ions. 2/MXene–Ti3C2 displays that most capacity does not come from characteristic behaviors of MoO2 from the slope between 0.2–1.0 V for the composite. Because we added some carbon black as conductive agent in the process of assembling the electrode sheet, it is also beneficial to improve the capacity.As shown in 2 and MnO2/MXene–Ti3C2 composites in the voltage range of 0.01–2.0 V. Compared with MnO2, MnO2/MXene–Ti3C2 composite material has obvious anode and cathode current response, large CV area and obvious capacity. The CV curve shows a sharp peak when it's lower than 0.2 V, which may be due to Mg2+ embedded at the active site of the electrode with high activation energy. This is consistent with the relatively flat discharge curve in the low voltage region of 0.01–0.2 V shown in 2/MXene–Ti3C2 sample is embedded pseudocapacitance, and the coulombic efficiency of the electrode material is close to 100%. MnO2/MXene–Ti3C2 sample has good cycle performance.2/MXene–Ti3C2 composite electrodes also show excellent rate performance. As shown in −1, the capacities are 54 mA h g−1, which are much higher than those of MnO2. In the first ten circles, there is some attenuation of capacity, which is due to the strong electrostatic interaction between Mg2+ and electrode materials, and Mg2+ is easy to be captured by some active sites. At a high current density of 100 mA g−1, the battery still has a stable capacity of 54 mA h g−1 and still has a high capacity at a wide range of current densities, indicating that MnO2/MXene–Ti3C2 is a very nice high rate cathode material for magnesium batteries.MnO4.2 and MnO2/MXene–Ti3C2 composites with different molar ratios are successfully prepared by one-step hydrothermal method in this paper. When the molar ratio was 1 : 2, MnO2 evenly adhered on and between MXene–Ti3C2 lamella, and the composite effect was the best, which was conducive to the imbedding and separation of magnesium ions. When 1 : 2 MnO2/MXene–Ti3C2 composite is used as cathode material of magnesium battery, the main energy storage mechanism is embedded pseudo capacitance. The first discharge capacity at 50 mA g−1 current density is 105 mA h g−1, which is much higher than that of MnO2. Even at a high current density of 500 mA g−1, the MnO2/MXene–Ti3C2 composite battery still has a stable capacity of 21 mA h g−1 and good rate performance. At the same time, MXene–Ti3C2 substrate material with high conductivity is very valuable for the study of new electrode materials.MnOThis work was supported by the Magnesium Industry Collaborative Innovation Center of University of Science and Technology Liaoning (USTLXT201801), Liaoning Natural fund project (2019-ZD-0027) and National Science and Technology Support Plan (2014BAB02B01).There are no conflicts to declare.


We showed a case with the onset of fulminant type 1 diabetes mellitus (FT1DM) whose HbA1c could not be measured with HPLC method. We think that the reason why his HbA1c was not be detected was associated with the presence of labile hemoglobin A1c (LHbA1c). These result mean that it is possible that LHbA1c can bring about a pitfall on HPLC method in diagnosis of onset of FT1DM. Dear Editor,Fulminant type 1 diabetes mellitus (FT1DM) is characterized by the acute onset of diabetic ketoacidosis (DKA) soon after the development of typical diabetes symptoms in spite of a near‐normal hemoglobin A1c (HbA1c) level at the onset  and negative serum GAD antibodyA 59‐year‐old Japanese man was referred to our hospital due to hyperglycemia. He had appetite loss, general fatigue, and repeated vomiting for 3 days. The plasma glucose level was as high as 1,464 mg/dL. HbA1c was not detected with a high performance liquid chromatography (HPLC) method  . If his HbA1c level had been under 8.7%, we could have diagnosed him as having fulminant type 1 diabetes mellitus. The next day, we re‐examined HbA1c with a HPLC method, and his HbA1c was detected at 7.1% (plasma glucose was 212 mg/dL at that time) Figure . MoreoveThe quality of the methods for the determination of HbA1c has been greatly improved over the past decades, and most of the analytical interferences have been controlledOur patient was in a special condition of having severe hyperglycemia and a near‐normal HbA1c level just after the onset of fulminant type 1 diabetes mellitus. To the best of our knowledge, this is the first report showing that unstable HbA1c interfered with the diagnosis of fulminant type 1 diabetes mellitus. We think that HbA1c was not detected because LHbA1c interfered in this subject with the onset of fulminant type 1 diabetes mellitus. Therefore, while examination of HbA1c is important for the diagnosis of fulminant type 1 diabetes mellitus, it is possible that LHbA1c can interfere in the HPLC method in the diagnosis of the onset of fulminant type 1 diabetes mellitus.The authors declare no conflict of interest.Since this is a case report, but not a clinical study or animal study, ethics approval is not applicable.Approval of the research protocol: N/A.Informed consent: Written informed consent was obtained from the patient.Registry and the registration no. of the study/trial: N/A.Animal studies: N/A.