The model development was conducted using a dataset determined in respiration chambers or head boxes (n = 121). Then, gas measurements in the AMS as well as in the head box were carried out with six lactating cows fed one of three different levels of neutral detergent fiber (NDF) content, following a 3 × 3 Latin square experimental design. The obtained equation that is suitable for practical use on farms to predict CH4 was CH4 (L/day) = −507 + 0.536 live weight (kg) + 8.76 energy‐corrected milk (kg/day) + 5,029 CH4/CO2 . Results showed that the predicted values correlated positively with the observed values, the determined CH4/CO2 ratio increased with increasing dietary NDF content, and the detected eructation rate was in the normal range. On the other hand, the CH4/CO2 ratio was affected by the time interval between measurement and last eating before the measurement.The aim of this study was to develop prediction equations for methane (CH This latter approach is called the “sniffer method”  and HPU equivalent in CO2  with different levels of dietary neutral detergent fiber (NDF), a major dietary factor affecting CH4 emissions. This measurement in the head box was carried out under the similar condition as the AMS, to compare estimated CH4 emission with actual emission in the AMS. Using data from the second trial, the CH4 emissions derived from the built equations and the effect of the time interval between eating and gas measurements were evaluated.To evaluate the prediction methods for CH22.1n = 121) of Holstein lactating cows from nine experiments covering 18 different diets were used for model development. All data were collected with an open‐circuit indirect calorimetry apparatus with a whole‐body chamber or a head box at the NARO Institute of Livestock and Grassland Science  and CH4 conversion factor . The independent variables were dry matter intake (DMI kg/day), live weight , energy‐corrected milk yield (ECM), and CH4/CO2 ratio (L/L). The ECM was calculated in accordance with the equation by Tyrrell and Reid . To develop a useful prediction equation for commercial farms, the effects of temperature, humidity, experiment, and animal were treated as residual errors. Correlations among the independent variables were determined using the JMP 15.2.1 software.Single and multiple regression equations were developed using the generalized linear model of JMP 15.2.1 software . The dependent variables were CHand Reid ; ECM  = (5.6 × LW0.75 [kg] + 22 × ECM [kg/day] + 1.6 × 10−3 × days in pregnancy)/103  were calculated as CH4 = CH4/CO2 ratio × 180 × HPU × 24. Due to the lack of data on the days in pregnancy for each cow, pregnancy length was estimated using an open period of 126 days, which was defined as subtracting 280 days of gestation length from 406 days of a median calving interval in Japan .This experiment was carried out in a free‐stall barn equipped with an individual door feeder and two boxes of AMS with one‐way traffic  in the experimental barn of the Institute of Livestock and Grassland Science, NARO. Six multiparous Holstein cows  were randomly assigned to a 3 × 3 Latin square design with three dietary treatments of different NDF level . Each experimental period was 21 days, consisting of a 16‐day adaptation period and a 5‐day data‐collection period. The PMRs were formulated to provide three levels of NDF content  three times daily . Additionally, the cows were offered 0.33 kg (as feed) of commercial concentrate  at the 13:00‐h feeding and at each milking in the AMS. Therefore, the cows consumed a total of 1.0 kg (as feed) of commercial concentrate daily. Water and mineral blocks  were freely accessed.During the last 5 days of each experimental period, the amount of refusals was weighed, and representative samples were collected daily before feeding at 10:00 h and kept in the refrigerator. Each daily sample of refusals was mixed for cows in each period, and the samples were collected. The samples of offered diets and refusals were dried at 60°C in an air‐forced oven for 48 h, and then ground through a 1‐mm mesh using a Wiley mill  for further analysis. Stored data for individual milk yields were collected from the AMS. Milk samples were automatically collected from the evening of Day 17 to the morning of day 21. The LW of cows was measured before morning feeding on the initial day of the experiment, then on Days 7 and 21 in each experimental period. Rumen fluid was collected orally using a catheter  before the morning feeding on the last day of each experimental period and filtered through 4 layers of cheese cloth; pH was determined using a glass‐electrode pH meter , after which the fluid was stored at −40°C for lab analysis.The time spent eating and ruminating by each cow was recorded using a neck‐tag device, including an accelerometer and a barometric pressure sensor . The device detects eating, ruminating, moving, standing, or lying, and then adds up time spent on those activities during each 10 min; the activity with the most time during the 10 min was defined as the dominant activity of each 10 min. The chewing time of each cow was recorded every 10 min and used for analysis.2.2.24 and CO2 analyzers  or a multigas infrared analyzer . Layout of the gas collection system is provided in 4 (0.193%) mixture, and a nitrogen‐balanced CO2 (1.92%) mixture. To obtain the background gas concentration, measurements were performed for 5 min before or after milking. The average CH4 and CO2 concentrations during a 5‐min period were used for background correction. Additionally, to eliminate data during which the cow's head was far from the feed bin, CH4 and CO2 data in each 1 s were removed if the difference between the detected CO2 concentration and background concentration was lower than 500 ppm. After background correction (sample gas concentration minus background gas concentration), CH4 and CO2 were averaged at each visit, and consequently, the CH4/CO2 ratio was obtained for the CH4 emission prediction. Separately, the eructation rate, defined as the peak number of CH4/CO2 ratio per minute calculated with CH4/CO2 ratio every 1 s during the visit, was determined with a custom Python script using the SciPy module (http://www.scipy.org/).Gas collection during milking in the AMS was carried out on Days 17–21 of each experimental period. Air around the feed bin in the AMS was vacuumed with the pump (approximately 6.5 L/min). Filtrated and dehumidified sample gas was sent to the infrared CH2.2.34 and CO2 emissions from cows were measured in two individual tie‐stalls (L1600 × W1170 mm) equipped with a ventilated caloriemeter using a head box (W980 × D900 × H2030 mm) in the experimental barn located next to the free‐stall barn. During 13:30 and 15:00 h of Days 18 and 21 of each experimental period, the cows were brought to the tie‐stall, and their gas emissions were measured for 15 min. To be a similar condition to the gas measurement in the AMS, cows were fed 0.33 g (as fed) of concentrate during measurement in the head box, whereas not fed the concentrate at the 13:00‐h feeding. The measurements were repeated four times during each period for each cow. The cows were returned to the free‐stall barn immediately after the measurement.The CH4 and CO2 analyzers  via a filter and dryer. The signals from the flowmeter and gas analyzers were converted to the flow rate and gas concentration with the I/O system (CPU‐CA20(FIT)GY; Contec CO., Ltd.) every 1 s. CH4 and CO2 emissions per minute were calculated by multiplying the vacuum gas flow  by the difference between the gas concentrations in the vacuumed air and those in the background gas that was measured before the gas measurement of cows. The total volume of emitted CH4 and CO2 during 15 min was used to calculate the CH4/CO2 ratio. Daily CH4 emissions were defined as the product of 1440/15 and total CH4 emissions over 15 min. The analyzers were calibrated daily using nitrogen (99.999%), a nitrogen‐balanced CH4 (0.193%) mixture, and a nitrogen‐balanced CO2 (1.92%) mixture. Prior to the experiment, the CO2 recovery test was conducted three times using 99.999% CO2 gas. The recovery rates of the two head boxes were 102.0% ± 1.57% and 100.5 ± 1.76%. The principles of the head box system, measurement, and calibration have been described elsewhere . Sample gas was collected from vacuumed gas and sent to the CH2.2.43PO4 on 80/100 mesh Chromosorb W . Milk samples were analyzed for fat, protein, and lactose concentrations by infrared spectroscopy .The dry matter  and chemical components of the diets and refusals were determined. The ether extract, Kjeldahl N, and crude ash values were determined according to Association of Official Analytical Chemists (AOAC)  and the 2.2.54 emission estimates from prediction equations using variables obtained from the present feeding trial were analyzed using the MIXED procedure of SAS. The model included the fixed effect of diet treatment and the random effects of square and cow within the square. The linear mixed model was used for the analysis of CH4/CO2 ratio, CH4 and CO2 concentrations, and eructation rate, which were collected in the AMS, using the MIXED procedure with the fixed effect of time interval between the measurement in the AMS and the end of the last eating before measurement, interaction of the time interval and diet treatment, diet treatment, and the random effect of square and cow within square. For those analyses, the covariance structure that resulted in the lowest Akaike's information criterion was chosen. The main effects of diet were examined using Tukey's multiple range test. Significance was declared at p < 0.05 and tendency when 0.05 ≤ p < 0.10. The association between observed and predicted CH4 emissions, MCF, and CH4/CO2 ratio was examined using the REG procedure in the SAS software.All data and CH33.14/CO2, and CH4 emission in dataset were 147 ± 69.1 day, 16.7 ± 3.68 kg/day, 27.4 ± 6.78 kg/day, 0.088 ± 0.0119, and 471 ± 99.9 L/day, respectively  correlations between independent variables for model development were found between LW and DMI (r = 0.51), LW and ECM (r = 0.32), and DMI and ECM (r = 0.80). The fitness of the model consisting of the DMI as the sole independent variable  and including LW and ECM  as variables were not shown, because of a little model improvement, considering practical utility. Moreover, the addition of LW as an independent variable to Equations R2 and a decrease in the RMSE  of the variables in Equation 4 emissions (<1.4). The volume of CH4 emission is primarily affected by the DMI  in the prediction equation, although a lower value of 174 L/h/HPU was reported for cows in the early lactation period  and HF (p = 0.053). Similar to the results of CH4 emission, the observed MCF was lower for cows fed the LF diet than for cows fed the HF diet. Daily CH4 emissions in the present study that were obtained from extension of measurement during only 15 min immediately after eating would be higher than actual daily CH4 emissions, which were measured over 24 h. In fact, CH4 emissions in the head box were higher than the predicted CH4 emissions using equations including GEI, dietary NDF and EE content, LW, and milk fat content as individual variables by Moraes et al. , respectively, for PMR, and 31.2%, 36.5%, and 46.3%, respectively, for PMR plus concentrate in the AMS  and the end of last eating before the milking, whereas CO2 concentration did not change with time after eating, resulting in a decrease in the CH4/CO2 ratio with time after eating. These decreasing ratios were not affected by the diet treatment. This effect of the time interval after eating would result in a lower CH4/CO2 ratio in the AMS compared with that determined in the head box  and that in the AMS adjusted at 0 h after eating (Y) was 0.92, showing that the values in the AMS immediately after eating were still 8% lower than those in the head box . The addition of LW to the model consisting of the CH4/CO2 ratio and DMI as a variable  was in the general range of 0.7 and 1.5 times per minute (summarized by Pickering et al., 4 emissions, the best fit and most useful models requiring no DMI measurement were the equations using HPU and Equation 4/CO2 ratio to eliminate the effect of the time interval after eating and derive the daily average. Intervals of feeding, measurements at various times of day, multiple measurements, or data correction using the present model based on time after eating or Fourier series approach (Løvendahl & Bjerring, 4/CO2 ratio and ECM as variables in the present equation without the measurement of GEI (Equation 4/CO2 ratio. The combination of the sniffer method and proposed models should be available for the evaluation of the effect of diet on CH4 emissions or for the evaluation of CH4 emission inhibitors.In conclusion, to predict CHEquation , but it All authors declare that they have no conflicts of interest.Table S1 Information for individual studiesTable S2 Characteristics of the dataset used for model developmentDiagram S1. Measurement system of methane to carbon dioxide ratio in the breath during milking.Figure S1 Diurnal changes in average eating time for each hour of each treatment. Black, dotted and grey lines show eating time in cows fed LF, MF or HF diet, respectively. The diets were offered at 10:00 h, 13:00 h, and 17:00 h. Black and grey two‐way arrow show duration of gas measurement in the head box and milking time permitted, respectively.Click here for additional data file.


Studying the creep–fatigue interaction of the coarse-grained soil (CGS) is very important for safety assessment and disaster prevention in subgrade engineering. Current research work is mainly focused on single creep or fatigue deformation. In this paper, a new creep–fatigue interaction model is established to predict the creep–fatigue interaction deformation of different gradation CGS based on the rheological mechanics and the interactive relationship between creep and fatigue complex compliance method. Triaxial creep–fatigue interaction tests of different gradations CGS under different average stresses and frequencies were conducted to verify the new creep–fatigue interaction model. Research results show that for the creep–fatigue and fatigue–creep interaction, the fatigue deformation is always larger than the creep deformation under the same stress level. For the creep–fatigue multi-interaction, the second creep and fatigue deformation are always smaller than the first creep and fatigue deformation. The results of the triaxial creep–fatigue interaction tests verify the validity of this new model. Coarse-grained soil (CGS in short) is a mixture of pebble, sand and clay, etc. ,2, and iCurrently, there are two main creep–fatigue loading forms: the simultaneous superposition of creep and fatigue loads ,11 and aIn this paper, two new interaction parameters are proposed to establish the new creep–fatigue interaction model based on rheology mechanics and the relationship between the creep and fatigue complex compliance. The interaction parameters were determined by the triaxial creep and fatigue tests, and the new interaction model was verified by the predicted and tested results of the triaxial creep–fatigue interaction tests.σ1> σ3, σ1 and σ3 are axial and confining stresses), where the interaction order can be the creep first followed by fatigue , or the fatigue first followed by creep . For each creep–fatigue interaction process, the creep stress  is applied to the CGS for a period of time (t = t1) and unloaded to be σ1 = σ3, and then the fatigue stress in terms of semi-sine  is applied to the CGS for a period of time (t = t2 − t1). Let the creep deviatoric stress (cσ − σ3) be equal to the average deviatoric stress of the fatigue cycle /2) since in order to establish a relationship under the same stress factor.In order to study the creep–fatigue interaction for the CGS deformation, it is necessary to seek a creep–fatigue interaction parameter to link up the two loading processes.J(t) and fatigue compliance J(ω), where ℱ is Fourier transformation and ℱ−1 is inverse Fourier transformation.In rheologic mechanics, there exists a relationship of Fourier equivalent transformation between the creep compliance aσ = cσ [J(t) and J(ω) cannot be equivalently transformed by Equation (1). For modifying Equation (1) to obtain the actual equivalent transform relationship between J(t) and J(ω) of the CGS, J(ω) is divided into a real part rJ(ω) and imaginary part iJ(ω), and J(t) can also be in terms of its real part rJ(t) and imaginary part iJ(t) by Fourier transform.Since test results show that the CGS has larger fatigue deformation than creep deformation under σa = σc , J(t) ank and g, define the matrices A1×2 = (rJ(t) iJ(t)), B1×2 = (rJ(ω) iJ(ω)) and M2×2 =rJ(t), iJ(t)) and fatigue (rJ(ω), iJ(ω)) compliances, i.e., the new creep–fatigue interaction model:Considering that both the creep and fatigue compliances have real and imaginary parts, define two new creep–fatigue interaction factors For simplifying the expression, that is Equation (5):rJ(t), iJ(t) and rJ(ω), iJ(ω)) are obtained by the following creep and fatigue tests, respectively, k and g can be calculated by Equation (4).Since k and g: (1) conduct the triaxial creep tests (creep stress cσ) and the fatigue tests (fatigue average stress aσ) under the same average stress condition (cσ − σ3 = aσ) to determine creep compliance and fatigue compliance; (2) calculate the creep and fatigue real and imaginary parts of compliance; and (3) compare the real parts and imaginary parts of the creep and fatigue compliance to determine the k and g.In order to determine the creep–fatigue interaction parameters γ) (with high elastic modulus), sand and clay , as listed in w)–dry density (dρ) curves for three different gradations of CGS, respectively. The CGS specimens are cylinders of Φ300 mm × 600 mm and prepared by the layered compacting method (According to the Code for the Design on Subgrade of Railway in China (TB10001-2005), three different gradations of CGS were prepared by different mass ratios of pebble (g method .σ3 was 0.2 MPa (σ3 < σ1). Let the average stress of fatigue test a = σcσ − σ3. There were a total of 9 creep tests (3 specimen × 3 stress) and 27 fatigue tests (3 specimen × 3 stress × 3 frequency). For each test, three identical specimens were prepared and there were 108 specimens in total. During the creep tests, the strain was recorded every 2 min to obtain the creep curves. During the fatigue tests, the strain and stress were recorded 10 times in one cycle.Triaxial compressive creep and fatigue tests were conducted on the TAJ-2000 triaxial testing system . Table 2(1)Creep parameters under different stressJ(t) can be obtained by fitting the tested creep curves:E1, E2, η1, η2 are creep parameters of the Burgers model.In this study, the Burgers creep model (cε) under different time (t) curves for different constant stress  for the CGS specimens of three different gradations, as well as their fitted curves by the Burgers creep model (Equation (14)). R2 > 0.995). It is seen that all the creep curves have three stages: the instantaneous deformation stage (t = 0), attenuation deformation stage (with decreasing slope), and stable creep deformation stage (with a constant slope). Obviously, for the same gradation of the CGS specimen, cε is increased with the increase in cσ. While for the different gradations of the CGS specimen, cε is increased with the decrease in pebble content γ since a smaller γ means more clay content with stronger rheological properties.(2)Unified creep parameters for different creep stresses and gradationscσ) or the deviatoric stress (σ = cσ − σ3), but also on the gradations . In order to obtain a unified creep parameter relationship  to describe the creep behaviors for different gradations of CGS under different stresses, the nonlinear regression is needed. Since the Burgers model .It was found in rs model  is the ME < 10%, which proves the validity of Equation (6). Based on Burgers creep model and its parameter (cε–t) under different creep stresses for three gradations of CGS. It is seen that they are almost the same at the instantaneous deformation stage. In the attenuation deformation stage, their differences increase with time but tend to be unchanged in the stable deformation stage. In a word, they are approximately close to each other, which again proves the validity of Equation (6).arameter , Figure (1)Fatigue compliance formulaefσ and fε are the peak stress and strain of fatigue, δ is the phase angle and |J(ω)| is the module of fatigue compliance.When the sine wave is adopted as the fatigue load:Equations (7) and (8) can be rewritten asSubstituting Equation (9) into Equation (10) yields the strain–stress relationship, i.e., the elliptic Equation:δ can be determined by Equation (11).Since this elliptic Equation is obtained by fitting the data of a one-cycle fatigue test, the phase angle rJ(ω) and imaginary parts iJ(ω) of the fatigue compliance can be calculated by Equation (8) and the relationship of the phase angle δ and the fatigue compliance [Therefore, the real parts mpliance  are as f(2)Experimental determination of fatigue complianceσ1 = σ3, and recorded 10 points of the stress and strain in one cycle by the test system. Dynamic loading adopts the stress-controlled cyclic loading method, applying semi-sine wave axial cyclic stress, and the fatigue load was applied on the specimen after the balance of f for the same average stress aσ) and the S2 specimen (under different σa for the same f) for a one-cycle load for example. A represents the energy dissipation in one cycle, Equation (13) [A slightly decreased with the increase in f, that is, the frequency effect is much smaller, while A was almost multiplied as it increased with the multiplied increasing of aσ for the same gradation CGS. Additionally, A increased with the decrease in pebble content (γ) for different gradations of CGS, because a greater γ means that the CGS specimen had weaker rheological properties; therefore, the smaller γ represents the stronger rheological properties which could dissipate more energy in one cycle. The fatigue compliance (rJ(ω), iJ(ω), J(ω) and δ) can be calculated by Equations (7)–(13).ion (13) ) obtainek and g can be determined by Equation (4) when the real part rJ(t) and imaginary part iJ(t) of the creep compliance J(t) is calculated by substituting Equation (5) with rJ(ω) and imaginary part iJ(ω) of the fatigue compliance iJ(ω) is calculated by Equation (12). aσ).The creep–fatigue interaction parameters f that the real part rJ(t) of creep compliance (representing the energy storage compliance) is unchanged while the imaginary part iJ(t) (representing the energy dissipation compliance) is deceased, which is the same as analytic results [rγ, J(t) is decreased but iJ(t) is increased, since a smaller value of γ means a greater clay content of the CGS specimen and thus stronger rheological properties with more energy dissipation in one cycle.It can be seen that with the increasing frequency  results . With thf, the real part rJ(ω) of fatigue compliance is unchanged while the imaginary part iJ(ω) is deceased. With the decrease in γ, rJ(ω) is decreased but iJ(ω) is increased.Similarly, with the increase in frequency k (corresponding to rJ(t) and rJ(ω)) is also unchanged while g (corresponding to iJ(t) and iJ(ω)) is increased with the increase in frequency f. With the decrease in γ, k changes non-monotonically while g is increased.Obviously, the creep–fatigue interaction parameter ε–t) curve can be calculated by the following steps: (1) calculate rJ(t) and iJ(t) by Equation (2) to obtain the cε–t curve; (2) calculate rJ(ω) and iJ(ω) by Equation (12) to obtain the fε–t curve; (3) according to the creep–fatigue interaction factors k and g in ε–t curve.Take the creep–fatigue interaction deformation of CGS as an example (the fatigue–creep interaction deformation is vice versa): the strain–time k and g) are proposed to establish a new creep–fatigue interaction model based on both the rheologic mechanics and the interactive relationship between creep and fatigue complex compliance, in order to predict the creep–fatigue interaction deformation of CGS.New transformation parameters ((2)k is almost unchanged with the frequency (f) and changed non-monotonic with the pebble content (γ). The creep–fatigue interaction factor g is increased with both f and γ. The creep strain and fatigue strain of the creep–fatigue and fatigue–creep interaction are increased with the increase in average stress (aσ)The creep–fatigue interaction factor (3)For the different interaction orders (creep–fatigue interaction or fatigue–creep interaction), the fatigue deformation is always larger than the creep deformation under the same stress level because of the dynamic effect.(4)For the creep–fatigue multi-interaction, the second creep and fatigue deformation is always smaller than the first creep and fatigue deformation because of the compaction effect.(5)The new creep–fatigue interaction model is proved valid by the good agreement between the predicted results and test results of the triaxial creep–fatigue interaction. It can be further developed for predicting the creep–fatigue interaction of multi-layered coarse-grained soil.


Although the diylide‐substituted cation forms spontaneous from the chlorophosphine precursor, the monoylidylphosphenium ions required the addition of a halide‐abstraction reagent. The molecular structures of the cations reflected the different degrees of electron donation from the ylide to the phosphorus center depending on the second substituent. Molecular orbital analysis confirmed the stronger donor properties of the ylide systems compared to NHPs with the mono‐ylide substituted cations featuring a more pronounced electrophilicity. This was mirrored by the reaction of the cations towards gold chloride, in which only the diylide‐substituted cation [Y2P]+ formed the expected LAuCl]+ complex, while the monoylide‐substituted compounds reacted to the chlorophosphine ligands by transfer of the chloride from gold to the phosphorus center. These results demonstrate the tunability of ylide‐functionalized phosphorus cations, which should allow for further applications in coordination chemistry in the future.Although N‐heterocyclic phosphenium (NHP) cations have received considerable research interest due to their application in organocatalysis, including asymmetric synthesis, phosphenium cations with other substitution patterns have hardly been explored. Herein, the preparation of a series of ylide‐substituted cations of type [YPR] Switching selectivity: The isolation and coordination chemistry of a series of ylide‐substituted phosphenium cations is reported. The monoylidyl cations exhibit a distinctly higher reactivity and electrophilicity, thus yielding a chlorophosphine gold cation via chloride shift from gold to phosphorus. In contrast, the diylidyl cation formed the phosphenium AuCl complex, demonstrating the tunability of the phosphenium cation reactivity. Since the first reports on NHPs in 1970sPhosphenium cations are compounds of type RA this delocalization even results in a partial phosphide character at the central P atom PCl (Y=ylide) can spontaneously dissociate into the phosphenium cations.9, 10 In the course of our research program on ylidic compounds we became interested in the stabilization of reactive main group compounds.2 a reported by Schmidpeter.4 was targeted. With only one π‐donating ylide substituent, we expected these phosphenium cations to be more reactive and stronger acceptor ligands. All three ligands were prepared via a chlorosilane elimination protocol by reaction of the silyl‐substituted ylide 1 with PCl3 and the dichlorophosphines (PhPCl2 or CyPCl2), respectively  and at 160 ppm (for 3b), respectively. In the molecular structures  A) shows a 55 pm longer P−Cl bond than 3a (2.191(1) A). Such varying P−X distances have been discussed in the past as snapshots of the pending dissociation.We began our studies with the synthesis of the diylidylphosphenium cation 3 was accomplished with AlCl3, thus delivering the cations 4 as colorless solids in good yields .2 and 4 were characterized by multi‐nuclear NMR spectroscopy, elemental and single‐crystal X‐ray diffraction analysis. 31P{1H} NMR spectroscopy shows that the cyclohexyl‐substituted cation 4b features the most deshielded signal  and presumably is the most nucleophilic species with the strongest acceptor properties. Interestingly, the 2JPP coupling constants increase from 4b to 4a and 2 and become significantly smaller compared to the chlorophosphine precursors. Overall, the mono‐ylidylphosphenium cations exhibited are considerably higher reactivities and more readily decomposed in solution. However, in the solid state they could be stored for weeks at −20 °C.With the chlorophosphines in hand, we next addressed their conversion into the corresponding phosphenium cations. Chloride abstraction from 2b, 4a and 4b with BF4− or AlCl4− as counter‐anions were obtained by layering DCM solutions of the cations with cyclohexane.2b, the diylide cation features the longest C1−P2 distance of approx. 1.72 Å. The P2−C1 bonds in the monoylide phosphenium cations are considerably shorter, with the phenyl compound featuring the shortest distance of 1.673(5) Å. The reverse trend is found for the P1−C1 distances to the phosphonium group. With increasing π‐bonding between the ylide and the phosphenium center the electrostatic attraction to the phosphonium group decreases. Consistent with the C1‐P2 bonds, this results in the shortest C1‐P1 bond for 2 and the longest in the phenyl‐substituted compound, suggesting that the strongest ylide‐P bond is found in cation 4a. It is noteworthy that the phenyl substituent in 4a is not or only little involved in π‐interaction with the central phosphorus atom. The same is true for the phenyl groups in the ylide‐backbone. While the two ylide groups in 2b form a fully delocalized π‐system over the planar P−C−P−C‐P linkage, the phenyl group in 4 a is oriented out of the P1−C1−P2 plane with dihedral angles of approx. 20°. Consequently, no changes in the C−C bond lengths are observed within the phenyl groups of 4a compared to that in 3a, which contrasts for example the quinoidal structure reported for the borinium cation Mes2B+.2 and 4 are observed in the solid‐state and in solution.2 leads to the conformer with the smaller phenyl groups facing each other.Single crystals for +2 is the by far weakest acceptor in this series of compounds. While the LUMO in all cations represents the empty p orbital at P2 and thus is always predominantly localized at the phosphenium center, the HOMO (except for 4b) displays a π‐symmetric orbital delocalized over the substituents with a strong contribution by the ylidic carbon centers. In general, the energy of the molecular orbitals representing the lone pair at the phosphenium center . Calculations of the molecular orbitals show that the ylide‐substituted phosphenium cations feature energetically high‐lying LUMOs  and hence are less electrophilic/weaker acceptors than NHPs AuCl (tht=tetrahydrothiophene) led to the clean formation of the expected gold chloride complex [2b‐AuCl]BF4 , which was found to weakly bind to the ylidic P−C bond in the solid state. A similar observation was made by Gudat with the cyclic diylide phosphenium cation A (see the Supporting Information for details).5b is characterized by a highfield shift in the 31P{1H} NMR spectrum for P2 from 290.4 in 2b to 229.2 ppm in 5b. The molecular structure AuCl, the signal of the central phosphorus atom experienced a distinct high field shift by more than 250 ppm in the 31P{1H} NMR spectrum, giving rise to a signal at 93.3 ppm for 4a and 73.2 ppm for 4b, respectively. This shift is much more pronounced than in case of 2 b, suggesting considerable changes in the ligand structure. This was confirmed by XRD analysis of the complex formed with 4a, which revealed the formation of complex 6a AuCl delivered the corresponding gold chloride complexes 7, which could both be isolated in moderate yields of approx. 40 % and unambiguously characterized, including XRD analysis  did not lead to the abstraction of the chloride at the phosphorus center in 6 to form the corresponding dication. The same holds true for the cationic gold complex 5b.6a could be obtained by slow vapor diffusion of pentane into a saturated dichloromethane solution. In the crystal  to 1.700(7) Å, thus accounting for an increasing shift of electron density from the ylidic carbon atom to the phosphorus  center. The C1‐P1 distance increases in the same sequence of compounds.Single crystals for ipso distance is shorter in the cationic gold complex 6a (3.160 Å) than in the neutral AuCl complexes 7 which exhibits an Au−Cipso distance of 3.220 Å. Also, the cationic Au complex 5b with the diylidylphosphenium ligand shows a short distance of 3.132 Å. Such short distances have been attributed to attractive arene gold interactions and have often been discussed in the context of gold catalysis and their importance for stabilizing catalytically active cationic gold species.6a thus indicating a weak attractive interaction. It is important to note that such interactions have also been suggested for gold complexes of ylide‐substituted phosphines (YPhos) and thought to be one reason for their high catalytic efficiency. clearly indicated the formation of the corresponding chlorophosphines 3, for example with two doublets at δ=78.4 and 17.4 ppm with a coupling constant of 9.2 Hz for 3a. In the case of [Rh(cod)Cl]2 however, the formation of a phosphenium complex was observed as evidenced by a considerably downfield‐shifted signal in the 31P{1H} NMR spectrum for the P(III) center . Although all attempts to isolate these complexes failed, single crystals were obtained from the crude reaction mixture of 4b in CD2Cl2, which confirmed the still intact Rh−Cl bond 2 complex with a bisnaphthalene framework,2P]+ and the monoylide cations clearly shows that a certain stabilization of the cation is required for selective applications in transition metal chemistry. One ylide moiety as sole π‐donating substituent seems to be insufficient so that future research endeavors should focus on the diylidyl or monoylide systems with a further π‐donor substituent.Unfortunately, all attempts to apply the cationic gold complexes as catalysts in hydroaminations or enyne cyclization reactions remained unsuccessful. This can probably be attributed to the partial phosphide character and the resulting lower electrophilicity compared with other cationic gold species as well as the sensitivity of the complexes. To further investigate the coordination properties of the monoylide‐substituted phosphenium cations 2P+ forms spontaneously from the corresponding chlorophosphine in solution, whereas the mono(ylidyl)phosphenium ions are only accessible by halide abstraction. The stronger electrophilic nature of the mono‐ylide substituted compounds was also confirmed by computational studies and led to a different coordination chemistry compared to [Y2P]+. Although the bis(ylidyl) cation formed the expected cationic LAuCl complex, the monoylide systems reacted with (THT)AuCl by chloride transfer from gold to phosphorus, thus resulting in the formation of a cationic chlorophosphine gold complex. Crystallographic studies on the phosphenium cations and their metal complexes reflected the electron donation from the ylide to the phosphorus center. As such, the P−C distances in the ligand backbone changed depending on the second substituent at phosphorus and the presence of a metal center.The synthesis of three phosphorus cations stabilized by two or one ylide moiety is reported. Due to the strong electron‐donating ability of the ylide group, these formal phosphenium cations are considerably more electron‐rich than N‐heterocyclic phosphenium cations but can be tuned by variation of the second substituent bound to the phosphorus center. Thus, the bis(ylidyl)phosphenium cation YOverall, these studies clearly demonstrate that ylide groups efficiently stabilize cationic phosphorus species and allow a tuning of their properties by changing the molecular design. Although systematic studies on the impact of the substituents in the ylide backbone on the stability and reactivity of phosphenium cations are missing, it can be assumed that a further control of reactivity should be possible.3I), 2121588 (for 1), 2121592 (for 2[BF4]), 2121599 (for 3 a), 2121593 (for 3 b), 2121594 (for 4 a), 2121596 (for 4 b), 2121589 (for 5 a), 2121600 (for 5 b), 2121598 (for 7 a), 2121595 (for 7 b), 2121590 (for 6 a), 2121591 (for [4 b⋅Rh(COD)Cl]AlCl4)2121597 (for HYSiMe contain(s) the supplementary crystallographic data for this paper. These data are provided free of charge by the joint Cambridge Crystallographic Data Centre and Fachinformationszentrum Karlsruhe Access Structures service.Deposition Number(s) The authors declare no conflict of interest.1As 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.


The method used Zeng's Rh(CAAC) carbene catalyst 4 in the hydrogenation following the protocol developed by Glorius. The resultant Janus pentafluorocyclohexylacetate methyl ester 16 was converted to the corresponding alcohol 18, aldehyde 13, bromide 29 and azide 14 through functional group manipulations, and some of these building blocks were used in Ugi‐multicomponent and Cu‐catalysed click reactions. NBoc protected pentafluoroarylphenylalanine methyl ester 35 was also subject to an aryl hydrogenation, and then deprotection to generate the Janus face β‐pentafluorocyclohexyl‐alanine amino acid 15, which was incorporated into representative members of an emerging class of candidate antiviral compounds. Log P measurements demonstrate that the all‐cis 2,3,4,5,6‐pentafluorocyclohexyl ring system is more polar than a phenyl ring. In overview the paper introduces new building blocks containing this Janus ring and demonstrates their progression to molecules typically used in bioactives discovery programmes.Monoalkylated derivatives of the unusually polar all‐ cisJanus all‐ 2,3,4,5,6‐pentafluorocyclohexyl building blocks have been incorporated into medicinal chemistry type products. These cyclohexanes have polarized faces and represent a unique motif for medicinal chemistry. The paper introduces a range of new accessible building blocks which can be elaborated into a diversity of drug type structures demonstrating their wider utility for exploration in bioactives discovery chemistry. The regiospecific nature of the defluorination was established by X‐ray crystallography of 18  were amenable to X‐ray structure analysis as shown in Figure cis‐pentafluorocyclohexane ring on lipophilicity of this product class, Log P values were determined for products 20–22 and compared to their corresponding analogues 26–28 with a phenyl ring in place of the 2,3,4,5,6‐all‐cis‐pentafluorocyclohexane rings. The Log P values were determined by HPLC (acetonitrile/water) as described previously[cis 2,3,4,5,6‐pentafluorocyclohexyl moiety increases hydrophilicity, with the Log P decreasing by 0.4–0.65 Log P units. This trend is consistent with that previously observed for the phenyltetrafluorocyclohexyl motifs,cis‐1,2,3‐trifluorocyclopropyl motif,24 and it suggests that this aspect reinforces its utility as a candidate isostereTwo of these products  and the reaction of 51 upon reaction with 42 gave a 1 : 1 mixture of 52. Knowing this, the de protection of Boc for the synthesis of 53 was performed in ethanol and achieved pure 53.A potentially interesting building block of wide utility is amino acid 45, 48, 52 and 53. The values were in the range Log P ∼1.5–2.0. These are low values and in a good range for candidate drug development, and they indicate again that the all‐cis 2,3,4,5,6‐pentafluoro‐cyclohexyl ring system possesses good properties for bioactive molecule discovery. In the event the candidate antivirals 45, 48, 52 and 53 were assessed for their antiviral activity against Zika virus and the SARS‐CoV‐2 virus, however they did not show any activity in these assays.Log P values were determined10, 1616 and the NBoc‐protected methyl ester of pentafluoroaryl phenylalanine. In particular a series of candidate bioactives were prepared from cyclohexylacetaldehyde 13 and amino acid 15. Aldehyde 13, was used to prepare a range of Ugi multicomponent products and the amino acid to access direct analogues of known peptidomimetic aldehydes and esters. Comparative Log P determinations between phenyl and all‐cis 2,3,4,5,6‐pentafluorocyclohexyl analogues illustrates an increase in hydrophilicity for the fluorocyclohexanes and suggests a utility for this motif in bioactives discovery programmes. These results should encourage the further exploration of this motif in medicinal chemistry.Several building blocks have been prepared by direct aryl hydrogenation of all‐ 2,3,4,5,6‐pentafluorophenyl acetaldehyde 14), 2098748 (15), 2098749 (17), 2098750 (18), 2098751 (19), 2098752 (20), 2098753 (25), 2098754 (31), 2098755 (34HCl), 2098756 (37), 2098757 (53)2098747 ( contain(s) the supplementary crystallographic data for this paper. These data are provided free of charge by the joint Cambridge Crystallographic Data Centre and Fachinformationszentrum Karlsruhe Access Structures service.Deposition Number(s) 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.


To this end, a dictionary is used that takes into account the slice profile as well as T2 relaxation along the echo train. For validation, the retrieved B1+ map is compared with the actual flip angle imaging (AFI) method in a phantom . Moreover, the phase of the first echo reflects the transceive phase. Overall, the CP echo train yields an estimate of the complex‐valued B1+, allowing electrical properties tomography with both permittivity and conductivity. The presented method is evaluated in phantom scans as well as for in vivo brain at 3 T.A Carr‐Purcell (CP) echo train generates pronounced flip‐angle dependent oscillations that can be used to estimate the magnitude of B1+ maps retrieved from the CP echo train and the AFI method show excellent agreement, and both the reconstructed estimated permittivity (79 ± 3) ε0 and conductivity (0.35 ± 0.04) S/m values are in accordance with expectations. In the brain, the obtained electrical properties are also close to expectations. In addition to the retrieved complex B1+ information, the decay of the CP echo trains also yields an estimate for T2.In the phantom, the obtained magnitude B1+ magnitude and phase estimations, and therefore allows for full reconstruction of the electrical properties.The CP sequence can be used to simultaneously provide both B Even though methods to estimate the complex‐valued B1+ have been reported,1+ amplitude, one generally reverts to existing B1 mapping methods.1 mapping value speed over resolution. In the context of this work, a method termed B1‐TRAP 1 field from the oscillations of the transient phase of a coherent steady state sequence. It can thus be expected that a train of spin echoes should exhibit similar signal oscillations as a function of the flip angle. In fact, this flip angle–dependent oscillatory behavior for multi‐spin‐echo sequences, such as the ones suggested by Carr and Purcell (CP)EPT exploits the relation between the EPs and the electromagnetic fields derived from the Maxwell equations. In fact, EPs depend on the curvature (second‐order derivative) of the complex RF transmit field B1+ inside 1+ magnitude can be retrieved from a CP echo train in conjunction with an estimate for the transceive phase. As a result, a CP sequence offers a unique setting for EPT. Moreover, the enveloping decay of the CP echoes offers an estimate for the transverse relaxation time T2.In this work, we will show that the local B2α denotes the flip angle of the refocusing pulse; Φ stands for the RF phase; and TE denotes the echo time . In the CP scheme, all excitations are applied along the same axis; thus, Φ0=Φ1 applies.Φ0‐Φ1=90∘ applies.A multi‐spin‐echo sequence with equidistant echo spacing is shown in Figure 2.1n th echo intensity of CP, as well as CPMG, signals in the absence of relaxation from a vector model for the sequence’s pseudo steady state:2ϕ is the phase accumulation of an isochromat during one TR, and M0 is the equilibrium magnetization.The echo amplitudes for both the CP and CPMG sequence as a function of the flip angle has been studied in the past.1+ amplitude can be retrieved from the echo amplitudes of CP and CPMG echo trains. Using a generating functions formalism, Lukzen et aln→∞) of Equations Despite the compact forms of Equations n≳8. Equations α/2π. This is illustrated in Figure α=45∘ 3. This results in a slower signal decay in CP than in CPMG . Thus, a refocusing flip angle of 90° appears to be a good compromise for the purpose of B1 mapping and is chosen for the following experiments.The refocusing flip angle will determine the frequency of the measured signal  enters the reconstruction. To get an estimate of the transmit phase, the so‐called transceive phase assumption is frequently used.The phase of a spin echo is free from external disturbances such as field inhomogeneities. Consequently, with the first echo, the phase directly at the time of excitation will be restored. This phase corresponds to the so‐called transceive phase, as it contains contributions from both the transmit field and the receive field or sensitivity.Because the transceive phase is contained in the measurement, the uncertainty in the transceive map can be estimated by the inverse of the SNR of the spin‐echo magnitude image.2.41+ magnitude, the signal decay is governed primarily by the transverse relaxation time2.In this study, a dictionary is used to retrieve the frequency of the oscillating echo intensities. Although the frequency of the acquired signals depends on the local BMATLAB  using the configuration model toolkit (CoMoTk)2 values (taking into account slice profile effects). The slice profile was taken into account by simulating the effect of the RF pulses using the hard pulse approximation.1 was fixed at 1 second, as simulations showed negligible impact of common brain‐tissue T1 values on the signal. For T2, 21 logarithmically spaced points between 10 and 1000 ms were cubically interpolated to have a total of 41 points in this range. Then, the range of T2 was extended by 10 linearly spaced points between 1200 and 3000 ms. The relative B1 was varied linearly between 0.5 and 1.3 with steps of 0.01. Finally, the simulated CP signals were multiplied with n to compensate for the inherent CP decay  unless stated otherwise.Simulations and calculations were performed in 2.5Imaging was performed in a phantom and for in vivo brain at 3 T  using the body coil for transmission and the manufacturer’s 20‐channel head and neck coil for reception. Phase images from multichannel coil data were reconstructed using the manufacturer’s “adaptive coil combine” method. To evaluate the appropriateness of the multichannel coil combination method for EPT, phantom scans were also performed with a 1H/23Na transmit/receive birdcage coil . If not otherwise explicitly stated, scanning was performed with the multichannel head and neck coil. In vivo human MR scans were approved by the local ethics committee, and informed written consent was obtained before the human experiments.z = 43.98 mT/m·ms and A = 24.75 mT/m·ms), as well as along the frequency encoding direction (Sx = 17.89 mT/m·ms and B = 46.17 mT/m·ms)  method.α was estimated from the signal ratio r=S2/S1 and the TR ratio n=TR2/TR1=5 using α≈arccosrn‐1/n‐r.For validation purposes, the phantom’s BSkull stripping for the figures was performed using the standard software package FSL .2.6εr and the conductivity σ was based on the homogeneous Helmholtz equation,Calculation of the relative permittivity ε0 is the vacuum permittivity; μ0 is the magnetic vacuum permeability; and ω is the Larmor frequency. The leading (first) terms in these expressions relate the permittivity and the conductivity to the curvature of the B1+ magnitude and its phase, respectively. The second terms can be seen as a correction, which is on the order of 10%–20% for typical EPs of human tissues at field strengths up to 3 T.B1+ is retrieved from the signal’s oscillatory behavior , and φ+ is estimated directly from the phase image of the first echo, using the transceive phase assumption.In Equations 2‐weighted image that was generated based on the received T2 map and the magnitude image of the first echo in the measurement.The Laplacian and gradients were estimated using the coefficients of a locally fitted second‐order polynomial, restricted to voxels with magnitude values similar to the center point of the window (within 15%).3α/2π /(mean B1) for every voxel. The “mean B1” corresponds to the voxel‐wise average of the B1,AFI and the B1,CP. The mean relative difference is calculated to be at −2.14% and is indicated in the figure together with the 95% confidence interval.Figure 1 maps, shown in coronal and transversal orientation, are shown for the AFI scan in Figure 1 maps are shown in Figure 0 is found for AFI, whereas for the CP approach a mean permittivity value of (79 ± 3) ε0 and a mean conductivity value of (0.35 ± 0.04) S/m is observed. A comparison of the results using either the birdcage coil or the multichannel receive coil is shown in Supporting Information Figure Example B1 maps based on the presented method are shown. In the field maps, a distinct asymmetry between the left and right brain hemispheres is visually notable. Figure 2 maps for the corresponding slices. The T2 maps are a direct result of the dictionary‐based reconstruction.After validation in the phantom Figure , the pre2‐weigthed magnitude image on which the EP reconstruction is based. Corresponding maps of the electrical properties, permittivity, and conductivity are shown in Figure 1 map  S/m values are in excellent agreement with the expected values ,Our results indicate that the transceive phase is properly estimated using the manufacturer’s “adaptive combine” algorithm for multichannel coil data , 73 ε0 (GM) and 84 ε0 (CSF), and the corresponding conductivity is expected to be about 0.34 S/m (WM), 0.59 S/m (GM), and 2.14 S/m (CSF).0 (WM), (69 ± 6 ε0) (GM), and (112 ± 14) ε0 (CSF)) are close to expectations. Overall, however, the permittivity map shows some inhomogeneity in brain tissues. It has already been reported that permittivity mapping at 3 T based on the Helmholtz equation is rather challenging in clinical acceptable scan times.For brain tissues at 3 T, the expected permittivity values are 52 ε2 map from the dictionary mainly separates fluids from tissue. Thus, in this work, we used both the proton density and the quantitative T2 map to generate a T2‐weighted image that offered the desired level of tissue contrast.Another source of error might arise from the use of a magnitude image to mitigate boundary errors in the reconstruction of the Laplacian.1 asymmetry introduces an erroneous region in the permittivity across the brain  method. E, Histogram showing the distribution of the obtained conductivity values in the range between 0 S/m and 0.8 S/m for both coils. In this range, the birdcage and the head and neck coil yield a mean conductivity value of (0.37 ± 0.09) S/m and (0.36 ± 0.10) S/m, respectively.Click here for additional data file.


The basic anions selected in this study with different basicity include sulfonate (Su), carboxylate (Ac), imidazolium (Im), and indolium (Ind). These ILs ([P66614]2[AA–R]) were applied to CO2 absorption. The results present that CO2 capacity increases first and then decreases later with the continuous increase in the activity of the anion site. Combined with CO2 absorption experiments, IR and NMR spectroscopic analyses and DFT calculation demonstrate that the ability of one site to capture CO2 would be suppressed when the activity of another site is much stronger. Thus, the cooperation of dual site-functionalized ILs and high CO2 capacity might be achieved through balancing the two sites to be equivalent. Based on this point, [P66614]2[5Am–iPA] was further synthesized by taking the advantage of the conjugated benzene ring. As expected, [P66614]2[5Am–iPA] showed capacity as high as 2.38 mol CO2 per mol IL at 30 °C and 1 bar without capacity decrease even after 10 times recycling performance of CO2 absorption and desorption.In this study, a variety of functionalized ILs with dual sites including amino acid group (AA) and basic anion (R) were synthesized to investigate the suppression and cooperation between the sites in CO 2 absorption by anion functionalized ILs with dual sites including amino acid group (AA) and basic anion (R) could be achieved through regulating the relative activation of two sites.Cooperative CO Unique physicochemical properties of ionic liquids (ILs) such as high thermal stability, low vapor pressure, and tunable properties make ILs suitable for CO2 absorption.2,3 Functionalized ILs, such as amine,4,5 azolium,6 phenolate,7 and carbene-based ILs8 were reported as potential CO2 absorption solvents owing to their electron-rich property, or the basicity of ILs. High CO2 absorption capacity is one of the performance evaluations of ILs. In this regard, a series of strategies, including tuning the basicity of the active sites,9–11 changing the steric hindrance of the ILs,12,13 utilization of entropic effects14,15 and hydrogen bond formation,16,17 were developed to enhance the CO2 absorption capacity. However, the CO2 capacity of ILs with single site was low compared to those multiple-sites, which have attracted attention to enhance the CO2 capacity.Rapid anthropogenic climate change caused by a large number of greenhouse gases is one of the most significant environmental problems in the world today.2 capacity as well as gas adsorption materials. Vaidhyanathan and Woo18 reported CO2 capture by an amine-functionalized nanoporous solid with cooperative sites for the low-pressure binding and large uptake of CO2. McDonald19 reported an energy-saving CO2 separation by small temperature or pressure swings via the cooperative insertion of CO2 in diamine-appended MOFs such as mmen-Mg2(dobpdc). It has been found that cooperative CO2 capture is a much feasible way to achieve high capacity and reversibility.20,21 Recently, cooperative sites were considered in designing ILs. Wang et al.22 synthesized hydroxyl-pyridinium based ILs with dual cooperative sites to fix CO2 for the delocalized π electrons, which enhanced by 85% of the capacity to 1.58 mol mol−1 IL. Similarly, the cooperation of Lewis acid–basic reaction and the hydrogen bond interactions of IL with CO2 were put to good use to improve CO2 capture with imidazolium ILs.16 Dai et al.23 found the dual sites of [P4442]2[IDA] could be activated by weakening the depression of amine and high capacity of 1.69 mol CO2 per mol [P4442]2[IDA] was achieved. Wang and Cui24 synthesized [P4442][Suc] with structural preorganization for improving the capture to 1.65 mol mol−1 IL of low-concentration CO2 as 10 vol% through multiple site cooperation, the capacity would be further enhanced to 2.21 mol mol−1 IL at 20 °C and 1.0 bar by tuning the anion substituent group.25 However, [apmim]26 with the active sites of imidazolium anion and amine group in cation, [aemmim][Tau]27 and [aP4443][AA]28 with an amine group both in cation and anion, [DAIL]29 with a dual amine group in cation as well as [Arg], [Lys], [AA–Im]-based ILs30,31 with a dual amine group in cation were reported as a CO2 absorbent but have capacity just up to equimolar similar to the ILs with a single site, which means one site might be suppressed or inactive. Mu27 thought that there is interplay of the dual amine in ILs, which might restrict their ability. As can be seen, cooperation is the key to the high capacity of ILs with dual sites,32,33 but the depression of one site is a common problem making the active site to be suppressed and have low CO2 capacity.Designing ILs with cooperative sites was considered as attractive to enhance the CO34 In this study, the interplay between dual sites was investigated; amino acids with binary acids are considered as an anion precursor to investigate the depression effects of CO2 absorption sites. Phosphonium ions [P66614] and [P4442] are selected as the cations. The structure of the used ILs is presented in 66614][AA] could capture CO2 efficiently via the reaction of an amine group with CO2 to carbamic acid. Indolium (Ind) and imidazolium (Im) ions are also good choices for CO2 absorption with high capacity, while carboxylate (Ac) anion prefers to react with CO2 and should be active to fix CO2 efficiently, sulfonate (Su) ion would not react with CO2. The results in this study indicate that the dual sites in ILs could cooperate and do their best in the CO2 capture if two sites have quite an activity; otherwise, the less active site would be suppressed by another site. Furthermore, [P66614]2[Am–iPA] was synthesized with equivalent dual sites to cooperative CO2 absorption, and the results showed that it presented high capacity as 2.38 mol CO2 per mol IL at 30 °C and 1 bar.A dual site-functionalized IL consists of three parts including cation, site A and site B in anion, as shown in 66614]2[AA–Im] and [P66614]2[AA–Ind] containing azole groups are 258 °C and 252 °C, respectively. [P66614]2[Am–PA] with a benzene substituent was stable until the temperature reached above 300 °C, and they are thermally stable enough for the application as a CO2 absorbent. The viscosity of these ILs are thousands of cPa and it is considered that the high viscosity was derived from the hydrogen bond formation in amine-based ILs.Some properties of these synthesized ILs such as their thermal property and viscosity were detected, and are shown in 2 absorption under 1 bar CO2 pressure at 30 °C  level, the optimized structures of the [AA–R], and its CO2 complexes are listed in Fig. S12 could be chemisorbed when the reaction enthalpy is less than about −50 kJ mol−1.6 As seen from 2 absorption according to the reaction enthalpy ΔH(AA–CO2). The reaction enthalpy of CO2 with an Ac anion in [AA–Ac] is −61.08 kJ mol−1, which means that Ac could react with CO2 efficiently, and this result coincides with the absorption capacity of [P66614]2[AA–Ac] as 1.97 mol CO2 per mol IL. The Su anion is not an active site for CO2 absorption because the reaction enthalpy of CO2 with the Su anion in [AA–Su] is −27.15 kJ mol−1, which causes the CO2 capacity of [P66614]2[AA–Su] presenting 0.49 mol mol−1 less than [P66614]2[AA–Ac]. The reaction enthalpies of the amine group and Im anion in [AA–Im] with CO2 are −102.28 and −130.68 kJ mol−1, which indicates that two sites might react with CO2 preferentially. However, [P66614]2[AA–Im] also showed 0.42 mol CO2 per mol IL less than [P66614]2[AA–Ac] and is similar to [P66614]2[AA–Ind]. There is an inhibiting effect between sites including anion and amine, where the amine site competes with anion in CO2 reaction. The CO2 capacity was associated with the relative activation of two sites, which was considered as the value of ΔH(R–CO2) divided by ΔH(AA–CO2). The results in 2 capacity when the activation of two sites are almost equivalent, whereas the CO2 capacity is much lower.The possible interaction process controlled by enthalpy was speculated 2 absorption with these ILs was investigated via IR and 13C NMR spectroscopy, as shown in 13C NMR spectra compared with CO2 saturated [P66614]2[AA–Ac] and its fresh state, while the chemical shift of the CH (marked with green circle) and CH2 (marked with red square) groups have a few ppm changes, which indicates that CO2 is fixed in two forms. As seen from the IR spectra of [P66614]2[AA–Ac] in −1 shift to 1610 cm−1 and the IR absorption intensity of the captured CO2 between 1630–1760 cm−1 increases with a gradual increase in the CO2 content, which indicates that the carboxylate anion assists in CO2 absorption.The CO36,37 Thereinto, the IR spectra of ILs associated with the CO2 content in 2D correction forms are shown in 66614]2[AA–Ac], it is interesting that the absorption between 1630–1780 cm−1 consists of several peaks. There are cross-correlation peaks marked with the elliptical line that appeared at , where 1585 cm−1 belongs to the carboxylate anion and 1715 cm−1 belongs to the fixed CO2. The Ψ in Φ in −1 precedes 1715 cm−1. Similarly, with the analysis of the correlation among the peaks of [P66614]2[AA–Ac] at 1585, 1660 and 1715 cm−1, it indicates that the absorption at 1660 cm−1 belongs to the fixed CO2 with the amine group in [AA–Ac] also follows 1585 cm−1, while 1715 cm−1 and 1660 cm−1 appear simultaneously for no cross-correlation peak at Φ, which is marked with dotted square in 2, then another CO2 fixed by an anion site, dual sites of ILs such as [P66614]2[AA–Ac] could be listed as path (a) in 2 per mol IL owing to the cooperation of amine group and the carboxylate anion.The 2D IR spectroscopy is a usual method to study the dynamics of interactions.66614]2[AA–Im] as a CO2 absorption agent?However, what happens on using [P66614]2[AA–Im] varied with the CO2 content, the IR absorption of the carboxylate anion at 1578 cm−1 gets blueshift with the uptake of CO2, and the absorption of the fixed CO2 with the Im and amine group appear at 1713 and 1664 cm−1, respectively. Compared with the synchronous and asynchronous 2D correction IR spectra of [P66614]2[AA–Im] associated with the CO2 content, the sign of Ψ in Φ in 2 by imidazolium at 1713 cm−1 before the change in the vibration absorption of the carboxylate anion at 1578 cm−1. Similarly, the IR absorption of the fixed CO2 with the amine group in [AA–Im] at 1664 cm−1 follows 1713 cm−1, while the absorption appears at 1664 cm−1 prior to 1578 cm−1. Thus, the reaction of CO2 with dual site ILs could be listed as path (b) in 2 following with CO2 fixed by anion site, which is different from [P66614]2[AA–Ac]. The 13C NMR spectra in 2 saturated [P66614]2[AA–Im] and its fresh state. It is noticed that the chemical shift of CH (marked with a green circle) group shifts tiny, which would be attributed to the reaction of the amine group with CO2 be suppressed. A similar phenomenon occurs in CO2 absorption with [P66614]2[AA–Ind]. We thought that cooperative CO2 absorption with dual site-functionalized ILs might be liable to occur when the dual sites have the equivalent ability.As can be seen from Fig. S32 absorption, we know that the valence electron delocalizes in the conjugated plane, so that the charge can be dispersed. Thereinto, [P66614]2[Am–iPA] was synthesized by taking advantage of a benzene ring, which is one of the most common conjugated planes. The reaction enthalpy of CO2 with the amine group and carboxylate anion were calculated to predict the possibility of the cooperative CO2 absorption of dual sites. The reaction enthalpy of CO2 with carboxylate anion and amine in [Am–iPA] are −64.53 and −75.85 kJ mol−1, respectively, which indicate that two sites might react with CO2, and the reactions are more moderate than with [AA–Im] and [AA–Ind], which is a benefit to CO2 desorption. [P66614]2[Am–iPA] was applied to CO2 absorption with capacity as high as 2.38 mol mol−1 IL within 20 min at 30 °C. There are two new carbon peaks of captured CO2 with [P66614]2[Am–iPA] that appeared at 157.7 and 156.5 ppm in the 13C NMR spectra from 2 in the absorption with ILs; therefore, the humid CO2 absorption performance with [P66614]2[Am–iPA] was tested at 30 °C , it was demonstrated that a small amount of water in IL did not significantly reduce the CO2 capture capability.33,34 The influence of temperature and pressure were investigated. The results in 2 capacity decreases to 1.19 mol mol−1 when temperature increase to 70 °C under 1.0 bar, or decreases to 1.79 mol mol−1 when the CO2 partial pressure decreases to 0.1 bar at 30 °C, which means that the captured CO2 could be desorbed by increasing the temperature and decreasing the CO2 partial pressure. The thermal stability of [P66614]2[Am–iPA] was characterized via TGA measurement with its decomposition temperature set as 322 °C. Ten consecutive absorption cycles of CO2 by [P66614]2[Am–iPA] are displayed in 2 being desorbed at 80 °C and 1 kPa vacuum for 1 hour. With the cooperation of dual sites, higher CO2 capacity as well as weaker interactions between CO2 and IL could be achieved.Based on this opinion that the sites with equivalent ability are more likely to form cooperative COC Fig. S5. The resdl-aspartic acid (AA–Ac), l-histidine (AA–Im), tryptophan (AA–Ind), dl-homocysteic acid (AA–Su), and 5-aminoisophthalic acid (Am–iPA) were purchased from Aladdin Industrial Co. Tributylethylphosphonium bromide and trihexyl(tetradecyl)phosphonium bromide were purchased from Nanjing Chemlin Biomedical Technology Company. An anion exchange resin in the chloride form (95% purity) and tributylamine (98% purity) were purchased from Sinopharm Group Chemical Company.The used reagents such as via synthesizing halide ILs, anion exchange, and neutralization with amino acids. Taking the synthesis of trihexyl(tetradecyl)phosphonium tryptophan ([P66614]2[AA–Ind]) as an example. Trihexyl(tetradecyl)phosphonium bromide ([P66614][Br]) was synthesized according to the reported 66614][OH]) in ethanol was obtained from [P66614][Br] by the anion-exchange method,4 and equimolar tryptophan was added to the ethanol solution of [P66614][OH]; the mixture was dealt with a vacuum-rotary evaporation procedure at 60 °C to remove the most of ethanol after stirring at room temperature for 24 h. Then, all ILs were dried under vacuum at 80 °C for 24 h and freeze-dried to remove possible traces of water.ILs were prepared via NMR and FTIR spectroscopies  level. 2D correlation IR spectroscopy was acquired via a 2D software based on Fourier transform and the analysis was according to the so-called Noda's rule. The intensity of the synchronous 2D correlation spectrum Φ represents the simultaneous or coincidental changes in two spectral intensity variations measured at ν1 and ν2 during the measurement interval of the NH3 content, while the intensity of an asynchronous spectrum Ψ represents sequential or successive but not coincidental changes in spectrum measured separately at ν1 and ν2.CO66614]2[AA–R] were synthesized with an amino acid group and basic anion including sulfonate, carboxylate, imidazolium, and indolium to investigate the suppression and cooperation between each site in CO2 absorption. Combined with CO2 absorption experiments, IR and NMR spectroscopic analyses, and DFT calculations, CO2 absorption results indicated that the CO2 capacity increases first but decreases later with the continuous increase in the CO2 absorption ability of R. The ability of the amine group to capture CO2 would be suppressed when the interactions of another site with CO2 is stronger. Thus, the dual site-functionalized ILs might be cooperative to achieve high CO2 capacity by balancing two sites to be equivalent. Based on this point, [P66614]2[Am–iPA] was further synthesized by taking the advantage of a conjugated benzene ring. As expected, [P66614]2[Am–iPA] showed capacity as high as 2.38 mol CO2 per mol IL and without capacity decrease within 10 times recycle performance of CO2 absorption and desorption. Cooperation exists widely in a variety of fields as well as gas absorption, and the investigation of the knowledge of suppression would be better to achieve cooperation.In summary, a variety of dual site-functionalized ILs [PThere are no conflicts to declare.RA-010-C9RA09293E-s001


With increasing pressure, the photocurrent with xenon lamp illumination exhibits a rapid increase and achieves an almost five orders of magnitude increment compared to its initial value. Impressively, a broadband photoresponse from 520 to 1650 nm with an optimal responsivity of 6.81 mA W−1 and fast response times of 95/96 ms at 1650 nm is achieved upon successive compression. The high‐gain, fast, broadband, and dramatically enhanced photoresponse properties of Cs3Bi2I9 are the result of comprehensive photoconductive and photothermoelectric mechanisms, which are associated with enhanced orbital coupling caused by an increase in Bi—I interactions in the [BiI6]3− cluster, even in the amorphous state. These findings provide new insights for further exploring the potential properties and applications of amorphous perovskites.Effective modification of the structure and properties of halide perovskites via the pressure engineering strategy has attracted enormous interest in the past decade. However, sufficient effort and insights regarding the potential properties and applications of the high‐pressure amorphous phase are still lacking. Here, the superior and tunable photoelectric properties that occur in the pressure‐induced amorphization process of the halide perovskite Cs −1 and fast response times of 95/96 ms at 1650 nm is achieved in the pressure‐induced amorphization process of the halide perovskite Cs3Bi2I9, which provides some new insights into further investigating the unexplored properties and applications of amorphous perovskites.The tunable and broadband photoresponse from 520 to 1650 nm with an optimal responsivity of 6.81 mA W Albeit the low stability, poor flexibility, and toxic heavy metals  are fundamental challenges for further practical applications. Tremendous progress has been achieved in exploring and optimizing metal halide perovskites during the past decade. Among the various perovskites, bismuth‐based halide perovskites with high stability, low toxicity and the isoelectronic nature of Bi+ compared to Pb+ have attracted tremendous interest as photoelectric materials. In particular, Cs3Bi2I9 has already been extensively employed for the fabrication of high‐performance photodetectors with excellent X‐ray imaging capability, impressive on/off ratio, and broadband photoresponse (254–1064 nm). Regrettably, except when used to assemble complicated heterojunctions, the intrinsic photoresponse of Cs3Bi2I9 is limited to within the UV‒vis waveband owing to its wide indirect bandgap of 1.9–2.8 eV. Consequently, further exploring new strategies to extend the photoresponse range to enrich the functionalities and applications of Cs3Bi2I9 is imperative.Metal halide perovskites are currently the subject of extensive investigations owing to their distinguished properties and attractive prospects for various potential applications, including high‐efficiency solar cells,1, 2 such as enhanced structural stability, pressure‐induced and enhanced emission, piezochromism, captured high‐pressure phase down to ambient conditions, and regulated photocurrents. In particular, a remarkably enhanced photocurrent by over three orders of magnitude via a pressure‐reduced exciton binding energy in the all‐inorganic perovskite Cs2PbI2Cl2 and even an extended spectral response range from the visible to near‐infrared waveband were achieved in bulk iodine, PbI2 and hypervalent CsI3. These efforts have indicated that pressure application is an efficient strategy to optimize photoelectric properties such as the photocurrent and detection bandwidth dominated by the photoconductive mechanism. Intriguingly, many halide perovskites, such as Cs3Bi2I9, exhibit successive bandgap reduction with increasing pressure, which hints at the possibility of extending the spectral response range to a longer waveband.High pressure is a straightforward and significant approach to regulate the crystal and electronic structure of materials, and great accomplishments have been achieved in optimizing the properties of halide perovskite materials,25 suc The thermal behavior of disordered amorphous materials is quite different from that of ordered crystalline materials, generally possessing lower thermal conductivity and superior flexibility, thus contributing to a considerable thermoelectric energy conversion and practical applications in flexible devices. The thermoelectric applications require excellent electrical conductivity, which is a considerable challenge in amorphous materials, and generally, the wide bandgap results in photoelectric applications mainly being limited to the solar‐blind region. Fortunately, this can be addressed in amorphous perovskites owing to the bandgap reduction and metallization occurring in the pressurization process. As a critical photoresponse mechanism, the photothermoelectric effect combines photothermal conversion processes and the thermoelectric effect and can achieve a broadband photoresponse with a self‐powered operation capability under zero external bias. The photothermal conversion is determined by the optical absorption and heat capacity. Not only highly pressure‐tunable absorption coefficients but also a lower heat capacity can be achieved in amorphous perovskites, which are responsible for the excellent photothermal conversion efficiency in amorphous perovskites. Therefore, exceptional photoelectric properties dominated by the photothermoelectric mechanism can be expected. Nevertheless, amorphous perovskites are usually overlooked, and further investigation is urgently required to obtain more valuable insights into the various potential properties and applications, especially for photodetection.Notably, some halide perovskites generally undergo pressure‐induced amorphization accompanied by changes in optical and electrical properties.25 The3Bi2I9 under high pressure. Significant enhancement in the photocurrent with xenon lamp illumination by almost five orders of magnitude is achieved upon compression, accompanying the amorphization process. Simultaneously, the spectral response range is successfully extended from the visible to optical communication waveband (1650 nm) with successively increasing pressure. Upon further compression, the fast, stable, high‐gain, and rapidly increasing photoresponse is the result of synergy of the photoconductive and photothermoelectric effects. The superb and tunable photoelectric properties of amorphous Cs3Bi2I9 are anticipated to inspire extensive interest in the study of amorphous perovskites.In this work, we demonstrate the fascinating photoelectric properties of the amorphous halide perovskite Cs23Bi2I9 adopts a hexagonal structure with the space group P63/mmc under ambient conditions. As illustrated in Figure3Bi2I9 consists of a [Bi2I9]3− dioctahedral cluster and Cs+ cations. Two neighboring [BiI6]3− octahedra share a face along the c‐axis direction to form a [Bi2I9]3− dioctahedral cluster, and the hexagonal channels are filled by Cs+ cations to form a 0D molecular salt structure. There are two groups of Bi—I bonds in the [Bi2I9]3− dioctahedral cluster: the three long bridging Bi—I bonds involve the I atoms that share bonds with two Bi atoms, and the six rigid terminal Bi—I bonds are oriented away from the shared face. Lattice constants of a = b = 8.41 Å and c = 21.18 Å were determined according to the powder X‐ray diffraction (XRD) pattern data  at 148.5 cm−1, and its antisymmetric partners are E″″ (v15) at 128.3 cm−1 and E″(v10) at 120.8 cm−1. The bridging Bi—I symmetric stretching mode A11(v2) and its antisymmetric mode E″″ (v7) are at 107.7 cm−1 and 91.9 cm−1, respectively. The lower energy modes at 51.6 and 59.3 cm−1 are associated with the various bending modes and ionic interactions of the [Bi2I9]3− cluster and nearby Cs+ cations.The Raman spectrum of Cse is A″1v1 at 148.3Bi2I9 sample was further characterized by photoluminescence (PL) spectroscopy and optical absorption spectroscopy. As shown in Figure  The optical absorption intensity rapidly attenuated along the absorption edge is shown in Figure 3Bi2I9 is an indirect bandgap semiconductor, and its optical bandgap can be extrapolated from the absorption spectrum via the Tauc equation (hνα)1/2 = A(hv−Eg), where h represents Planck's constant, v is the photon frequency, α is the absorption coefficient, Eg is the bandgap, and A is a constant. As illustrated in Figure 3Bi2I9 sample can be estimated as 2.0 eV, agreeing with prior reports.The Csn Figure 15 TheFigure3Bi2I9 upon compression, we fabricated an in situ high‐pressure photoelectric measurement setup via a two‐point probe method within a diamond anvil cell (DAC). The labeled O position corresponds to the center of the device, and the labeled A and B positions are located near the two interfaces between the sample and the two probes. The photoelectric properties of Cs3Bi2I9 under global xenon lamp illumination were evaluated and are displayed in Figure I–V curves of the Cs3Bi2I9 device under illumination and in the dark at the initial pressure, which shows the significant enhancement in the photocurrent with increasing external bias  is a figure of merit for a photodetector and can be determined via the equation R = Iph/(Pin×S), where Iph is the photocurrent, Iph = Iillumination − Idark, S is the active illuminated area, and Pin is the light power density. S and Pin are 4.5 × 10−4 cm−2 and 2 mW cm−2 in our measurement for the xenon lamp illumination, respectively. As shown in Figure −1 are determined at an initial pressure of 1.2 GPa. The photocurrent density Jph of Cs3Bi2I9 was derived from Figure Jph = Iph/S, as illustrated in Figure Iph slowly increases upon compression and reaches 2.7 nA (1 mA W−1 for R) at 9.5 GPa, which is ten times that at 1.2 GPa. Subsequently, Iph rapidly increases with further increasing pressure and reaches ≈18 µA (20 A W−1 for R) at 26.7 GPa, which is almost five orders of magnitude higher than that at 1.2 GPa. Under higher pressure, photoresponse of Cs3Bi2I9 will weaken and eventually disappear owing to it transform into the metallic state.The responsivity  exhibits a significant increase at different rates under the laser spot at position A and position O. To obtain further insight into the difference in the photocurrents with laser illumination at position A and position O, the variations in the photocurrent ratio Iph‐A/Iph‐O as a function of pressure are illustrated in Figure The photocurrents of Cs3Bi2I9‐Pt where breaks the electron‐hole symmetry. The incident light intensity dependence of the photoelectric properties at 17.8 GPa was further evaluated. As shown in Figure I–V curves shift upward nearly parallelly upon increasing the illumination intensity, which corresponds well with the photothermoelectric characteristics of the device. With increasing incident light power, the photocurrent exhibits a monotonic increase, and the dependence can be fitted via the general power equation Iph = 0.33×P0.93  with 635 nm laser illumination, which indicates that the photothermoelectric effect is very weak and that the photoconductive effect contributes almost all of the photocurrent at a current pressure of 6.7 GPa. With further increasing pressure, the photocurrents exhibit rapid enhancement, especially for the laser spot at position A. The photocurrents reach 16.7 and 1.2 µA (Jph of 21 210 and 1567 mA cm−2) with laser illumination at positions A and O, respectively, which are almost five and four orders of magnitude enhancements in comparison to the initial values at 6.7 GPa, respectively.The photoresponse properties of Cs3Bi2I9 can be extended to the near‐infrared band and successively generates a photoresponse to 980, 1270, 1450, and 1650 nm laser illumination via the photoconductive effect or photothermoelectric effect at higher pressure  under laser illumination with different wavelengths of 520, 635, 980, 1270, 1450, and 1650 nm are achieved when the pressure reaches 26.3 GPa. Impressively, Cs3Bi2I9 delivers a stable, fast, reproducible and broadband photoresponse from 520 nm to the optical communication waveband (1650 nm) with a responsivity R of 6.81 mA W−1 at 1650 nm , the valence band maximum (VBM) mainly consists of the I‐5p orbital with a small contribution of the Bi‐6s orbital, whereas the conduction band minimum (CBM) originates from the I‐5p orbital and Bi‐6p orbital in each [Bi2I9]3− cluster  rapidly blueshifts and surpasses the terminal Bi—I antisymmetric stretching mode E′(v10) with the pressure reaching ≈3 GPa, which is associated with the more pronounced shrinkage of bridging Bi—I bonds than of terminal Bi—I bonds in Figure To understand the dynamic behavior of the [Bictahedra.29 The3Bi2I9 starts to transform into the amorphous state owing to the pressure‐induced unordered arrangement of the [Bi2I9]3− octahedra. Intriguingly, the pressure‐induced amorphization of Cs3Bi2I9 would not restrict the enhanced atomic orbital overlap within the [Bi2I9]3− octahedra upon further compression, indicating successive enhancement of photoelectric properties in amorphous Cs3Bi2I9. Generally, amorphization may result in the increase B—X  bond distance or B—X—B bond angles, which would decrease the degree of orbital overlap, ultimately result in the bandgap and resistance increase, and the photocurrent is suppressed. Typical examples include MAPbBr3, MAPbI3, and FAPbBr3. Thus, significant enhancement of photoresponse in amorphous Cs3Bi2I9 is precious and unachieved in previous literatures. Impressively, the pressure‐induced amorphization would result in a lower lattice thermal conductivity, which would promote enhancement of photoelectric properties of Cs3Bi2I9 dominated by the photothermoelectric mechanism, as evidenced by the more rapid enhancement in the photocurrent with laser illumination at position A than at position O  with a responsivity of 6.81 mA W−1 at 1650 nm is achieved upon further successive compression, which originates from the comprehensive result of the photoconductive and photothermoelectric mechanisms. Extensive spectroscopy characterizations and theoretical calculations reveal that the tunable and exceptional photoelectric properties of Cs3Bi2I9 are associated with a dramatic increase in Bi—I interactions within the [BiI6]3− cluster, which would enhance the degree of orbital overlap, even in the amorphous structure form. Ultimately, this causes bandgap narrowing and significantly enhanced photoelectric properties in the halide perovskite Cs3Bi2I9. Our findings signify that amorphous Cs3Bi2I9 possesses immense potential for photoelectric applications, which opens up a new avenue for further investigating the unexplored properties and applications of amorphous perovskites.In conclusion, we systematically investigated the photoelectric properties of the halide perovskite Cs43Bi2I9 single crystals using a procedure described in previous work. The crystal structure of the Cs3Bi2I9 sample was determined by XRD (DX‐2700BH) with Cukα radiation (λ = 1.5406 Å). The PL spectrum was obtained via a Renishaw inVia notch filter spectrometer with a 514.5 nm excitation laser under ambient conditions.The inverse temperature crystallization method was used to grow high‐quality, cm‐scale Csous work.14 The3Bi2I9 were performed in a symmetrical DAC with a pair of anvil culets of 300 µm. A T301 stainless steel gasket was preindented to ≈50 µm in thickness, and a hole with a suitable diameter was drilled via a laser drilling system to serve as the sample chamber. Photoelectric property measurements were carried out via the two‐probe method. A mixture of epoxy and boron nitride (c‐BN) powder was loaded into the DAC chamber and then firmly compressed to achieve electrical insulation between the metal electrodes and steel gasket. A layer of crushed Cs3Bi2I9 single crystal sample with a thickness of ≈30 µm and size of ≈300 µm was placed on the c‐BN insulating layer. Pt possesses excellent ductility, the Seebeck coefficient (−1.87 µV K−1) was much lower than that of the sample, and variations in Seebeck coefficient and resistance of Pt with pressure was relatively small, which hardly interfered with the measurement results. Thus two platinum sheets served as electrodes to contact the Cs3Bi2I9 sample in the DAC chamber. No pressure‐transmitting medium was used. The photoelectric property measurements under laser illumination were conducted using a high‐precision photocurrent scanning test microscope system (MStarter 200) combined with a combination of sourcemeters (Keithley 6482), and lasers of different wavelengths  were used as the light illumination source. The I–t and I–V data with xenon lamp (CEL‐HXF300) illumination were recorded using a combination of sourcemeters (Keithley 2461). The incident light power was obtained via a probe of the power meter placed under the one‐side diamond anvil on the original measurement position. The area of the laser spot with diameter of 10 µm was the active area to obtain the responsivity under laser illumination.High‐pressure in situ measurements of Cs3Bi2I9 were recorded on a LabRAM HR Evolution Raman spectrometer (λ = 785 nm). No pressure‐transmitting medium was used in the high‐pressure Raman scattering experiments. Optical absorption spectra were acquired using an iHR‐320 spectrometer. A KBr film was loaded into the DAC chamber as the pressure‐transmitting medium and the background. The optical absorption spectra were calculated via the expression α = log10(Tref/Ts), where Tref and Ts are the transmittances of KBr and Cs3Bi2I9, respectively.Raman spectra of Cs The Perdew−Burke−Ernzerhof (PBE) functional within the generalized gradient approximation (GGA) was selected to describe the exchange‐correlation effects, and the projector augmented wave (PAW) method was used in this work. Cs3Bi2I9 possesses a 0D molecular salt crystal structure, the van der Waals (vdWs) dispersion correction was required. Combined with literatures and calculation results of different methods .50 TheThe authors declare no conflict of interest.Supporting InformationClick here for additional data file.


The authors would like to correct an error in their recently published paper . The preThe authors apologize for any inconvenience caused to the readers by the changes. Although the prevalence of inadequacy for iron for older infants has fallen, 75% is still high.1. Abstract“Exceptions were iron and zinc where the prevalence of inadequacy was estimated to be 90% and 20%, respectively, for infants aged 6–11.9 months.”was changed to:“Exceptions were iron and zinc where the prevalence of inadequacy was estimated to be 75% and 20%, respectively, for infants aged 6–11.9 months.”2. The following content in the Results section, paragraph 3“More than 90% of older infants and one quarter of toddlers had inadequate iron intakes (Tables 3 and 4).”was changed to:“More than 75% of older infants and one quarter of toddlers had inadequate iron intakes (Tables 3 and 4).”6, mg/d” row under the “<EAR” column, the number has been changed from 92 to 75.3. Table 3 in the “Iron4. The following content in the Discussion section, paragraph 1“Exceptions were a very high prevalence of inadequacy for iron (>90%) in infants 6–11.9 months and excessive sodium consumption in a high proportion of toddlers 12–24 m (30%).”was changed to:“Exceptions were a very high prevalence of inadequacy for iron (75%) in infants 6–11.9 months and excessive sodium consumption in a high proportion of toddlers 12–24 m (30%).”5. The following content in the Discussion section, paragraph 3“For the two nutrients with EARs, iron and zinc, the prevalence of inadequacy was estimated to be 90% and 20%, respectively.”was changed to:“For the two nutrients with EARs, iron and zinc, the prevalence of inadequacy was estimated to be 75% and 20%, respectively.”