Revealing structural isomerization in metal clusters would bridge a huge structural gap between small molecular isomerization and solid–solid phase transformation.However,genuine structural isomerism in metal cluster...Revealing structural isomerization in metal clusters would bridge a huge structural gap between small molecular isomerization and solid–solid phase transformation.However,genuine structural isomerism in metal clusters is still rare.In this work,we report the first example of structural isomerismin Cu clusters.By utilizing the coordination flexibility of alkyne to enable the migration of partial Cu atoms in Cu metal cores,two Cu_(15)cluster complexes(Cu_(15)-a and Cu_(15)-c)possessing identical composition but different metal core structures have been successfully isolated.Interestingly,although the structure of Cu_(15)-a can be retained in CH_(2)C_(l2)solution below 27°C,it will gradually change to give an intermediate state,Cu_(15)-b,as the temperature rises(at about 31°C)before it eventually transforms into Cu_(15)-c(at 40∼65°C).Significantly,atomically precise Cu_(15)-b clearly provides footprints for tracing the thermal migration process of Cu atoms during the thermal transformation from Cu_(15)-a to Cu_(15)-c.In addition,Cu_(15)-a and Cu_(15)-c exhibit diverse crystallization-induced emission enhancement phenomena.Crystalline Cu_(15)-c displays redshifted photoluminescence(820 nm)compared with Cu_(15)-a(726 nm)due to the shorter mean Cu···Cu distance in Cu_(15)-c.Notwithstanding,crystalline Cu_(15)-a exhibits much more intense photoluminescence at room temperature than that in Cu_(15)-c,which might be attributed to the stronger intermolecular C–H⋯πinteractions in Cu_(15)-a.These results indicate that cluster isomerism provides valuable opportunities for insight into the structure–property relationships and understanding the complex evolution of phase transformation in nanometallic solids.展开更多
Two lowly fused non-fullerene acceptors(NFAs)with isomeric structures,named as BTP-out-4F and BTP-in-4F,were developed by tailoring the fused 7-ring central core of Y6 into a lowly fused 5-ring linked with two octylox...Two lowly fused non-fullerene acceptors(NFAs)with isomeric structures,named as BTP-out-4F and BTP-in-4F,were developed by tailoring the fused 7-ring central core of Y6 into a lowly fused 5-ring linked with two octyloxythiophene bridges.BTP-out-4F with octyloxy side chains away from the central core exhibited large steric hindrance that restrained the rotational freedom between the thiophene bridge and end group but maintained free rotation between the central core and the thiophene bridge.In contrast,BTP-in-4F with octyloxy side chains close to the central core had much lower rotation freedom due to the non-covalent S⋯O interactions locked the central core,thiophene bridge and end group simultaneously,making BTP-in-4F have higher molecular crystallinity.On the other hand,the optical properties,energy levels and the blend morphology properties were significantly influenced,leading to distinctive photovoltaic performances.BTP-out-4F formed favorable energy level alignment and morphology when matching with PBDB-T donor,thus its device realized a much higher PCE of 13.32%,which was over 13 times than that of BTP-in-4F based device(PCE=0.97%).展开更多
The chlorocarbenoid , CHCl2Li , was studied by means of ab initio molecular or- bital theory. Three equilibrium structures and two isomerization transition states were located. The calculations showed that the three-m...The chlorocarbenoid , CHCl2Li , was studied by means of ab initio molecular or- bital theory. Three equilibrium structures and two isomerization transition states were located. The calculations showed that the three-membered ring structure is the most stable. The 'classical tetrahedral' structure is not the local minimum on the potential energy surface.展开更多
In this work, the use of computational methods was essential to distinguish the three possible isomeric structures of the [RuCl3(H2O)2(Gly)] molecule. The characterization of these molecules was performed using IR, NM...In this work, the use of computational methods was essential to distinguish the three possible isomeric structures of the [RuCl3(H2O)2(Gly)] molecule. The characterization of these molecules was performed using IR, NMR and UV-VIS simulations. Some calculations related to the optimization of structures and properties such as chemical hardness and dipole moment were also conducted. The fac-cis isomer presented promising data when compared to the experimental data, indicating that this is the likely experimentally synthesized isomer. This study demonstrates the technical utility of the computational calculations by virtue of situations that prevent the realization of X-ray diffraction.展开更多
In this work, a systematic study of some possible isomer structures of the Cu5 cluster obtained from density functional theory methods is presented. The polarisation and pseudopotential basis sets are employed in the ...In this work, a systematic study of some possible isomer structures of the Cu5 cluster obtained from density functional theory methods is presented. The polarisation and pseudopotential basis sets are employed in the calculations. The results show that the binding energies, frequencies, coordination numbers and average bond lengths are in reasonable agreement with reported experimental data. Moreover, four isomers of the Cu5 cluster are obtained according to calculations, in which the most stable configuration is the planar structure. Meanwhile, two three-dimensional structures of the Cu5 cluster are obtained in this work, which might be valuable for further theoretical and experimental studies. In addition, our study proves the possibility of the isomer structures of the Cu5 cluster.展开更多
Based on the octadecahedron of eleven-vertex closo-borane, the eleven-vertex closo-heteroborane was suggested with nonmetallic atoms instead of the different nonequivalent boron, and the stabilities were predicted at ...Based on the octadecahedron of eleven-vertex closo-borane, the eleven-vertex closo-heteroborane was suggested with nonmetallic atoms instead of the different nonequivalent boron, and the stabilities were predicted at G96PW91/6-31＋G（3d,2p） level. The small heteroatoms, C, N, O, preferentially occupy vertex 2 with the absolutely lowest relative energy to form the high stabilization closo-heteroboranes. They cap four-membered rings to satisfy the geometrical demand of short B--Z bonds. The electron attractions from the vicinal boron atoms make the frameworks shrink. Differently, Si and Ge preferentially substitute for boron at vertex 1 with six tight B--Z bonds and form stabilized molecules. P, As, S, and Se tend to occupy vertex 4 and the optimized structures belong to the nido configura- tions. In contrast to high electronegative heteroatoms, S and Se transfer less negative charges to framework and the electropositive heteroatoms, Si and Ge transfer more negative charges to framework to form the delocalization structures. The HOMO-LUMO gaps show that most of predicted clusters possess chemical stabilities. The substitutions of heteroatoms for boron atoms in eleven-vertex closo-heteroboranes are consistent with the topological charge stabilization rule proposed by Gimarc.展开更多
Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound w...Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound which were well known as reaction products of cyanate esters and epoxy resins, compounds with hybrid ring structure of cyanurate/isocyanurate were determined. Gibbs free energies of the compound having hybrid ring structure of cyanurate/isocyanurate with two isocyanurate moiety were found to be lower than that of the compound with cyanurate ring structure through calculations. Calculation data supported the existence of hybrid ring structure of cy-anurate/isocyanurate. It was revealed that isomerization from cyanurate to isocyanurate occurs via hybrid ring structure of cyanurate/isocyanurate in the reaction of aryl cyanurate and epoxy.展开更多
The isomeric structures, isomerization and decomposition of silylenoids H(2)SiMX (MX=KF, KCl, LiBr, NaBr and KBr) have been investigated by ab initio molecular orbital theory. These silylenoids have four kinds of very...The isomeric structures, isomerization and decomposition of silylenoids H(2)SiMX (MX=KF, KCl, LiBr, NaBr and KBr) have been investigated by ab initio molecular orbital theory. These silylenoids have four kinds of very similar equilibrium structures. The three-membered ring and p-complex structures should be stable and experimentally detectable. The lifetime of sigma-complex and tetrahedral structures would be very short and experimentally undetectable.展开更多
The proliferation of adulterated health foods and beverages in the market demands a comprehensive analytical strategy to identify the adulterants,particularly those of isomeric phosphodiesterase 5(PDE5)inhibitors.An i...The proliferation of adulterated health foods and beverages in the market demands a comprehensive analytical strategy to identify the adulterants,particularly those of isomeric phosphodiesterase 5(PDE5)inhibitors.An instant coffee premix(ICP)purchased from an online retailer was flagged for suspected adulteration through PDE5 inhibition assay.The ICP was then analysed using suspected-target and non-targeted screenings of a liquid chromatography-quadrupole time-of-flight mass spectrometry.Based on these findings,a PDE5 inhibitor initially assigned as compound X was isolated from the ICP by employing a liquid chromatography-diode array detection before its structural elucidation with liquid chromatography-ultraviolet(LC-UV)spectroscopy and nuclear magnetic resonance(NMR)spectroscopy.The suspected-target screening matched the protonated molecule([MþH]þ)precursor ion of compound X at m/z 499.2310 with two suspected analytes that are structural isomers of one another.The fragmentation patterns of compound X were comparable to those analogues in the dithiocarbodenafil group through the non-targeted screening.These findings,complemented by the LC-UV and NMR spectroscopy data,together with the chromatographic separation of related structural isomers,conclude the identity of compound X.To our best knowledge,this is the first study to report the presence of 3,5-dimethylpiperazinyl-dithiodesmethylcarbodenafil in an ICP sample.展开更多
It remains elusive to realize the distinct catalysis of isomeric catalysts because it becomes challenging to identify structural isomers in the polydisperse nanoparticles.Herein we investigate catalysis of two geometr...It remains elusive to realize the distinct catalysis of isomeric catalysts because it becomes challenging to identify structural isomers in the polydisperse nanoparticles.Herein we investigate catalysis of two geometric isomers for 36-gold-atom nanoclusters with different Au cores arrangements but the same thiolate ligands,thereby providing access to isomer catalysts readily participate in a desired reaction.Compared to the Au_(36)(SR)_(24)with a one-dimensional(1D)layout of Au4 tetrahedral units,the Au_(36)(SR)_(24)with a two-dimensional(2D)layout of Au4 tetrahedral units is more effective for the intramolecular hydroamination of alkyne.Our study suggests that the exposed Au sties of the two Au_(36)(SR)_(24)catalysts favor different reaction intermediates and pathways.The intramolecular H transfer leads to intermediates with the C-N and with C=N for the 1D and 2D Au_(36)(SR)_(24)respectively,and hence the different on-site and off-site pathways for the successive reaction steps account for the different performances of the two Au_(36)(SR)_(24)catalysts.展开更多
Organic semiconductors have drawn extensive atten-tion due to their optoelectronic properties and wide applications in organic optoelectronics.In comparison with the popular 1,4,5,8-naphthalene diimides(1,4,5,8-NDIs),...Organic semiconductors have drawn extensive atten-tion due to their optoelectronic properties and wide applications in organic optoelectronics.In comparison with the popular 1,4,5,8-naphthalene diimides(1,4,5,8-NDIs),the angular-shaped 1,2,5,6-NDIs have exhibited tunable photophysical properties,self-as-sembly behaviors and charge transporting properties.Due to these unique features,1,2,5,6-NDIs show great potential for construction of high performance n-func-tional materials.In this review,we highlight the recent advances and future prospects of 1,2,5,6-NDI-basedπ-systems in the field of organic optoelectronics,in-cluding molecular design,synthesis,structure-prop-erty relationships as well as the applications in high performance organic field-effect transistors,organic photovoltaics,perovskite solar cells,and so on.展开更多
基金supported by the National Natural Science Foundation of China(grant nos.22101048,22005054,and 21975044)the Natural Science Foundation of Fujian Province(grant no.2021J01150).
文摘Revealing structural isomerization in metal clusters would bridge a huge structural gap between small molecular isomerization and solid–solid phase transformation.However,genuine structural isomerism in metal clusters is still rare.In this work,we report the first example of structural isomerismin Cu clusters.By utilizing the coordination flexibility of alkyne to enable the migration of partial Cu atoms in Cu metal cores,two Cu_(15)cluster complexes(Cu_(15)-a and Cu_(15)-c)possessing identical composition but different metal core structures have been successfully isolated.Interestingly,although the structure of Cu_(15)-a can be retained in CH_(2)C_(l2)solution below 27°C,it will gradually change to give an intermediate state,Cu_(15)-b,as the temperature rises(at about 31°C)before it eventually transforms into Cu_(15)-c(at 40∼65°C).Significantly,atomically precise Cu_(15)-b clearly provides footprints for tracing the thermal migration process of Cu atoms during the thermal transformation from Cu_(15)-a to Cu_(15)-c.In addition,Cu_(15)-a and Cu_(15)-c exhibit diverse crystallization-induced emission enhancement phenomena.Crystalline Cu_(15)-c displays redshifted photoluminescence(820 nm)compared with Cu_(15)-a(726 nm)due to the shorter mean Cu···Cu distance in Cu_(15)-c.Notwithstanding,crystalline Cu_(15)-a exhibits much more intense photoluminescence at room temperature than that in Cu_(15)-c,which might be attributed to the stronger intermolecular C–H⋯πinteractions in Cu_(15)-a.These results indicate that cluster isomerism provides valuable opportunities for insight into the structure–property relationships and understanding the complex evolution of phase transformation in nanometallic solids.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.21825502,22075190,21905185 and 22105135)Special funds for local science and technology development guided by the central government(No.2020ZYD004)+1 种基金the Foundation of State Key Laboratory of Polymer Materials Engineering(No.SKLPME 2017-2-04)the Fundamental Research Funds for the Central Universities.
文摘Two lowly fused non-fullerene acceptors(NFAs)with isomeric structures,named as BTP-out-4F and BTP-in-4F,were developed by tailoring the fused 7-ring central core of Y6 into a lowly fused 5-ring linked with two octyloxythiophene bridges.BTP-out-4F with octyloxy side chains away from the central core exhibited large steric hindrance that restrained the rotational freedom between the thiophene bridge and end group but maintained free rotation between the central core and the thiophene bridge.In contrast,BTP-in-4F with octyloxy side chains close to the central core had much lower rotation freedom due to the non-covalent S⋯O interactions locked the central core,thiophene bridge and end group simultaneously,making BTP-in-4F have higher molecular crystallinity.On the other hand,the optical properties,energy levels and the blend morphology properties were significantly influenced,leading to distinctive photovoltaic performances.BTP-out-4F formed favorable energy level alignment and morphology when matching with PBDB-T donor,thus its device realized a much higher PCE of 13.32%,which was over 13 times than that of BTP-in-4F based device(PCE=0.97%).
文摘The chlorocarbenoid , CHCl2Li , was studied by means of ab initio molecular or- bital theory. Three equilibrium structures and two isomerization transition states were located. The calculations showed that the three-membered ring structure is the most stable. The 'classical tetrahedral' structure is not the local minimum on the potential energy surface.
文摘In this work, the use of computational methods was essential to distinguish the three possible isomeric structures of the [RuCl3(H2O)2(Gly)] molecule. The characterization of these molecules was performed using IR, NMR and UV-VIS simulations. Some calculations related to the optimization of structures and properties such as chemical hardness and dipole moment were also conducted. The fac-cis isomer presented promising data when compared to the experimental data, indicating that this is the likely experimentally synthesized isomer. This study demonstrates the technical utility of the computational calculations by virtue of situations that prevent the realization of X-ray diffraction.
基金supported by the National Natural Science Foundation of China (Grant No. 10375028)
文摘In this work, a systematic study of some possible isomer structures of the Cu5 cluster obtained from density functional theory methods is presented. The polarisation and pseudopotential basis sets are employed in the calculations. The results show that the binding energies, frequencies, coordination numbers and average bond lengths are in reasonable agreement with reported experimental data. Moreover, four isomers of the Cu5 cluster are obtained according to calculations, in which the most stable configuration is the planar structure. Meanwhile, two three-dimensional structures of the Cu5 cluster are obtained in this work, which might be valuable for further theoretical and experimental studies. In addition, our study proves the possibility of the isomer structures of the Cu5 cluster.
文摘Based on the octadecahedron of eleven-vertex closo-borane, the eleven-vertex closo-heteroborane was suggested with nonmetallic atoms instead of the different nonequivalent boron, and the stabilities were predicted at G96PW91/6-31＋G（3d,2p） level. The small heteroatoms, C, N, O, preferentially occupy vertex 2 with the absolutely lowest relative energy to form the high stabilization closo-heteroboranes. They cap four-membered rings to satisfy the geometrical demand of short B--Z bonds. The electron attractions from the vicinal boron atoms make the frameworks shrink. Differently, Si and Ge preferentially substitute for boron at vertex 1 with six tight B--Z bonds and form stabilized molecules. P, As, S, and Se tend to occupy vertex 4 and the optimized structures belong to the nido configura- tions. In contrast to high electronegative heteroatoms, S and Se transfer less negative charges to framework and the electropositive heteroatoms, Si and Ge transfer more negative charges to framework to form the delocalization structures. The HOMO-LUMO gaps show that most of predicted clusters possess chemical stabilities. The substitutions of heteroatoms for boron atoms in eleven-vertex closo-heteroboranes are consistent with the topological charge stabilization rule proposed by Gimarc.
文摘Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound which were well known as reaction products of cyanate esters and epoxy resins, compounds with hybrid ring structure of cyanurate/isocyanurate were determined. Gibbs free energies of the compound having hybrid ring structure of cyanurate/isocyanurate with two isocyanurate moiety were found to be lower than that of the compound with cyanurate ring structure through calculations. Calculation data supported the existence of hybrid ring structure of cy-anurate/isocyanurate. It was revealed that isomerization from cyanurate to isocyanurate occurs via hybrid ring structure of cyanurate/isocyanurate in the reaction of aryl cyanurate and epoxy.
基金Project supported by the National Natural Science Fundaion of China.
文摘The isomeric structures, isomerization and decomposition of silylenoids H(2)SiMX (MX=KF, KCl, LiBr, NaBr and KBr) have been investigated by ab initio molecular orbital theory. These silylenoids have four kinds of very similar equilibrium structures. The three-membered ring and p-complex structures should be stable and experimentally detectable. The lifetime of sigma-complex and tetrahedral structures would be very short and experimentally undetectable.
文摘The proliferation of adulterated health foods and beverages in the market demands a comprehensive analytical strategy to identify the adulterants,particularly those of isomeric phosphodiesterase 5(PDE5)inhibitors.An instant coffee premix(ICP)purchased from an online retailer was flagged for suspected adulteration through PDE5 inhibition assay.The ICP was then analysed using suspected-target and non-targeted screenings of a liquid chromatography-quadrupole time-of-flight mass spectrometry.Based on these findings,a PDE5 inhibitor initially assigned as compound X was isolated from the ICP by employing a liquid chromatography-diode array detection before its structural elucidation with liquid chromatography-ultraviolet(LC-UV)spectroscopy and nuclear magnetic resonance(NMR)spectroscopy.The suspected-target screening matched the protonated molecule([MþH]þ)precursor ion of compound X at m/z 499.2310 with two suspected analytes that are structural isomers of one another.The fragmentation patterns of compound X were comparable to those analogues in the dithiocarbodenafil group through the non-targeted screening.These findings,complemented by the LC-UV and NMR spectroscopy data,together with the chromatographic separation of related structural isomers,conclude the identity of compound X.To our best knowledge,this is the first study to report the presence of 3,5-dimethylpiperazinyl-dithiodesmethylcarbodenafil in an ICP sample.
基金supports from Fundamental Research Funds for the Central Universities,Programs for high-level entrepreneurial and innovative talents introduction of Jiangsu Province,and Scientific and Technological Innovation Foundation of Shunde Graduate School of USTB(No.BK19BE024).
文摘It remains elusive to realize the distinct catalysis of isomeric catalysts because it becomes challenging to identify structural isomers in the polydisperse nanoparticles.Herein we investigate catalysis of two geometric isomers for 36-gold-atom nanoclusters with different Au cores arrangements but the same thiolate ligands,thereby providing access to isomer catalysts readily participate in a desired reaction.Compared to the Au_(36)(SR)_(24)with a one-dimensional(1D)layout of Au4 tetrahedral units,the Au_(36)(SR)_(24)with a two-dimensional(2D)layout of Au4 tetrahedral units is more effective for the intramolecular hydroamination of alkyne.Our study suggests that the exposed Au sties of the two Au_(36)(SR)_(24)catalysts favor different reaction intermediates and pathways.The intramolecular H transfer leads to intermediates with the C-N and with C=N for the 1D and 2D Au_(36)(SR)_(24)respectively,and hence the different on-site and off-site pathways for the successive reaction steps account for the different performances of the two Au_(36)(SR)_(24)catalysts.
基金the financial support from the National Natural Science Foundation of China(Nos.21790362,21674126,21522209,22225506)the Science and Technology CommissionofShanghaiMunicipality(20ZR1468900,19xD1424700,18JC1410600)+1 种基金the Shanghai Rising-Star Program(21QA1411100)the Youth Innovation Promotion Association CAS(No.2022252).
文摘Organic semiconductors have drawn extensive atten-tion due to their optoelectronic properties and wide applications in organic optoelectronics.In comparison with the popular 1,4,5,8-naphthalene diimides(1,4,5,8-NDIs),the angular-shaped 1,2,5,6-NDIs have exhibited tunable photophysical properties,self-as-sembly behaviors and charge transporting properties.Due to these unique features,1,2,5,6-NDIs show great potential for construction of high performance n-func-tional materials.In this review,we highlight the recent advances and future prospects of 1,2,5,6-NDI-basedπ-systems in the field of organic optoelectronics,in-cluding molecular design,synthesis,structure-prop-erty relationships as well as the applications in high performance organic field-effect transistors,organic photovoltaics,perovskite solar cells,and so on.
