We analyzed the excited-state structures and emission spectra of firefly emitter, the anionic keto form of firefly oxyluciferin（keto-l）, determined by the time dependent-density functional theory（TD-DFT） approach....We analyzed the excited-state structures and emission spectra of firefly emitter, the anionic keto form of firefly oxyluciferin（keto-l）, determined by the time dependent-density functional theory（TD-DFT） approach. The analysis is based on a direct comparison with the highly correlated CASSCF（MS-CASPT2） ab initio approach. 49 DFT functionals were considered and applied to the study. Among the tested functionals, mPW3PBE, B3PW91 and B3P86 give the best performance for ground-state geometry, absorption spectrum, excited-state geometry and emis- sion spectrum.展开更多
Absorption and photoluminescence spectroscopies are useful tools to study the photo-physical properties of materials. The theoretical methods for calculation of the spectra of molecules/supermolecules and aggregates, ...Absorption and photoluminescence spectroscopies are useful tools to study the photo-physical properties of materials. The theoretical methods for calculation of the spectra of molecules/supermolecules and aggregates, whose structures can differ significantly, are reviewed from the viewpoint of computational efficiency. Several model compounds/multimers are taken as examples for the spectral calculations. The numerical results achieve a satisfactory agreement between the theory and experiment.展开更多
The molecular structures of ground state and first single excited state for pyrazoline derivatives are optimized with DFT B3LYP method and ab initio “configuration interaction with single excitations”（CIS） method,...The molecular structures of ground state and first single excited state for pyrazoline derivatives are optimized with DFT B3LYP method and ab initio “configuration interaction with single excitations”（CIS） method, respectively. The frontier molecular orbital characteristics have been analyzed systematically, and the electronic transition mechanism has been discussed. Electronic spectra are calculated by using TD-DFT method. These results are consistent with those from the experiment.展开更多
In this study, the first raw transition metals from V to Co complexes with benzene-1,2-dithiolate (L2-) ligand have been studied theoretically to elucidate the geometry, electronic structure and spectroscopic properti...In this study, the first raw transition metals from V to Co complexes with benzene-1,2-dithiolate (L2-) ligand have been studied theoretically to elucidate the geometry, electronic structure and spectroscopic properties of the complexes. Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) methods have been used. The ground state geometries, binding energies, spectral properties (UV-vis), frontier molecular orbitals (FMOs) analysis, charge analysis and natural bond orbital (NBO) have been investigated. The geometrical parameters are in good agreement with the available experimental data. The metal-ligand binding energies are 1 order of magnitude larger than the physisorption energy of a benzene-1, 2-dthiolate molecule on a metallic surface. The electronic structures of the first raw transition metal series from V to Co have been elucidated by UV-vis spectroscopic using DFT calculations. In accordance with experiment the calculated electronic spectra of these tris complexes show bands at 522, 565, 559, 546 and 863 nm for V3+, Cr3+, Mn3+, Fe3+ and Co3+ respectively which are mainly attributed to ligand to metal charge transfer (LMCT) transitions. The electronic properties analysis shows that the highest occupied molecular orbital (HOMO) is mainly centered on metal coordinated sulfur atoms whereas the lowest unoccupied molecular orbital (LUMO) is mainly located on the metal surface. From calculation of intramolecular interactions and electron delocalization by natural bond orbital (NBO) analysis, the stability of the complexes was estimated. The NBO results showed significant charge transfer from sulfur to central metal ions in the complexes, as well as to the benzene. The calculated charges on metal ions are also reported at various charge schemes. The calculations show encouraging agreement with the available experimental data.展开更多
The molecular structures of the ground and the lowest triplet states for a series of Pt（ll） complexes PtLCl（l）[L=6-（2-hydroxyphenyl）-2,2＇-bipyridine], Pt（pp）2[pp=2-（2-hydroxyphenyl）pyridine]（2）, PtbpyClz...The molecular structures of the ground and the lowest triplet states for a series of Pt（ll） complexes PtLCl（l）[L=6-（2-hydroxyphenyl）-2,2＇-bipyridine], Pt（pp）2[pp=2-（2-hydroxyphenyl）pyridine]（2）, PtbpyClz（bpy=2,2＇- bipyridine）（3）, and the free tridentate L ligand（4） were optimized by the density functional theory B3LYP and UB3LYP methods, respectively. On the basis of optimized geometries, the spectral properties were investigated with time-dependent density functional theory（TD-DFT）. In comparison with those of complexes 2 and 3, the more rigid structure of complex 1 together with its low rate of the radiationless decay via nonemissive d-d state leads to higher photoluminescence quantum efficiency. And the phosphorescence quantum efficiency of complex 1 can be easily controlled by modifying auxiliary ligands. The introduction of fluorine ligand into complexes can effectively increase the radiation transition rate and decrease the radiationless d-d transition rate, and as a result, a novel complex PtLF（5） might be a good phosphorescent material suitable for organic electronic devices.展开更多
A well-known deep-blue emitting iridium（III） complex was selected for deuterium isotope effect evalua- tion, both on deuterated locations and numbers, through theoretical investigation. It was revealed that the cont...A well-known deep-blue emitting iridium（III） complex was selected for deuterium isotope effect evalua- tion, both on deuterated locations and numbers, through theoretical investigation. It was revealed that the containment of the d site deuteriation of ancillary ligand picolinate enabled the non-radiative deactivation process to be repessed, and thereby improving the quantum efficiency through such a simple and controllable approach.展开更多
The electronic structures and spectroscopic properties of heteroleptic cyclometalated iridium（Ⅲ） complexes were investigated. The geometries, electronic structures, and the lowest-lying excited states of （DBQ）2Ir...The electronic structures and spectroscopic properties of heteroleptic cyclometalated iridium（Ⅲ） complexes were investigated. The geometries, electronic structures, and the lowest-lying excited states of （DBQ）2Ir（acac） and （MDQ）2Ir（acac） were investigated via density functional theory-based approaches. A series of designed models of （DBQ）2Ir（dpis）, （DBQ）2Ir（tpip）, （MDQ）2Ir（dpis） and （MDQ）2Ir（tpip） was also calculated for comparison. The structures in the ground and excited states were optimized via B3LYP method. The lowest absorptions and emissions spectra were evaluated via TD-B3LYP and TD-PBE1PBE methods, The computational results reveal that the emission peaks of the designed complexes are at around 585-640 nm, which belong to the orange-yellow wavelength. The frontier molecular orbital properties indicate that the Ir（Ⅲ） complexes have low efficiency roll-off.展开更多
基金Supported by the National Natural Science Foundation of China（Nos.21173099, 20973078, 51164017）, the Applied Basic Research Plans Program of Yunnan Province, China（No.2011FZ040）, the Scientific Research Fund of Yunnan Provincial Educa- tion Department, China（No.2012Y545）, the Training Foundation for Talents of Kunming University of Science and Technolo- gy（No.KKSY201232040） and the Foundation of State Key Laboratory of Theoretical and Computational Chemistry, China.
文摘We analyzed the excited-state structures and emission spectra of firefly emitter, the anionic keto form of firefly oxyluciferin（keto-l）, determined by the time dependent-density functional theory（TD-DFT） approach. The analysis is based on a direct comparison with the highly correlated CASSCF（MS-CASPT2） ab initio approach. 49 DFT functionals were considered and applied to the study. Among the tested functionals, mPW3PBE, B3PW91 and B3P86 give the best performance for ground-state geometry, absorption spectrum, excited-state geometry and emis- sion spectrum.
基金supported by the National Natural Science Foundation of China (Grant Nos. 20673104, 20833003)the 973 project (Grant Nos. 2004CB719901 and 2006CB922004)
文摘Absorption and photoluminescence spectroscopies are useful tools to study the photo-physical properties of materials. The theoretical methods for calculation of the spectra of molecules/supermolecules and aggregates, whose structures can differ significantly, are reviewed from the viewpoint of computational efficiency. Several model compounds/multimers are taken as examples for the spectral calculations. The numerical results achieve a satisfactory agreement between the theory and experiment.
基金Supported by Anhui university scientific finance fund for distinguished young scholar (2004jq181)
文摘The molecular structures of ground state and first single excited state for pyrazoline derivatives are optimized with DFT B3LYP method and ab initio “configuration interaction with single excitations”（CIS） method, respectively. The frontier molecular orbital characteristics have been analyzed systematically, and the electronic transition mechanism has been discussed. Electronic spectra are calculated by using TD-DFT method. These results are consistent with those from the experiment.
文摘In this study, the first raw transition metals from V to Co complexes with benzene-1,2-dithiolate (L2-) ligand have been studied theoretically to elucidate the geometry, electronic structure and spectroscopic properties of the complexes. Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) methods have been used. The ground state geometries, binding energies, spectral properties (UV-vis), frontier molecular orbitals (FMOs) analysis, charge analysis and natural bond orbital (NBO) have been investigated. The geometrical parameters are in good agreement with the available experimental data. The metal-ligand binding energies are 1 order of magnitude larger than the physisorption energy of a benzene-1, 2-dthiolate molecule on a metallic surface. The electronic structures of the first raw transition metal series from V to Co have been elucidated by UV-vis spectroscopic using DFT calculations. In accordance with experiment the calculated electronic spectra of these tris complexes show bands at 522, 565, 559, 546 and 863 nm for V3+, Cr3+, Mn3+, Fe3+ and Co3+ respectively which are mainly attributed to ligand to metal charge transfer (LMCT) transitions. The electronic properties analysis shows that the highest occupied molecular orbital (HOMO) is mainly centered on metal coordinated sulfur atoms whereas the lowest unoccupied molecular orbital (LUMO) is mainly located on the metal surface. From calculation of intramolecular interactions and electron delocalization by natural bond orbital (NBO) analysis, the stability of the complexes was estimated. The NBO results showed significant charge transfer from sulfur to central metal ions in the complexes, as well as to the benzene. The calculated charges on metal ions are also reported at various charge schemes. The calculations show encouraging agreement with the available experimental data.
文摘The molecular structures of the ground and the lowest triplet states for a series of Pt（ll） complexes PtLCl（l）[L=6-（2-hydroxyphenyl）-2,2＇-bipyridine], Pt（pp）2[pp=2-（2-hydroxyphenyl）pyridine]（2）, PtbpyClz（bpy=2,2＇- bipyridine）（3）, and the free tridentate L ligand（4） were optimized by the density functional theory B3LYP and UB3LYP methods, respectively. On the basis of optimized geometries, the spectral properties were investigated with time-dependent density functional theory（TD-DFT）. In comparison with those of complexes 2 and 3, the more rigid structure of complex 1 together with its low rate of the radiationless decay via nonemissive d-d state leads to higher photoluminescence quantum efficiency. And the phosphorescence quantum efficiency of complex 1 can be easily controlled by modifying auxiliary ligands. The introduction of fluorine ligand into complexes can effectively increase the radiation transition rate and decrease the radiationless d-d transition rate, and as a result, a novel complex PtLF（5） might be a good phosphorescent material suitable for organic electronic devices.
基金Supported by the National Natural Science Foundation of China（No.21171065） and the Young Scholar Training Program of Jilin University, China.
文摘A well-known deep-blue emitting iridium（III） complex was selected for deuterium isotope effect evalua- tion, both on deuterated locations and numbers, through theoretical investigation. It was revealed that the containment of the d site deuteriation of ancillary ligand picolinate enabled the non-radiative deactivation process to be repessed, and thereby improving the quantum efficiency through such a simple and controllable approach.
基金Supported by the National Natural Science Foundation for Creative Research Group, China（No.21003057）, the China Post- doctoral Science Foundation（No.2013M541286） and the Science and Technology Planning Project of Jilin Province, China（Nos. 20101512, 20110320, 201201078, 20140520109JH and 20150414003GH）.
文摘The electronic structures and spectroscopic properties of heteroleptic cyclometalated iridium（Ⅲ） complexes were investigated. The geometries, electronic structures, and the lowest-lying excited states of （DBQ）2Ir（acac） and （MDQ）2Ir（acac） were investigated via density functional theory-based approaches. A series of designed models of （DBQ）2Ir（dpis）, （DBQ）2Ir（tpip）, （MDQ）2Ir（dpis） and （MDQ）2Ir（tpip） was also calculated for comparison. The structures in the ground and excited states were optimized via B3LYP method. The lowest absorptions and emissions spectra were evaluated via TD-B3LYP and TD-PBE1PBE methods, The computational results reveal that the emission peaks of the designed complexes are at around 585-640 nm, which belong to the orange-yellow wavelength. The frontier molecular orbital properties indicate that the Ir（Ⅲ） complexes have low efficiency roll-off.
