Metalloporphyrins have devastating effects on the deep processing and efficient utilization of petroleum resources. Various porphyrins are derived from porphin by substitution at the β, meso, or both positions. Herei...Metalloporphyrins have devastating effects on the deep processing and efficient utilization of petroleum resources. Various porphyrins are derived from porphin by substitution at the β, meso, or both positions. Herein, we focus on the interaction between nickel(Ⅱ) and the porphyrin skeleton. Five different density functionals were selected for determining a reliable approach to simulate porphyrin-nickel(Ⅱ) complexes. At D4h symmetry, the 10b1g, 15a1g, 4e1g and 9b2g were dominated by the 3d character of nickel. Compared with pure density functional, the hybrid functional gave larger highest occupied molecular orbital(HOMO) and lowest unoccupied molecular orbital(LUMO) gap, and the higher HOMO-LUMO gap also corresponded to a higher excitation energy. The characteristic Soret and Q bands modeled by timedependent density functional theory(TDDFT) calculations matched well with experimental results, and the absorption was discussed in detail with natural transition orbitals(NTO) analysis. Furthermore, the binding character of nickel(Ⅱ) with various substituted porphyrins were calculated at perdew-burke-ernzerhof(PBE) level, showed that the geometry and complexation behavior of porphyrin-nickel(Ⅱ) complexes could be significantly tuned by different substituents. The symmetry of the complex was reduced and the skeleton ring get distortion when introducing different substituents. Compared with ETIO porphyrin, the introduction of phenyl on the β position can expand the conjugated system and promote the covalent character of Ni-N bond.展开更多
The different fluorescence behavior caused by the excited state proton transfer in 3-hydroxy-4-pyridylisoquinoline(2a)compound has been theoretically investigated.Our calculation results illustrate that the 2a monomer...The different fluorescence behavior caused by the excited state proton transfer in 3-hydroxy-4-pyridylisoquinoline(2a)compound has been theoretically investigated.Our calculation results illustrate that the 2a monomer in tetrahydrofuran solvent would not occur proton transfer spontaneously,while the 2a complex in methanol(MeOH)solvent can undergo an asynchronous excited state intramolecular proton transfer(ESIPT)process.The result was confirmed by analyzing the related structural parameters,infrared vibration spectrum and reduced density gradient isosurfaces.Moreover,the potential curves revealed that with the bridging of single MeOH molecular the energy barrier of ESIPT was modulated effectively.It was distinctly reduced to 4.80 kcal/mol in 2a-MeOH complex from 25.01 kcal/mol in 2a monomer.Accordingly,the ESIPT process induced a fluorochromic phenomenon with the assistant of proton-bridge.The elucidation of the mechanism of solvent discoloration will contribute to the design and synthesis of fluorogenic dyes as environment-sensitive probes.展开更多
Excited-state double proton transfer(ESDPT)in the 1-[(2-hydroxy-3-methoxy-benzylidene)-hydrazonomethyl]-naphthalen-2-ol(HYDRAVH_(2))ligand was studied by the density functional theory and time-dependent density functi...Excited-state double proton transfer(ESDPT)in the 1-[(2-hydroxy-3-methoxy-benzylidene)-hydrazonomethyl]-naphthalen-2-ol(HYDRAVH_(2))ligand was studied by the density functional theory and time-dependent density functional theory method.The analysis of frontier molecular orbitals,infrared spectra,and non-covalent interactions have crossvalidated that the asymmetric structure has an influence on the proton transfer,which makes the proton transfer ability of the two hydrogen protons different.The potential energy surfaces in both S_(0)and S_1 states were scanned with varying O-H bond lengths.The results of potential energy surface analysis adequately proved that the HYDRAVH_(2)can undergo the ESDPT process in the S_1 state and the double proton transfer process is a stepwise proton transfer mechanism.Our work can pave the way towards the design and synthesis of new molecules.展开更多
利用B3LYP方法优化了多吡啶钌乙炔配合物[(tpy)(bpy)RuC≡CC6H4R]+[tpy=2,2′:6′,2"-terpyridine,bpy=2,2′-bipyridine;R=Cl(1),H(2),OMe(3)]的基态几何结构,得到的几何参数与实验结果吻合。利用SCRF方法中的CPCM模型来模拟溶剂...利用B3LYP方法优化了多吡啶钌乙炔配合物[(tpy)(bpy)RuC≡CC6H4R]+[tpy=2,2′:6′,2"-terpyridine,bpy=2,2′-bipyridine;R=Cl(1),H(2),OMe(3)]的基态几何结构,得到的几何参数与实验结果吻合。利用SCRF方法中的CPCM模型来模拟溶剂化效应,采用TDDFT(Time-Dependent Density Functional Theory)方法计算得到了配合物在CH3CN溶液中的激发态电子结构和电子吸收光谱。研究结果表明,配合物1~3溶液吸收光谱的跃迁性质相似,其中低能吸收均被指认为MLCT和LLCT混合激发跃迁。展开更多
We have studied the ground and excited states of the three dendritic polynuclear Pt(II) complexes 1-[Cl(PH3)2PtC≡≡ C]-3,5-[HC≡≡ C]C6H3 (1), 1,3-[Cl(PH3)2PtC≡≡ C]2-5-[HC≡≡ C]C6H3 (2), and 1,3,5-[Cl(PH3)2- PtC≡...We have studied the ground and excited states of the three dendritic polynuclear Pt(II) complexes 1-[Cl(PH3)2PtC≡≡ C]-3,5-[HC≡≡ C]C6H3 (1), 1,3-[Cl(PH3)2PtC≡≡ C]2-5-[HC≡≡ C]C6H3 (2), and 1,3,5-[Cl(PH3)2- PtC≡≡ C]3C6H3 (3), by using the B3LYP and UB3LYP methods, respectively. TDDFT approach with the PCM model was performed to predict the emission spectra properties of 1―3 in CH2Cl2 solution. We first predicted the excited-state geometries for the three complexes. With the change of the number of Pt(II) atom, 1―3 show the different geometry structures in both the ground and excited states; fur- thermore, the increase of the metal density from 1 to 3 results in the red shift of the lowest-energy emissions along the series. The luminescent properties of 1 are somewhat different from those of 2 and 3. The emission properties of 2 and 3 are richer than 1. Our conclusion can give a good support for designing the high efficient luminescent materials.展开更多
Excited-state hydrogen-bonding dynamics of N-methylformamide (NMF) in water has been investigated by time-dependent density functional theory (TDDFT) method. The ground-state geometry optimizations were calculated by ...Excited-state hydrogen-bonding dynamics of N-methylformamide (NMF) in water has been investigated by time-dependent density functional theory (TDDFT) method. The ground-state geometry optimizations were calculated by density functional theory (DFT) method, while the electronic transition energies and corresponding oscillation strengths of the low-lying electronically excited states of isolated NMF, water monomers and the hydrogen-bonded NMF-H 2 O were calculated by TDDFT method. According to Zhao's rule on the excited-state hydrogen bonding dynamics, our results demonstrate that the intermolecular hydrogen bond C=O···O-H is strengthened and weakened in different electronically excited states. The hydrogen bond strengthening and weakening in the electronically excited state plays an important role in the photophysics of NMF in solutions.展开更多
The photochromic mechanism of 1-phenyl-3-methyl-4-(6-hydro-4-amino-5-sulfo-2,3- pyrazine)-pyrazole-5-one has been investigated using the density functional theory(DFT). The solvent effect is simulated using the polari...The photochromic mechanism of 1-phenyl-3-methyl-4-(6-hydro-4-amino-5-sulfo-2,3- pyrazine)-pyrazole-5-one has been investigated using the density functional theory(DFT). The solvent effect is simulated using the polarizable continuum model(PCM) of the self-consistent reaction field theory. According to the crystal structure of the title compound, an intramolecular proton transfer mechanism from enol to keto form was proposed to interpret its photochromism. Bader's atom-in-molecule(AIM) theory is used to investigate the nature of hydrogen bonds and ring structures. Time-dependent density functional theory(TDDFT) calculation results show that the photochromic process from enol to keto form is reasonable. The conformation and molecular orbital analysis of enol and keto forms explain why only intramolecular proton transfer is possible. The results from analyzing the energy and dipole moments of enol form, transition state and keto form in the gas phase and in different solvents have been used to assess the stability of the title compound.展开更多
A series of polypyridine ruthenium(II)acetylide complexes,[(tpy)(bpy)RuC≡CC6H4R]+(tpy=2,2′:6′,2″-terpyridine,bpy=2,2′-bipyridine;R=F(1),Cl(2),H(3),Me(4)and OMe(5))are investigated theoretically to explore their e...A series of polypyridine ruthenium(II)acetylide complexes,[(tpy)(bpy)RuC≡CC6H4R]+(tpy=2,2′:6′,2″-terpyridine,bpy=2,2′-bipyridine;R=F(1),Cl(2),H(3),Me(4)and OMe(5))are investigated theoretically to explore their electronic structures and spectroscopic properties.Their ground/excited state geometries,electronic structures and spectroscopic properties are first calculated using density functional theory(DFT)and time-dependent DFT(TDDFT).The absorption and emission spectra of the complexes in acetonitrile solution are also obtained by using TDDFT(B3LYP)method associated with the CPCM model.The calculations show that the energy levels of HOMOs for 1–5 are sensitive to the substituent on phenylacetylide ligand and increase with the same order of the electron-donating ability of the substituents;however,those of polypyridine-based LUMOs vary slightly.The lowest-energy absorptions and emissions for 1–5 are progressively red-shifted in the order of 1≈2<3<4<5 when the electron-donating groups are introduced into the phenylacetylide ligand.The phosphorescence of 1 are attributed to{[dxz(Ru)+π(C≡C)]→[π*(tpy)]}(3MLCT/3LLCT)transition,whereas those of 2–5 are originated from{[dxz/dxy(Ru)+π(C≡C)+π(C6H4R)]→[π*(tpy/bpy)]}(3MLCT/3LLCT)transitions.展开更多
基金supported by National Key R & D program of China (No.2021YFA1501204)Contract Projects of China Petroleum & Chemical Corporation (SINOPEC Corp.) (grant number 123017grant number 121043-2)。
文摘Metalloporphyrins have devastating effects on the deep processing and efficient utilization of petroleum resources. Various porphyrins are derived from porphin by substitution at the β, meso, or both positions. Herein, we focus on the interaction between nickel(Ⅱ) and the porphyrin skeleton. Five different density functionals were selected for determining a reliable approach to simulate porphyrin-nickel(Ⅱ) complexes. At D4h symmetry, the 10b1g, 15a1g, 4e1g and 9b2g were dominated by the 3d character of nickel. Compared with pure density functional, the hybrid functional gave larger highest occupied molecular orbital(HOMO) and lowest unoccupied molecular orbital(LUMO) gap, and the higher HOMO-LUMO gap also corresponded to a higher excitation energy. The characteristic Soret and Q bands modeled by timedependent density functional theory(TDDFT) calculations matched well with experimental results, and the absorption was discussed in detail with natural transition orbitals(NTO) analysis. Furthermore, the binding character of nickel(Ⅱ) with various substituted porphyrins were calculated at perdew-burke-ernzerhof(PBE) level, showed that the geometry and complexation behavior of porphyrin-nickel(Ⅱ) complexes could be significantly tuned by different substituents. The symmetry of the complex was reduced and the skeleton ring get distortion when introducing different substituents. Compared with ETIO porphyrin, the introduction of phenyl on the β position can expand the conjugated system and promote the covalent character of Ni-N bond.
基金Project supported by the National Basic Research Program of China(Grant No.2019YFA0307701)the National Natural Science Foundation of China(Grant No.11874180)the Young and Middle-aged Scientific and Technological Innovation Leaders and Team Projects in Jilin Province(Grant No.20200301020RQ).
文摘The different fluorescence behavior caused by the excited state proton transfer in 3-hydroxy-4-pyridylisoquinoline(2a)compound has been theoretically investigated.Our calculation results illustrate that the 2a monomer in tetrahydrofuran solvent would not occur proton transfer spontaneously,while the 2a complex in methanol(MeOH)solvent can undergo an asynchronous excited state intramolecular proton transfer(ESIPT)process.The result was confirmed by analyzing the related structural parameters,infrared vibration spectrum and reduced density gradient isosurfaces.Moreover,the potential curves revealed that with the bridging of single MeOH molecular the energy barrier of ESIPT was modulated effectively.It was distinctly reduced to 4.80 kcal/mol in 2a-MeOH complex from 25.01 kcal/mol in 2a monomer.Accordingly,the ESIPT process induced a fluorochromic phenomenon with the assistant of proton-bridge.The elucidation of the mechanism of solvent discoloration will contribute to the design and synthesis of fluorogenic dyes as environment-sensitive probes.
基金Project supported by the National Basic Research Program of China(Grant No.2019YFA0307701)the National Natural Science Foundation of China(Grant No.11874180)the Young and Middle-aged Scientific and Technological Innovation leaders and Team Projects in Jilin Province,China(Grant No.20200301020RQ)。
文摘Excited-state double proton transfer(ESDPT)in the 1-[(2-hydroxy-3-methoxy-benzylidene)-hydrazonomethyl]-naphthalen-2-ol(HYDRAVH_(2))ligand was studied by the density functional theory and time-dependent density functional theory method.The analysis of frontier molecular orbitals,infrared spectra,and non-covalent interactions have crossvalidated that the asymmetric structure has an influence on the proton transfer,which makes the proton transfer ability of the two hydrogen protons different.The potential energy surfaces in both S_(0)and S_1 states were scanned with varying O-H bond lengths.The results of potential energy surface analysis adequately proved that the HYDRAVH_(2)can undergo the ESDPT process in the S_1 state and the double proton transfer process is a stepwise proton transfer mechanism.Our work can pave the way towards the design and synthesis of new molecules.
文摘利用B3LYP方法优化了多吡啶钌乙炔配合物[(tpy)(bpy)RuC≡CC6H4R]+[tpy=2,2′:6′,2"-terpyridine,bpy=2,2′-bipyridine;R=Cl(1),H(2),OMe(3)]的基态几何结构,得到的几何参数与实验结果吻合。利用SCRF方法中的CPCM模型来模拟溶剂化效应,采用TDDFT(Time-Dependent Density Functional Theory)方法计算得到了配合物在CH3CN溶液中的激发态电子结构和电子吸收光谱。研究结果表明,配合物1~3溶液吸收光谱的跃迁性质相似,其中低能吸收均被指认为MLCT和LLCT混合激发跃迁。
基金Supported by the National Natural Science Foundation of China (Grant Nos. 20573042, 20333050 and 20173021)Natural Science Foundation of Heilongjiang Province of China (Grant No. B200601)Science Foundation for Excellent Youth of Heilongjiang University of China (Grant No. JC2006L2)
文摘We have studied the ground and excited states of the three dendritic polynuclear Pt(II) complexes 1-[Cl(PH3)2PtC≡≡ C]-3,5-[HC≡≡ C]C6H3 (1), 1,3-[Cl(PH3)2PtC≡≡ C]2-5-[HC≡≡ C]C6H3 (2), and 1,3,5-[Cl(PH3)2- PtC≡≡ C]3C6H3 (3), by using the B3LYP and UB3LYP methods, respectively. TDDFT approach with the PCM model was performed to predict the emission spectra properties of 1―3 in CH2Cl2 solution. We first predicted the excited-state geometries for the three complexes. With the change of the number of Pt(II) atom, 1―3 show the different geometry structures in both the ground and excited states; fur- thermore, the increase of the metal density from 1 to 3 results in the red shift of the lowest-energy emissions along the series. The luminescent properties of 1 are somewhat different from those of 2 and 3. The emission properties of 2 and 3 are richer than 1. Our conclusion can give a good support for designing the high efficient luminescent materials.
基金Supported by the Fundamental Research Funds for the Central Universities (No.2012QN066,2011QN142)
文摘Excited-state hydrogen-bonding dynamics of N-methylformamide (NMF) in water has been investigated by time-dependent density functional theory (TDDFT) method. The ground-state geometry optimizations were calculated by density functional theory (DFT) method, while the electronic transition energies and corresponding oscillation strengths of the low-lying electronically excited states of isolated NMF, water monomers and the hydrogen-bonded NMF-H 2 O were calculated by TDDFT method. According to Zhao's rule on the excited-state hydrogen bonding dynamics, our results demonstrate that the intermolecular hydrogen bond C=O···O-H is strengthened and weakened in different electronically excited states. The hydrogen bond strengthening and weakening in the electronically excited state plays an important role in the photophysics of NMF in solutions.
基金Supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region(No.2013211B04)
文摘The photochromic mechanism of 1-phenyl-3-methyl-4-(6-hydro-4-amino-5-sulfo-2,3- pyrazine)-pyrazole-5-one has been investigated using the density functional theory(DFT). The solvent effect is simulated using the polarizable continuum model(PCM) of the self-consistent reaction field theory. According to the crystal structure of the title compound, an intramolecular proton transfer mechanism from enol to keto form was proposed to interpret its photochromism. Bader's atom-in-molecule(AIM) theory is used to investigate the nature of hydrogen bonds and ring structures. Time-dependent density functional theory(TDDFT) calculation results show that the photochromic process from enol to keto form is reasonable. The conformation and molecular orbital analysis of enol and keto forms explain why only intramolecular proton transfer is possible. The results from analyzing the energy and dipole moments of enol form, transition state and keto form in the gas phase and in different solvents have been used to assess the stability of the title compound.
基金supported by the National Natural Science Foundation of China(Grant No.51073048)the National Natural Science Foundation ofHei Long Jiang Province of China(Grant No.B201102)+1 种基金the Science Foundation for Leaders in Academe of Harbin City of China(Grant No.2013RFXXJ024)the Science Foundation for Elitists of Harbin University of Science and Technology
文摘A series of polypyridine ruthenium(II)acetylide complexes,[(tpy)(bpy)RuC≡CC6H4R]+(tpy=2,2′:6′,2″-terpyridine,bpy=2,2′-bipyridine;R=F(1),Cl(2),H(3),Me(4)and OMe(5))are investigated theoretically to explore their electronic structures and spectroscopic properties.Their ground/excited state geometries,electronic structures and spectroscopic properties are first calculated using density functional theory(DFT)and time-dependent DFT(TDDFT).The absorption and emission spectra of the complexes in acetonitrile solution are also obtained by using TDDFT(B3LYP)method associated with the CPCM model.The calculations show that the energy levels of HOMOs for 1–5 are sensitive to the substituent on phenylacetylide ligand and increase with the same order of the electron-donating ability of the substituents;however,those of polypyridine-based LUMOs vary slightly.The lowest-energy absorptions and emissions for 1–5 are progressively red-shifted in the order of 1≈2<3<4<5 when the electron-donating groups are introduced into the phenylacetylide ligand.The phosphorescence of 1 are attributed to{[dxz(Ru)+π(C≡C)]→[π*(tpy)]}(3MLCT/3LLCT)transition,whereas those of 2–5 are originated from{[dxz/dxy(Ru)+π(C≡C)+π(C6H4R)]→[π*(tpy/bpy)]}(3MLCT/3LLCT)transitions.
