引用本文:
【打印本页】   【HTML】   【下载PDF全文】   View/Add Comment  【EndNote】   【RefMan】   【BibTex】
←前一篇|后一篇→ 过刊浏览    高级检索
本文已被:浏览 1941次   下载 2162 本文二维码信息
码上扫一扫!
分享到: 微信 更多
DFT Study on Structural Distortion and Vibronic Coupling of Vanadyl Porphyrin Anion and Cation
Hui-ling Gao, Fang Chen, Guo-hua Yao, Dong-ming Chen*
Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
Abstract:
The geometries of one-electron reduced/oxidized species ([TOP]-/[VOP]+) of vanadyl por-phyrin (VOP) have been calculated with PBE1PBE method. The results show that for both [VOP]- and [VOP]+ the ground states are triplet, in which one of the two unpaired electron occupies the dxy orbital of the V atom while the other occupies the π-orbital of porphyrin ring. Thus both [VOP]- and [VOP]+ can be considered as π-radicals. The ground state of neutral VOP molecule is doublet with the unpaired electron occupying dxy orbital of V atom. In contract to the C4v symmetry of neutral VOP molecule, [VOP]- anion has a "rectangular" distorted C2v structure due to Jahn-Teller effect. The linear vibronic coupling constants for the Jahn-Teller active modes of [TOP]- were evaluated and the node patterns of frontier KS orbitals are used to explain the reason why the distortion occurs along specific modes. The ground state [VOP]+ has a porphyrin ring with pronounced bond length alternation due to pseudo-Jahn-Teller effect, causing its symmetry declined from C4v to C4. The bond length alternation is well explained with the node patterns of re-constructed frontier KS orbitals.
Key words:  Vanadyl porphyrin, Jahn-Teller effect, Vibronic coupling
FundProject:
附件
钒氧卟啉正负离子的结构畸变与电子-振动耦合的DFT研究
高慧玲, 陈方, 姚国华, 陈东明*
中国科学技术大学化学物理系,合肥230026
摘要:
用PBE1PBE方法研究了钒氧卟啉一价阴离子([VOP]-)、一价阳离子([VOP]+)的单态和三重态结构. 结果表明[VOP]-和[VOP]+的最稳定电子态均为三重态,其未配对电子一个占据钒的dxy轨道,另一个占据卟啉环的π轨道,因此两者均为π-自由基. 中性分子(VOP)的双重态最稳定,其未配对电子占据钒的dxy轨道. 双重态VOP具有较高的C4v对称性,而三重态[VOP]- 离子由于发生姜-泰勒效应对称性降低为C2v. 计算了[VOP]-姜-泰勒活性振动模式的电子-振动耦合常数,并用前线KS轨道的节面分布解释了姜-泰勒畸变沿特定简正模式发生的原因. 三重态[VOP]+ 阳离子的卟啉环发生键长交替变化,构型畸变起源于电子态近简并引起的赝姜-泰勒效应,导致其对称性从C4v降低为C4,其结构变化可以用重组的前线KS轨道的节面分布解释.
关键词:  钒氧卟啉,π-自由基,姜-泰勒效应,电子-振动耦合
DOI:10.1063/1674-0068/26/05/504-511
分类号: