物理化学学报 >> 2011, Vol. 27 >> Issue (08): 1847-1853.doi: 10.3866/PKU.WHXB20110840

理论与计算化学 上一篇    下一篇

乙烯基噻吩共轭螺噁嗪化合物的密度泛函理论研究

孙海涛1, 田晓慧1, 元以中1, 孙金煜1, 孙真荣2, 卓小玲1   

  1. 1. 华东理工大学材料科学与工程学院, 超细材料制备与应用教育部重点实验室, 上海 200237;
    2. 华东师范大学, 精密光谱科学与技术国家重点实验室, 上海 200062
  • 收稿日期:2011-04-21 修回日期:2011-05-18 发布日期:2011-07-19
  • 通讯作者: 田晓慧 E-mail:tianxh@263.net
  • 基金资助:

    国家高技术研究发展计划(0099AA03500), 上海市重点学科(B502)和重点实验室(08DZ2230500, 09JC1404300)资助项目

Density Functional Theory Study on Vinyl Thiophene Group Conjugated Spirooxazines

SUN Hai-Tao1, TIAN Xiao-Hui1, YUAN Yi-Zhong1, SUN Jin-Yu1, SUN Zhen-Rong2, ZHUO Xiao-Ling1   

  1. 1. Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China;
    2. State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, P. R. China
  • Received:2011-04-21 Revised:2011-05-18 Published:2011-07-19
  • Contact: TIAN Xiao-Hui E-mail:tianxh@263.net
  • Supported by:

    The project was supported by the National High Technology Research and Development Program of China (0099AA03500), Shanghai Leading Academic Discipline Project (B502) and Shanghai Key Laboratory Project, China (08DZ2230500, 09JC1404300).

摘要:

采用密度泛函理论(DFT)方法, 在B3LYP/6-31G* 水平上对乙烯基噻吩共轭螺噁嗪化合物 SO-SO3 的几何构型、电子结构、前线分子轨道等进行了理论研究, 计算结果表明: SO-SO3的开环过程会使得开环体的左右两个部分键长均等化, 导致共轭体系变大, 能隙明显减小; 乙烯基噻吩基团共轭接入螺噁嗪母体后, 导致体系的共轭作用变大, 在激发态下电子流动增强, 形成由乙烯基噻吩向萘并噁嗪的有效电荷转移与能量转移; 结合前线分子轨道成分分析乙烯基噻吩单元在最高占据分子轨道(HOMO)和最低未占据分子轨道(LUMO)中的轨道贡献率明显增加. 含时密度泛函理论(TD-DFT)计算的电子吸收光谱结果显示: 当接入的乙烯基噻吩单元达到2-3个时, 影响SO2和SO3开环的最低能量激发态变为第一激发单重态S1, 并且均源自电子从HOMO至LUMO的跃迁且为π-π*跃迁; 其最大吸收波长λmax 达到466-540 nm, 且红移十分明显, 其对应开环体O-SO2与O-SO3的λmax 达到605和647 nm.

关键词: 乙烯基噻吩, 螺噁嗪, 密度泛函理论, 前线分子轨道, 电子吸收光谱

Abstract:

We carried out a theoretical study on the geometries, electronic structures, and frontier molecular orbitals of vinyl thiophene group conjugated spirooxazines (SO-SO3) using density functional theory (DFT) at the B3LYP/6-31G* level. The calculated results show that the equalization of bond lengths at the left and right parts of the open-forms occurred during the ring-opening process. A large conjugated system was formed and this significantly narrowed the energy gap. The conjugated system became larger and its electrons flowed easily because of the introduction of different lengths of vinyl thiophene conjugation moieties into the spirooxazine molecule. The electrons and energy efficiently transferred from the vinyl thiophene to naphthoxazine. The orbital contribution rate of the vinyl thiophene group in the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) increased obviously. Time-dependent DFT (TD-DFT) calculations showed that as the conjugated vinyl thiophene unit reached 2-3 the first singlet excited state of SO2 and SO3 resulted from the electron transition from the HOMO to the LUMO, which were also assigned to the π* transition. Meanwhile, λmax was between 466 and 540 nm with an obvious red-shift while the λmax of O-SO2 and O-SO3 reached 605 and 647 nm, respectively.

Key words: Vinyl thiophene, Spirooxazine, Density functional theory, Frontier molecular orbital, Electronic absorption spectrum

MSC2000: 

  • O641