乙烯基噻吩共轭螺噁嗪化合物的密度泛函理论研究

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λ_max 达到466-540 nm, 且红移十分明显, 其对应开环体O-SO2与O-SO3的λ_max 达到605和647 nm.

Density Functional Theory Study on Vinyl Thiophene Group Conjugated Spirooxazines

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 ele...