中文摘要：

采用密度泛函理论（DFT）B3LYP方法对含有噻吩环的吡啶Ru（II）配合物的电子结构和非线性光学（NLO）性质进行理论研究.结果表明：配合物[RuII（NH3）5L]2＋（L为含噻吩环的有机基团）中,配位原子与中心金属离子间没有形成稳定的化学键,但存在较强的供体-受体（D-A）相互作用;NH3被羰基（CO）取代后,Ru-C间形成了稳定的σ-π配键,降低了受体的空轨道能级.噻吩环的增加增大了体系的共轭程度,有利于分子内电荷转移,使配合物的极化率α和一阶超极化率β明显增加.结合配合物的前线分子轨道分析发现,电荷转移过程中,对体系二阶NLO系数贡献较大的是配体内电荷转移（ILCT）和配体间电荷转移（LLCT）跃迁,羰基引入后配体到金属的电荷转移（LMCT）使配合物[RuII（CO）5L]2＋比对应的配合物[RuII（NH3）5L]2＋的β值增大约7倍.

英文摘要：

Density functional theory（DFT） with the B3LYP functional was used to investigate the electronic structures and nonlinear optical（NLO） properties of a series of pyridine-based Ru（II） complexes containing thiophene rings.The results indicate that stable chemical bonds do not form between the coordinated atoms and the metal ion for [RuII（NH3）5L]2＋（L：organic groups containing the thiophene ring） complexes.However,strong donor-acceptor（D-A） interactions do exist.The Ru（II） and carbon atoms form stable σ-π coordinated bonds after NH3 is substituted by CO,which decreases the unoccupied orbital energies of the acceptor groups.The degree of system conjugation increases because of an increase in the number of thiophene rings,which is favorable for intramolecule charge transfer.The polarizability α and the first-order hyperpolarizability β values of all the systems are enhanced significantly because of the abovementioned reasons.According to the frontier molecular orbitals,the contribution to the second-order NLO coefficient mainly comes from an intraligand charge transfer（ILCT） and an interligand charge transfer（LLCT）.The introduction of CO increases the β value for the [RuII（CO）5L]2＋ complex about seven times compared with the [RuII（NH3）5L]2＋ analogue,which can be attributed to a ligand-to-metal charge transfer（LMCT）.