【作者】 赵光金；

【导师】 张红星；

【作者基本信息】 吉林大学 ， 物理化学， 2007， 硕士

【摘要】 本文利用从头算和密度泛函方法对一价铼炔基配合物发光材料进行了理论研究。通过理论计算详细的给出了一价铼炔基配合物的平衡几何结构、电子结构、最低能三重激发态的几何构型和吸收、发射光谱等信息,为探索发光材料的结构-性质间关系及相关实验研究提供了可靠的理论依据。主要结果如下:研究了配合物Re（bpy）（CO）₃（C≡CR）（bpy = 2,2’-bipyridine; R = H （1）, CH₂OH （2）, and C₆H₅ （3））的电子结构和光谱性质。计算表明,炔基上不同的取代基对配合物基态和激发态结构的影响很小,但却引起了电子结构的很大变化。在吸收和发射中,1-3的HOMO对炔基上取代基的变化比较敏感,而且HOMO能级随着取代基给电子能力的增强而增大,而由bpy特征主导的非占据轨道的能级却几乎保持稳定。1-3的源自HOMO-1→LUMO的最低能吸收光谱被指认为单重态d（Re）/π（C≡C）/p（CO）→π*（bpy） MLCT/LLCT跃迁特征,而最低能磷光发射光谱则具有三重态d（Re）/π（C≡CR）/p（CO）→π*（bpy） ³MLCT/³LLCT特征。计算得到的1-3的具有MLCT/LLCT和MLCT/LLCT/ILCT跃迁特征的低能吸收光谱（311 （1）, 323 （2）, and 341 nm （3））和最低能磷光发射光谱随着炔基上取代基给电子能力的增强而以1 < 2 < 3的顺序发生红移,但是具有MLCT/LLCT跃迁特征的最低能吸收光谱和具有ILCT跃迁特征的高能吸收光谱（281 （1）, 281 （2）, and 283 nm （3））几乎不随炔基上取代基的改变而发生变化。更多还原

【Abstract】 Recently, the scientific researchers endeavor to design and develop new type of luminescent devices with high efficient, high stability, high brightness. The transition metal materials have good performance, such as long luminescent life and single color. Particularly, the rhenium（I） diimine complexes have been well studied because they can serve as excellent emitters, photocatalysts, and building blocks for supramolecules. Furthermore, the introduction of the acetylide moieties into the rhenium（I） diimine system would render the metal center more electron rich, with the additional advantage of raising the energy of the d-d states which would improve the population of the MLCT state.In this thesis, the ground-state structures of the Re（I） acetylide complexes were carried out using density functional theory （DFT）. The nature and the energy of singlet-singlet electronic transitions have been obtained by the TD-DFT/PBE1PBE calculations upon the optimized geometries. The excited geometries were optimized by the ab initio （CIS） method. Based on the excited geometries, the emission spectra were investigated. The theoretical studies show that the modification of chemical structures could greatly modulate and improve the electronic and optical properties of light-emitting materials. The following is the main results:Electronic structures and spectroscopic properties of Re（bpy）（CO）₃（C≡CR） （bpy = 2,2’-bipyridine; R = H （1）, CH₂OH （2）, and C₆H₅ （3）） were studied by the ab initio and DFT methods. The ground- and excited-state structures were optimized by the DFT-B3LYP and CIS methods, respectively. The absorption and emission spectra in the dichloromethane solution were calculated by the TD-DFT method at PBE1PBE level associated with the PCM model. The calculated results indicated that the variation of the substituents on the acetylide ligand slightly changes the structures in the ground and excited states but leads to a great difference in the electronic structures. The HOMOs of 1-3 are sensitive to the change of the substituents on the acetylide ligand, and the energy levels of HOMOs are increased obviously with the introduction of the electron-donating groups; but those of the bpy-based LUMOs vary slightly. The lowest-energy absorptions arising from the HOMO-1→LUMO transitions for 1-3 were attributed to the singlet d（Re）/π（C≡C）/p（CO）→π*（bpy） charge transfer （MLCT/LLCT） transitions, while the lowest-energy emissions were attributed to the triplet d（Re）/π（C≡CR）/p（CO）→π*（bpy） charge transfer （³MLCT/³LLCT） transitions. The low-lying absorptions （311 （1）, 323 （2）, and 341 nm （3）） with the MLCT/LLCT and MLCT/LLCT/ILCT characters and the lowest-energy emissions for 1-3 are red- shifted in the order 1 < 2 < 3 when the electron-donating groups are introduced into the acetylide ligand, but the lowest-energy absorptions with MLCT/LLCT character for 1-3 and the intense absorptions （281 （1）, 281 （2）, and 283 nm （3）） with ILCT character are almost not changed. By comparison of the results obtained using the different functionals embedded in the TD-DFT method, the calculated results indicated that the PBE1PBE functional is appropriate for the Re（I） acetylide complexes to get the relatively satisfactory results.更多还原