手性络合物[M(bpy)_2(phen)]^(2+)和[M(phen)_2(bpy)]^(2+)(M=Ru,Os)圆二色谱的理论解析  

Theoretical analysis of the CD spectra and chiroptical properties of [M(bpy)_2(phen)]^(2+) and [M(phen)_2(bpy)]^(2+) (M=Ru,Os) chelates

作　　者：高小丽[1] 王越奎[1] 王炎[2] 贾杰[1] 苏晓玲[1] 

机构地区：[1]化学生物学与分子工程教育部重点实验室山西大学分子科学研究所,太原030006 [2]吕梁学院化学化工系,吕梁033000

出　　处：《中国科学：化学》2011年第7期1145-1155,共11页SCIENTIA SINICA Chimica

基　　金：国家自然科学基金(20673069);山西省自然科学基金(2007011021)资助

摘　　要：应用密度泛函理论,在B3LYP/LanL2DZ水平上对C2对称性的混配络合物[M(bpy)2(phen)]2+和[M(phen)2(bpy)]2+(M=Ru、Os;bpy=2,2'-bipyridine;phen=1,10-phenanthroline)在水溶液中的几何构型进行了优化,并用TDDFT/B3LYP方法和相同的基组计算了其激发能、旋转强度和振子强度,绘制了相应的圆二色谱(CD).在分析有关跃迁性质的基础上,对实验圆二色谱的谱带进行了明确的解析和指认,同时讨论了短波区激子裂分的规律性.结果表明:四种络合物在长波区(λ>320nm)的CD吸收带主要是由d-π*跃迁产生的荷移谱带;短波区(λ<320nm)则是配体上平行于长轴的π-π*跃迁产生的激子耦合带,且对于Λ构型表现为正的手性激子裂分.其中,[M(bpy)2(phen)]2+只显示出正负两个激子带,分属于联吡啶和邻菲咯啉配体;而[M(phen)2(bpy)]2+则有三个激子带,其中左侧的两个(一负一正)属于邻菲咯啉配体,右侧的正带则属于联吡啶配体.此外,尽管激子耦合属于远程相互作用,但用TDDFT计算的激子裂分样式仍是正确的.这些结论对于深入理解有关混配络合物的电子结构、关联络合物的绝对构型和探讨手性识别机理等具有重要的科学意义.Calculations of the excitation energies,oscillator and rotational strengths,and the CD spectra of the chelates [M（bpy）2（phen）]2＋ and [M（phen）2（bpy）]2＋ （M=Ru,Os;bpy=2,2＇-bipyridine;phen=1,10-phenanthroline） have been performed at the TDDFT/B3LYP/LanL2DZ//DFT/B3LYP/LanL2DZ level including solvent effects.The calculated CD spectra are in good agreement with the observed ones.Detailed analysis for the dominant transitions reveals that the CD bands in the long wavelength region （320-700 nm） are dominated by the charge transfer transitions d-π,while in the short wavelength region （200-320 nm）,the stronger CD bands are mainly from the exciton coupling of the long-axis-polarized π-π transitions on the ligands.The chelate [M（bpy）2（phen）]2＋ shows only two exciton absorption bands,in which the negative one can be assigned to the π-π transition of the phenanthroline,and the positive one to those of bipyridine ligands.However,the chelate [（phen）2（bpy）]2＋ has three excition bands,in which the left two with opposite signs can be assigned to the π-π transitions of phenanthroline ligands,and the right positive one to that of the bipyridine.These findings provide a deep insight into both the electronic structures and chiroptical properties of the chelates with different ligands.

关 键 词：钌、锇的混配络合物 ECD谱理论解析 TDDFT计算 手征光学性质 

分 类 号：O641.4[理学—物理化学]