Theoretical Study on the Dissociation of Ligands in the Rhodium and Iridium Complexes Containing 1,1,1,5,5,5-Hexafl uo roacetylaceto nato

作     者：Xiufang Ma Yanhua Lei Zhaoxu Chen 

作者机构：Institute of Theoretical and Computational Chemistry Key Laboratory of Mesoscopic Chemistry of MOE School of Chemistry and Chemical Engineering Nanjing University Nanjing Jiangsu 210093 China Institute of Molecular Engineering and Applied Chemistry Anhui University of Technology Ma' anshan Anhui 243002 China 

出 版 物：《Chinese Journal of Chemistry》 (中国化学（英文版）)

年 卷 期：2013年第31卷第3期

页      面：421-429页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 070303[理学-有机化学] 0703[理学-化学] 

基　　金：support from the National Key Basic Research Development Program of China (973 Program) 

主　　题：C-H activation protonation conformatiom bond dissociation energy 

摘      要：Functionalization of the inert C-H bonds of unsaturated molecules by transition metal complex is an important means to form new C-C bonds. The functionalization is usually initiated by the ligand dissociation of a complex. In this paper we employ both ab initio and density functional methods to explore the influence of central metals, conformation, solvent and protonation on the ligand dissociation of the （hfac-O,O）2M（L）（py） complexes [M=Rh（Ⅲ） or Ir（Ⅲ）, hfac-O,O=k^2-O,O-1,1,1,5,5,5-hexafluoroacetylacetonato, L = CH3, CH3CO2, （CH3CO）2CH, CH30 or OH, py=pyridine]. We demonstrate that ligand pyridine dissociates more easily than the ＂L＂ ligands un-der study in aprotic solvent and gas phase and the dissociation of pyridine is more facile in the trans-conformation than in the cis-isomer. These phenomena are rationalized based on electronic structure and molecular orbital inter-actions. We show that solvation only slightly stabilizes the complexes and does not change the ligand dissociation ordering. In particular, we show that pyridine is no longer the labile ligand in protic media. Instead, the oxy-gen-containing ligands （apart from those like hfac that form a cyclic structure with the central metal） that coordinate to the central metal via oxygen atom become the labile ones. Finally our calculations indicate that hfac is a stable ligand, even in protic media.