Unsymmetrical bidentate ligands of £\-aminoaldimines leading to sterically controlled selectivity of geometrical isomerism in square planar coordination
Journal
Dalton Transactions
Journal Volume
0
Journal Issue
43
Pages
5945-5956
Date Issued
2008
Author(s)
Lee, Jen-Jeh
Yang, Feng-Zhao
Lin, Ya-Fan
Chang, Ya-Chun
Yu, Kuo-Hsuan
Chang, Mu-Chieh
Lee, Gene-Hsiang
Liu, Yi-Hung
Wang, Yu
Liu, Shiuh-Tzung
Chen, Jwu-Ting
Abstract
New alpha-aminoaldimines with the formula of Et(2)NCMe(2)CH[double bond, length as m-dash]NR (R = (i)Pr, (t)Bu, Ph) and their dichloro or diacetato complexes of Ni, Pd, Pt are prepared and structurally characterized. A nickel complex is in a distorted tetrahedral configuration, and the Pd and Pt complexes () are of square planar form. The alpha-aminoaldimines can chelate to the metal in a C(2)-unsymmetric bidentate motif through the hetero functionalities of amine and imine, which show comparable trans influence. Square planar organometallic palladium derivatives bearing alpha-aminoaldimines, including Pd-methyl, Pd-acetyl, and Pd-(eta(2)-acetylnorboryl) (), are also synthesized. The latter two species are a result of CO-insertion into Pd-methyl complexes and ensuing norbornene-insertion, respectively. The geometrical isomerism is found in the trans configuration in most studied cases. Such a stereoselectivity results from the thermodynamic stability governed predominantly by steric control. The stereoselectivity is also supported by DFT calculations.
Type
journal article