Copper(II) complexes of a heterotopic N-heterocyclic carbene ligand: Preparation and catalytic application

摘要

Copper complexes containing aN-heterocylic carbene (NHC)/amidate/pyridine tridentate, 3-mesityl-1-(2-oxo-2-[{pyridin-2-ylmethyl}amino]ethyl)-imidazolin-2-ylidene (HL), were synthesized and characterized. By X-ray single crystal analysis, both Cu(L)(OAc) (3a) and Cu(L)Br (3b) show that the metal center is coordinated by a CNN-tridentate and a anionic donor in a slightly distorted square-planar geometry. These copper complexes are active as catalysts for oxidative bromination of dimethoxybenzene and styrene with the use of LiBr as the bromine source and oxygen as the terminal oxidant.