RU(II) AND NI(II) N, S-HETEROCYCLIC CARBENE COMPLEXES AND THEIR CATALYTIC PROPERTIES

Abstract

This thesis describes the synthetic, structural and catalytic studies of Ru(II) and Ni(II) N,S-heterocyclic (NSHC) carbene complexes. It includes: 1) A series of Ru(II) and Ni(II) N,S-heterocyclic carbene complexes have been synthesized and characterized. They represent the first isolation of Ru/Ni-NHC complexes of benzothiazol-2-ylidene kind. Their catalytic activities towards transfer hydrogenation of ketones, Ullmann-type coupling and hydrosilylation of terminal alkynes have been examined and discussed. 2) The reactivity of Ru(II)-NSHC complexes RuBr(RCOO)(3-R¿BzTh)(PPh3)2 (R = Me, Et; 3-R¿BzTh = 3-benzylbenzothiazol-2-ylidene) have also been examined. Specifically, phosphine substitution of RuIIBr(MeCOO)(3-RBzTh)(PPh3)2 with diphosphine ligands gives complexes of two structural types depending on the relative dispositions of the ligands; a simple way to prepare solvato (CH3CN) Ru(II)-NSHC complexes is provided which avoids the use of silver source; intramolecular sp2 and sp3 C-H bond activation at carbene ligands is studied.