Synthesis and Structures of Novel Zerovalent Ruthenium <i>p</i>-Quinone Complexes and a Bimetallic <i>p</i>-Biquinone Complex

Abstract

Ru( η 6 -cot)( η 2 -dmfm) 2 ( 1; cot = 1,3,5-cyclooctatriene, dmfm = dimethyl fumarate) reacted with p -quinones to give novel p -quinone-coordinated ruthenium(0) complexes, Ru( η 6 -cot)( p -quinone) ( 2 ), in good to high yields via the replacement of two dimethyl fumarates by p -quinones. The reaction of 1 with p -biquinone gave a novel bimetallic zerovalent complex {Ru( η 6 -cot)} 2 ( p -biquinone) ( 3 ), in which p -biquinone coordinates to two isolated “Ru(cot)” moieties with a unique mode and the two Ru(cot) groups are located at endo positions. Complexes 2 and 3 have either p -quinone or p -biquinone as π-acceptor ligands. The structures of complexes Ru( η 6 -cot)(2,6-dimethoxy- p -quinone) ( 2f ) and 3 were determined by X-ray crystallography.