Synthesis, Characterization, and Substituent Effects of Binuclear Ruthenium Vinyl Complexes [RuCl(CO)(PMe₃)₃]₂(μ-CH═CH−Ar−CH═CH)

Abstract

A series of binuclear ruthenium vinyl complexes [RuCl(CO)(PMe 3 ) 3 ] 2 (μ-CH═CH−Ar−CH═CH) (Ar = C 6 H 4 ( 6a ), C 6 H 3 CH 3 ( 6b ), C 6 H 3 OCH 3 ( 6c ), C 6 H 3 F ( 6d ), C 6 H 3 Cl ( 6e ), C 6 H 3 Br ( 6f ), C 6 H 3 CN ( 6g ), C 6 H 3 NO 2 ( 6h ), C 6 H 2 (CH 3 ) 2 -2,5 ( 6i ), C 6 H 2 (OCH 3 ) 2 -2,5 ( 6j ), C 6 H 2 (F) 2 -2,5 ( 6k ), C 6 H 2 (CF 3 ) 2 -2,5 ( 6l ), and C 6 H 3 CF 3 ( 6m )) have been prepared. The respective products have been characterized by elemental analyses, NMR spectrometry, and UV/vis spectrophotometry. The structures of 6h, 6i, and 6j have been established by X-ray crystallography. Electrochemical studies have revealed that intermetallic electron communication between the two Ru centers may be fine-tuned by modification of the bridging spacers, that is, by introducing one or two substituent groups on the 1,4-diethenylphenylene bridge. Electron-releasing substituents have been found to facilitate electron communication between the two metal centers.