Reduction of tris(triphenylphosphine)dichlororuthenium(II) in acetonitrile: reformulation of the nature of the product; detection of the first paramagnetic d8 complex

Abstract

The complex alleged to have the stoicheiometry Ru(MeCN)₂(PPh₃)₄ and to contain a π-bonded acetonitrile, produced by electrochemical reduction of RuCl₂(PPh₃)_n(n= 3 or 4) in presence of acetonitrile, has been shown to be the hydrido ortho-metallated phosphine species RuH(MeCN)(C₆H₄PPh₂)(PPh₃)₂; in the reduction of RuCl₂(PPh₃)₃ in tetrahydrofuran–MeCN a red transient intermediate, believed on the basis of e.s.r. studies to be a d⁸ ruthenium(0) species, is formed.