Neutral and anionic halide complexes of ruthenium(IV)

Abstract

Treatment of the ruthenium(IV) complex [{Ru( η 3: η 3−C 10H 16)Cl( μ-Cl)} 2] ( 3a) with [PPh 4]Cl in CH 2Cl 2 at room temperature results in the immediate formation of an orange solution of the anoinic trichloro complex [PPh 4][Ru( η 3: η 3−C 10H 6)Cl 3] ( 4a) in which the chloride ligands adopt a meridional type arrangement. Complex 4a has been characterised by spectroscopic means and by X-ray crystallography. The equatorial RuCl distance is found to be significantly longer than the axial RuCl bond lengths (2.418(1) av. versus 2.458(1) Å). The bromo analogue [PPh 4][Ru( η 3: η 3−C 10H 16)Br 3] ( 4b) is formed along with the bromo analogue of 3a, [{Ru( η 3: η 3−C 10H 16)Br( μ−Br) 2] ( 3b), by reaction of 4a with LiBr i acetone. Complex 3b has been synthesized more simply by reaction of 3a with LiBr, whilst pre-treatment of 3a with Ag[BF 4] followed by addition of LiI gives the iodo complex [{Ru( η 3: η 3−C 10H 16)I( μ-I) 2] 3c. The reactions of 3b and 3c with a number of Lewis bases have been investigated by a series of NMR experiments and are similar to, although slower than, those of 3a. The new anionic complex has also been used to form mixed valence and mixed metal chloro-bridged binuclear species, one which [( η 3: η 3−C 10H 16)ClRu( μ−Cl) 2ClRu( η 5−C 5Me 5)] ( 10), has been characterised by X-ray crystallography.