NEUTRAL AND ANIONIC HALIDE-COMPLEXES OF RUTHENIUM(IV)

Treatment of the ruthenium(IV) complex [{Ru(eta(3):eta(3)-C10H16)Cl(mu-Cl)}(2)] (3a) with [PPh(4)]Cl in CH2Cl2 at room temperature results in the immediate formation of an orange solution of the anionic trichloro complex [PPh(4)][Ru(eta(3):eta(3)-C10H16)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) Angstrom). The bromo analogue [PPh(4)][Ru(eta(3):eta(3)-C10H16)Br-3] (4b) is formed along with the bromo analogue of 3a, [{Ru(eta(3):eta(3)-C10H16)Br(mu-Br)}(2)] (3b), by reaction of 4a with LiBr in acetone. Complex 3b has been synthesized more simply by reaction of 3a with LiBr, whilst pre-treatment of 3a with Ag[BF4] followed by addition of LiI gives the iodo complex [{Ru(eta(3):eta(3)-C10H16)I(mu-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 of which, [(eta(3): eta(3)-C10H16)ClRu(mu-Cl)(2)RhCl(eta(5)-C(5)Me(5))] (10), has been characterised by X-ray crystallography.