Coordinatively unsaturated σ-aryl complexes of ruthenium(II) and osmium(II)

The hydrido complexes MHCl(CO)(PPh3)3 (M = Ru, Os) react with the organomercury compounds R2Hg (R = phenyl, p-tolyl, o-tolyl, trans-β-styryl) to give the five-coordinate, σ aryl and alkenyl complexes MRCl(CO)(PPh3)2 in high yield. Bromide and iodide analogues of these compounds can be prepared through reaction with silver perchlorate followed by addition of excess bromide or iodide ions. The X-ray crystal structures of two of the complexes, Ru(p-tolyl)Cl(CO)(PPh3)2 and Ru(o-tolyl)Cl(CO)(PPh3)2, have been determined.