Complexes of the platinum metals. Part 29. Pyridine-2-thiolate derivatives of ruthenium and osmium: X-ray crystal structures of [Ru(C5H4NS)2(CO)2(PPh3)] and [Ru(C5H4NS)2(CO)(PPh3)

Abstract

Ruthenium and osmium precursors [MH(Cl)(CO)(PPh3)3], [MH2(CO)(PPh3)3], [Ru(CO)3(PPh3)2], [OsH2(CO)2(PPh3)2], [RuH2(PPh3)4], and [OsH4(PPh3)3] react with pyridine-2-thiol (pySH) or dipyridyl-2,2′-disulphide (pySSpy) in boiling benzene or toluene to afford a range of pyridine-2-thiolate complexes including [MCl(pyS)(CO)(PPh3)2], (2 isomers), [M(pyS)2(CO)2(PPh3)], [M(pyS)2(CO)(PPh3)], and [M(pyS)2(PPh3)2] in which the pyridine-2-thiolate ligands are bound in monodentate (S-bonded) or bidentate (N,S-chelated) mode. Similar products are obtained from [RuCl2(PPh3)3] and [RuCl2(CO)2(PPh3)2] in the presence of triethylamine and pyridine-2-thiol. The new complexes have been characterised by i.r. and n.m.r. (31P-{1H} and 1H) spectroscopy; reaction pathways are discussed. The X-ray crystal structures of [Ru(pyS)2(CO)2(PPh3)] and [Ru(pyS)2(CO)(PPh3)] have been determined. The dicarbonyl [Ru(pyS)2(CO)2(PPh3)], which undergoes facile conversion to [Ru(pyS)2(CO)(PPh3)], displays structural evidence of incipient attack by the non-co-ordinated N atom of the monodentate pyridine-2-thiolate ligand on a carbonyl group [N ⋯ C 2.782(7)A]. Crystals of [Ru(pyS)2(CO)2(PPh3)] are monoclinic, space group P21/c, with a= 11.307(2), b= 11,083(3), c= 24.090(5)A, β= 109.47(2)°, and Z= 4. The structure, which has been refined to R= 0.045 for 4 375 observed reflections, consists of highly distorted octahedral ruthenium(II) molecules with monodentate (S-bonded) and bidentate (N,Sbonded) pyridine-2-thiolate ligands, a cis pair of carbonyl groups, and a triphenylphosphine ligand trans to the S-bonded pyridine-2-thiolate. Crystals of [Ru(pyS)2(CO)(PPh3)] are triclinic, space group P, with a= 10.317(3), b= 11.749(3), c= 12.517(3)A, α= 67.65(2), β= 70.55(2)γ= 86.43(2)°, and Z= 2. The structure, which has been refined to R= 0.040 for 12 196 observed reflections consists of highly distorted octahedral ruthenium(II) molecules with a cis pair of bidentate (N,S-bonded) pyridine-2-thiolate ligands (trans S atoms), a carbonyl group, and a triphenylphosphine ligand.