OSMIUM COMPLEXES CONTAINING EITHER CHELATING OR NONCHELATING 8-QUINOLYL LIGANDS

The reaction of Qn(2)Hg (Qn = 8-quinolyl) with OsHCl(CO)(PPh3)(3) give s Os(eta(2)-Qn)Cl(CO)(PPh3)(2) (1), in which the 8-quinolyl ligand bin ds through both N and C-8 forming a 4-membered chelate ring. Reaction of 1 with AgPF6 to remove chloride, followed by addition of either NaI or NaS2CNMe2, gives the neutral compounds Os(eta(2)-Qn)I(CO)(PPh3)(2) (2) or Os(eta(1)-Qn)(eta(2)-S2CNMe2)(CO)(PPh3)(2) (3), respectively, while reaction with AgPF6 followed by CO gives [Os(eta(2)-Qn)(CO)(2)(P Ph3)(2)]+PF6- (4). Single crystal X-ray structures of 2 and 3 have bee n determined. In 2, the 8-quinolyl ligand is chelated through C-8 and N, but in 3 it is coordinated only through C-8. (C) 1997 Elsevier Scie nce S.A.