Osmium complexes containing either chelating or non-chelating 8-quinolyl ligands

The reaction of Qn(2)Hg (Qn = 8-quinolyl) with OsHCl(CO)(PPh(3))(3) gives Os(eta(2)-Qn)Cl(CO)(PPh(3))(2) (1), in which the 8-quinolyl ligand binds through both N and C-8 forming a 4-membered chelate ring. Reaction of 1 with AgPF(6) to remove chloride, followed by addition of either NaI or NaS(2)CNMe(2), gives the neutral compounds Os(eta(2)-Qn)I(CO)(PPh(3))(2) (2) or Os(eta(1)-Qn)(eta(2)-S(2)CNMe(2))(CO)(PPh(3))(2) (3), respectively, while reaction with AgPF(6) followed by CO gives [Os(eta(2)-Qn)(CO)(2)(PPh(3))(2)](+)PF(6)(-) (4). Single crystal X-ray structures of 2 and 3 have been 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 Science S.A.