SYNTHESES, STRUCTURES AND SPECTROSCOPIC PROPERTIES OF NOVEL INORGANOMETALLIC COMPLEXES RU(E)(E')(CO)(2)(IPR-DAB) (E=CL, E'=SNPH3, PBPH3, E=ME, E'=SNPH3, PBPH3, E=SNPH3, E'=SNPH3, SNME3, GEPH3, E=PBPH3, E'=PBPH3, PBME3, GEPH3, IPR-DAB=N,N'-DIISOPROPYL-1,4-DIAZA-1,3-BUTADIENE)

This article describes the syntheses, structures and spectroscopic ( I R, Raman, NMR, visible absorption) properties of novel inorganometalli c complexes of the type Ru(E) (E') (CO)(2)(iPr-DAB) in which E represe nts a Cl, Me, SnPh3 or PbPh3 group and E' = GePh3, SnR3 or PbR3 (R = P h, Me) depending on E. The X-ray structures of Ru(Cl) (SnPh3) (CO)(2)( iPr-DAB) and Ru(Cl) (PbPh3) (CO)(2)(iPr-DAB) show that these complexes have a distorted octahedral geometry with E and E' in axial positions . The latter complex is, to our knowledge, the first with a Ru-PbR3 bo nd for which a crystal structure has been reported. Replacement of Cl by the more electron releasing ligands Me, SnR3 or PbR3 causes a shift of v(CO) and v(CN) to lower frequencies. At the same time, the strong absorption band shifts from similar to 440 to 510-550 nm, with a conc omitant decrease of solvatochromism. The very large decrease of solvat ochromism upon replacement of Me by GePh3 or ER3 (E = Pb, Sn; R = Me, Ph) is tentatively explained with a delocalisation of charge over the axial ER3 groups. Support for this explanation is provided by the H-1 NMR spectra, which show very large (4)J(Sn-117/119,H) and (4)J(Pb-207, H) coupling constants of the imine protons in the SnR3 and PbR3 contai ning complexes respectively.