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)

Abstract This article describes the syntheses, structures and spectroscopic (IR, Raman, NMR, visible absorption) properties of novel inorganometallic complexes of the type Ru(E)(E′)(CO) 2 (iPr-DAB) in which E represents a Cl, Me, SnPh 3 or PbPh 3 group and E′=GePh 3 , SnR 3 or PbR 3 (R=Ph, Me) depending on E. The X-ray structures of Ru(Cl)(SnPh 3 )(CO) 2 (iPr-DAB) and Ru(Cl)(PbPh 3 )(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–PbR 3 bond for which a crystal structure has been reported. Replacement of Cl by the more electron releasing ligands Me, SnR 3 or PbR 3 causes a shift of ν (CO) and ν (CN) to lower frequencies. At the same time, the strong absorption band shifts from ∼440 to 510–550 nm, with a concomitant decrease of solvatochromism. The very large decrease of solvatochromism upon replacement of Me by GePh 3 or ER 3 (E=Pb, Sn; R=Me, Ph) is tentatively explained with a delocalisation of charge over the axial ER 3 groups. Support for this explanation is provided by the 1 H NMR spectra, which show very large 4 J ( 117/119 Sn,H) and 4 J ( 207 Pb,H) coupling constants of the imine protons in the SnR 3 and PbR 3 containing complexes respectively.