Transition metal complexes of tris(dimethylphosphino)methane and of bis(dimethoxyphosphino)methyl and phenylamine
Description
The chemistry of the PNP ligands ((MeO)$\sb2$P)$\sb2$NR (R = Me, Ph) with rhodium (I) has been explored. The ligands serve preferentially as chelates forming square-planar or trigonal-bipyramidal complexes. PNP is shown to act as a bridging ligand in the complexes (Rh(PNP)$\sb2$) $\sb2$(ClO$\sb4$)$\sb2$ and in ((PNP)$\sb2$Rh(PNP)Rh(PNP)$\sb2$) (ClO$\sb4$)$\sb2$. The chemical and spectroscopic properties of these compounds are reported Secondly, the ligating properties of tris(dimethylphosphino)methane, TMPM, towards transition metals have been studied. The mode of bonding and the number of attached metals varies with reaction conditions. Ru$\sb3$(CO)$\sb{12}$ reacts with TMPM to form the capped cluster Ru$\sb3$(CO)$\sb9$(TMPM), while Fe$\sb3$(CO)$\sb{12}$ undergoes fragmentation to give Fe$\sb2$(CO)$\sb7$(TMPM). Ru$\sb3$(CO)$\sb9$(TMPM) can be protonated to give a fluxional hydride and will also react with Au(PPh$\sb3$)$\sp+$ to give the heteronuclear cluster (Ru$\sb3$Au(CO)$\sb9$(TMPM)(PPh$\sb3$)) $\sp+$. The structure of this cluster has been analyzed crystallographically and possesses a nearly planar Ru$\sb3$Au core. TMPM acts as a chelate in the complexes M(CO)$\sb4$(TMPM) (M = Cr, Mo). TMPM can bridge a dinuclear complex with two phosphorus atoms leaving the third phosphorus atom uncoordinated. It is then possible to bind a third metal to the uncoordinated phosphorus atom in a subsequent step. This is demonstrated by the formation of Re$\sb2$(CO)$\sb8$(TMPM) and Cp$\sb2$W$\sb2$(CO)$\sb4$(TMPM) which form the heteronuclear complexes trans- (Re$\sb2$(CO)$\sb8$(TMPM)) $\sb2$M(CO)Cl (M = Rh, Ir) and (W$\sb2$IrCp$\sb2$(CO)$\sb5$Cl(TMPM)(PPh$\sb3$)). A dirhenium-platinum complex is also observed spectroscopically. The chemical and spectroscopic properties of these compounds are reported