Coordination of some monodentate and hybrid multidentate phosphine ligands to platinum group metals

A range of low-valent late transition-metal triarylphosphine complexes have been prepared and characterised by a combination of 1H, 31P and 19F (as appropriate) NMR and IR spectroscopies and mass spectrometry. Some of these complexes have been isolated as single crystals and characterised by X-ray diffraction.;The triarylphosphine ligands used in this study were P(4-CH3OC6H4)3, P(4-HOC6H4)3, P(2-CH3OC6H4)3, PPh2(2-CH3OC6H4), P(2-HOC6H4)3 and PPh2(2-C2H3C6H4) whilst the transition-metals were platinum(II), palladium(II), rhodium(I), rhodium(III), osmium(II) and ruthenium(II). This work has shown that the former four phosphine ligands act as monodentate ligands whilst the last two ligands act as hybrid multidentate ligands. The metal complexes of the ortho-hydroxy substituted ligand exhibit fluxional behaviour in solution, where the phosphine is interchanging between mono- and bi-dentate modes of coordination. In contrast, fluxionality has not been observed in the case of the ortho-vinyl substituted ligand.;A set of platinum(II)-, osmium(II)- and ruthenium(II)-fluoride triarylphosphine complexes have been prepared and characterised. The electron-donating substituents in the phosphine strengthen the metal-phosphine and metal fluoride bonds as compared to those for the non-substituted triarylphosphine ligand, PPh3. Furthermore, these substituents affect the geometry at the metal centre in these complexes. In the reactions of P(2-HOC6H4)3 with [Pt(-F){lcub}P(4-CH3OC6H4)3{rcub}2]2 or [M(-F)F(CO)3]4 (M = Os, Ru), metal chelates are formed by the displacement of fluoride by phenoxide and liberation of HF, whereas, in the related reactions, the ortho-vinyl substituted ligand acted in a monodentate mode.