Bis(diphenylphosphino)amine and their dichalcogenide derivatives as ligands in rhodium(III), iridium(III), and ruthenium(II) complexes. Crystal structures of [(η5-C5Me5)MCl{η2-(SePPh2)2N}] (M=Rh, Ir)

Abstract

Reaction of the dimers [{(η5-C5Me5)MCl}2(μ-Cl)2] (M=Rh, Ir) or [{(η6-arene)RuCl}2(μ-Cl)2] (arene=p-MeC6H4iPr, C6Me6) with NH(PPh2)2 in the presence of AgA (A=BF4, PF6) leads to the mononuclear cationic complexes [(η5-C5Me5)MCl{η2-(PPh2)2NH}]A (M=Rh (1), Ir (2)) or [(η6-arene)RuCl{η2-(PPh2)2NH}]A (arene=p-MeC6H4iPr (3), C6Me6 (4)). Similar reactions using the chalcogenide derivatives NH(EPPh2)2 (E=S, Se) yield the neutral complexes [(η5-C5Me5)RhCl{η2-(EPPh2)2N}] (E=S (5), Se (6)), [(η5-C5Me5)IrCl{η2-(EPPh2)2N}] (E=S (7), Se (8)), [(η6-arene)RuCl{η2-(SPPh2)2N}] (arene=C6H6 (9), p-MeC6H4iPr (10)) and [(η6-arene)RuCl{η2-(SePPh2)2N}] (arene=C6Me6 (11), p-MeC6H4iPr (12)). Chloride abstraction from complexes 5–8 with AgPF6 in the presence of PPh3 gives the cationic complexes [(η5-C5Me5)Rh{η2-(EPPh2)2N}(PPh3)]PF6 (E=S (13), Se (14)) and [(η5-C5Me5)Ir{η2-(EPPh2)2N}(PPh3)]PF6 (E=S (15), Se (16)). Complexes 13–16 can also be synthesised from the starting dinuclear complexes, AgPF6, NH(EPPh2)2 and PPh3. Using this alternative synthetic route the related ruthenium complexes [(η6-C6Me6)Ru{η2-(EPPh2)2N}(C5H5N)] BF4 (E=S (17), Se (18)) can be prepared. All described compounds have been characterised by microanalysis and NMR (1H, 31P) and IR spectroscopy. The crystal structures of the neutral complexes [(η5-C5Me5)MCl{η2-(SePPh2)2N}] (M=Rh (6), Ir (8)) have been determined by X-ray diffraction methods. Both complexes exhibit analogous pseudo-octahedral molecular structures with a C5Me5 group occupying three coordination positions and a bidentate chelate Se,Se′-bonded ligand and a chloride atom completing the coordination sphere.