Di- and tri-nuclear molybdenum–palladium complexes bearing strong π-acceptor “P–N–P” ligands, MeN{P(OR) 2} 2 (R = CH 2CF 3 or Ph)

Abstract

The dipalladium complexes, [PdCl(μ-MeN{P(OR) 2} 2)] 2 (R = CH 2CF 3, 1a; Ph, 1b) react with [Mo 2(η 5-C 5H 5) 2(CO) 6] in boiling benzene to afford the molybdenum–palladium heterometallic complexes, [(η 5-C 5H 5)(CO)Mo(μ-MeN{P(OR) 2} 2) 2PdCl] (R = CH 2CF 3, 3a; Ph, 3b), [(η 5-C 5H 5)Mo(μ 3-CO) 2(μ-MeN{P(OR) 2} 2) 2Pd 2Cl], (R = CH 2CF 3, 5a; Ph, 5b), [(η 5-C 5H 5)(Cl)Mo(μ 2-CO)(μ 2-Cl)(μ-MeN{P(OR) 2} 2)PdCl], (R = CH 2CF 3, 6a; Ph, 6b) and also the mononuclear complex [Mo(CO)Cl(η 5-C 5H 5)(κ 2-MeN{P(OR) 2} 2)], (R = Ph, 4b). These complexes have been separated by column chromatography and are characterised by elemental analysis, IR, 1H, 31P{ 1H} NMR data. The structures of 1a, 3a, 4b, 5b and 6a have been confirmed by single crystal X-ray diffraction. The CO ligands in 5b and 6a adopt a semi-bridging mode of bonding; the Mo–CO distances (1.95–1.97 Å) are shorter than the Pd–CO distances (2.40–2.48 Å). The Pd–Mo distances fall in the range, 2.63–2.86 Å. The reaction of [Mo 2(η 5-C 5H 5) 2(CO) 6] with MeN{P(OPh) 2} 2 in toluene gives [Mo 2(CO) 4(η 5-C 5H 5) 2(κ 1-MeN{P(OPh) 2} 2) 2] ( 2) in which the diphosphazane acts as a monodentate ligand.