Coordination chemistry of 2,6-dixylyl-4-phenylphosphabarrelene with selected transition metals

The 2,6-dixylyl-4-phenylphosphabarrelene has been synthesised from the parent phosphinine and its properties as a ligand explored through the preparation and characterisation of the complexes W(CO)5(L), Re(CO)4(L)Cl, (η6-cymene)RuCl2(L), [(η5-Me3SiC5H4)Fe(CO)2(L)]PF6, Rh(1,5-COD)(L)Cl, Ir(1,5-COD)(L)Cl, and cis-Pt(L)2Cl2, where L = 4-phenyl-2,10-bis-(2,4-dimethylphenyl)-4H-1,4-ethenophospholine (xPB), cymene = 4-isopropyltoluene, η5-Me3SiC5H4 = trimethylsilylcyclopentadienyl and 1,5-COD = 1,5-cyclooctadiene. The new complexes were characterised by spectroscopic and analytical techniques and, for [(η5-Me3SiC5H4)Fe(CO)2(L)]PF6 and Ru(η6-cymene)(L)Cl2, by single-crystal X-ray structure determination. The coordination properties of the phosphabarrelene have been established and compared with analogous complexes of triarylphosphines and triarylphosphites. Most spectroscopic and structural indicators suggest that the phosphabarrelene has coordination behaviour similar to that of simple triarylphosphines such as PPh3.