Study of the coordination chemistry of phosphinines and phosphabarrelenes

The syntheses of a series of 2,6-(2'-haloaryl)-4-tolylphosphinines, ranging from the fluoro, chloro, bromo and iodo derivatives, as well as the 2,6-dixylyl-4- phenylphosphinine ligand are reported. The coordination chemistry of these ligands has been evaluated by coordinating them to pentacarbonyltungsten(O), to form the complex W(CO)s(L), where L = fluoro, choloro, bromo, iodo or dixylyl derivatives of the phosphinine secondly to Rh(COD)Cl 2, to form the complex Rh(COD)Cl(L), where COD = 1,5-cyclooctadiene, and L= fluoro, chloro, bromo or dixylyl derivatives of the phosphinine and thirdly to Rh(CO)2Cl 2 to form Rh(CO)Cl(L) 2, where L = 2,6,-dixylyl-4-phenylphosphinine only. These complexes were fully characterised by spectroscopic means, their coordination chemistry studied and the metal-phosphorus bond in these complexes is elucidated by comparison to analogous complexes of phosphines, and phosphites. Finally the 2,6-dixylyl-4-phenylphosphabarrelene is synthesised from its parent phosphinine, and applied in a survey of transition metal complexes to evaluate its properties as a ligand. The complexes made were W(CO)s(L), Re(CO)4Cl(L), Ru(cymene)(L)Cl2, Fe(r 5-C5H4SiMe3)(CO)2L + PF6", Rh(CO)Cl(L)2, Rh(COD)Cl(L), Ir(COD)Cl(L), PtCl2(L)2, Ag(L)2 + Tf Cu(L)Cl, and Pd(L). Where L = 2,6-dixylyl-4-phenylphosphabarrelene, cymene = 4-isopropyltoluene, Cp = cyclopentadienyl and COD = 1,5-cyclooctadiene are described. The coordination chemistry of the phosphabarrelene was established and the nature of the phosphorus- metal bond in each complex was elucidated by comparison to analogous complexes of triarylphosphines and triarylphosphites. In addition the phosphabarrelene was tested in the rhodium catalysed hydroformylation of 4-octene, in comparison with the commonly used (2,4-di-t-butylphenyl)phosphite.EThOS - Electronic Theses Online ServiceGBUnited Kingdo