Coordination complexes of bidentate phosphino-imine ligands: Synthesis, characterisation and reactivity.

This thesis describes the synthesis, reactivity and coordination chemistry of a range of bidentate phosphino-imine ligands. The reactivity of the resultant complexes is also probed, while testing of the complexes for catalytic activity in a range of carbon-carbon bond-forming reactions is documented. Chapter 1 introduces the concepts of 'hemi-lability' and 'trans-influence', along with heteroditopic bidentate ligands, and specifically examines imine- and phosphine-based ligands, particularly aminophosphines. The nature of the phosphorus centre in terms of its steric and electronic properties is surveyed, and the bonding of phosphines and imines with metals is discussed. A review of transition metal-catalysed olefin oligomerisation and polyketone formation then follows. Finally, the aims of this work are outlined. Chapter 2 introduces the PNP ligand {lcub}(Pri2N)2PCH2C(=NPri)CH2P(NPri2)2{rcub}, previously synthesized within the Dyer group. The reactivity and coordination chemistry of this ligand are then explored, and the reactivity of the resultant complexes probed. The complex [PdCl(Me)(PNP)] has been crystallographically characterised. Chapter 3 briefly introduces guanidines, before describing the synthesis of two new types of phosphino-imine ligand derived from bicyclic and acyclic guanidines {lcub}R2P(TBD), R = Ph, Mes, Pri 2N, Ph2N and Ph2P(DMC), respectively{rcub}. The reactivity and coordination chemistry of these ligands is then explored, with particular attention paid to the effects of varying the substituents at phosphorus in R2P(TBD). The reactivity of the resulting complexes is then documented. The molecular structures of the ligands Ph2P(TBD), (Pri2N)2P(TBD) and Ph2P(DMC), and of twenty of their complexes have been determined. Chapter 4 describes the synthesis of the new P.;N ligand Ph2P(2-IP). The reactivity and coordinationchemistry of this ligand is then appraised, as is the reactivity of the resulting complexes. The structures of four complexes of this ligand have been probed crystallographically, as has a serendipitously formed nickel complex. Chapter 5 documents the catalytic testing conducted, using the complexes prepared in the chapters 2 - 4.