Synthesis and reactions of allyl and related complexes of transition metals.

This thesis describes the chemistry of some allyl complexes and related metallacycles of the transition metals molybdenum, tungsten, rhodium and iridium. Chapter 1 reviews the literature concerning the synthesis of oxatrimethylenemethane and allyl complexes of transition metals and then goes on to discuss the application of such complexes in organic synthesis. Chapter 2 describes the synthesis and characterisation of eta3-allyl complexes of molybdenum and tungsten of the type [MX(CO)2L2(eta3-allyl)], where X = Cl or I, L2 = 2,2'-bipyridine, 4,4'-dimethyl-2,2'-bipyridine, 2,9-dimethyl-1,10-phenanthroline or 3,4,7,8-tetramethyl-l,10-phenanthroline, and eta3-allyl = C3H5, C4H7, C5H9 or C5H9O2. Crystal structures of seven selected complexes have been determined and are discussed here. The latter part of this chapter discusses the attempts to synthesis oxatrimethylenemethane complexes from some of these eta3-allyls. Chapter 3 describes the silver(I) oxide mediated synthesis of N-bonded 1-aza-allyl complexes of pentamethylcyclopentadienylrhodium and -iridium fragments, of general type [Cp*ML{lcub}N(C0Me)C(=CHR)C02{rcub}], where L = PPh3, AsPh3, SbPh3 or pyridine, and R = H or Ph. Some of these complexes undergo novel isomerisation reactions to form C,O-bonded vinyl complexes via C-bonded 1-aza-allyls. These reactions are discussed here together with the X-ray crystal structure of [Cp*RhPPh3 {lcub}N(C0Me)C(=CHPh)CO2{rcub} ]. Chapter 4 describes the reactions of amino acids with Cp*Rh and Ir species in the presence of silver(I) oxide to form metallacyclic amino acidate complexes of the type [Cp*ML{lcub}N(C0Me)CHRC02{rcub}], where L = PPha, pyridine, 4-cyanopyridine or 3-picoline, and R = H or CH2Ph, with high stereoselectivity. The structures of [Cp*RhL{lcub}N(COMe)CHRCO2{rcub}] (L = PPh3 or pyridine and R = H or CH2Ph) have been determined by X-ray crystallography and are reported here. The latter part of this chapter discusses the reactions of these amino acidate complexes with peifluorocarboxylic acids and crystal structures of [Cp*RhPPh3(O2CCF3)2], [Cp*RhPPh3(O2CC4F9)2] and [Cp*Rh(C24H20)] are reported.