The preparation of alkene-alkyne complexes of rhodium, and some platinacycles.

In chapter one, the series of complexes of the type [Rh (dpm) (alkene) (C4F6)] is extended by alkene displacement reactions of [Rh (dpm) (C2F4) (C4F6)]. The reaction of some of these alkene-alkyne complexes with cyclopropane, propene and tetramethylallene, to give 1,4-diene complexes of rhodium is described, together with the X-ray crystal structure of the tetramethylallene derivative. Complexes of the type [Rh (acac) (L)2 (C4F6)] (L=PPh3, PPh2Me, AsPh3, SbPh3) and [Rh (dpm) (L)(C4F6)] (L=PPh3, P(C6H11)3, AsPh3) are characterised, and rhodacyclopentene complexes [Rh{lcub}CH2CH2C(CF3)=C(CF3){rcub} (dpm) (L)2] are isolated from the reaction of pyridine derivatives (L=C5H5N, 3-MeC5H4N,3,5-Me2C5H3N) with [Rh (dpm) (C2H4) (C4F6)]. The X-ray crystal structure of the complex, where L=pyridine, is described. Chapter two presents a review of the preparation, physico-chemical properties and reactions of platinum(O)-alkyne complexes. This is followed by a description of the characterisation of some platinacyclic complexes which are isolated from the reactions of hexafluoropropanone with alkynediolbis (triphenylphosphine) platinum(O) complexes. The result of the X-ray crystal structure determination of the but-2-yne-1,4-diol derivative is discussed. A series of alkyne displacement reactions is described, for the reactions of some electrophilic alkenes and alkynes with [Pt (H2C(OH)C=CCH2OH) (PPh3)2], and the 31P n.m.r. spectroscopic data for the products are reported. After a review of the preparation and reactions of metallacyclobutane complexes of palladium and platinum, chapter three describes the preparation and characterisation of a series of metallacyclobutanone complexes, from the reactions of acetonedicarboxylic acid dimethyl ester with the complexes ML4 (M=Pt, L=PPh3, PPh2Me, PPhMe2; M=Pd, L=PPh3).