Structural studies of complexes of group VIII metals

Abstract

Recent interest in the preparation and reactions of thiocarbonyl and selenocarbonyl organometallic complexes has resulted in the synthesis of a large number of new compounds. This thesis describes the single crystal x-ray analyses of six of these novel complexes. The crystal structure of a carbon monoselenide complex of ruthenium, Rucl2 (CO) (CSe) (PPh3)2, shows linear seleno-carbonyl co-ordination similar to that of the thiocarbonyl ligand and a strong trans influence of the –CSe ligand. Two dithiomethyl ester complexes of ruthenium, produced in the synthesis of thiocarbonyl complexes, have been studied. The crystal structure of [Ru (?2-CS2Me) (CO)2 (PPh3)2]ClO4 C6H12 has been determined and that of [Ru(?2-CS2Me) (CN-p-tolyl) (CO)-(PPh3)2] ClO4 ½CHCl3 ½H2O partially solved. In both compounds the dithioester ligand is co-ordinated through carbon and the un-methylated sulphur atom. The crystal structure of the iridium complex of composition [Ir (CS2) (CO) (PPh3)3]BF4, also produced during the preparation of thiocarbonyl complexes, has been determined. The iridium is found to be five co-ordinate with a bidentate sulphur-bound triphenylphosphine-carbon disulphide zwitterions ligand spanning one equatorial and one axial site. Previously the compound had been formulated as containing a ?-CS2 ligand. The structure determination of an osmium complex containing a novel ligand produced by the interligand reaction of thiocarbonyl-and thiocarboxamido- ligands has been carried out. The compound is shown to contain a four membered metallocycle in which the osmium is bound to two carbon atoms, each of which is bound to a sulphur. Finally, the structure analysis of a ruthenium complex, initially thought to contain a co-ordinated tetrafluoroborate ligand shows that the tetrafluoroborate is an anion, hydrogen bound to the cation through solvent ethanol molecule. A second solvent molecule, water, completes the octahedral co-ordination of the ruthenium and also hydrogen bonds to both the tetrafluoroborate anion and the cation.