A crystallographic and spectroscopic investigation of some organo-chalcogen complexes of ruthenium
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
The work described in this thesis is concerned principally with the study, by crystallographic and spectroscopic methods, of a series of divalent ruthenium complexes [RUX₃(NO)L₂] (X = Cl, Br or I, and the ligands L are dialkyl and phenyl alkyl sulphides or selenides). A small number of Pt, Pd, Rh and Ru complexes containing the chelating ligands cis-bis(1,2-benzylthio)ethylene and αα'-dibenzylthio-o-xylene have also been prepared. The spectroscopic methods employed were infrared and ultraviolet-visible absorption and ¹H and ¹³C nuclear magnetic resonance. The results have been related, where possible, to the nature of the metal-ligand bond. A detailed investigation of the variable temperature ¹H n.m.r. spectra of the [RuX₃(NO)L₂] complexes, employing computer simulation techniques, has resulted in the determination of the rate of inversion of configuration about the sulphur (or selenium) atom (of the chalcogen ligand). Variations in the rate of inversion have been correlated with the halogen ligand X and the chalcogen ligand. An oxidation reaction involving the complex [RuBr₃(NO)(Et₂S)₂] is stimulated by the energy of visible radiation when the complex is dissolved in chloroform. The study of the reaction using crystallographic and spectro-scopic techniques has lead to the isolation of an intermediate product [RuBr₃(NO)(Et₂SO)(Et₂S)] and an end product [RuBr₃(NO)(Et₂SO)]₂. The crystal and molecular structures of [RuBr₃(NO)(Et₂SO)]₂ and [RuBr₃(NO)(Et₂SO)(Et₂S)] have been determined using three-dimensional X-ray diffractometer data. In both crystal structures the octahedrally coordinated ruthenium atoms have a diethyl sulphoxide ligand bonded through the oxygen atom. A linearly coordinated nitrosyl group occupies the position trans to the sulphoxide group. The crystal and molecular structure of [RuBr₃(NO)(PhSEt)₂] contains two crystallographically independent molecules (they are mirror images) in the asymmetric unit. The ruthenium atom is octahedrally coordinated to trans sulphur atoms and a meridional arrangement of bromine atoms.