Kinetics of substitution at inorganic centres
The general theme of this thesis is the effect of solvents on the initial state and transition state contributions. This has involved kinetic and thermodynamic measurements. The kinetics were examined for a variety of inorganic reactions with the aim of investigating rate laws, products of reaction (where possible) and suitability for an initial state-transition state analysis. The following reactions were followed:- (a) 2,2'- Bipyridyltetracarbonylmolybdenum (0) and various related compounds with cyanide and other nucleophiles; (b) manganese and rhenium carbonyl halides with cyanide and amino-acids; (c) potassium tetrachloroplatinate (II) with cyanide; (d) hexadentate Schiff base complexes of iron(II) with cyanide and with hydroxide. An extension of mercury (II) catalysis was carried out in the examination of solvent effects on such catalysis, and on the hydrolysis reaction, of the pharmaceutical fenclorac (?-3-dichloro-4-cyclohexyl-benzeneacetic acid). The thermodynamics and solubility measurements have enabled the calculation of Gibbs free energies of transfer. This has been done for potassium cyanide in non-aqueous and in mixed aqueous media, also for potassium tetrachloroplatinate (II) and 2,2'-bipyridyltetracarbonyl-molybdenum (0) in limited ranges of solvents and solvent mixtures. From this [special character omitted](non electrolytes), directly, and (ions), using standard extrathermodynamic assumptions, may be obtained to get data on the initial state. These together with the kinetic data permit an initial state - transition state dissection of solvent effects on reactivity. Such an analysis was successfully carried out for 2,2'-bipyridyltetracarbonylmolybdenum (0) and potassium tetrachloro-platinate(II). In connection with the reaction of the iron(II)-hexadentate Schiff base complex with cyanide and hydroxide, it was necessary to carry out an X-ray structure determination to be certain the central moiety of the hexadentate ligand was in the form -NHCH2CH2-NH rather than the diimine form -N=CH CH=N-.