Browsing by Author "Powell, Harry Kipton James"

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"A study of the formation of some aliphatic Schiff base complexes of nickel"
(Te Herenga Waka—Victoria University of Wellington, 1961) Powell, Harry Kipton James
Under anhydrous conditions, nickeltrisethylenediamine salts condense with acetone to form yellow or orange diamagnetic salts containing azo-methine groups. N.F.Curtis, Thesis, University of New Zealand, 1954. During the reaction, one ethylenediamine ligand is lost per molecule of complex, and two, three or four acetone groups may be incorporated in the molecule. These complexes were initially thought to be isopropylidene derivatives involving a direct condensation between a molecule of ketone and the primary amine group. The compounds containing two and four acetone residues are remarkably stable to hydrolysis. However, Schiff base compounds are readily susceptible to aqueous and acid hydrolysis. On the basis of this, and the steric hindrance involved M.Blight, Thesis, University of New Zealand, 1959. between methyl groups in adjacent azo-methine groups e.g. (l) and (2), the above structural type seems improbable.
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"The Thermodynamics of Copper (II) and Nickel (II)- Diamine Complex Formation in Aqueous Solution"
(Te Herenga Waka—Victoria University of Wellington, 1965) Powell, Harry Kipton James
This work describes the accurate measurement of the thermodynamic functions ∆G˚ and ∆H˚ for the step-wise coordination equilibria between each of the ions H+, Ni2+, Cu2+, and, a series of C1-substituted 1,2-diaminoethanes in aqueous solution. The study Involved. (a) The construction of a sensitive constant temperature environment calorimeter for measuring the enthalpy changes in the complex-formation reactions, (b) The rigorous calibration of an electrode system, incorporating a glass electrode, for the direct potentiometric measurement of equilibrium hydrogen ion concentrations in the solutions containing complex ions. The thermodynamic functions ∆G˚ and ∆H˚ led to accurate ∆S˚ values for the step-wise complex-formation reactions. The thesis considers the contribution of the entropy of ligation to the stability of complex ions. The molar entropies of the complex ions have been calculated and their values considered with respect to the coordination number and the possible structure, degree of hydration and steric properties of the ions.