The Stability constants of some cadmium (II) ligand complexes have been measured by glass electrode potentiometry. These constants were used in computer model systems in order to assess the ligand's suitability as a cadmium sequestering agent in vivo. It is suggested that nitrogen and oxygen containing amino-acids complex zinc preferentially with respect to cadmium, and that the existing cadmium therapeutical, EDTA, is highly unspecific. Glutathionate is proposed as the most promising ligand for the treatment of cadmiumism. An investigation was undertaken to assess the reliability and accuracy of a solid state cadmium-ion selective electrode. A new system of metal buffers was introduced into the calibration but it was found impossible to obtain reproducible results with this electrode. The electrode was used in a study of the cadmium asparaginate and serinate systems and checked against a computer simulation. The best 'fit' was obtained from a value of mV/pCd far from the theoretical value of -29.586 and it was concluded that the glass electrode was the more reliable means of measuring titration data. The partition coefficient of the cadmium(II) glutathionate system was calculated for octanol/water as a model for cell membranes. This suggested a maximum of 2% of cadmium inside a cell being partitioned out by glutathionate and that ratios of ligand: metal greater than 1:1 would be the most efficient for complexing the metal. The Belousov-Zhabotinsky oscillating reaction was taken as a primitive model of biochemistry and the qualitative effect of introducing different materials to the system was noted. The computer program COMICS was modified for loading on to the St. Andrews IBM 560/44 computer and adapted to include three plotter routines.

The temperature and stress fields for the Vertical Bridgman growth of CdTe were calculated using the finite element method. The critical resolved shear stress (CRSS) of CdTe was measured at elevated temperatures. The measured CRSS and the calculated shear stress were compared to determine the onset of dislocation formation in the crystal. The effect of furnace gradient, crucible velocity, hot furnace temperature and cold furnace temperature on the solid/liquid interface shape and calculated resolved shear stress were examined using the model. Etch pit density measurments were carried out in order to verify the stress model. / Applied Science, Faculty of / Materials Engineering, Department of / Graduate

Anhydrous monophenylphosphinates of manganese(II), Mn[H(C₆H₅)PO₂]₂ (Form I, Form II and Form 1(B)) and cadmium(II), Cd[H(C₆H₅)PO₂]₂ (Form I and Form II) were synthesized and characterized by solubility tests, Differential Scanning Calorimetry (DSC), Infrared Spectroscopy, X-ray Powder Diffractometry, Electron Spin Resonance (ESR) spectroscopy, magnetic susceptibility measurements and Electron Spectroscopy for Chemical Analysis (ESCA). These materials are considered to be polymeric with metal ions connected in chains by double bridging phosphinate groups with cross-linkage forming sheets and octahedral metal centers. Magnetic susceptibility studies showed that Mn[H(C₆H₅)PO₂]₂ (Form I) exhibits relatively strong antiferromagnetic exchange interactions (J is about -4.50 cm⁻¹) and the effects on this magnetic exchange of doping diamagnetic cadmium ions into the material have been investigated. A series of mixed metal phosphinates of the form Mn₁₋x Cdx [H(C₆H₅)PO₂]₂ (Form I) where x=0 to 1.00 were prepared and investigated. The effect of doping with cadmium is to break the infinite manganese(II) monophenylphosphinate chain into finite segments and to generate monomer impurities in odd numbered segments. As the extent of doping is increased the average chain length decreases and the fraction of monomer increases. In addition, the exchange coupling constant, J, was found to decrease (from -4.50 to -2.70 cm⁻¹) as the average chain length decreases. Mn[H(C₆H₅)PO₂]₂ (Form 1(B)), which is precipitated from concentrated solutions, contains much shorter chain fragments than the pure Form I material. Mn[H(C₆H₅)PO₂]₂ (Form II) has a distinct infrared spectrum and X-ray powder diffraction pattern and shows much weaker antiferromagnetic behavior (J is about -2.40 cm⁻¹) than the Form I compound. Magnetic studies suggest that in this compound the average chain length is significantly smaller than in Mn[H(C₆H₅)PO₂]₂ (Form I). The hydrated monophenylphosphinates of manganese(II), Mn[H(C₆H₅)PO₂]₂•H₂0 and Mn[H(C₆H₅)PO₂]₂•2H₂0, were synthesized and characterized in this work. The structures of these compounds are considered to be similar to those of the anhydrous materials except in the hydrated compounds one or two of the metal coordination sites are occupied by water molecules. The dihydrate shows only very weak antiferromagnetic properties (J is about -0.50 cm⁻¹). The diphenylphosphinates of manganese(II) and cadmium(II) were also prepared and characterized. The infrared spectra and X-ray powder diffraction patterns for these materials are distinct from each other,which indicates the compounds are not isomorphous. Only rather weak magnetic exchange was observed in the manganese compound. Zn[H(C₆H₅)PO₂]₂ has also been synthesized and partially characterized in this work. The infrared spectrum and X-ray powder diffraction pattern obtained for this compound are unique among all the metal phosphinates studied in this work. / Science, Faculty of / Chemistry, Department of / Graduate

The area of study for this project was the development of an accurate, reliable, and inexpensive method of trace analysis for copper, cadmium, and lead in foods. AT this time, the Association of Official Analytical Chemists Manual, eleventh edition, (4) has only official and recognized methods of analysis for copper (25.023), cadmium (25.018), and lead (25.041). In general, these procedures are long and tedious. The digestions involved often require many hours and are quite dangerous due to leakage of metallic and organometallic fumes from the digestion apparatus. The official methods of analysis for these elements require a very large outlay of money for special equipment and reagents. It was the purpose of this project to determine the following: (A) The feasibility of using polarographic detection for copper, cadmium, and lead in trace amounts.; (B) Fina da new method of sample decomposition to replace the present digestion methods.; (C) Study the selection media prior to polarographic detection.; (D) Develop a method of simultaneous polarographic detection of copper, cadmium, and lead.

published_or_final_version / abstract / Anatomy / Doctoral / Doctor of Philosophy