Dr. Kenneth (Ken) R. Ashley

The specific nature of my research can be found in my publications. In general, the research involves characterizing the equilibrium and kinetic properties of transition metal compounds in aqueous solution. Ultra violet-visible spectroscopy is the primary instrumental method used. However, infrared, nuclear magnetic resonance, voltametry, potentiometric, high performance liquid chromatography, absorption chromatography, ion exchange chromatography, gel permeation chromatography and atomic absorption techniques have been employed in the studies.

The research interests of this laboratory continue to be the reactions of transition metal ions in solution. The kinetic and thermodynamic properties of the ligated metal ions are under investigation. One of the current efforts is directed toward the understanding of the ability of porphyrins to labilize the axial substitution reactions of chromium(III). It appears that the porphyrins are able to promote dissociative activation. This labilization toward substitution is substantially enhanced when one of the axial ligands is hydroxide, the reaction becoming even more dissociative in nature. Additional systems, including rhodium (III) and ruthenium(II)/(III) porphyrins, will be studied to see if this effect is general.

The study of the trans-cis isomerization of trans-Cr(C2O4)2(H2O)21- as the aqua ligands are converted to hydroxyl ligands has been completed. The values of the activation parameters imply that the hydroxyl ligands promote dissociative activation in the isomerization reaction. The investigation of the isomerization of trans-Cr(C3H2O4)2(H2O)21- and the hydroxyl complexes is planned to see if this labilization effect is general and to see how it affects the activation parameters. The aquation of Cr(H2O)5X2+ where X is a monodentate ligand, as a function of pH, will be studied in order to ascertain the kinetic behavior of the hydroxy complexes. It is anticipated that these complexes also will demonstrate dissociative activation.

Recently a new area of research has been undertaken. The investigation of the electrochemical behavior of the metalloporphyrins in aqueous solution is currently underway. While there has been a great deal of effort to understand this behavior in nonaqueous solvents, there has been very little yet done in aqueous solutions. It is anticipated that the influence of the porphyrin on the behavior of the metal ion in aqueous solution will be significant.

The investigation of the properties of the new anion exchange resin Reillex™–HPQ are currently underway. The determination of Kd for a wide variety of simple anions as well as ReO4- and Fe(CN)6-4 are being determined.

The development of ion exchange methods for the separation of lanthanides is currently underway. The approach here is to identify, from published data, potentially good ligands for the separation and then to determine if an acceptable analysis can be obtained.

The investigation of the reaction of the actinides, lanthanides, thorium, and uranium with sodium silicate under hydrothermal conditions in a Parr Pressure Reaction Vessel is currently underway. The synthesis and solid state characterization of these silicates is the initial goal of the project.

Complete Vitae

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