Michael D. Ryan, Ph.D.
Professor Emeritus, Analytical Chemistry
(414) 288-1625
E-mail: michael.ryan@mu.edu

Biography
Professor Ryan obtained his B.S. degree in 1969 from the University of Notre Dame and his Ph.D. in 1973 from the University of Wisconsin. His interest in electroanalytical chemistry led him to a postdoc at the University of Arizona before joining the faculty here in 1974. He also took a sabbatical leave at the University of Iowa with D. Coucouvanis (1981-82), and the University of Paris VII with J.-M. Saveant (1995-96).

Research Fields
The primary aim of our research has been to investigate multi-electron reactions that occur either in solution or at the electrode surface. This has led to the study of two important systems: 1) the multi-electron reduction of iron nitrosyls to hydroxylamine/ammonia, and, 2) the electrochemistry of electroactive materials in room temperature ionic liquids (RTILs). The first system has been observed in nature with the assimilatory and dissimilatory nitrite reductases. The assimilatory nitrite reductases contain a unique heme group, called a siroheme (a derivative of tetrahydroporphines), while the latter reductase often contains heme d1, a porphinedione. Using uv/visible and infrared spectroelectrochemistry, the effect of the macrocycle on the redox properties of the metalloporphyrin derivative, and its nitrosyl complex was studied, and interpreted using DFT calculations. The primary focus of the work now is the identification and characterization of the protonated iron nitroxyl complex (Fe(P)(HNO)). This species is an important intermediate in many biological processes. By combining electrochemical methods with spectroscopy, important intermediates can be identified using UV/visible and infrared spectroscopy. In addition, isolation and characterization of important species have been carried out using NMR, resonance Raman and x-ray methods. The second area of research has been the investigation of redox species in RTILs. The ionic nature of the solvent provides unique opportunities for the interaction of the redox products with the solvent, sometimes collapsing two separate reductions into a single wave. The RTILs have some very important properties that make them useful in chemistry, but their high viscosity and high cost can limit their applications. Mixtures of RTILs with molecular solvents provide a way to overcome these problems. One important aspects of molecular solvent/RTIL mixtures is that they are not homogeneous on the nanoscale. Even at relatively low concentrations of an RTIL, aggregates of RTIL species form and are able to solvate ionic species, leading to reactivity more closely related to the RTIL. The focus of our work has been to understand these interactions so that they can be used to make more efficient redox/catalytic systems with lower costs and solution viscosity.

Selected Publications

For complete publications text: e-publications.
For a complete list of publications see Dr. Ryan's profile on ORCID qr code


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