Research-active Emeritus Professor – Analytical Chemistry, Inorganic Chemistry, Electrochemistry
Research and/or Creative Works
An electron is the simplest chemical reagent. Chemists have increasingly recognized the role of electron-transfer reactions in the laboratory and in nature. Our research focuses on the electron-transfer properties of transition-metal containing complexes, with the primary aim of understanding how the structure and reactivity of the complex is changed by addition or removal of electrons.
Many important chemical transformations can be initiated electrochemically or modeled by electrode processes. In doing so we can often uncover fundamentally important aspects of reactions that are inaccessible through ordinary reaction chemistry.
We use a variety of physical methods to address these problems, including voltammetry experiments that can observe intermediates with lifetimes as short as 10 µs. Many of our electrochemical experiments are interfaced with spectroscopic instruments that enable us to use magnetic resonance spectroscopies, optical spectroscopy (including the near-IR region) and infrared spectroscopy to characterize electron-transfer products. A significant aspect of our research involves the development of fiber-optic technologies to better interface the IR region with electrochemical methods.
Our present research involves molecules and electron-transfer reactions which are important in homogeneous catalysis, molecular wires, or battery technologies.
Nafady, A.; Costa, P.J.; Calhorda, M.J.; Geiger, W.E. "Electrochemical Oxidation of CoCp(CO)2: Radical-Substrate Reaction of a 17e-/18e- Pair and Production of a Unique Dimer Radical" J. Am. Chem. Soc. 2006, 128, 16587.
Barriére, F.; Geiger, W.E. "Use of Weakly-Coordinating Anions to Develop an Integrated Approach to the Tuning of Delta E½ Values by Medium Effects" J. Am. Chem. Soc. 2006, 128, 3980.
Chong, D.; Nafady, A.; Costa, P.J.; Calhorda, M.J.; Geiger, W.E. "Anodic Preparation of [Re2Cp2(CO)6]2+: a Dimeric Dication that Provides the Powerful One-electron Oxidant [ReCp(CO)3]+" J. Am. Chem. Soc. 2005, 127, 15676.
Stoll, M.; Geiger, W. E. (et al.) "Stepwise Hapticity Changes in Sequential One-Electron Redox Reactions of Indenyl-Mo Complexes," J. Am. Chem. Soc. 2001, 123, 10595.
LeSuer, R. J.; Geiger, W. E. "Improved Electrochemistry in Low-Polarity Media Using Tetrakis(penta-fluorophenyl)borate Salts as Supporting Electrolytes," Angew. Chem. Int. Ed. Engl. 2000, 39, 248.