Monday, June 18, 2007
Golden Eagle Eyrie (Boise Centre on the Grove)

Carbon dioxide reactivity of a mononuclear cadmium hydroxide complex

Sara Ann Huefner and Lisa M. Berreau. Utah State University, Logan, UT

Carbonic anhydrases form a family of extraordinarily active enzymes that are essential for many forms of life, including mammals, prokaryotes, and plants. These enzymes, including those found in humans, usually employ a zinc metal center to reversibly convert carbon dioxide and water to bicarbonate and protons. A newly discovered carbonic anhydrase, however, utilizes a cadmium metal center. In this research project I synthesized a molecular model for the new enzyme, a mononuclear cadmium(II) hydroxide complex, and investigated the model's reactivity with carbon dioxide. I propose that this reaction results in the formation of a binuclear cadmium(II) carbonate complex. This product has been characterized by 1H NMR, 13C NMR, 113Cd NMR, FTIR, elemental analysis, and mass spectrometry. Reversibility studies show that unlike the cadmium carbonic anhydrase, the cadmium(II) carbonate model complex does not perform the reverse reaction.