Low-valent Chromium - Molecules, Reactivity and Catalysis

点击翻译按钮获取中文摘要

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The Inorganic, Bioinorganic, and Organometallic Chemistry Program supports the efforts of Dr. Klaus Theopold of the University of Delaware on the reaction chemistry of low-valent organometallic compounds of chromium, with particular emphasis on the catalysis of selective ethylene oligomerization. The paramagnetic chromacycles (heterocycles containing chromium ligated by beta-diketiminate (nacnac) ligands) of various ring sizes have been synthesized. These molecules are investigated in terms of their selectivity with respect to elimination versus ring expansion. Chromium complexes supported by non-innocent diimine ligands are also used for studies of metallacycle reactivity with ethylene. The charge and formal oxidation state of the metal impacts the ethylene oligomerization reaction. This project is fundamental in nature but may have practical impact on commercial catalyst development. Selective catalytic processes such as those developed here are inherently more sustainable and environmentally benign, as they avoid the production of undesirable byproducts and are more energy efficient. Undergraduate and graduate students experience varied research methodology and gain a strong background in synthetic and mechanistic chemistry, which is in high demand in the chemical industry.