Activation of Carbon Dioxide at Uranium Complexes

Seminar series
Inorganic Chemistry
Wed, Feb 20 4:30pm
Cram Conference Room, 3440 Mol Sci
Speaker Professor Karsten Meyer
University of Erlangen – Nuremberg (Germany)
Department of Chemistry & Pharmacy

In our efforts to activate small molecules of industrial and biological relevance, we have turned our attention to coordinatively unsaturated, highly reactive, low- and high-valent uranium coordination complexes.  For instance, the hexadentate tris(aryloxide) triaza­cyclo­nonane chelating ligand, (t-BuArO)3tacn3–, and its sterically more demanding and protective neo­pentyl and adamantyl derivatives have provided access to reactive coordination compounds of uranium, [((RArO)3tacn)U] (R = t-Bu, Neo, Ad), in oxidation states III, IV, V, and VI and custom-tailored ligand environments.  These complexes display a pronounced selectivity and reactivity towards carbon dioxide and related heteroallene molecules, such as COS and CS2

Here, reactions are presented that result in CO2 coordination, activation, stoichiometric and catalytic “disproportionation” to CO and CO32–, insertion, and functionalization via multiple bond metathesis.  Most recently, we also could show that oxalates form under optimized conditions.

It is shown that charge-separated complexes of uranium are particularly reactive species that often lead to unprecedented chemistry.