Scope of chemical fixation of carbon dioxide catalyzed by a bifunctional monomeric tungstate

The tungsten-oxo moiety in a simple monomeric tungstate, TBA(2)[WO4] (I, TBA = tetra-n-butylammonium), showed bifunctional activation of both CO2 and 1,2-phenylenediamine (la). It was confirmed by H-1, C-13, and W-183 NMR spectroscopies that adducts I la and I (CO2)(n) (n=1 and 2) were formed by the reactions of I with la and CO2, respectively. These adducts played important roles in formation of the corresponding carbamic acid intermediates. The present bifunctionality could be applied to chemical fixation of CO2 even at atmospheric pressure with various kinds of structurally diverse aryl diamines, primary monoamines, propargylic alcohols, and propargylic amines into cyclic urea derivatives, 1,3-disubstituted urea derivatives, cyclic carbonates, and cyclic carbamates, respectively. (C) 2013 Elsevier B.V. All rights reserved.