Synthesis and characterization of Nb(OR)4[OC(O)OR] (R = Me,Et, Allyl) and their reaction with the parent alcohol to afford organic carbonates

Nb(OR)(4)OC(O)OR] (R = Me, Et, allyl) compounds have been synthesized by the reaction of dimeric alkoxo complexes Nb(OR)(5)](2) with CO(2). The kinetics of the reaction has shown that the monomer in equilibrium with the dimer is the species that reacts with CO(2). The resulting compounds are monomeric with a eta(2)-O,O-bonded hemicarbonate group. The CO(2) uptake is reversible. The hemicarbonates react with the parent alcohol to afford the relevant organic carbonate (RO)(2)CO with a turnover number (TON) of >2.