Highly Efficient and Selective Methanol Production from Paraformaldehyde and Water at Room Temperature

An efficient catalytic system using a water-soluble iridium complex, Cp*IrL­(OH2)2+ (Cp* = pentamethylcyclopentadienyl, L = 2,2′,6,6′-tetrahydroxy-4,4′-bipyrimidine), was developed for highly selective methanol production at room temperature (initial turnover frequency of 4120 h–1) with a very high yield (93%). This catalytic system features paraformaldehyde as the sole carbon and hydride source, leading to a record turnover number of 18200 at 25 °C. A step-by-step mechanism has been proposed for the catalytic conversion of paraformaldehyde to methanol on the basis of density functional theory (DFT) calculations. The proposed pathway holds the potential capacity to extend the scope of indirect routes for methanol production from CO2.