CO2 conversion to phenyl isocyanates by uranium(VI) bis(imido) complexes

Leonor Maria, Nuno Bandeira, Joaquim Marçalo, Isabel Cordeiro Santos, and John K Gibson

Uranium(VI) trans-bis(imido) complexes [U(κ⁴-{(^tBu2ArO)₂Me₂-cyclam})(NPh)(NPh^R)] react with CO₂ to eliminate phenyl isocyanates and afford uranium(VI) trans-[O=U=NR]²⁺ complexes, including [U((κ⁴-{(^tBu2ArO)₂Me₂-cyclam})(NPh)(O)] that was crystallographically characterized. DFT studies indicate that the reaction proceeds by endergonic formation of a cycloaddition intermediate; the secondary reaction to form a dioxo uranyl complex is kinetically hindered.