Carbon Dioxide Reduction by N‑Phosphinoamidinate-Stabilized Silylenes

The reduction of carbon dioxide mediated by N-phosphinoamidinato silylenes was described. The reaction of an N-phosphinoamidinato chlorosilylene 1 with CO2 afforded carbon monoxide and a dioxo-bridged siloxane 2. Compound 1 was then reduced with KC8 to form base-stabilized disilyne 5, where the interconnected silylene centers reduce CO2 to form CO and carbonate(dioxo)-bridged siloxane derivative 6. In the CO2 reduction, the N-phosphinoamidinate ligand interchanges between N,N′- and N,P-chelate, showing the hemilabile character depending on the oxidation state of the silicon center.