An all-aqueous and phosphine-free integrated amine-assisted CO 2 capture and catalytic conversion to formic acid.

A phosphine-free Ir(III)-NHC-based efficient catalytic system is developed for integrated CO 2 capture with tetramethylguanidine as a capturing agent and conversion to formate with H 2 gas, conducting both the steps in water, affording product yield up to 85% and TON up to 19 171 in just 12 h. In the segment of "integrated CO 2 -capture and conversion to formate", this system represents not only the first phosphine-free module, but also one of the few best known homogeneous catalysts.