Boryl transfer reactivity of a POCOP-supported Ir-diboryl: Reduction of CO2 to CO and borylation of other small molecules

Abstract Reactions of a trivalent diboryl Ir complex Ir-(Bpin) 2 supported with a POCOP-type pincer ligand with a series of small molecules have been explored (pin = pinacolate). Ir-(Bpin) 2 deoxygenated CO 2 to make Ir-CO and O(Bpin) 2 . Attempts to deoxygenate other carbonyl compounds were not successful. The reaction with CO led to loss of B 2 pin 2 by reductive elimination and its replacement on Ir with CO. Ir-(Bpin) 2 did not react with p-trifluoromethylbenzaldehyde, acetone, ethyl acetate or benzonitrile. The reaction with ethyl formate resulted in formal dehydroethoxylation of this substrate, with formation of Ir-CO and HBpin and EtOBpin. Finally, treatment of Ir-(Bpin) 2 with ethylene resulted in diboration of ethylene to produce pinB-CH 2 CH 2 -Bpin and Ir-(C 2 H 4 ) .