Trialkylborane-Assisted CO_2 Reduction by Late Transition Metal Hydrides
Trialkylborane additives promote reduction of CO_2 to formate by bis(diphosphine) Ni(II) and Rh(III) hydride complexes. The late transition metal hydrides, which can be formed from dihydrogen, transfer hydride to CO_2 to give a formateborane adduct. The borane must be of appropriate Lewis acidity: weaker acids do not show significant hydride transfer enhancement, while stronger acids abstract hydride without CO_2 reduction. The mechanism likely involves a pre-equilibrium hydride transfer followed by formation of a stabilizing formateborane adduct.
Additional Information© 2011 American Chemical Society. Published In Issue August 22, 2011; Article ASAP July 18, 2011; Received: May 02, 2011. This research was generously funded by BP through the Methane Conversion Cooperative (MC2) Program and by the Moore Foundation. The Varian 400-MR spectrometer was purchased through NIH grant RR027690.
Supplemental Material - om200364w_si_001.pdf