Activation of N2O, CO2 , and CO at a sterically protected phosphorus center

Abstract

Functionalization of a sterically encumbered phosphorus precursor enables varied activation pathways for N2O, CO2, and CO. The potasssium phosphanide salt, [K(crypt)][(MsFluInd*)PH] (crypt = 2.2.2.cryptand; MsFluInd* = a sterically demanding hydrindacenyl substituent), was synthesized and treated with either N2O or 13CO2 to afford the potassium phosphinate, [K(crypt)][(MsFluInd*)PHO2], or the potassium phosphacarboxylate, [K(crypt)][(MsFluInd*)PH(13CO2)], respectively. Deprotonation of the TMS-functionalized (TMS = trimethylsilyl) phosphine, (MsFluInd*)PTMSH, followed by treatment with either N2O or 13CO2 resulted in the formation of a phoshanorcaradiene, (MsFluInd*)P, and an arylphosphaketene, (MsFluInd*)P13CO, respectively. Reversible CO binding at phosphorus allows for the interconversion between (MsFluInd*)P and (MsFluInd*)PCO. The mechanism for the formation of (MsFluInd*)PCO from (MsFluInd*)P and CO was investigated computationally.