The reaction of the phosphine oxides, OPEt31 and OPn-Bu32 with pinacolborane (HBpin) results in phosphine oxide reduction and the formation of O (Bpin) 23. In contrast, the phosphine oxide OPn-Bu3 reacts with HB (C6F5) 2 or B (C6F5) 3 to give only the donor– acceptor adducts. Compound 3 reacts with HNPt-Bu3 to give the phosphinimonium borate salt,[t-Bu3PNH2][(Bpin (OBpin) 2] 6, while reaction with Cp2ZrMe2 affords the species ...