Bis-Phosphaketenes LM(PCO)2 (m=ga, In): A New Class of Reactive Group 13 Metal-Phosphorus Compounds

Phosphaketenes are versatile reagents in organophosphorus chemistry. We herein report on the synthesis of novel bis-phosphaketenes, LM(PCO)(2) (M=Ga 2a, In 2b; L= HC[C(Me)N(Ar)](2); Ar=2,6-i-Pr2C6H3) by salt metathesis reactions and their reactions with LGa to metallaphosphenes LGa(OCP)PML (M=Ga 3a, In 3b). 3b represents the first compound with significant In-P pi-bonding contribution as was confirmed by DFT calculations. Compounds 3a and 3b selectively activate the N-H and O-H bonds of aniline and phenol at the Ga-P bond and both reactions proceed with a rearrangement of the phosphaethynolate group from Ga-OCP to M-PCO bonding. Compounds 2-5 are fully characterized by heteronuclear (H-1, C-13{H-1}, P-31{H-1}) NMR and IR spectroscopy, elemental analysis, and single crystal X-ray diffraction (sc-XRD).