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 2 a, In 2 b; L=HC[C(Me)N(Ar)] 2 ; Ar=2,6-i-Pr 2 C 6 H 3 ) by salt metathesis reactions and their reactions with LGa to metallaphosphenes LGa(OCP)PML (M=Ga 3 a, In 3 b). 3 b represents the first compound with significant In-P π-bonding contribution as was confirmed by DFT calculations. Compounds 3 a and 3 b 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 ( 1 H, 13 C{ 1 H}, 31 P{ 1 H}) NMR and IR spectroscopy, elemental analysis, and single crystal X-ray diffraction (sc-XRD).