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-Pr₂ C₆ H₃ ) 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).