Reaction of a germylene, stannylene, or plumbylene with trimethylaluminum and trimethylgallium: insertion into Al-C or ga-C bonds, a reversible metal-carbon insertion equilibrium, and a new route to diplumbenes.

The reaction of the tetrylenes Ge(ArMe6)2, Sn(ArMe6)2, and Pb(ArMe6)2 [ArMe6 = C6H3-2,6-(C6H2-2,4,6-(CH3)3)2] with the group 13 metal alkyls trimethylaluminum and trimethylgallium afforded (ArMe6)2Ge(Me)AlMe2 (1), (ArMe6)2Ge(Me)GaMe2 (2), and (ArMe6)2Sn(Me)GaMe2 (3) in good yields via insertion reaction routes. In contrast, the reaction of AlMe3 with Sn(ArMe6)2 afforded the [1.1.1]propellane analogue Sn2{Sn(Me)ArMe6}3 (5) in low yield, and the reaction of AlMe3 or GaMe3 with Pb(ArMe6)2 resulted in the formation of the diplumbene {Pb(Me)ArMe6}2 (6) and AlArMe6Me2 (7) or GaArMe6Me2 (8) via metathesis. The reaction of Sn(ArMe6)2 with gallium trialkyls was found to be reversible under ambient conditions and analyzed through the reaction of Sn(ArMe6)2 with GaEt3 to form (ArMe6)2Sn(Et)GaEt2 (4), which displayed a dissociation constant Kdiss and ΔGdiss of 8.09(6) × 10–3 and 11.8(9) kJ mol–1 at 296 °C. The new compounds were characterized by X-ray crystallography, NMR (1H, 13C, 119Sn, and 207Pb), IR, and UV–vis s...