Flash Communication: Metathesis of Heavy Alkyne Analogues in Solution via Dissociation of m-Terphenyl Substituted Distannynes and Diplumbynes

The terphenyl substituted distannynes and diplumbynes ArEEAr (E = Sn, Pb; Ar = Ar^iPr4, C₆H₃-2,6-(C₆H₃-2,6-ⁱPr₂)₂; Ar = Ar^iPr6, C₆H₃-2,6-(C₆H₂-2,4,6-ⁱPr₃)₂) undergo metathesis and ligand redistribution reactions in solution at ambient temperature to yield mixtures of asymmetrically substituted and heterometallic heavy alkyne analogues. The ambient temperature solution EPR spectrum of Ar^iPr6SnSnAr^iPr6 shows a weak signal corresponding to the (SnAr^iPr6)^· radical, and the thermolysis of Ar^iPr8PbPbAr^iPr8 (Ar^iPr8 = C₆H-3,5-ⁱPr₂-2,6-(C₆H₂-2,4,6-ⁱPr₃)₂) in toluene yields the plumbylene Pb(CH₂C₆H₅)Ar^iPr8, also suggesting that a transient Pb(Ar^iPr8)^· radical is liberated on heating. These results provide further evidence to the solution equilibria of the heavy group 14 analogues with the respective one-coordinate metal radicals.