Reversible Sn–Sn Triple Bond Dissociation in a Distannyne: Support for Charge-Shift Bonding Character

The tin–tin triple bond in the distannyne Ar^iPr4SnSnAr^iPr4, Ar^iPr4 = C₆H₃-2,6­(C₆H₃-2,6-iPr₂)₂, undergoes reversible cleavage in deuterated toluene to afford two :SṅAr^iPr4 radicals in solution as shown by ¹H nuclear magnetic resonance and electron paramagnetic resonance spectroscopy. Variable temperature data afforded an enthalpy of dissociation of ΔH_diss = 17.2 ± 1.7 kcal mol^–1 via van‘t Hoff analysis.