Spontaneous Decomposition of an Extraordinarily Twisted and Trans-Bent Fully-Phosphanyl-Substituted Digermene to an Unusual Ge~I Cluster

摘要

Ditetrelenes R2E=ER2 (E=Si, Ge, Sn, Pb) substituted by multiple N/P/O/S-donor groups are extremely rare due to their propensity to disaggregate into their tetrylene monomers R2E. We report the synthesis of the first fully phosphanyl-substituted digermene {(Mes)2P}2Ge=Ge{P(Mes)2}2 (3, Mes = 2,4,6-Me3C6H2), which adopts a highly unusual structure in the solid state, that is both strongly trans-bent and highly twisted. Variable-temperature 31P{~1H} NMR spectroscopy suggests that 3 persists in solution, but is subject to a dynamic equilibrium between two conformations, which have different geometries about the Ge=Ge bond (twisted/non-twisted) due to a difference in the nature of their π-stacking interactions. Compound 3 undergoes unprecedented, spontaneous decomposition in solution to give a unique Ge~I cluster {(Mes)2P}4Ge4-5CyMe (7).