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

Ditetrelenes R E=ER (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 R E. We report the synthesis of the first fully phosphanyl-substituted digermene {(Mes) P} Ge=Ge{P(Mes) } (3, Mes=2,4,6-Me C H ), which adopts a highly unusual structure in the solid state, that is both strongly trans-bent and highly twisted. Variable-temperature P{ H} 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 cluster {(Mes) P} Ge ⋅5 CyMe (7).