A silylene-stabilized ditin(0) complex and its conversion to methylditin cation and distannavinylidene

Due to their intrinsic high reactivity, isolation of tin(0) complexes remains challenging. Herein, we report the synthesis of a silylene-stabilized ditin(0) complex ( 2 ) by reduction of a silylene-supported dibromostannylene ( 1 ) with 1 equivalent of magnesium (I) dimer in toluene. The structure of 2 was established by single crystal X-ray diffraction analysis. Density Functional Theory calculations revealed that complex 2 bears a Sn=Sn double bond and one lone pair of electrons on each of the Sn(0) atoms. Remarkably, complex 2 is readily methylated to give a mixed-valent methylditin cation ( 4 ), which undergoes topomerization in solution though a reversible 1,2-Me migration along a Sn=Sn bond. Computational studies showed that the three-coordinate Sn atom in 4 is the dominant electrophilic center, and allows for facile reaction with KHBBu s 3 furnishing an unprecedented N-heterocyclic silylenes-stabilized distannavinylidene ( 5 ). The synthesis of 2 , 4 and 5 demonstrates the exceptional ability of N-heterocyclic silylenes to stabilize low valent tin complexes. Due to their intrinsic high reactivity, isolation of tin(0) complexes remains challenging. Here, the authors report the synthesis of a silylene-stabilized ditin(0) complex by reduction of a silylene-supported dibromostannylene and its conversion to methylditin cation and distannavinylidene