Unexpected transformation of a diamagnetic Mo3(μ3-S)(μ-S)3 to a paramagnetic Mo3(μ3-S)2(μ-S)3 cluster core by reaction of [Mo3S4(dppe)3Br3]PF6 with (t)BuSNa.

The electron precise [Mo(3)(μ(3)-S)(μ-S)(3)(dppe)(3)Br(3)](+) incomplete cuboidal complex with six cluster skeletal electrons (CSE) can be converted to the paramagnetic bicapped [Mo(3)(μ(3)-S)(2)(μ-S)(3)(dppe)(3)](+) cluster with an unusual seven metal electron population by treatment with (t)BuSNa, which simultaneously serves as a reducing agent and a source of the additional capping sulfur atom.