Redox chemistry of niobium chalcogenide halides: a mixed valency NbIII/NbIV tetramer. Preparation and crystal structure of a (µ-diselenido-µ-selenido)-tetraniobium complex, Nb4Br10Se3(NCMe)4

Abstract

The reaction of NbBr₄(NCMe)₂ with Sb₂Se₃ in MeCN solution yields a tetranuclear adduct Nb₄Br₁₀Se₃(NCMe)₄, in which two of the metal atoms have a valence state of four, the remaining two being tervalent; in the adduct the niobium(III) atoms are not involved in any metal-metal interaction and, since the compound is diamagnetic, they must have a doubly occupied d_z², ground state electronic configuration.