Heptabismuthate [Bi₇I₂₄]^3–: A Main Group Element Anderson-Type Structure and Its Relationships with the Polyoxometalates

Abstract

We describe the unique structural and electronic arrangement in the heptanuclear polyiodobismuthate [Bi(7)I(24)](3-) which displays striking similarities with the Anderson-type structures found in polyoxometalates. This main group element anion is part of the complex [Bi(OAc)(2)(thf)(4)](3)[Bi(7)I(24)] (1) which has been characterized by X-ray crystallography. We investigated the structure, stability, and bonding of [Bi(7)I(24)](3-) using relativistic dispersion-corrected density functional theory in combination with a quantitative energy decomposition and electron localization function analysis in order to better understand the main features of this isopolyanion. A comparative analysis of the properties of [Bi(7)I(24)](3-) and previously reported high-nuclearity [Bi(n)X(3n+m)](m-) anions, in the gas phase and in solution, has been performed, in the latter case to track the macroscopic solvent effects. [Bi(7)I(24)](3-) is the largest building block in the class of trianionic iodobismuthates and the sole heptanuclear framework in the family of iodobismuthates.