Gold(III)-Mediated Insertion of Se and Te into Au–P Bonds: En route to Diphosphane Chalcogenides and σ-Hole Modulation

Abstract

We report an unprecedented gold(III)-templated insertion of selenium and tellurium into Au–P bonds of bis(diphenylphosphane)methane (dppm), affording the first examples of κ²-(E,P) Au(III) metallacycles (E = Se, Te) via direct chalcogen transfer under mild conditions. This transformation represents a rare case of heavy-chalcogen incorporation into a metal–phosphorus bond, providing synthetic access to previously elusive Te-functional diphosphanes and extending to their selenium congeners. Structural, spectroscopic, and computational analyses reveal that Au coordination modulates P–E covalency and charge distribution, yielding electronically diverse chalcogenated frameworks. Beyond synthetic novelty, these Au–E–P scaffolds act as potent chalcogen-bond (ChB) donors in transfer hydrogenation, with Te complexes outperforming their Se analogues in line with deeper, more accessible Te σ-holes. Remarkably, their catalytic efficiency parallels that of metal-free phosphonium chalcogenides, prepared by direct methylation of (ⁱPr)₃P=E for comparative evaluation. The synergy between Au coordination and chalcogen identity furnishes direct access to otherwise inaccessible Te-functional diphosphanes and establishes a modular platform for tuning σ-hole interactions, advancing the design of main-group/transition-metal hybrids for noncovalent catalysis and molecular materials.