Highly emissive dinuclear complexes [Au2{μ-(PPh2)2C2B9H10}(C6F5)(PR3)] with different gold fragments coordinated to an anionic diphosphine

Abstract

Reaction of the yellow-green emitters [Au{(PPh₂)₂C₂B₉H₁₀}(PR₃)] with [Au(C₆F₅)(tht)] affords orange-red emissive gold complexes [Au₂{μ-(PPh₂)₂C₂B₉H₁₀}(C₆F₅)(PR₃)] which contain different neutral (PR₃) and anionic (C₆F₅) auxiliary ligands and an anionic diphosphine. The resulting complexes are among the few reported in which an ortho-carborane diphosphine acts in a bridging mode, and are unique in containing not a closo- (neutral), but a nido-carborane (anionic) cluster. DFT and TDDFT calculations led to the prediction of the origin of the two first singlet–triplet transitions, which is consistent with the experimental results. Although the blue emissive nido-diphosphine plays a key role in the transitions of the three-coordinate precursors and the final dinuclear complexes, it is the environment around the gold centre that controls the emission energy.