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{(PPh(2))(2)C(2)B(9)H(10)}(PR(3))] with [Au(C(6)F(5))(tht)] affords orange-red emissive gold complexes [Au(2){µ-(PPh(2))(2)C(2)B(9)H(10)}(C(6)F(5))(PR(3))] which contain different neutral (PR(3)) and anionic (C(6)F(5)) 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.