Quest for an intermolecular Au( iii )⋯Au( iii ) interaction between cyclometalated gold( iii ) cations

We reported our endeavour in the quest for an attractive metallophilic interaction between two cyclometalated Au(III) cations without a bridging ligand. Among the newly prepared gold(III) complexes, namely [Au(C^N^N)(C≡CC6H4-4-R)](PF6) [HC^N^N = 6-aryl-2,2′-bipyridine, R = H (1), Me (2), Ph (3), OMe (4), and NMe2 (5)], complex 5 is stable in solution and in the solid state. An X-ray crystallographic determination of the crystal structure of 5 revealed the shortest intermolecular Au(III)⋯Au(III) contact (3.495 Å) reported between two gold(III) complex cations. Further spectroscopic and luminescent characterizations and density functional theory calculations on this system converge to the existence of weakly attractive Au(III)⋯Au(III) interactions.