Luminescent Au(III)−M(I) (M = Cu, Ag) aggregates based on dicyclometalated bis(alkynyl) gold anions

The syntheses and structures of a series of complexes based on the C^C-chelated Au(III) unit (C^C = 4,4′-bis(t-butyl) 2,2′-biphenyl-1,1′-diyl) are reported, namely [{(C^C)Au(C≡CtBu)2}2M2], (C^C)Au(C≡CR)(C≡NXyl), ) and [{(C^C)Au(C≡CR)2}{M(C≡NXyl)}] (M = Ag, Cu; R = tBu, C6H4tBu-4, C6H4OMe-4; Xyl = 3,5-Me2C6H3). The X-ray structures reveal a broad range of dispositions determined by the different coordination modes of Ag(I) or Cu(I) in the different structures. The complexes are bright photoemitters in the solid state and in poly(methyl methacrylate) (PMMA) films. The photoluminescence is dominated by 3IL(C^C) transitions, with indirect effects from the rest of the molecules, as supported by theoretical calculations. This work opens up the possibility of accessing Au(III) carbon rich anions to construct photoluminescent aggregates.