Theoretical study of Au(I)-Ag(I) metallophilic attractions and luminescence of [Au2(carb)2Ag(μ-3,5-Ph2pz)] (with Ph = phenyl, pz = pyrazolate) and [Au(im)CH3(pz)Ag2(μ-3,5-H2pz)2] (with im = imidazole) complexes

The study of trimeric mixed-metal complexes is of great importance for their potential use in sensor devices and nanoparticle design, due to the fascinating luminescent and catalytic activity properties. The goal of this work is to understand the Au(I)-Ag(I) closed-shell metallophilic attraction and phosphorescent character in the representative Au-Ag complexes [Au2(carb)2Ag(μ-3,5-Ph2pz)] (1) and [Au(im)CH3(pz)Ag2(μ-3,5-H2pz)2] (2) through ab initio and DFT techniques. The metal-metal intramolecular interactions are ruled by a Au 5d and Ag 4d mixing, while the intermolecular attractions are governed by a Au 6s and Ag 5s mixing, by π-stacking attractions coming from pz groups and dispersion interactions in complex 2. The phosphorescence reported experimentally may be addressed to MLCT transitions, with intrametallic contributions, where a distortion of the lowest-energy excited state geometry of the monomer and dimer are also involved.