Supramolecular assembly of trimeric gold(I) pyrazolates through aurophilic attractions

The supramolecular architecture of trinuclear gold(I) pyrazolato aggregates is held together by intermolecular aurophilic attractions, sterically governed by the substituents on the pyrazole rings. A two-dimensional network of Au(mu-pz)]3 complexes, 1 (pz = pyrazolato anion, C3H3N2-), and a large intricate aggregate of 16 Au(mu-4-Me-pz)]3 complexes in 2 have been determined crystallographically. Under UV irradiation at ambient temperature, solid samples of 1 and 2 luminesce with lambda max = 626 and 631 cm-1, respectively, attributed to intermolecular Au...Au aurophilic contacts.