A new mixed-azolate Cu(I)-framework based on dinuclear and tetranuclear clusters: Synthesis, structure and luminescence

A new two-dimensional Cu(I)-framework [Cu3(deppz)(mtta)I] (1) [(Hdeppz = 3,5-diethyl-4-(4-pyridyl)-pyrazole, Hmtta = 5-methyltetrazole] has been solvothermally synthesized and structurally characterized. The framework contains an unprecedented cyclic Cu4(μ-pz)2(μ-mtta)2 cluster (Cu4) with twelve-membered coplanar Cu4N8 metallocycle, which contains coordinatively unsaturated Cu(I) centers and acts as a soft π-acid motif to contact with iodine atoms from Cu2I2 dimer of adjacent layers, generating a 3D supramolecular framework. The framework exhibits high thermostability and bright green-blue solid-state luminescence.