Crystal structure and photoluminescent properties of a Ag(I)-carboxylate coordination compound: Luminescence modulation by a π-conjugated ancillary ligand.

Abstract: Reaction of the 2-D MOF [AgL] n ·nH2O (1; L=4-cyanobenzoate) with pyrazine (L′) in water yielded [Ag2L2L′] n ·2nH2O (2) with a chain-like structure. Compound 1 features tunable yellow-to-white photoluminescence when its wavelength of excitation light varies. The photoluminescence of 2 obviously differs from that of 1: the former displays intense yellowish green phosphorescence with a shorter lifetime of ~3.58μs and an unresolved peak shape, and does not exhibit tunable photoluminescence upon irradiation of 280–380nm UV light. Electron transition from the [Ag2(COO)2] cluster to pyrazine is probably responsible for the phosphorescence of 2 based on the experimental and theoretical results. [Copyright &y& Elsevier]