Synthesis and crystal structure of a 3-D Ag⁺ coordination polymer with white-light emission

Treatment of AgNO₃ with a tetrazolyl ligand H₂L₁ afforded a 3-D coordination polymer [Ag₂(L¹)]n (1). The crystal structure was determined by X-ray crystallography and it shows that both Ag1 and Ag2 atoms in the asymmetric unit exhibit distorted tetrahedron geometries, which are modified by Ag⋯Ag interactions. The flexible methylene –CH₂– linkage between tetrazolate and phenyl ring effectively reduces the steric strain in the resultant 3D-framework. L¹ exhibits an unsual coordination mode in which all nitrogen atoms in the two tetrazolato units are coordinated to the Agᴵ centers. The luminescent property of 1 was also investigated. It exhibits multiple emission bands; the high energy emission band is assigned to the ligand-centered π⋯π transition, while the low energy emission bands are tentatively assigned to ligand-to-metal charge transfer (LMCT) that are modified by Ag⋯Ag interaction. The independence of the chromaticity coordinates of 1 on the excitation wavelength also suggests that it is a potentially useful single–component white-light-emitting material. Copyright © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.