Hydrothermal synthesis, crystal structures and photoluminescence of a 2D cadmium(II) coordination polymer based on in situ synthesized tetrazole derivative ligand

Abstract

Hydrothermal reaction of methyl 4-(cyanomethoxy)benzoate, Cd(NO 3 ) 2 ·4H 2 O and NaN 3 yielded a new 2D Cd(II) coordination polymer, {[Cd 3 (N 3 ) 2 (mtzb) 4 (H 2 O) 2 ]·(H 2 O) 2.5 } n 1 (Hmtzb = methyl 4-(1 H -tetrazol-5-ylmethoxy)benzoate), which was characterized by single-crystal X -ray diffraction. The in situ [2 + 3] cycloaddition reaction of nitrile and azide in presence of Cd(II) salt afforded a new tetrazolate-based mtzbˉ ligand. In polymer 1 , The cross-linkage of the mtzbˉ ligands and Cd(II) atoms forms a 2D layer network, and the mtzbˉ ligand displays two distinct μ 3 -bridging coordination modes, μ 3 - κ N1: κ N2: κ N3 and μ 3 - κ N1: κ N2: κ N4. Photoluminescent analyses revealed that 1 exhibits a strong blue emission with a fluorescent lifetime of 3.22 ns. The relevant density of states (DOS) calculation results showed that the photoluminescence mainly originates from ligand-centered charge transition.