A (3,9)-connected cadmium 1,2,4-triazolate framework based on a trinuclear inorganic cluster

摘要

Hydrothermal reaction of 1.2,4-triazole with CdCl_2·2.5H_2O generated a 3-D metal-organic framework, {[Cd_3Cl_2(Trz)_4] ·H_2O}_n (1) (Trz= 1,2,4-triazole), which was characterized by elemental analysis, FT-IR. X-ray powder diffraction, X-ray single-crystal diffraction, TG/DTA, and phololumincsccnce measurements. Compound 1 crystallizes in the orthorhom-bic system, space group Pnma, a= 16.906(3) A, 6 = 8.3151(17) A, c= 13.080(3) A, V= 1838.6(6)A~3, Z = 4. Cd(l) is coordinated by four nitrogen atoms and one chloride to form a distorted trigonal-bipyramidal geometry. Cd(2) is an octahedron defined by four triazole nitrogen atoms and two chlorides. Two Cd(2) and one Cd(l) are linked by μ_3-Cl(1) to give a [Cd_3Cl] cluster, which is connected by μ_2-Cl(2) to generate a 1-D inorganic chain. The 1-D inorganic chains are extended by μ_3-Trz to form a 2-D hybrid layer in the b, c-plane, which is ultimately linked by residual triazole ligands to give a 3-D framework. The [Cd_3Cl] clusters and the Trz ligands can be regarded as 9- and 3-connected nodes, which lead to an unusual (3,9)-connected net. with Schlafli symbol of (4~23) -6~(13))(4~3). The solid 1 exhibits high thermal stability and shows strong blue fluorescence emission at 410nm in the solid state at ambient temperature.