Synthesis, crystal structure, luminescent property and DFT investigation on a novel metal–organic framework constructed from rigid tetrapodal ligand 1,2,3,4-tetra(4-pyridyl)thiophene

Employing the tetrapodal compound 1,2,3,4-tetra(4-pyridyl)thiophene (TPT) as a bridging ligand, a new metal–organic framework was obtained and characterized by single crystal X-ray diffraction, [Cd(TPT)(N3)2·(H2O)] (1). This polymer exhibits a 2D layer network and an unprecedented 3,4-connected topology, which is constructed from the three-connector TPT and EE azido bridges. It also displays good thermal stability and strong photoluminescence in the blue regionband thus may serve as a candidate of thermally stable blue-light-emitting electroluminescence material. The nature of electronic transitions in the photoluminescent process has also been investigated by means of time-dependent density functional theory (TDDFT) calculations and molecular orbital analyses, which shows that the luminescent property is ligand-based.