Synthesis, structure, photoluminescence and theoretical calculation on a novel Zn(II) coordination polymer with (4,8)-connected topology

A new compound, namely [Zn2(pbdc)1.5(TAZ)]n 2nH2O (1 H2pbdc = terephthalic acid, HTAZ = 1H-1,2,4-triazole), has been hydrothermally synthesized from H2pbdc, HTAZ and Cd(II) salts. Single crystal X-ray diffraction analysis reveals that compound 1 represents an unprecedented (4,8)-connected 3D topological network. Notably, two TAZ ligands in uniform μ3-1,2,4 bridging mode connect four Zn(II) ions together, giving rise to a [Zn4(TAZ)2] metallo-ligand subunit, which are further bridged via pbdc ligands in two kinds of coordination modes, resulting in the final 3D complicated framework. The relevant density of states (DOS) calculation result showed that the luminescence of 1 mainly originates from HTAZ intraligand charge transition.