Two mixed-ligand Cd(II)–organic frameworks with unique topologies: selective luminescence sensing of TNP and Cu2+ ions with recyclable performances

Two novel luminescent Cd(II)-organic frameworks, [Cd-2(2-abpt)(Hbtca)(H(2)btca)(0.)5(H2O)](n) (1) and {[Cd-3 (2-abpt)-(btca)(1.5)]center dot H2O}(n) (2) (2-abpt = 3,5-di(2 -pyridyl)-4-amino-1,2,4-triazole, H(4)btca = 1,2,4,5-benzenetetracarboxylic acid), were hydrothermally synthesized from a rigid aromatic carboxylate ligand and a pyridine ligand containing free amino groups. 1 exhibits a novel (4,4,5,5)-c 2D layer architecture with 1D pipe-like chains. 2 shows a 3D framework with an unprecedented (4,4,4,6,7)-c topology. Their structural differences mainly stem from the various coordination modes of the rigid aromatic carboxylate ligand. Luminescence sensing experiments exhibit that 1 can highly sensitively and selectively detect TNP in DMF and H2O. Moreover, test paper was developed to detect TNP as a convenient and practicable approach. In addition, 1 shows highly sensitive and selective sensing of Cu2+. The possible detection mechanisms of 1 towards TNP and Cu2+ have been discussed. These experimental results suggest that 1 should be a potential sensor for TNP and Cu2+.