LAUSR

Abstract Five zinc coordination polymers, namely {[Zn(L)(NO 3 )]·(H 2 O)} n ( 1 ), {Zn 2 (L) 2 ( p -BDC)} n ( 2 ), {[Zn 2 (H 2 O) 2 (L)(1,3,5-BTC)]·H 2 O} n ( 3 ), {[Zn 2 (L) 2 (H 2 BTEC)]·2H 2 O} n ( 4 ) and {[Zn 3 (H 2 O) 4 (L) 2 (BTEC)]·6(H 2 O)} n ( 5 ), {HL = 3,5-di(4H-1,2,4-triazol-4-yl)benzoic acid, H 2 p -BDC = 1,4-benzenedicarboxylic, 1,3,5-H 3 BTC = 1,3,5-benzenetricarboxylic acid, H 4 BTEC = 1,2,4,5-benzenetetracarboxylic acid}, were synthesized under solvothermal conditions. Single-crystal X-ray analyses show that complex 1 exhibits two-dimensional (2D) double-layered 3,4L88 nets with π–π interactions. Complexes 2 , 3 and 4 display the same 2D topological structures as that of complex 1 , except for the further formation of different 2D → 3D supramolecular structures in 2 and 4 . Complex 2 , with a deprotonated [ p- BDA] 2− ligand, forms interpenetrated structures with the (6 2 ·8 4 )(6 6 ) 4 topology built by π–π interactions, whereas complex 4 , built by partially deprotonated [H 2 BTEC] 2− ligands, forms a similar interpenetrated three-dimensional (3D) framework with a point symbol of (6 6 ). When the mixed ligand was changed into 1,3,5-H 3 BTC in 3 , the coordination mode of one Zn(II) atom is trigonal–bipyramidal as opposed to tetrahedral in 1 , 2 and 4 , and each [L] − anion acts as a tetradentate ligand linking four Zn(II) ions instead of a tridentate ligand, generating a 3,4,4,5-connected (6 3 )(6 6 ) 2 (6 9 ·8) framework in 3 . In complex 5 , the completely deprotonated H 4 BTEC ligand connects four Zn(II) ions as a tetracarboxylate ligand to produce a 2-fold interpenetrated three-dimensional (3D) framework with a point symbol of (4·6·7 2 ·8 2 ) 2 (4 2 ·7 2 ·8 2 )(6 2 ·7 3 ·8) 2 . The five complexes have also been characterized by elemental analysis, infrared spectroscopy, powder X-ray diffraction and thermogravimetry measurements. It was also found that the fluorescence of complexes 1 – 5 could be quenched by nitrobenzene (NB), indicating their potential application as sensory materials.