2D and 3D coordination polymers constructed by a novel hexakis(1,2,4-triazol-ylmethy1)benzene ligand and different carboxylate anions: syntheses, structures, and luminescent properties

A series of new coordination polymers, namely, [Zn₂(Htrb)_0.5(L1)(SO₄)]·H₂O (1), [Zn_1.5(Htrb)_0.5(L2)_0.5(SO₄)]·5H₂O (2), [Zn₃(Htrb)(SO₄)₃(H2O)₃]·H₂O (3), [Zn(Htrb)_0.5(L1)]·3.5H₂O (4), [Cd(Htrb)_0.5(L1)(H₂O)]·2.5H₂O (5), [Co(Htrb)_0.5(L1)(H₂O)]·2H₂O (6), and [Cu₂(Htrb)_0.5(L1)₂(H₂O)]·1.5H₂O (7), where Htrb = hexakis(1,2,4-triazol-ylmethy1)benzene, H₂L1 = 1,3-benzenedicarboxylic acid and H₂L2 = fumaric acid, have been synthesized under hydrothermal conditions. The structures of the seven compounds have been determined by single-crystal X-ray diffraction analyses and further characterized by infrared spectra (IR), elemental analyses, and powder X-ray diffraction (PXRD). Compound 1 displays a 3D (4,8)-connected net with the rare (3²·4²·5²)(3⁶·4⁸·5¹⁰·6⁴) topology. Compound 2 shows a typical 3D (4,6)-connected (4⁴·6²)(4⁴·6¹⁰·8) net. Compound 3 furnishes an unusual 3D (3,5,6)-connected net with (4²)₂(6³)(4²·6⁸)₃(4²·8⁶·10³)₂ topology. Compounds 4–6 exhibit similar 2D layer structures with (4,4)-connected (4·6⁴·8)(4²·6⁴) topology. Compound 7 possesses a 3D 2-fold interpenetrating (3,4,6)-connected net with (4·6²)(8·6⁵)(4²·6⁸·8³·10²) topology. The effects of the Htrb ligand and anions on the structures of the coordination polymers have been discussed. In addition, photoluminescent properties of the compounds have also been investigated in detail.