Aminopyridine derivatives controlled the assembly and various properties of Cu-BTC metal-organic frameworks

Three Cu(II) metal-organic frameworks (MOFs) based on 1,3,5-benzenetricarboxylic acid (H3BTC) and three aminopyridine derivatives with different lengths and coordination groups, namely [Cu-2(3-azpy) (HBTC)(H2BTC)(mu(3)-OH)(H2O)(2)] (1), [Cu-2(3-ppca)(BTC)(H2O)(3)]center dot H2O (2), [Cu-2(3-ebpba)(BTC)(mu(3)-OH)] (3) [3-azpy = 3,3'-azopyridine, 3-ppca = N-(pyridin-3-yl)pyrazine-2-carboxamide, 3-ebpba = (E)-4,4'-(ethene1,2-diyl)bis(N-pyridin-3-yl) benzamide)], have been hydrothermally synthesized and structurally characterized by elemental analyses,IR, PXRD, TG and single crystal X-ray diffraction analyses. The title MOFs display versatile structural features with 2D and 3D frameworks. Complex 1 exhibits a 2D layer, which is constructed from the 3-azpy bridging ligands and a 1D ladder-like Cu-BTC chain with tetranuclear copper clusters. The 3-azpy was in situ transformed from 3-aminopyridine under the hydrothermal conditions. Complex 2 shows a rare 3D framework, which features a (3,3,3,3)-connected topology with a Schlafli symbol of {8.10.12}(2){8(2).10}(2). Complex 3 exhibits a (3,8)-connected {4.6(2)}(2){42.6(22).7.8(3)} topology based on tetranuclear copper clusters. The influence of aminopyridine- based ligands on the structures and properties of the title complexes has been discussed. The electrocatalytic and photocatalytic properties of complexes 1-3 have also been investigated in detail.