| Metal-organic coordination polymers have attracted more and more attentions as new functional materials in recent years.Due to their novel structure,adjustable size,and good thermal stability,coordination polymers have many potential applications such as gas adsorption,magnetic materials,fluorescent materials,and electrochemistry.Because imidazole has many coordination sites and strong coordination ability,it has become one of the most commonly used ligands for the construction of coordination polymers.Imidazole-containing ligands can not only be directly coordinated with metals,but also can be combined with metals and polyoxometalates(POMs)to construct novel ternary complexes.These compounds have shown excellent performances in many fields such as biology,chemistry,medicine,and so on.In this study,six nitroimidazole derivative ligands L1-6 were obtained by alkylation reaction.Finally,ten new coordination polymers have been successfully synthesized,namely Cu5Cl(SiW12O40)(L1)4(1),[Cu(PW12O40)(L1)][Cu2(L12](2),[Cu(PMo12O40)(L1)]{[Cu2(L1)2]·H2O}(3),Cu4(SiW12O40)(L2)4(4),[Cu2(SiW12O40)(L3)2·H2O]·H2O(5),Cu2Cl2(L4)(6),Cu2Cl2(L4)(7)·Cu2(Mo6O19)(L4)2(8),Cu2(Mo6O19)(L5)2(9),Cu2Cl2(L6)(10).The structures of 1-10 have been characterized by single crystal X-ray diffraction and infrared spectroscopy.Complex 1 has two structural units which is shown as chain and ring.The(SiW12O40)4-serves as a connection point to expand the chain into a layer,and the layers are expanded into a 3D structure by C1(Ⅰ).Complexes 2 and 3 have similar structures which consist of two chains,one chain containing organic ligands and Cu(Ⅰ).The other chain contains organic ligand,Cu(Ⅰ)and POMs.In complex 4,L2 and Cu(Ⅰ)form a "W"-shaped chain,and the[SiW12O40]4-is located on one side of the chain,then the chains are expand to a 2D structure by intermolecular forces.In complex 5,the tridentate ligands L3 are linked by Cu(Ⅱ)ions to form a layer containing a pore-like structure.The[SiW12O40]4-anions are scattered in the hole by intermolecular force to produce a new 2D layered structure.In complex 6,L4 ligands are connected by Cu(Ⅰ)ions to form a wave chain.In complex 7,L4 and Cu(Ⅰ)are built a cyclic structural unit,and Cl(Ⅰ)serves as a connection point and expands the unit into a 2D layer.In complex 8,L4 ligands are bridged by Cu(Ⅰ)ions to constitute a "S"-shaped chain,and[Mo6O19]2-anions are is used as bridges to connect the two chains to form a 2D layer.In complex 9,L5 ligands are linked by Cu(Ⅰ)ions to generate a 1D chain,and[Mo6O19]2-anions connect two short chains to give a cyclic unit and then extend to a new double-stranded chain.In complex 10,L6 ligands and Cu(Ⅰ)ions are linked each other to form a 1D chain,and Cl(Ⅰ)ions connect the two chains side by side to form a 2D layer,and the layers are expanded into a 3D network structure by Cu-Cl bonds.In order to improve the conductivity of the complexes 1-10,they were combined with polyaniline and then conducted electrochemical performance tests.The results show that the CV curves of the composite n-PANI(n=complexes 1-10)have a pair of obvious redox peaks.All of them exhibit pseudocapacitive behaviors.Among them,5-PANI exhibits good supercapacitance performance,and the specific capacitance is 443 F g-1 at 1 A g-1,which can be used as a positive electrode material in the field of supercapacitors. |
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