| In this paper,twelve polyoxometalates?POMs?-directed?including Keggin-type and isopolymolybdates?transition metal-organic complexes based on pyridine monoamide ligands have been synthesized under hydrothermal or solvothermal conditions and characterized by elemental analyses,IR,TG,single crystal X-ray diffractions and PXRD.And the adsorption properties,photocatalytic properties,and electrochemical properties of some complexes were studied.1.Using several nitrogen-containing amide-pyridyl as organic ligands to react with CuCl2·2H2O, AgNO3 and Keggin-type POMs under the hydrothermal conditions,seven Keggin-based functional metal-organic complexes were obtained.In complexes 1 and 2,the original ligands were in-situ transformed to L1 and L2.[Ag3?L1?3?PMo12O40?]·3H2O?1?Ag4?L2?2?HL2??PW12O40?Na2??-OH?]·1.5H2O?2?H3[?PIA?2?PMo12O40?]·2H2O?3?[Ag3?PIA?3][Ag?Si W12O40?]?4?[Ag3?PIA?3][Ag?VW11VIWVO40?]?5?H[Ag3Na2?H2O?2?PIA?6?VW12O40?2]·8H2O?6?Ag2?PIA?2?HPMo12O40?·H2O?7?[L1 =1,2,4-triazole;HL2 =4-amino-1,2,4-triazole;PIA=N-?pyridin-3-yl?isonicotinamide)]In complex 1,the [Ag6?L1?6] crown-shaped ring was clamped by two[PMo12O40]3-polyanions,forming a sandwich-like [Ag6?L1?6(PMo12O40)2] unit,which was extended to a 1D supramolecular chain through hydrogen bonding interaction.Complex 2 is a 3D metal–organic framework containing the[Ag6?L2?4?HL2?2] crown-shaped ring and 1D [Na2(PW12O40)??-OH?]n inorganic chains,which represents a novel?3,3,4,6,10-c?-connected 3D topological framework.In complex 3,neutral nitrogen-containing PIA ligand and [PMo12O40]3-anion were assembled into a 3D supramolecular structure.4and 5 are isostructural 3D frameworks constructed from 1D [Ag3?PIA?3]chains and 1D [Ag?POM?] chains;6 exhibits a 1D chain,which was extended into a 3D supramolecular framework through the non-covalent interactions;while 7 shows a 3D structure based on 1D [Ag2?PIA?2] chains and PMo12O?40?3-anions.The influences of different Keggin anions,the types of metal ions and the ligands on the final structures were discussed.In addition,the electrochemical properties of different POM-based complexes were investigated using complexes 1,2,4 and 5 as examples.The photocatalytic experiments were carried out on complexes 1-3.The results showed that complexes 1-3 had obvious photocatalysis activity on degradation of methylene blue solution under UV irradiation,while complexes 4-7 was subjected to dye adsorption test.They can effectively adsorb cationic dyes methylene blue and rhodamine B.2.The multizole-containing or carboxyl-containing asymmetric mono-amide ligands were introduced into the?NH4?6Mo7O24·4H2O isopolymolybdates system,and five POMs-based functional complexes were obtained under solvent thermal conditions.H4[(Mo8O26)?PIA?2]·H2O?8?H4[Zn2?TAAP?4?H2O?4](Mo8O26)2·16H2O?9?H2[Cd2?PPA?2?H2O?2]??-Mo8O26?·2CH3OH·9H2O?10?H2[Co4?PPA?2?H2O?12?Mo10O34?]·6H2O?11?[Ni4?PPA?4?H2O?6??-Mo8O26?]·8H2O?12?[PIA=N-?pyridin-3-yl?isonicotinamide;TAAP=3-?1H-tetrazole-1-acetic acid amido?pyridine;PPA=6-?pyridin-3-ylcarbamoyl?picolinic acid]Complex 8 is a 3D supramolecular structure derived from the 0D[(Mo8O26)?PIA?] cluster containing Mo–N bond.Complex 9 features a two-fold interpenetrating 3D network with [Mo8O26]4-anions as templates and possess 4-connected lvt net.10 exhibits a 3D supramolecular framework,which is built from binuclear [Cd2?PPA?2?H2O?2]2+ subunits and ?-[Mo8O26]4-anions through the non-covalent interactions;In 11,Co II was used and the[Mo10O34]8-anion was in-situ constructed,which was linked by[Co2?PPA??H2O?6]3+ subunits to yield a 1D double chain.The 1D chains were further linked by H-bond to afford a 3D supramolecular framework;12 is also a 3D supramolecular structure based on 1D[Ni2?PPA?2?H2O?2(?-Mo8O26)]2-anionic chains and the free[Ni2?PPA?2?H2O?4]2+ units with the H-bond interaction.Examples of introducing carboxy-containing pyridine monoamide ligands into POMs system are very few.Furthermore,the electrochemical properties,photocatalysis and adsorption for the organic dyes of these compounds have been investigated. |
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