| Arsenotungstate polyoxometalates?POMs?are an important brabch of heteropoly acid,which not only rich in chemical composition and certain photosensitivity but also have reversible multielectron redox properties.Therefore it is an ideal catalytic materials,have potential application in electrocatalysis and photoatalysis.In this paper,eight kinds of novel structural organic-inorganic hybrids with arsenic as heteroatom were success-fully synthesized by a one-step hydrothermal method using sodium arsenite as a arsenic source,selecting appropriate organic ligands and making full use of the bridging effect of alkali metals and transition metals.According to the elemental composition analysis and single crystal X-ray diffraction results,the molecular formula:?H2bib?5[Co4?H2O?2(AsW9O34)2]?2H2O?1?[Cu6?imi?6{AsIIIW9O30Cl3}2]·6H2O?2?[Cu3I?pz?2?phen?3]2[CuI?phen?2][{Na?H2O?2{AsIIIW9 O33}2(V5IVCuIIO6)]·6H2O?3??H3btp?4[Fe4?OH?2(AsW9O34)2]·4H2O?4??H2bth?3(As2W18O62)?5??Hbpy?2{Mn?bpy?3}2[As2W18O62]?6??H2imi?5[As2W18O62]?H2O?7?{Ag?Hptp?2}2[AsWVW11VIO40]?3H2O?8?Bib=1,4-Bis?imidazol-1-ylmethyl?benzene;imi=imidazole;pz=pyrazine;phen=1,10-phenanthroline;bth=1,6-bis?triazol?hexane;bpy=2,2'Bipyridine;ptp=4'-4?4-pyridine?-2,2':6',2"-terpyridine)Thestructuralanalysisexhibitsthatcompounds1and4are tetra-substituted sandwich arsenictungstate compound composed of two trivacant of[AsW9O34]9-ions and[Co4?H2O?2]and[Fe4?OH?2]cations,respectively.compound 2 is 6-copper substituted sandwich compoundformed by[Cu6?imi?6]complex bridge unit connecting two chloride substituted[AsIIIW9O30Cl3]anions.Compound 3 is a 3-D host-guest structure based on a supramolecular organic metal host network with 1-D channels and a 6-TM mixed guest chain of arsenotungstate.The host network is formed by a unique tri-nuclear complex{Cu3?phen?3?pz?2}through an overlapping?-?stacking,The guest chain is embedded in the tunnel of the main network by weakly interacting.It is the first host-guest sandwich arsenotungstate compound based on inorganic chain and 3-D metallic organic network.Compound 4 is a 12-connected dense packing network with{324·436·56}topological structure consisting of 6-copper complex substituted sandwich arsenotungstate.Compound 5-7 is a Dawson type arsenictungstate supramolecular networks modified with organic ligands.Compound 8 is a keggin-type supramolecular compound modified by complexes formed by in-situ ligands.Compound 1-8 can catalyze both oxidizing substances such as hydrogen peroxide and reducing substances such as ascorbic acid,and is a potential dual-functional sensor material.Under ultraviolet irradiation,compound 1-8 exhibited excellent photocata-lytic activity for degradation of typical dyes such as methylene blue?MB?and Rhodamine B?RhB?.The catalytic activity of host-guest molecular intercalated arsenotungstate?compound 3?containing pure inorganic 1-D chain and 3-D metal-organic network is higher than that of other zero-dimensional compounds.The capacitance performance of compound 1-8,as the electrode material,has been studied for the first time.The constant current charge-discharge performance of compounds 1-8has demonstrated their excellent capacitance,which are high specific capacitance materials under high current density.The result has verified its advantages as electrode materials in capacitance performance.In addition,compounds 1-8 showed good electrode stability.Compared with the results of the experiment,we found that compound 3,as the electrode active material of the supercapacitor,had higher specific capacitance(825 F·g-1,Current density 2.4F·g-1).This value is higher than not only the other seven POMs but also reported POMs and POM matrix composites.The better capacitance performance of compound 3 can be attributed to the introduction of V4+,unique host-guest structure,and abundant?electron system,,which improves the conversion efficiency and migration rate of ions and electrons in the redox reaction.At the same time,the shost-guest structure with a tunnel increases the specific surface area of the material and provides space for electronic transmission. |
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