Syntheses,structures And Properties Of Wheel-shaped {P₈W₄₈} Tungstophosphates Decorted By Carboxyethyltin And Transition Metals

Multi-nuclear metal-oxygen clusters have a number of characteristic,such as nano-size,high degree of polymerization and huge bulky.The study of multi-nuclear metal-oxygen clusters involves not only the field of nanomaterials but also catalysis,photochemistry,magnetic and electrochemistry.Thus,the synthesis of such multi-nuclear metal-oxygen clusters has become a hot research topic in polyoxometalates(POMs).Using estertin(SnR,R=CH2CH2COOCH3/CH2CH(CH3)COOCH3)as an organic precursor,and the wheel-shaped[P8W48O184]40-(abbreviated as {P8W48})and transition metal(TM)ions as starting materials,seven novel carboxyltin group grafted wheel-shaped tungstophosphates were successfully constructed in aqueous solution by the routine synthetic method.All compounds have been characterized by X-ray single-crystal diffraction,elemental analysis,NMR,IR spectroscopy,TG analysis,X-ray powder diffraction and electrochemical analysis.Single-crystal X-ray diffraction analysis revealed that all of these organotin groups or TM ions are decorated on the inner of the polyoxoanion wheels,and the estertin precursors hydrolyze into the carboxyethyltin groups.The electrocatalytic activities of these compounds toward the reduction of H2O2 and NaNO2 are performed.Selecting the oxidation of cyclohexanol to cyclohexanone as a model reaction,the oxidation catalytic activities of 1-7 were evaluated and the convertion of cyclohexanone were more than 80%.A preliminary photocatalytic ability of 1-7 towards organic dye degradation were performed using the photocatalytic degradation of RhB as a model reaction,at the same time,the reusability of these compounds has been studied and the degradation efficiency were more than 95%.Experimental results showed that this kinds of compounds exhibit high stability and good catalytic performance,and the POM-TiO2 can be recycled when it using as heterogeneous photocatalytic catalysts for degradation of RhB,which showed the excellent characteristics of green catalysts.The molecular formulas of the new seven compounds are as follows:K2Na29[Sn(C3H4O2)(H2O)2)4(HP8W48O184)]·93H2O(SnR-P8W48)K2Na20[Sn(C4H6O2)(H2O)2)4(H10P8W48O184)]·74H2O(SnR(CH3)-P8W48)KNa22H3[{Co(H2O)3Sn(C3H4O2)(H2O)(?-OH)Sn(?-C3H4O2)(H2O)Sn(C3H4O2)(H2O)}2(P8W48O184)]·85H2O(SnR-Co2-P8W48)Na19H7[{Mn(H2O)3Sn(C3H4O2)(H2O)(?-OH)Sn(?-C3H4O2)(H2O)Sn(C3H4O2)(H2O)}2(P8W48O184)]·72H2O(SnR-Mn2-P8W48)Na19H7[{Ni(H2O)3Sn(C3H4O2)(H2O)(?-OH)Sn(?-C3H4O2)(H2O)Sn(C3H4O2)(H2O)}2(P8W48O184)]·75H2O(SnR-Ni2-P8W48)KNa17[{Ni(H2O)3(SnC3H4O2)(H2O)(?-OH)(SnC3H4O2)(H2O)(SnC3H4O2)(H2O)Ni(H2O)4}2(H2P8W48O184)]·70H2O(SnR-Ni4-P8W48)Na14[{Mn(H2O)3(SnC3H4O2)(H2O)(?-OH)(SnC3H4O2)(H2O)(SnC3H4O2)(H2O)Mn(H2O)4}2(H6P8W48O184)]·60H2O(SnR-Mn4-P8W48)...