Syntheses,Structures And Properties Of New Polyoxotantalate

Tantalum-containing compounds are attracting much attention,due to the application in photocatalysis.However,polyoxotantalates(POTas)are mainly dominated by the Lindqvist-type anion[Ta6O198-]and only keep stable under basic conditions,which limited the development of POTas.In this paper,the design and synthesis of new heteropolytantalate in alkaline and acidic condition were studied.Under conventional reaction conditions,twelve novel polyoxotantalates have been successfully obtained by the reaction of Lindqvist-type K8Ta6O19· 17H2O,transition metal(TM)salts,and rare earth in alkaline and acidic condition separately.In addition,they have been systematiclly characterized by X-ray single-crystal diffraction,X-ray powder diffraction(XRPD),thermogravimetric analyses,IR,UV-vis and elemental analysis.The properties of photocatalysis,fluorescence have also been studied.1.Two organic-inorganic hybrids based on[Ta6O19]8-polyanion,have been successfully obtained by the reaction of Lindqvist-type K8Ta6O19 ·17H2O and TM salts in aqueous method.[Cu(phen)]2[Cu(phen)2]2[Ta6O19]·21H2O(1)[Cu(2,2’-bpy)]2[Cu(2,2’-bpy)2]2[Ta6O19]·20H20(2)X-ray crystallographic analysis shows that Compounds 1 and 2 are isomorphic.They are all composed of one lindqvist[Ta6O19]8-block supporting two[Cu(L)]2 and two[Cu(L)2]2(L=phen,2,2’-bpy)segments.II.The first heteropolytantalate included selenium has been synthesized with the reaction of K8Ta6O19· 17H2O and sodium selenite under the protection of H2O2 in acidic condition.Cs2KH[H4(Ta02)6Se4O21]·6H20(3)The polyanion is considered as two {Ta3Se2} subunits connected through three bridging oxygen atoms.3 could be used as catalysts for the photocatalytic decomposition of RhB in waterIII.Nine lanthanide derivatives of heteropolytantalate included selenium have been successfully obtained by the reaction of K8Ta6O19 17H2O,sodium selenite and rare earth in aqueous method.CsKH3[Ln(H20)6(TaO2)6Se4O21]·H20(4-12)(Ln= Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu)X-ray crystallographic analysis shows that Compounds 4-12 are isomorphic,and they are all consist of {Ta6Se4} unit linked rare earth ions.The luminescent properties of compounds 4,6,7,9,10 were studied.