Hydrothermal Synthesis And Characterization Of The Metal-coordinated-bridging Substituted Lanthanide-tungsten-oxo Clusters

According to the literature, we prepared lacunary tungsten-oxo clusters as precursors, such as Na9[A-α-PW9O34]·7H2O, Na10[A-α-Si W9O34]·24H2O, K8-x Nax[A-α-Ge W11O39]·n H2 O. We introduced TM-/Ln-cations and different kinds of Keggin-type lacunary precursors as well as various organic ligands into the hydrothermal reaction system expecting to obtain novel polyoxotungstates with various tungsten-oxo cluster fragments or TM-Ln heterometallic clusters. We synthesized six new metal-coordinated-bridging substituted lanthanide-tungsten-oxo clusters, one Ag-Ce heterometallic tungsten-oxo cluster and one hexa-NiII cluster. These compounds were characterized by elemental analyses, IR spectra, powder X-ray diffractions, thermogravimetric(TG) analyses and X-ray single-crystal diffraction. The formulas of these compounds are as follows: [Cu(en)2]4[Cu(en)2(H2O)]2{[Dy(α-Si W11O39)(H2O)2]2(ox)}·6H2O(1) [ox=oxalate] [H2en][Cu(en)2(H2O)]2{[Cu(en)2]3[Cu(en)(ox)]2[Er2(ox)(α-Si W11O39)2]}·10H2O(2) [H2en][Cu(en)2(H2O)]2{[Cu(en)2]3[Cu(en)(ox)]2[Sm2(ox)(α-Si W11O39)2]}·8H2O(3) [H2en][Cu(en)2(H2O)]2{[Cu(en)2]3[Cu(en)(ox)]2[Dy2(ox)(α-Si W11O39)2]}·8H2O(4) [Cu(en)2(H2O)]3[(α-Ge W11O39)Eu(CH3COO)(H2O)]·4H2O(5) H8[H2(en)]2[Cu(en)2(H2O)]4[Cu(en)2]3{[Tb(α-PW11O39)2]2}·22H2O(6) H9[H3(dien)]2{[Ag2(H2O) 5Ce(Si W9O34)2}·7H2O(7) [dien=diethylenetriamine] [Ni6(μ-OH)3(oeen)3(H2O)4(α-PW9O34)]2·6H2O(8) [en= ethylenediamine, oeen= N-(2-hydroxyethyl) ethylenediamine]Compound 1 is a oxalate-bridging Cu–Dy heterometallic hybrid silicotungstate {[Cu(en)2]2[(?-Si W11O39)Dy(H2O)2]2(μ-ox)}6- dimeric units. Compounds 2-4 are isomorphic and exhibit the interesting 2D layer built by monovacant-lanthanide substituted Keggin-type {Cu2Ln2(ox)(Si W11)2}(Ln=ErIII, SmIII, DyIII) dimers via [Cu(en)(ox)]/[Cu(en)2] bridges. Compound 5 displays typical acetate-bridging dimeric structure [(?-Ge W11O39)Eu(H2O)(η2,μ-1,1)-CH3COO]212- modified by [Cu(en)2(H2O)]2+ fragments. Compound 6 consists of sandwich-type {Tb(α-PW11O39)2} diamers, exhibits {Tb2(α-PW11O39)4} via [Cu(en)2]2+ and then forms the 1D zigzag chain architecture via another [Cu(en)2]2+ cations. Compound 7 exhibits Ag-Ce heterometallic clusters in the absence of diethylenetriamine. Compound 8 exhibits [Ni6PW9] clusters with N-(2-hydroxyethyl) ethylenediamine.