| The research work of this thesis is directed by the synthetic consideration that thelacunary sites of lacunary polyoxotungstates (POTs) can act as structure-directing agents toinduce the formation of the second transition-metal (TM) clusters which was initiated byour group. We introduced3d,4f elements and different kinds of Keggin-type orDawson-type lacunary precursors as well as various organic ligands into the hydrothermalreaction system expecting to obtain novel polyoxotungstates with various tungsten-oxocluster fragments or3d-4f heterometallic clusters. Through numerous hard experiments, wealmost mastered the law of transformation of lacunary Keggin or Dawson anions underhydrothermal conditions, and successfully synthesized twenty new lanthanide(Ln)/transition (TM)-metal substituted polyoxotungstates. These compounds werecharacterized by elemental analyses, IR spectra, thermogravimetric (TG) analyses, X-raysingle-crystal diffraction and magnetic properties.Organic–inorganic hybrids based on monovacant Keggin-type polyoxotungstates and3d-4f heterometals:[Cu(en)2(H2O)]2[Tb(α-HSiW11O39)(H2O)3]·12H2O (3-1),[Cu(en)2(H2O)]2[Eu(α-HGeW11O39)(H2O)3]·12H2O (3-2),K2[Cu(en)2(H2O)]2{[Cu(en)2(H2O)]2[Tb(α-PW11O39)(CH3COO)(H2O)]2}·15H2O (3-3),Na2[Cu(en)2(H2O)]4[Sm(α-PW11O39)(CH3COO)(H2O)]2·10H2O (3-4),[Cu(en)2(H2O)]5[Cu(en)2][Tb(α-GeW11O39)(CH3COO)(H2O)]2·14H2O (3-5),K2[Cu(en)2(H2O)]2{[Cu(en)2]3[Ce(α-GeW11O39)(H2O)2]2(ox)}·11H2O (3-6),[Cu(en)2(H2O)][Cu(en)2][Tb(α-PW11O39)(H2O)2(ox)Cu(en)]·6H2O (3-7),[Cu(dap)2]3.5[Cu(dap)2(H2O)]3[La(α-SiW11O39)2]·5H2O (3-8),[Cu(dap)2]3.5[Cu(dap)2(H2O)]2[La(α-PW11O39)2]·6H2O (3-9),[Cu(dap)2]5.5[Er(α-PW11O39)2]·10H2O (3-10),H[Cu(dap)2(H2O)][Cu(dap)2]4[Eu(α-PW11O39)2]·13H2O (3-11) andK4Na4[Ce2(ox)3(H2O)2]2{[Mn(H2O)3]2[Mn4(GeW9O34)2(H2O)2]·14H2O (3-12). Compounds3-1and3-2are isomorphic and exhibit the interesting one-dimensional chain arrangementsbuilt by monovacant-lanthanide substituted Keggin-type [Ln(-HXW11O39)(H2O)3]4(Ln=TbIII, EuIII; X=SiIV, GeIV) units via W–O–Ln–O–W bridges. Compounds3-3,3-4and3-5 display typical hybrid acetate-bridging dimeric structure[(-XW11O39)Ln(H2O)(2,μ-1,1)–CH3COO]210/12-modified by [Cu(en)2(H2O)]2+fragments.Compound3-6exhibits the1D zigzag chain architecture formed by dimericoxalate-bridging {[Cu(en)2]3[Ce(α-GeW11O39)(H2O)2]2(ox)}6-units and [Cu(en)2]2+linkerswhereas compound3-7represents the first oxalate-bridging Ln–TM heterometallic hybridbuilt by oxalate-bridging terbium-substituted phosphotungstate{[Cu(en)2]2[(-PW11O39)Tb(H2O)2]2(μ-ox)}6-dimeric units and dinuclearcopper(II)–oxalate [Cu2(en)2(μ-ox)]2+linkers. Compounds3-8,3-9,3-10and3-11allconsist of sandwich-type [Ln(-P/SiW11O39)2]11/13polyoxoanions and [Cu(dap)2]2+coordination cations. Compound3-12represents the first3d4f3D organic inorganichybrid framework constructed by sandwich-type TM-substituted polyoxoanions and mixed3d and4f metal linkers in POM chemistry, in which each tetra-MnIIsubstitutedsandwich-type unit acts as14-dentate ligands to link eight Ce3+centers and six Mn2+centers further into a three-dimensional (3D) organic-inorganic hybrid architecture.Organic-inorganic hybrids based on lanthanide-substituted Dawson-typephosphotungstate dimers and copper-en linkers:Na2H(H2en)6[Cu(en)2][TbIII(2-P2W17O61)2]·2en·26H2O (4-1),Na2H(H2en)6[Cu(en)2][EuIII(2-P2W17O61)2]·2en·28H2O (4-2),Na2H(H2en)6[Cu(en)2][SmIII(2-P2W17O61)2]·4en·24H2O (4-3) andNa2H(H2en)6[Cu(en)2][CeIII(2-P2W17O61)2]·en·21H2O (4-4). Compounds4-1,4-2,4-3and4-4are isomorphic and represent the first family of1-D chain-like architectures constructedby1:2-type mono-Ln substituted Dawson-type [LnIII(2-P2W17O61)2]17dimeric units and[Cu(en)2]2+connectors, in which the sandwich-type Ln-substituted monolacunary Dawsonphosphotungstate fragment is found for the first time in TM–Ln–polyoxotungstatechemistry.Other TM/Ln-substituted organic-inorganic hybrid polyoxotungstates:[Cu2(OH)2(2,2′-bipy)2][Cu2(α-HPW11O39)(2,2′-bipy)2(H2O)]·17H2O (5-1),[Cu(2,2′-bipy)(H2O)][Cu2(α-HPW11O39)(2,2′-bipy)2(H2O)]·H2O (5-2),K[Cu3(α-PW11O39)(1,10-phen)4]·3phen·2H2O (5-3) and[Cu(en)2(H2O)]4[Ce(W5O18)]2·4H2O (5-4). Compounds5-1,5-2and5-3are the rare magnetic di-transition metal-complex substituted monovacant Kegginpolyoxotungstates. Compound5-4represents the first organic-inorganic hybrid based on[W5O18]6-building blocks and3d-4f heterometals.The successful syntheses of these novel compounds reveal that not only hydrothermaltechnique is an effective synthetic method in the POM field but also the utilization of theorganic ligands is an effective method to synthesize more novel3d4f heterometallicPOMs, which endows us with great opportunities in exploiting and making more novelextended organic inorganic hybrid Ln TM heterometallic POM derivatives by means ofthe appropriate choice of changeable TM ions, Ln cations, different lacunary POTprecursors, and various organic ligands. |
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