| Under hydrothermal conditions, three series of novel high-nuclear transition-metal （TM） cluster ortransition-metal–rare-earth （TM–RE） heterometallic substituted polyoxometalates （POMs）（about twentycompounds） were successfully synthesized by the reaction of trivacant Keggin arsenotungstates/germanotungstates （ATs/GTs） with the TM and/or RE cations in the presence of organic amine ligands asstructure-stabilizing agents and characterized by spectroscopies, crystal structures, luminescence, magneticand photocatalytic properties. The successful preparations of these POMs not only realize theinterdisciplinary of RE chemistry, TM chemistry and POM chemistry, but also provide a novel researchthinking for the sustainable development of POM chemistry.1. Two rare eighteen and twenty NiⅡsubstituted ATs [enH2]2[Ni（H2O）4]2[Ni（en）2]2[Ni（en）]2{[(α-AsW6O26)Ni6（OH）2（H2O）3（en）(B-α-AsW9O34)]2[W4O16][Ni3（H2O）2（en）]2}·（16）H2O （1） and [Ni（H2O）（en）2]2[Ni（H2O）3（en）][Ni（H2O）（en）]{[(α-AsW6O26)Ni6（OH）2（en）2.5(B-α-AsW9O34)]2H4[W4O16][Ni4（H2O）2（en）2]2}·13H2O （2）（en=ethylenediamine）, and two1D and3D organic–inorganic hybrid hexa-CuⅡsubstituted sandwich-type ATs [Cu（en）2（H2O）]2[Cu（en）2][Cu6（en）2（H2O）2(B-α-AsW9O34)2]·en·9H2O （3）and [Cu（dap）2]3[Cu6（dap）2（H2O）2(B-α-AsW9O34)2]·4H2O （4）（dap=1,2-diaminopropane） have beenisolated under hydrothermal conditions.1and2display an unusual construction motif simultaneouslycontaining the [B-α-AsW9O34]9-,[α-AsW6O26]11-and [W4O16]8–fragments.3and4represent the firsthigh-dimensional ATs containing hexa-CuⅡsandwiched units. Magnetic measurements demonstrate that1–4indicate the ferromagnetic couplings.2. Four types of organic–inorganic hybrids Na[Cu（en）2（H2O）]4[Cu（en）2]2[Cu（H2O）4]0.5{Cu（en）2[H2CeⅣ(α-AsW11O39)2]2}·10H2O （5）, Na3[Cu（en）2（H2O）][Cu（en）2]1.5[H3Ln(α-AsW11O39)2]·xH2O [Ln=PrⅢ, x=5（6）; Ln=NdⅢ, x=4.5（7）; Ln=SmⅢ, x=5.5（8）; Ln=EuⅢ, x=4（9）; Ln=TbⅢ, x=4（10）],[Cu（dap）（HI2O）2]0.5[Cu（dap）2（H2O）]2[Cu（dap）2]3[Ln(α-AsW11O39)2]·xH2O [Ln=PrⅡ, x=3（11）; Ln=EuⅢ,x=3（12）] and [Cu（dap）2]5.5[Ln(α-AsW11O39)2]·xH2O [Ln=TbⅢ, x=6（13）; Ln=DyⅢ, x=5（14）] havebeen synthesized. The common structural features of5–14are that they all consist of sandwich-type[Ln(α-AsW11O39)2]10/11-)polyoxoanions as the fundamental building blocks and [Cu（en）2]2+/[Cu（dap）2]2+cations as bridges. The photocatalytic measurements show that5–14can to some extent inhibit thephotodegradation of rhodamine-B. 3. Three organic–inorganic hybrid CuⅡ–LnⅢheterometallic germanotungstates {[Cu（en）2（H2O）][Cu3Eu（en）3（OH）3（H2O）2](α-GeW11O39)}2·11H2O （15）,{[Cu（en）2（H2O）][Cu3Tb（en）3（OH）3（H2O）2](α-GeW11O39)}2·11H2O （16） and {[Cu（en）2（H2O）][Cu3Dy（en）3（OH）3（H2O）2](α-GeW11O39)}2·10H2O （17） havebeen hydrothermally synthesized.15–17are essentially isomorphous and their main skeletons display theinteresting dimeric motif {[Cu3Ln（en）3（OH）3（H2O）2](α-GeW11O39)}24–constructed from two {Cu3LnO4}cubane anchored monovacant [α-GeW11O39]8–fragments through two W–O–Ln–O–W linkers.15exhibitsthe antiferromagnetic coupling interactions, while16and17display the dominant ferromagneticinteractions. |
PDF Full Text Request