| Polyoxometalates (POMs) represent a fascinating class of inorganic chemistry with a structural variety and interesting properties, which are of use in fields as diverse as catalysis, sorption, molecular electronics, medicine, etc. A great progress in metal-oxo cluster chemistry has been study of polyoxoanion-supporting inorganic or organometallic complexes, in which Keggin unit and its derivative-supporting metal complexes is an important family. There exist two kinds of Keggin cluster-supported metal complexes. One is molecular clusters possessing discrete structures, the other is cluster polymers constructed from Keggin units as building blocks and metal complexes as bridges. During our research for the metal-oxygen clusters, we synthesized some decorated metal-oxygen clusters, the cluster based on molybdenum-vanadium, cobalt phosphomolybdate, polyoxovanadate, polyoxotungstate and hetero-nuclear Cu'/Cu" compound involving hydroxylation of N-heterocycle ligands. On the bases of X-ray structural analyses, some compounds have been characterized by IR, XPS, ESR spectra. The thermal analyses and magnetic properties of some compounds have also been studied, which would take a role in the explorations of structures and functions for the compounds. 1. The mixed molybdenum-vanadium polyoxometalates. The hydrothermal reactions give six novel compounds ,which consist of highly reduced tetra or bi-capped pseudo-Keggin polyoxoanion supporting transition metal complexes, {[Co(phen)2]2-C2O4}{H2PMoVI3MoV5VIV8O44[Co(phen)2 (H2O)]2}·7H2O 1 和[Cu(phen)2]4{HPMo8VIVIV6O42[Cu(phen)]2}·2H2O 2,{[Ni(2,2'-bipy)2H2O]4 [MoV3MoVI5VIV8O40(PO4)]}{[Ni(2,2'-bipy)2H2O]2[MoV3MoVI5VIV8O40(PO4)]}·5H2O 3 , {[Co(2,2'-bipy)2H2O]4[MoV4MoVI4VIV8O40(PO4)]}{[Co(2,2'-bipy)2H2O]2[MoV3 MoVI5VIV8O40(PO4)]}(H3O)·4H2O 4, [Ni(phen)3]2H[PMoV4MoVI4 VIV6 M2O44]·4H2O 5 和[Co(phen)3]2H[PMoV4MoVI4 VIV6 M2O44]·4H2O 6. Their structure were determined by single crystal X-ray diffraction analysis and characterized by XPS, EPR, IR, ICP, TG, etc. The magnetic behavior of compound 1 ,2,3 and 4 was measured, There exist antiferromagnetic interaction in 1, 3 and 4. There exists ferromagnetic interaction in 2. Compound 1 and 2 consist of highly reduced tetra or bi-capped pseudo-Keggin polyoxoanion supporting two transition complexes, modified polyoxometalates Compound 3, 4 are isostructural constructed of positive and negative metal-oxo cluster ions, Compound 5, 6 are isostuctural too, constructed of tetra-capped pseudo-Keggin polyoxoanion, but two V atoms on the V8 ring are replaced by Mo atoms. All the six compounds are in triclinic system with space group P-1, cell parameters: 1 a = 13.1098(2) ?, b = 14.2845(3) ?, c = 17.0576(4) ?, α= 90.7550(10)o, β= 104.6340(10)o, γ= 100.8690(10)o, V = 3029.03(11) ?3. 2 a = 14.5976(4) ?, b = 15.8988(4) ?, c = 16.2805(4) ?, α= 116.292(2)o, β= 102.968(2)o, γ= 94.841(2)o, V = 3227.29(14) ? 3. 3 a = 15.628(3) ?, b = 24.948(5) ?, c = 25.071(5) ?, α= 76.34(3) o, β= 78.11(3)o, γ= 80.39(3)o. 4 a = 15.722(3) ?, b = 25.000(5) ?, c = 25.315(5) ?, α= 76.40(3)o, β= 78.19(3)o, γ= 80.41(3)o, V = 9392(3) ?3. 5 a = 12.0953(7) ?, b = 14.0715(8) ?, c = 14.6211(8) ?, α= 105.1600(10)o, β= 92.1230(10)o, γ= 91.4210(10)o, V = 2398.7(2) ?3. 6 a = 12.1351(5) ?, b = 14.0182(6) ?, c = 14.6468(7) ?, α= 105.134(2)o, β= 91.841(3))o, γ= 91.401(2)o, V = 2402.55(18) ? 3.2. Phosphorous -molybdate The hydrothermal reactions give a phosphorous-molybdate (NH3CH2CH2NH3) (NH3CH2CH2NH2)3Na3[Co4Moi2O24(OH)6(H2O)2(HPO4)2(PO4)6]-8H2O 7 and two cobalt molybdate NaCo2OH(H2O)(MoO4)2 8, NH4Mo6Oi8 9. The structure of compound 7 is based on Co[Mo6P4]2 units connected together via additional Co2+ ions to give a new three-dimensional framework. This is the first open-framework cobalt molybdenum phosphate constructed from M[Mo6P4]2 building blocks and containing both tetrahedrally and octahedrally coordinated transition metals. Compound 8 belongs to 3-D heavy-metal molybdate. Compound 9 is a polyoxomolybdate. Their structure were determined by single crystal X-ray diffraction analysis and characterized by IR, ICP. The magnetic behavior of compound 7 was measured; there exist antiferromagnetic interaction in 7. 7 crystallizes in monoclinic system with space group C2/c, cell parameters a = 12.328(3) A, b = 21.579(4) A, c = 26.024(5) A, 0 = 99.54(3)°, V = 6827(2) A3. 8 crystallizes in Monoclinic system with space group C2/m, cell parameters a = 9.3647(19)A, 6=6.3143(13), c = 7.6009(15) A, /3= 115.81(3)°, V = 404.62(14) A3. 9 crystallizes in Monoclinic system with space group P6(3)/m, cell parameters a = 10.6166(15) A, b = 10.6166(15), c = 3.7290(7), y = 120°, V = 363.99(10) A3. 3. Heteropoly and isopolyoxovanadate Hydrothermal reactions give four isovanadate [Co(2,2'-bipy)3]2[V4Oi2]-HH2O 10, [Co(2,2'-bipy)(H2O)(VO3)2] 11, [Co(l,10-phen)(H2O)(VO3)2] 12, [Cu(en)2]V6O14 13, and two heteropolyoxovanadate [Co(l,10-phen)3AsgVi4O42] 14, [Ni(l,10-phen)3 AS8V14O42] 15. Their structures were determined by single crystal X-ray diffraction analysis and characterized by IR, ICP, etc. 10 crystallizes in Monoclinic with space group C2/c, cell parameters a = 21.987(4) A, b = 14.025(3) A, c = 23.854(5) A, ]3 = 106.08(3)°, V = 7068(2) A3. 11 crystallizes in Orthorhombic with space groupPca2(l), cell parameters a = 9.2280(2) A, b = 10.5604(3) A, c = 9.4684(19)A, V = 1401.51(7) A3, 12 crystallizes in Monoclinic with space group P2(l)/c, cell parameters a = 7.8623(16) A, b = 21.149(4) A, c = 23.854(5)A,^ = 112.87(3)°, V = 1450.7(5) A3. 13 crystallizes in Monoclinic with space group P2(l)/ n, cell parameters a = 8.9373(18)A, b =6.5175(13)A, c = 15.722(3) A, fi= 100.01(3)°, V = 901.8(3) A3. 4. Polyoxotungstate Three heteropoly tungstates [Co(2,2'-bipy)3]2{[Co(2,2'-bipy)]WV2Wvlio036 (CoO4)[Co(NH3)2]}-3H2O 16, [Ni(2,2'-bipy)3]2{[Ni(2,2'-bipy)]WV4WVI8O36(NiO4) [Ni(NH3)2]} 17 and [Co(l,10-phen)3]2{[Co(l,10-phen)]2WV2WVI10O36(CoO4)} 18 have been synthesized by using hydrothermal method. Their structures were determined by single crystal X-ray diffraction analysis and characterized by IR, ICP, etc. The feature of three compounds is that the Keggin unit capped by neighboring Co or Ni atom through bridging four u-2 oxygen atoms. 16 crystallizes in Monoclinic with space group P2(l)/n, cell parameters a = 18.776(4)A, b = 26.547(5) A, c = 19.782(4) A, 0 = 98.50(3)°, V = 9752(3) A3. 17 crystallizes in Monoclinic with space group P2(l)/n, cell parameters a = 18.8732(4)A, b = 26.6571(5) A, c = 19.7826(4) A, J3 = 98.252(3)°, V = 9849 A3. 18 crystallizes in Monoclinic with space group C2/c, cell parameters a = 27.3225(4)A, b = 14.6945(5) A, c = 25.9856(4) A, p = 97.987(3)°, V = 10331.8(3) A3. 5. Hetero-nuclear CuVCu11 compound involving hydroxylation of N-heterocycle ligands A novel compound [MoO3Cu2(obpy)2]2O 19 is the first hetero-nuclear molybdenum-copper cluster involving hydroxylation of N-heterocycle ligands, which has been hydrothermally synthesized and characterized by single crystal X-ray diffraction, IR, XPS, ESR and elemental analysis. The magnetic behavior of...
|
PDF Full Text Request