| Polyoxometalates （POMs, also called metal-oxygen clusters）, represent a vastclass of inorganic materials with a virtually unmatched range of physical andchemical properties, which hold considerable promise for numerous potentialapplications ranging from catalysis to medicine. In most cases, discrete POM ions ascatalysts were not easily separated and usually need to be further treated to obtaincomposite materials, such as POM-based MOFs, POM-loaded porous materials orPOM/nanoparticles composites. The aim of this thesis is to synthesize novelmetal-oxygen clusters （mainly POMs）-based crystalline catalysts by introducingdifferent metal cations or metal-organic fragments by covalent modification.Furthermore, the composites with synergistic catalysis are prepared on the basis ofthese crystalline materials. Moreover, their catalytic activities towards to the reductionof potassium hexacyanoferrate（III）,4-nitrophenol （4-NPh） and H2O2are investigated,as well as biodesel production.1. A inorganic-organic hybrid compound based on the dimer of {P4Mo6O31H6}cluster （noted as {P4Mo6}） has been isolated by hydrothermal technique at170°C, inwhich Na2MoO4·2H2O, H3PO3, MnCl2·4H2O, Zn（OAc）2·2H2O and im were employedas precursors, and the pH value of the mixture was adjusted by hydrochloric acid （6mol·L1）.Mn[Zn（im）]2{[Na（H2O）]2[Mn（H2O）2][Zn（im）2][P4Mo6O31H6]2}·8H2O（IFMC-100）In IFMC-100, while two {P4Mo6} units assemble together, one manganese ion,two sodium ions and four water molecules fill the gap between them forming a{[Mn（H2O）2][Na（H2O）]2} core, which finally results in the target cluster{[Mn（H2O）2][Na（H2O）]2[Zn（im）2][P4Mo6O31H6]2} linking through a {Zn（im）2}fragment. Furthermore, dimeric clusters {[Na（H2O）]2[Mn（H2O）2][Zn（im）2][P4Mo6O31H6]2} connect to each other by Mn（II） ions and {Zn（im）} fragments to giverise to a4-connected classical diamondoid net. IFMC-100is the first tubularPOM-based single-crystal material.Immersion of as-prepared IFMC-100in an EtOH solution of HAuCl4（30mM） atambient temperature afforded Au-anchored tubular microreactors Au@IFMC-100asa result of solid–liquid autoredox reaction between AuCl4–ions and POM host, where IFMC-100served as reductant as well as stabilizing agent. Moreover, the catalyticactivities of Au@IFMC-100and IFMC-100tubes toward electron-transfer reactionswere demonstrated by studying the reduction of potassium hexacyanoferrate（III） and4-nitrophenol （4-NPh） with NaBH4as test reactions.2. Two3D pure inorganic compounds based on tetrameric {P4Mo6} clusters havebeen prepared by hydrothermal method at170180°C, in which Na2MoO4·2H2O,H3PO3, im, and MnCl2·4H2O （or ZnCl2） were used as raw materials, and the pH valueof the mixture was adjusted by6mol·L1hydrochloric acid.H{[Na6Mn4（PO4）（H2O）4][Mo6O12（OH）3（HPO4）3（PO4）]4[Mn6（H2O）4]}·22.5H2O（IFMC-101）H7{[Na12（PO4）（H2O）12][Mo6O12（OH）3（HPO4）3（PO4）]4（Zn6O2）}·38H2O（IFMC-102）In IFMC-101, while four {P4Mo6} fragments assemble together, one PO43–ion,six sodium ions, four Mn（II） ions and four H2O molecules fill the center among them,resulting in a {Na6Mn4（PO4）（H2O）4} core, which finally gives rise to a nanosizedtetrameric cluster {[Na6Mn4（PO4）（H2O）4][P4Mo6O31H6]4}13–. In IFMC-102, whilefour {P4Mo6} fragments assemble together, one PO43–ion, twelve sodium ions, andtwelve H2O molecules fill the center among them, generating a Keggin-like{Na12（PO4）（H2O）12} core, which finally results in a nanosized tetrameric cluster{[Na12（PO4）（H2O）12][P4Mo6O31H6]4}15–. Furthermore, the tetrameric clustersconnect to each other by Mn（II） or Zn（II） ions to result in two3D8-connected pureinorganic open architectures, respectively.In addition, IFMC-101was employed as a reducing agent and stabilizer forpreparation of a noble metal NPs-loaded crystalline catalyst by a spontaneous redoxapproach. And the catalytic activity toward the reduction of4-NPh was also studied.The result indicates that Au@IFMC-101exhibits enhanced catalytic behaviorcompared with IFMC-101due to the synergistic effect of both noble metal NPs andPOM component. Meanwhile, the electrochemical behavior and diffuse reflectanceUV-Vis spectrum of IFMC-102were also investigated.3. A nanosized {Zn16（HPO3）4}-based inorganic-organic hybrid compound hasbeen prepared by hydrothermal method at180°C, in which Na2MoO4·2H2O, ZnCl2,H3PO3, Mo powder, TMAOH and H8L （H8L=5,5’-（2,2-bis（（3,5-dicarboxyphenoxy）methyl）propane-1,3-diyl）bis（oxy）diisophthalic acid） were used asprecursors, and the pH value of the mixture was adjusted by dilute HCl solution (2mol·L-1. [Zn16（HPO3）4]L3（IFMC-200）In IFMC-200, sixteen Zn（II） cations were connected by four HPO32–anions,resulting in a nanocluster subunit [Zn16（HPO3）4]24+. Each [Zn16（HPO3）4]24+cluster isstabilized by24carboxyl groups originated from twelve L8–moieties. Suchconnectivity leads to the first3D （3,4,24）-connected open architecture. IFMC-200exhibits superior thermal stability, good water-stability, and even insensitivity to theexistence of acid and base within a certain range of pH values. Furthermore,IFMC-200was employed as a heterogeneous catalyst for the preparation of biodiesel,which is the first time to employ a crystalline material of entire d10metal oxide clusterwith Lewis acid nature.4. A series of novel POM-based inorganic-organic hybrid materials have beenobtained by introducing metal ions with different sizes and N-or O-containingorganic ligands to the systems containing saturated or vacant Keggin-typephosphotungstate or silicontungstate under hydrothermal conditions （150170°C）.[Hen]2[Cu（en）2（H2O）]2{[Cu（en）2]2[Ge2W23CuO79]}·4H2O1H8[Cu（en）2H2O]4[Cu（en）2]{[Cu（en）2][La(PW11O39)2]}2·18H2O2H6[Na2（en）2（H2O）5][Cu（en）2H2O]4[Cu（en）2]{[Cu（en）2][Ce(PW11O39)2]}2·16H2O3H7[Cu（en）2]2[Sm(PW11O39)2]·10H2O4[Cu（en）2H2O]3[(α-SiW11O39)Nd（H2O）(η2,μ-1,1)-CH3COO]·3.5H2O5H2[Cu（en）2H2O]8[Cu（en）2]3[{(α-SiW11O39)Ce（H2O）（η2,μ-1,1）-CH3COO}4]·22H2O6The six compounds were characterized by IR, XRPD, elemental analysis andTGA. Additionally, the electrochemical behavior of1and the magnetic properties of2,3,5and6were investigated. |
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