Solid State Coordination Chemistry of Oxomolybdenum Organoarsonate Materials

Extended Architectures Constructed from Sandwich Tetra-Metal-Substituted Polyoxotungstates and Transition-Metal Complexes

Three unprecedented 2D architectures made up of sandwich-type tetra-metal-substituted polyoxotungstates and transition-metal complexes, [Cu(dien)(H2O)]2{[Cu(dien)(H2O)]2[Cu(dien)(H2O)2]2[Cu4(SiW9O34)2]} x 5 H2O (1; dien = diethylenetriamine), [Zn(enMe)2(H2O)]2{[Zn(enMe)2]2[Zn4(HenMe)2(PW9O34)2]} x 8 H2O (2; enMe = 1,2-diaminopropane), and [Zn(enMe)2(H2O)]4[Zn(enMe)2]2{(enMe)2{[Zn(enMe)2]2[Zn4(HSiW9O34)2]}{[Zn(enMe)2(H2O)]2[Zn4(HSiW9O34)2]}} x 13 H2O (3) were hydrothermally synthesized and structurally characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and single-crystal X-ray diffraction. Compound 1 consists of anions [Cu4(SiW9O34)2]12- linked by copper complexes into a 2D structure, whereas 2 is constructed from novel inorganic-organic hybrid anions [Zn4(HenMe)2(PW9O34)2]8- linked by zinc complexes into a 2D structure. The most interesting is the unique 2D network 3, which consists of anions [Zn4(PW9O34)2]10- with two types of bridging groups: zinc complexes and enMe ligands.

A Series of New Organic−Inorganic Molybdenum Arsenate Complexes Based on [(ZnO6)(As3O3)2Mo6O18]4- and [HxAs2Mo6O26](6-x)- Clusters as SBUs

By synthesizing the novel molybdenum arsenate complexes, we have obtained eight new structures, namely, (4,4'-bipy)[Zn(4,4'-bipy)2(H2O)2]2[(ZnO6)(AsIII3O3)2Mo6O18].7H2O, 1, [Zn(phen)2(H2O)]2[(ZnO6)(AsIII3O3)2Mo6O18].4H2O, 2, [Zn(2,2'-bipy)2(H2O)]2[(ZnO6)(AsIII3O3)2Mo6O18].4H2O, 3, [Zn(H4,4'-bipy)2(H2O)4][(ZnO6)(AsIII3O3)2Mo6O18].8H2O, 4, (H24,4'-bipy)[CuI(4,4'-bipy)]2[H2AsV2Mo6O26].H2O, 5, (H24,4'-bipy)3[AsV2Mo6O26].4H2O, 6, (H24,4'-bipy)3[AsV2Mo6O26(H2O)].4H2O, 7, and (H24,4'-bipy)2.5(H3O)[AsV2Mo6O26(H2O)].1.25H2O, 8 (4,4'-bipy = 4,4'-bipyridine, 2,2'-bipy = 2,2'-bipyridine, phen = 1,10-phenanthroline). These structures were determined by single-crystal X-ray diffraction analysis and were further characterized by elemental analysis, IR, XPS spectroscopy, and TG analysis. The structure of 1 is constructed from two-dimensional square gridlike sheets linked by the polyanions [(ZnO6)(AsIII3O3)2Mo6O18]4- via hydrogen-bonding interactions to form a three-dimensional supramolecular framework with two types of channels. Compounds 2 and 3 display similar bisupported structures. Compound 4 features a three-dimensional supramolecular architecture. Compound 5 possesses a 1D infinite ladderlike ribbon. Compounds 6-8 are discrete structures exhibiting three isomeric forms of [HxAs2Mo6O26](6-x)-. Furthermore, compound 8 represents a new isomer B'-[As2Mo6O26(H2O)]6-. In addition, the fluorescent properties of compounds 1-3 are reported.

A Novel Series of Vanadium-Sulfite Polyoxometalates: Synthesis, Structural, and Physical Studies

Reaction of NH4VO3 with sulfur dioxide affords the hexanuclear cluster (NH4)2(Et4N)[(V(IV)O)6(mu4-O)2(mu3-OH)2(mu3-SO3)4(H2O)2]Cl x H2O (1), and the decapentanuclear host-guest compound (Et4N)5{Cl subset [(VO)15(mu3-O)18(mu-O)3]} x 3 H2O (2). Sequential addition of magnesium oxide to an acidic aqueous solution of NH4VO3 (pH approximately 0) followed by (NH4)2SO3 resulted in the formation of either the non-oxo polymeric vanadium(IV) compound trans-(NH4)2[V(IV)(OH)2(mu-SO3)2] (3) or the polymeric oxovanadium(IV) sulfite (NH4)[V(IV)O(SO3)1.5(H2O)] x 2.5 H2O (4) at pH values of 6 and 4, respectively. The decameric vanadium(V) compound {Na4(mu-H2O)8(H2O)6}[Mg(H2O)6][V(V)10(O)8(mu6-O)2(mu3-O)14] x 3 H2O (5) was synthesised by treating an acidic aqueous solution of NH4VO3 with MgO and addition of NaOH to pH approximately 6. All the compounds were characterised by single-crystal X-ray structure analysis. The crystal structure of compound 1 revealed an unprecedented structural motif of a cubane unit [M4(mu4-O)2(mu3-OH)2] connected to two other metal atoms. Compound 3 comprises a rare example of a non-oxo vanadium(IV) species isolated from aqueous solution and in the presence of the reducing agent SO3(2-), while compound 4 represents a rare example of an open-framework species isolated at room temperature (20 degrees C). In addition to the synthesis and crystallographic studies, we report the IR and magnetic properties (for 1, 2 and 3) of these vanadium clusters as well as theoretical studies on compound 3.