RESUMEN
Organofunctionalized tetranuclear clusters [(MII Cl)2 (VIV O)2 {((HOCH2 CH2 )(H)N(CH2 CH2 O))(HN(CH2 CH2 O)2 )}2 ] (1, M=Co, 2: M=Zn) containing an unprecedented oxometallacyclic {M2 V2 Cl2 N4 O8 } (M=Co, Zn) framework have been prepared by solvothermal reactions. The new oxo-alkoxide compounds were fully characterized by spectroscopic methods, magnetic susceptibility measurement, DFT and ab initio computational methods, and complete single-crystal X-ray diffraction structure analysis. The isostructural clusters are formed of edge-sharing octahedral {VO5 N} and trigonal bipyramidal {MO3 NCl} units. Diethanolamine ligates the bimetallic lacunary double cubane core of 1 and 2 in an unusual two-mode fashion, unobserved previously. In the crystalline state, the clusters of 1 and 2 are joined by hydrogen bonds to form a three-dimensional network structure. Magnetic susceptibility data indicate weakly antiferromagnetic interactions between the vanadium centers [Jiso (VIV -VIV )=-5.4(1); -3.9(2) cm-1 ], and inequivalent antiferromagnetic interactions between the cobalt and vanadium centers [Jiso (VIV -CoII )=-12.6 and -7.5â cm-1 ] contained in 1.
RESUMEN
Six- and eight-membered hydrogen-bonded water clusters of novel structure types have been found in crystalline hydrates.
RESUMEN
The solvothermal reaction of (HOCH2CH2)3N with [(n-C4H9)4N]3[H3V10O28] and MnCl2 x 4H2O in CH3CN and CH3OH yields a novel cationic heteropolyoxovanadium(IV) cluster, [Mn(II)V(IV)6O6[(OCH2CH2)2N(CH2CH2OH)]6]2+, containing a fully reduced new cyclic [MnV6N6O18] core with the Anderson structure.
RESUMEN
The hydrothermal reaction of a mixture of vanadyl acetylacetonate (VO(acac)(2)), Na(2)SO(4), 2,2'-bipyridine (2,2'-bpy), and H(2)O for 48 h at 160 degrees C gives brown crystals of [V(2)O(2)(OH)(2)(SO(4))(2,2'-bpy)(2)] (1) in 70% yield. The structure of 1 consists of ribbons constructed from the infinite inorganic chains, [-{V(2)O(2)(OH)(2)}-&mgr;(2)-SO(4){V(2)O(2)(OH)(2)}-SO(4)](infinity), incorporating organic (2,2'-bipyridine) ligands. The inorganic chains are composed of the pairs of edge-sharing octahedra joined by {SO(4)} tetrahedra through octahedral-tetrahedral corner sharing. The octahedral geometry around each vanadium(IV) ion is defined by {VO(2)(OH)(2)N(2)} with each V(IV) center coordinated to a terminal oxo group, two &mgr;(2)-OH groups, two nitrogen donor atoms from a chelating 2,2'-bipyridine ligand, and an oxygen donor atom from a &mgr;(2)-SO(4)(2)(-) ligand. Crystal data for 1: monoclinic space group P2(1)/n (No. 14), a = 11.7937(2) Å, b = 12.1161(3) Å, c = 15.5763(2) Å, beta = 93.750(2) degrees, Z = 4. 1 constitutes the first example of a fully reduced vanadosulfate (V/O/SO(4)) based solid incorporating both the organic and inorganic ligands. The novel solid exhibits Curie-Weiss paramagnetism at high temperature (T > 140 K) and short-range antiferromagnetic coupling between the V(IV) centers at lower temperature.
RESUMEN
New framework materials composed of well-defined vanadium oxide clusters were prepared by low-temperature reactions and characterized by X-ray crystal structure analysis. The structures of these solids contain {V18 O42 } cages linked into two interpenetrating three-dimensional networks by bridging {M(H2 O)4 } groups (M=FeII , CoII ; see picture).
RESUMEN
A new heteropolyoxovanadium compound, [NaV6O6{(OCH2CH2)2NH}6]·(OH)0.5Cl0.5·3(H2O), was synthesized and characterized by single-crystal X-ray diffraction analysis, cyclic voltammetry, FTIR and UV-vis spectroscopy, and TGA. [NaV6O6{(OCH2CH2)2NH}6]·(OH)0.5Cl0.5·3(H2O) contains the diethanolamine functionalized oxovanadium cationic cluster, [NaV(IV)6O6{(OCH2CH2)2NH}6](+). The cluster cation is composed of a fully reduced cyclic {NaV6N6O18} framework which adopts an Anderson-like structure and is comprised of a ring of six edge-sharing {VO5N} octahedra linked to a central {NaO6} unit. Two (OCH2CH2-) arms of each of the six diethanolamine ligands are incorporated into the oxometalate core. FTIR spectra are consistent with the presence of expected V=Ot stretching modes and functionalization with diethanolamine. Electrochemical and UV-vis absorption properties are consistent with two distinct MLCT processes: the characteristic V=Ot dπ-pπ interaction, and a second process occurring through the hydrogen-terminated nitrogen atoms (V-N-H) of the octahedra forming the cyclic {NaV6N6O18} core.
RESUMEN
The synthesis and characterization of the novel systems [Zn(2)(H(2)N(CH(2))(2)NH(2))(5)][(Zn(H(2)N(CH(2))(2)NH(2))(2))(2)V(18)O(42)(H(2)O)].9H(2)O (1), [Cd(2)(H(2)N(CH(2))(2)NH(2))(5)][(Cd(H(2)N(CH(2))(2)NH(2))(2))(2)V(18)O(42)(Br)].9H(2)O (2), and [Zn(2)(H(2)N(CH(2))(2)NH(2))(5)][(Zn(H(2)N(CH(2))(2)NH(2))(2))(2)V(18)O(42)(Cl)].9H(2)O (3) have been described. These materials represent a new class of solids that have been prepared by combining conventional coordination compounds with spherical polyoxovanadate clusters. The isomorphous structures of these hybrid solids consist of two-dimensional arrays of container cluster molecules [V(18)O(42)(X)] (X = H(2)O, Br-, Cl-) interlinked by the transition metal complex moieties [M(H(2)N(CH(2))(2)NH(2))(2)] (M = Zn, Cd). These compounds contain an unprecedented complex cation, [M(2)(H(2)N(CH(2))(2)NH(2))(5)](4+). Crystal data for 1: C(9)H(46)N(9)O(26)V(9)Zn(2), monoclinic space group P2(1)/m (No. 11), a = 12.3723(7) A, b = 20.9837(11) A, c = 15.8379(8) A, beta = 97.3320(10) degrees, Z = 4.
RESUMEN
A novel series of fully reduced heteropolyoxovanadium(IV) compounds, [MVIV6O6[(OCH2CH2)2N(CH2CH2OH)]6]X (1, M = Li, X = Cl x LiCl; 2, M = Na, X = Cl x H2O; 3, M = Mg, X = 2Br x H2O; 4, M = Mn, X = 2Cl; 5, M = Fe, X = 2Cl; 6, M = Co, X = 2Cl x H2O; 7, M = Ni, X = 2Cl x H2O), have been synthesized and characterized by FT-IR and UV-vis spectroscopies, thermogravimetric analysis, elemental analysis, manganometric titration, temperature-dependent magnetic susceptibility measurements, bond valence sum calculations, X-ray powder diffraction, and single-crystal X-ray diffraction analyses. The structures of the crystals are comprised of discrete units of fully reduced cluster cations, [MVIV6O6[(OCH2CH2)2N(CH2CH2OH)]6]n+, counterions (chloride or bromide), and water of crystallization (in the case of 2, 3, 6, 7). In each case the cluster ion is composed of a fully reduced cyclic [MV6N6O18] (M = Li, Na, Mg, Mn, Fe, Co, Ni) framework decorated with six triethanolamine ligands. Two arms of each triethanolamine ligand are coordinated to the metallacycle, and the third arm projects outward from the hexagonal ring. The [MV6N6O18] core adopts the Anderson-type structure. The cyclic core is comprised of a ring of six edge-sharing [VO5N] octahedra linked to a central [MO6] unit. The hexametalate ring contains six d1 ions [VIV] and shows remarkable flexibility to encapsulate a variety of metal centers Mn+ (Mn+ = Li+, Na+, Mg2+, Mn2+, Fe2+, Co2+, Ni2+) with different (dn) spins. The compounds show good thermal stability and exhibit interesting magnetic properties that make these magnetic clusters promising building blocks for constructing supramolecular structures and extended structure magnetic solids. Crystal data for 1; C36H78Cl2N6Li2O24V6, trigonal space group R, a = 13.7185(3) angstroms, c = 24.8899(8) angstroms, Z = 3. Crystal data for 2: C36H80ClN6NaO25V6, triclinic space group P, a = 11.1817(5) angstroms, b = 12.1612(5) angstroms, c = 21.5979(10) angstroms, alpha = 75.8210(10), beta = 78.8270(10), gamma = 71.1400(10), Z = 2. Crystal data for 4: C36H78Cl2N6MnO24V6, monoclinic, space group P2(1), a =11.2208(5) angstroms, b = 21.5041(9) angstroms, c = 11.8126(5), beta = 111.2680, Z= 2. Crystal data for 5: C36H78Cl2N6FeO24V6, monoclinic, space group P2(1), a = 11.3057(7) angstroms, b = 21.4372(13) angstroms, c = 11.8167(7) angstroms, beta = 111.4170, Z = 2.