Ya-Qin Yu

catena-Poly­[[[μ-pyridinium-3-carboxylato-bis[di­oxomolybdenum(VI)]]-di-μ3-oxo] monohydrate]

A novel chain molybdenum compound, [[Mo2O6(C6H5NO2)].H2O]n, which was synthesized under hydrothermal conditions, consists of an infinite rail-like chain formed by molybdenum oxide units linked by zwitterionic nicotinic acid ligands. Each Mo atom is coordinated octahedrally by six O atoms and the MoO6 octahedra are linked to one another via edge-sharing to produce a zigzag polymeric chain, with nicotinic acid ligands located, alternately, on each side of the rail-like chain plane.

Synthesis, Structural Characterization, and Magnetic Properties of a New Charge-Transfer Salt Composed of Polyoxotungstate Acceptors [WVWVI5O19]3− and Cationic Ferrocenyl CpFe+Cp Donors

The crystal structure of the charge-transfer slat (CpFe+Cp)3[WVWVI5O19] (CpFeCp=Fe(C5H5)2), synthesized from the reaction of Na2WO4⋅2H2O with ferrocene under acid conditions, has been determined by single-crystal X-ray diffraction. The crystal is of triclinic space group P(−1) with a=13.0374(3), b=15.0406(3), c=16.8239(1) Å, α=91.417(1), β=98.931(1), γ=115.294(1)°, V=2931.20(9) Å3, Z=1, Mr=5895.57, F(000)=2652, μ=18.735 mm−1, and Dc=3.340 g⋅cm−3. The final R factor is 0.0502 for 10173 (Rint=0.0563) unique reflections and 770 parameters. The structural analysis reveals that there are two crystallographically distinct [WVWVI5O19]3− polyoxoanions and six independent ferrocene cations per unit cell. Each polyoxoanion consists of six WO6 octahedra with three types of W–O bond lengths. Interestingly, CpFe+Cp moieties are stacked to form octagonal channels that incorporate the polyanions. The closest Fe⋅⋅⋅Fe distances between the neighboring ferrocenyl cations are more than 6.49 Å, therefore, a good magnetic isolation between the iron centers is expected.

Synthesis and Structure of Two Keggin-Type Heteropolyanions: [VMo12O40]3n−n (1) and [H3PMoVMoVI11O40]1− (2)

Two Keggin-type heteropolyanions were synthesized and characterized by X-ray crystal structure and elemental analysis as well as infrared spectroscopy. Both K3[VMo12O40]⋅19H2O (1) and [Ni(H2O)6][H3PMoVMoVI11O40]2⋅30 H2O (2) were prepared in aqueous solution. Compound 1 crystallized in the space group Pm-3m, a=10.6513(1) Å, V=1208.4(3) Å3, Z=1. Compound 2 crystallized in the space group R-3 with a=b=13.9669(2) Å, c=42.0075(5) Å, V=7096.71(2) Å3, Z=3. The compound 1 contains a {K6VMo12O40} group in which six potassium ions form a regular {K6} octahedron. The heteropolyanion [VMo12O40]3− was capped by six potassium ions and enclosed by {K6} octahedron. A three-dimensional structure was formed by the buildup of {K3[VMo12O40]}n. Compound 2 contains a one-electron reduced heteropolyanion [H3PMoVMoVI11O40]1−. Ni2+ coordinated by six water molecules as the counter cation balances the negative charge of the molecule.