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Interaction of the trilacunary 9-tungstosilicate [A-α-SiW9O34]10− with cobalt(II), nickel(II) and zinc(II) ions in pH 9 aqueous medium at room temperature led to the formation of the respective M4-containing heteropolytungstates [M4(OH)3(H2O)2(α-SiW10O36.5)2]13− (M = Co2+ (1), Ni2+ (2), and Zn2+ (3)). Polyanions 1–3 were characterized in the solid state by single-crystal XRD, FT-IR spectroscopy, and thermogravimetric and elemental analyses. Electrochemical studies showed that the Co2+ ions in 1 can be oxidized to Co3+ and the CVs of the WVI centers of the polyanions feature well-defined and chemically reversible reduction waves. Magnetic measurements on 1 and 2 showed paramagnetism with complex ferromagnetic and antiferromagnetic interactions. A model was presented for extracting the exchange constants for the magnetic exchange interaction. [ABSTRACT FROM AUTHOR]

Magnetizabilities and magnetically induced ring-current strength susceptibilities have been calculated at the Hartree–Fock, density functional theory and second order Møller–Plesset levels for a number of antiaromatic closed-shell carbaporphyrins, carbathiaporphyrins and isophlorins. The calculations yield a linear relation between magnetizabilities and ring-current strength susceptibilities. The calculations show that the porphyrinoids with the largest ring-current strength susceptibility are closed-shell paramagnetic molecules with positive magnetizabilities. The closed-shell paramagnetism is due to the large paramagnetic contribution to the magnetizability originating from the strong paratropic ring current in the antiaromatic porphyrinoids. [ABSTRACT FROM AUTHOR]

The idea of NMR crystallography was conceived as soon as NMR spectroscopy was invented. Over the years, several efforts have been devoted to the development of NMR tools to complement X-ray diffraction results. Many of the NMR-related observables are short-ranged in nature, but the paramagnetic ones are not. Therefore, paramagnetism-based restraints are in principle suitable to assess spatial relationships among molecules. We will here review some of the underlying concepts and see how they apply to the problem of obtaining structural information on molecules in the lattice, and on the lattice itself. We will provide positive examples and discuss the negative issues that still haunt paramagnetism-based NMR crystallography. [ABSTRACT FROM AUTHOR]

The combination of some three-atom bridges with paramagnetic 3d transition metal ions results in the systematic isolation of molecular magnetic materials, ranging from single-molecule and single-chain magnets to layered weak ferromagnets and three-dimensional porous magnets. The design strategy and role of secondary components, such as co-ligands, templates and other mixed short ligands are discussed. [ABSTRACT FROM AUTHOR]