The crystal structure of the title compound has been determined by X-ray diffractometry. Two dimethylsulphoxide molecules co-ordinate to the Pb atom through their O atoms in trans position. The skeletal structure is a linear chain of [>Pb〈II〉] unit.

The synthesis and room-temperature single-crystal X-ray structure determination are recorded for a 1:1 adduct of lead(II) thiocyanate with pyridine (' py '). [( py ) Pb (SCN)2](∞|∞) is triclinic, Pī , a 10.544(1), b 7.3729(7), c 6.705(2) Ǻ, α 103.91(2), β 95.99(2), γ 100.51(1)°, Z = 2 f.u .; R was 0.041 for 3226 'observed' (I > 3σ(I)) reflections. The structure is a two-dimensional polymer in the be plane with eight-coordinate ( py -N)PbN3S4 linked by the familiar four- membered Pb2S2 and eight-membered Pb2(NCS)2 motifs by way of bridging thiocyanate groups; one of the latter, unusually, has a bifurcating bridging nitrogen atom leading to the introduction of Pb2N2 motifs. The structure of the parent lead(II) thiocyanate is also discussed.

A series of quasi-one-dimensional halogen-bridged Ni(III) complexes, [Ni(chxn)(2)X]Y(2) (chxn = 1R,2R-diaminocyclohexane; X = Cl, Br, and mixed halides; Y = Cl, Br, mixed halides, NO(3), BF(4), and ClO(4)) have been synthesized in order to investigate the effect of the bridging halogens and counteranions on their crystal, electronic structures, and moreover the spin density wave strengths. In the crystal structures, the [Ni(chxn)(2)] moieties are symmetrically bridged by halogen ions, forming linear-chain Ni(III)-X-Ni(III) structures. The hydrogen bonds between the aminohydrogens of chxn and the counteranions are constructed not only along the chains but also over the chains, forming the two-dimensional hydrogen-bond networks. While the Ni(III)-X-Ni(III) distances or b axes are almost constant in the compounds with the same bridging halogens, the c axes which correspond to the interchain distances in the directions of the interchain hydrogen bonds are remarkably lengthened with the increase of the ionic radius of the counterions; X < NO(3) < BF(4) < ClO(4). These compounds show the very strong antiferromagnetic interactions among spins on Ni 3d(z)2 orbitals through the superexchange mechanisms via the bridging halogen ions. Judging from the results of X-ray photoelectron spectra (XPS), Auger spectra, and single-crystal reflectance spectra, these Ni compounds are not Mott-insulators but charge-transfer-insulators. Their electronic structures or the spin density wave strengths are found to be tuned by the combinations of the counteranions and the bridging halogens.

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