A diarylethene annulated isomer as a highly-conductive molecular wire evaluated by the exchange interaction between two nitroxides

Bis(imino nitroxide) bridged by a diarylethene annulated isomer was found to show a strong exchange interaction, suggesting the use of the annulated isomer as a highly-conductive molecular wire.

Low-dimensional compounds containing cyanido groups. Part XXXV. Structure, spectral, thermal and magnetic properties of a binuclear CuII–biquinoline complex with bridging and terminal dicyanamide ligands

From the system CuCl2–biq–NaN(CN)2 (biq is 2,2′-biquinoline), the binuclear molecular complex bis(μ-dicyanamido-κ2 N 1:N 5)bis[(2,2′-biquinoline-κ2 N,N′)(dicyanamido-κN 1)copper(II)], [Cu2(C2N3)4(C18H12N2)2] or [Cu2(biq)2(dca)2(μ1,5-dca)2] (1) [dca is dicyanamide, N(CN)2 −] was isolated and characterized by crystal structure analysis, and spectral, thermal and magnetic measurements. IR spectroscopy confirmed the presence of the biq and dca ligands in 1. Its solid-state structure consists of discrete centrosymmetric binuclear copper(II) units with double end-to-end dca bridges. Each CuII atom is in a distorted square-pyramidal environment with the equatorial plane formed by two nitrile N atoms from bridging dca groups, one of the two N atoms of the chelate biq molecule and one nitrile N atom from a terminal dca ligand, whereas the second biq N atom occupies the axial position. Thermal decomposition of 1 in an air atmosphere proceeds gradually, with copper(I) cyanide being the final decomposition product. Magnetic measurements revealed the formation of alternating spin chains and a relatively strong exchange interaction within the binuclear units was also confirmed by Broken Symmetry DFT (density functional theory) calculations.

Paramagnetic resonance in palladium and platinum group compounds

The paramagnetic resonance method has been applied to investigate the magnetic properties of complexes containing elements of the 4 d and 5 d groups. It is shown that the resonance results, and such information as is available from susceptibility measurements, can be accounted for to a good approximation by assuming that there are either covalent σ -bonds or very strong electrostatic bonds in the complex (Van Vleck 1935). In the case of d 5 complexes, however, accurate measurements of the spectroscopic splitting factors show small discrepancies with this theory. Furthermore, an anomalous hyperfine structure is observed for the complex [IrCl 6 ] 2- , which displays lines arising not only from the Ir nucleus, but also from the surrounding Cl nuclei. These effects are ascribed to the presence of weak π -bonds, in addition to σ -bonds, in the complex (Stevens 1953). In magnetically concentrated salts of the 5 d group, it is found that there is strong exchange interaction between paramagnetic neighbours.