Search

Abstract: A novel magnetic coupling is observed in a unpublished crystal that consists of a mono-nuclear manganese(II) complex, namely, [Mn(DPP)(NCS)2] (DPP=2-(3,5-dimethyl-1H-pyrazol-1-yl)-1,10-phenanthroline), in which neutral DPP molecule functions as tridentate chelated ligand. In the complex Mn(II) ion assumes a distorted trigonal bipyramidal geometry and in the crystal there is a π–π stacking interaction between the adjacent complexes, which involves pyridyl ring and the symmetry-related pyrazolyl ring and pyridyl ring. The fitting for the data of the variable-temperature magnetic susceptibilities with infinite uniform Mn(II) chain formula gave the magnetic coupling constant J =−0.11cm−1, and theoretical calculations reveal that there exists a very weak anti-ferromagnetic coupling between the adjacent Mn(II) ions with J =−0.02cm−1. The magnetic coupling sign is explained based on McConnell I spin-polarization mechanism with the analysis of the spin density population and the factors that dominate the magnetic coupling magnitude. [Copyright &y& Elsevier]

Two mononuclear sulfur-based dysprosium complexes [(dtc) 3 Dy(bipy)] ( 1Dy , dtc −  = diethyldithiocarbamate anion, bipy = 2,2′-bipyridine) and [(dtc) 3 Dy(dmbipy)]·0.68CH 3 CN ( 2Dy , dmbipy = 4,4′-dimethyl-2,2′-bipyridine) were successfully synthesized and structurally characterized by X-ray diffraction. The Dy III centers of 1Dy and 2Dy are eight-coordinated by six S atoms from three dtc − ligands and two N atoms from bipy ( 1Dy ) or dmbipy ( 2Dy ). Magnetic measurements reveal that the magnetic properties of 2Dy are obviously better than those of 1Dy . Theoretical calculations based on the molecular crystal structures are performed to analyze the difference of the magnetic behavior in two complexes. [ABSTRACT FROM AUTHOR]