Syntheses, crystal structures, and magnetic properties of two novel Ni(mnt)(2)-based molecular magnetic materials containing substituted triphenylphosphinium

摘要

Two novel molecular magnetic materials, [RBzTPP][Ni(mnt)(2)] (mnt(2-) = maleonitriledithiolate, [RBzTPP](+) = 4-R-benzyltriphenylphosphinium; R = CN (1), Cl (2)) were synthesized and characterized by X-ray diffraction, IR spectroscopy, and magnetic susceptibility measurements. In crystal of 1, the [Ni(mnt)(2)](-) anions form a dimer via Ni center dot center dot center dot S and pi center dot center dot center dot pi stacking interactions between Ni(mnt)(2) planes, and the C-H center dot center dot center dot Ni and C-H center dot center dot center dot N H-bonding interactions are found between the [Ni(mnt)(2)](-) anions and the neighboring [CNBzTPP](+) cations. The anions and cations of 2 stack into well-segregated columns in the solid state; and the Ni(III) ions form a ID alternating chain in a Ni(mnt)(2) column through intermolecular Ni center dot center dot center dot S, or pi center dot center dot center dot pi interactions with the Ni center dot center dot center dot Ni distances of 3.900, 4.198, and 4.165 angstrom. Magnetic susceptibility measurements for these complexes in the temperature range 1.8-300 K show that the overall magnetic behavior for 1 and 2 indicates the presence of antiferromagnetic interaction, but I exhibits an activated magnetic behavior in the high-temperature (HT) region together with a Curie tail in the low-temperature (LT) region. (C) 2007 Elsevier B.V. All rights reserved.