Syntheses, structures, and magnetic properties of two new molecular magnets containing Ni(mnt)(2) monoanion and substituted 4-dimethylaminopyridinium

摘要

Two new molecular magnets, [BzPyN(CH3)(2)][Ni(mnt)(2)] (1) and [NO(2)BzPyN(CH3)(2)][Ni(mnt)(2)] (2)([BzPyN(CH3)(2)](+) = 1-benzyl-4-dimethylaminopyridinium, [NO(2)BzPyN(CH3)(2)](+) = 1-(4'-nitrobenzyl)-4-dimethylaminopyridinium, and mnt(2) = maleonitriledithiolate) have been prepared and characterized by elemental analyses, IR, MS spectra, single crystal X-ray diffraction and magnetic susceptibility. The Ni(III) ions of both 1 and 2 form a 1D zigzag alternating magnetic chain within a Ni(mnt)(2)(-) column through Ni center dot center dot center dot S, Ni center dot center dot center dot Ni, Ni center dot center dot center dot N, S center dot center dot center dot S, or p center dot center dot center dot p interactions. Magnetic susceptibility measurements in the temperature range 1.8-300 K show that 1 exhibits antiferromagnetic behavior, while 2 shows a spin gap transition around 170 K, and antiferromagnetic interaction in the high-temperature phase (HT) and spin gap in the low-temperature phase (LT). The phase transition for 2 is second-order by determination of DSC analyses.