Syntheses, spectra, crystal structures and magnetic properties of molecular solids based on the [formula omitted] ion (M = Ni, Pt)

Abstract

Two new ion-pair complexes [1-(4′-nitrobenzyl)-4-aminopyridinium]-bis(maleonitriledithiolato)nickel ([NO 2BzPyNH 2][Ni(mnt) 2]) ( 1) and [1-(4′-nitrobenzyl)-4-aminopyridinium]-bis(maleonitriledithiolato)platinum ([NO 2BzPyNH 2][Pt(mnt) 2]) ( 2) have been prepared and characterized by elemental analyses, IR, electronic and MS spectra, single crystal X-ray diffraction and magnetic susceptibility. 1 and 2 crystallize in the monoclinic space group P2 1/ c, a = 12.331(3) Å, b = 26.937(6) Å, c = 7.322(2) Å, V = 2349.0(10) Å 3, Z = 4 for 1, and a = 10.600(3) Å, b = 8.376(2) Å, c = 27.089(7) Å, V = 2362.2(11) Å 3, Z = 4 for 2. The Ni(III) ions of 1 form a 1D zigzag chain within a Ni ( mnt ) 2 - column, while 2 is a dimer. Magnetic susceptibility and DSC measurements for 1 in the temperature range 2.0–300 K show the occurrence of an unusual magnetic phase transition around 160 K, and an antiferromagnetic interaction in the high-temperature phase (HT) and a spin gap in the low-temperature phase (LT), while 2 is diamagnetic.