Two New bis(maleonitriledithiolate)nickelate Anion Salts with Substituted Chlorobenzylpiperidinium Counterion: Syntheses, Crystal Structures, and Magnetic Properties

Two new salts [4-ClBzPid](2)[Ni(mnt)(2)](1) and [4-ClBzPid][Ni(mnt)(2)](2)([4-ClBzPid](+) = 1-(4'-chlorobenzyl)-piperidinium and mnt(2-) = maleonitriledithiolate) were synthesized and characterized by elemental analyses, IR, UV-Vis, ESI-MS, single crystal X-ray diffraction, and magnetic measurements. The [Ni(mnt)(2)](2-) anions of 1 form a one-dimensional side-by-side structure via N center dot center dot center dot N short interaction, whereas the [Ni(mnt)(2)](-) anions in 2 form a one-dimensional face-to-face column through short inter-molecular Ni center dot center dot center dot Ni, Ni center dot center dot center dot S, and S center dot center dot center dot S interactions in which the Ni(III) ions form a nonuniform magnetic chain with the Ni center dot center dot center dot Ni distances of 3.676 angstrom and 4.357 angstrom. Furthermore, the [4-ClBzPid](+) cations in 1 stack into 1D columns via C-H center dot center dot center dot Cl and Cl center dot center dot center dot Cl interactions, while the cations (C) and [Ni(mnt)(2)](-) anions (A) of 2 stack into a 1D column with a A-CC-A-CC-A sequence by N center dot center dot center dot pi and N-H center dot center dot center dot N weak interactions. Some other weak interactions including C-H center dot center dot center dot N and C-H center dot center dot center dot Ni hydrogen bonds result in the forming of a 3D network. Magnetic susceptibility measurements in the temperature range 2 to 300 K show that two salts exhibit diamagnetic behavior.