Syntheses, weak interactions, and 3-D network structures of two salts based on [Ni(i-mnt)2]2- (i-mnt2-=iso-maleonitriled-ithiolate) anion with substituted pyridinium cation.

Two new salts, [2-NaMePy]2[Ni(i-mnt)2] (1) and [2-NaMe-4-MePy]2[Ni(i-mnt)2] (2) ([2-NaMePy]+ = 1-(2'-naphthylmethyl)pyridinium, [2-NaMe-4-MePy]+ = 1-(2'-naphthylmethyl)-4-methylpyridinium and i-mnt2- = iso-maleonitriledithiolate), have been prepared and characterized by elemental analyses, UV, IR, molar conductivity, and single crystal X-ray diffraction. The anions in 1 form a 1-D chain through short C ··· N interactions between the anions, while the cations in 2 stack a 1-D column via C-H ··· π and π ··· π stacking interactions between the cations. The effect of weak intramolecular interactions such as C-H ··· N, C-H ··· S, C-H ··· Ni hydrogen bonds, and π ··· π stacking interactions between the cations and the anions further generate a 3-D network structure. The change of the molecular topology of the countercation when the 4-substituted group in the pyridine ring is changed from H atom to CH3 group results in different crystal system, space group, and the stacking mode of the cations and anions of 1 and 2. [ABSTRACT FROM AUTHOR]