Inversion of Odd-Even Effect Observed in the Crystal Structure of ω-Cyclohexylalkylammonium-[Ni(dmit)2]− Salts

Abstract

Abstract A previously reported odd-even effect is found to invert by substituting a phenyl with a cyclohexyl group. Crystal structures of [Ni(dmit)2]− complex salts of ω-cyclohexylalkyltrimethylammonium (CncHx; n = 1–5) are revealed by X-ray crystallographic analysis. Alternant stacks are found in all complex salts, but some differences are found in each crystal structure. Terminal cyclohexyl groups adopt chair conformation in the series, and alkylene chains adopt all-trans conformation. Ion pairs found in these crystals are classified by the angle between cations and anions. In these series, odd-even effect is observed in cation length, anion length, Ni-Ni distance and the angle of cation and anion. These are different from the case of terminal methyl and phenyl groups previously reported, indicating that odd-even effect depends on the terminal substituent.