Crystal structure of N,N′-bis(pyridin-3-ylmethyl)cyclohexane-1,4-diammonium dichloride

Abstract

The title salt, C18H26N42+·2Cl−, was obtained by the protonation of N,N-bis(pyridin-4-ylmethyl)cyclohexane-1,4-diamine with hydrochloric acid in ethanol. The asymmetric unit consists of one half of an N,N-bis(pyridin-3-ylmethyl)cyclohexane-1,4-diammonium dication, with a crystallographic inversion centre located at the centre of the cyclohexyl ring, and a chloride anion. The central cyclohexyl ring in the dication adopts a chair conformation. The two trans-(4-pyridine)–CH2–NH2– moieties at the 1- and 4-positions of the central cyclohexyl ring occupy equatorial sites. The terminal pyridine ring is tilted by 53.72 (6)° with respect to the mean plane of the central cyclohexyl ring (r.m.s. deviation = 0.2413 Å). In the crystal, N+—H...Cl− hydrogen bonds between the dications and the chloride anions, and π–π stacking interactions between the pyridine rings of the dications afford a two-dimensional sheet extending parallel to the ab plane. These sheets are further connected through weak C—H...Cl− hydrogen bonds, resulting in the formation of a three-dimensional supramolecular network.

Keywords

• crystal structure
• diprotonated structure
• dipyridyl salt
• hydrogen bonding
• condensation reaction