Crystal structures of three new N-halomethylated quaternary ammonium salts

Abstract

In the crystals of the title N-halomethylated quaternary ammonium salts, C19H23IN+·I−, (I) [systematic name: N-(4,4-diphenylbut-3-en-1-yl)-N-iodomethyl-N,N-dimethylammonium iodide], C20H25IN+·I−, (II) [systematic name: N-(5,5-diphenylpent-4-en-1-yl)-N-iodomethyl-N,N-dimethylammonium iodide], and C21H27IN+·I−, (III) [systematic name: N-(6,6-diphenylhex-5-en-1-yl)-N-iodomethyl-N,N-dimethylammonium iodide], there are short I...I− interactions of 3.564 (4), 3.506 (1) and 3.557 (1) Å for compounds (I), (II) and (III), respectively. Compound (I) crystallizes in the Sohncke group P21 as an `enantiopure' compound and is therefore a potential material for NLO properties. In the crystal of compound (I), molecules are linked by C—H...I− and C—H...π interactions which, together with the I...I− interactions, lead to the formation of ribbons along [100]. In (II), there are only C—H...I− interactions which, together with the I...I− interactions, lead to the formation of helices along [010]. In (III), apart from the I...I− interactions, there are no significant intermolecular interactions present.

Keywords

• crystal structure
• N-halomethylated quaternary ammonium salts
• cation–π interaction
• halogen bond
• hydrogen bonding