Crystal and Molecular Structure of 2:1 Complex of Tetradecyltrimethylammonium Bromide with Rac-1,1′-bi-2-naphthol

ABSTRACT

The crystal and molecular structure of 2:1 complex of the tetradecyltrimethylammonium bromide with rac-1,1′-bi-2-naphthol (14TAB/BNP) is reported. The 14TAB/BNP complex crystallizes in monoclinic space group C2/c. The asymmetric unit of the complex consists of two crystallographically independent molecules of 14TAB and one crystallographically independent molecule of BNP. The crystal structure of the complex is stabilized by mainly the intermolecular hydrogen bonding between the bromide anions and OH groups of BNP. The molecules are held in their aggregates by Ol … Br2, 3.220(4) Å and O2 … Br1, 3.161 (4) Å hydrogen bonding. The crystal-structure studies revealed that one of the alkyl chains has an all trans conformation, whereas the second alkyl chain does not have all trans conformation but has at least a gauche conformation. The packing structure is unique and different from those observed in complexes of monoalkyltrimethylammonium halides with planar aromatic molecules as well as those of 1:1 complexes of monoalkyltrimethylammonium halides with nonplanar aromatic molecules. The manner in which the 14TAB molecules lay parallel to the naphthol moieties are similar to that observed in 2:1 complex of 10TAB/BNP.

Keywords:

• crystal engineering
• crystal structure
• molecular interactions
• molecular recognition
• monoalkylammonium halides
• surfactants

ACKNOWLEDGMENTS

The author, E. M., expresses his sincere gratitude to the Ministry of Culture, Science, Sports, and Education of Japan for awarding him the Monbusho Scholarship.