Architecture of the hydrophobic and hydrophilic layers as found from crystal structure analysis of N-benzyl-N,N-dimethylalkylammonium bromides.
The molecular and crystal structures of N-benzyl-N,N-dimethylalkylammonium bromides monohydrates with chain length n=8-10 have been determined. The crystals are isostructural with the N-benzyl-N,N-dimethyldodecylammonium bromide monohydrate. The structures consist of alternated hydrophobic and hydrophilic layers perpendicular to [001]. The attraction between N+ of the cation head-groups and Br- anions is achieved through weak C_H...Br interactions. The water molecules incorporated into ionic layers are donors for two O_H...Br hydrogen bonds and serve as the acceptors in two weak interactions of C_H...O type. The methylene chains, with the slightly curved general shape, have the extended all-trans conformation. The mutual packing of the chains in the hydrophobic layers is governed by weak C_H...pi interactions.
Hodorowicz
Maciej
M
Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland. hodorowm@chemia.uj.edu.pl
Stadnicka
Katarzyna
K
Czapkiewicz
Jan
J
D000327:Adsorption; D003460:Crystallization; D018360:Crystallography, X-Ray; D006842:Hydrocarbons, Brominated / Q000032:analysis*; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D008567:Membranes, Artificial; D008958:Models, Molecular; D000644:Quaternary Ammonium Compounds / Q000032:analysis*; D013499:Surface Properties; D014867:Water / Q000737:chemistry
D006842:Hydrocarbons, Brominated; D008567:Membranes, Artificial; D000644:Quaternary Ammonium Compounds; D014867:Water