title: Effect of stereochemistry on the molecular aggregation of phenylalanine dipeptide-type surfactants.
abstract: The aggregation behaviors of three stereoisomers of tetramethylammonium N-dodecanoyl phenylalanylphenylalaninate in dilute aqueous solution were investigated. From surface tension, fluorescence intensity using probes, and heat of dilution measurements, it was suggested that the critical aggregation concentration was the same between the enantiomers, but was obviously different between the diastereomers. It was also found that these surfactants formed large aggregates at lower concentrations. These large aggregates were then transformed to micelles at higher concentrations similarly to the potassium N-acyl phenylalaninate system. Furthermore, the fluorescence intensity of auramine increased strikingly in the N-dodecanoyl-L-phenylalanyl-L-phenylalanine (homo-chiral dipeptide-type surfactant) system. The fluorescence intensity of auramine in the aggregate of homo-chiral dipeptide-type surfactant was 20 times larger than that in the hetero-chiral dipeptide-type surfactant.
authors.affiliation: Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Ishikawa, Japan. akio-o@t.kanazawa-u.ac.jp
authors.forename: Akio
authors.initials: A
authors.lastname: Ohta
authors.forename: Mari
authors.initials: M
authors.lastname: Shirai
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Asakawa
authors.forename: Shigeyoshi
authors.initials: S
authors.lastname: Miyagishi
mesh_terms: D001576:Benzophenoneidum / Q000737:chemistry; D004151:Dipeptides / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry; D046911:Macromolecular Substances / Q000737:chemistry; D008823:Micelles; D015394:Molecular Structure; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013237:Stereoisomerism; D013500:Surface Tension; D013501:Surface-Active Agents / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D004151:Dipeptides; D005456:Fluorescent Dyes; D046911:Macromolecular Substances; D008823:Micelles; D013501:Surface-Active Agents; C534035:tetramethylammonium N-dodecanoyl phenylalanylphenylalaninate; D001576:Benzophenoneidum; D010649:Phenylalanine