title: Structural and orientational studies of chiral N-[4(1-pyrene)butyroyl]-phenylalanine in cast film.
abstract: Cast films of chiral material N-[4(1-pyrene)butyroyl]-l-phenylalanine (Py-l-Phe) and the racemic modification (the 1:1 mixture of Py-l-Phe and Py-d-Phe) have been investigated in the present study. The microscopic structure, molecular orientation and the aggregation in the film have been studied by using ultraviolet-visible (UV-vis) and infrared (IR) spectroscopy. When a cast film is formed from the chloroform solution at room temperature, the J-aggregates of Py-l-Phe and Py-d-Phe are observed by UV-vis spectra. A comparison of Fourier transform infrared (FT-IR) transmission and reflection-absorption (RA) spectroscopy has been applied to reveal the orientation and structural characterization of the cast films. It has been found that the pyrenyl ring in the cast film of Py-l-Phe assumes a nearly vertical orientation with respect to the surface of the solid substrate. And there are two different hydrogen bonding species, cyclic dimer and linear dimer, exist in carboxyl groups in cast films. The detailed analysis of the OH and NH stretching modes of Py-l-Phe and Py-d-Phe allows us to reveal the hydrogen bonds existing in the films.
authors.affiliation: Key Laboratory for Supramolecular Structure and Materials of the Ministry of Education, Jilin University, Changchun, 130012, PR China.
authors.forename: Chunxi
authors.initials: C
authors.lastname: Zhai
authors.forename: Wen
authors.initials: W
authors.lastname: Li
authors.forename: Lijun
authors.initials: L
authors.lastname: Ma
authors.forename: Lixin
authors.initials: L
authors.lastname: Wu
authors.forename: Yuqing
authors.initials: Y
authors.lastname: Wu
mesh_terms: D002725:Chloroform; D006860:Hydrogen Bonding; D007536:Isomerism; D008958:Models, Molecular; D015394:Molecular Structure; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000737:chemistry; D011721:Pyrenes / Q000737:chemistry*; D012996:Solutions; D013057:Spectrum Analysis; D013696:Temperature
chemical_list: D011721:Pyrenes; D012996:Solutions; D010649:Phenylalanine; C114414:N-(1-phenylalanine)-4-(1-pyrene)butyramide; D002725:Chloroform