title: The protonation of a retinyl Schiff base: a study by FTIR spectroscopy at low temperature in solution.
abstract: The hydrogen bonding-protonation equilibrium for retinyl Schiff base/propionic acid or 3-chloropropionic acid systems was examined by Fourier transform infrared spectroscopy in non polar solutions at temperatures ranging from 25 degrees C to about -150 degrees C. The spectra give evidence for the gradual increase in the degree of protonation as temperature is lowered. The bearing of this on applying low temperature spectroscopic results to physiological conditions in rhodopsin research is discussed.
authors.forename: S
authors.initials: S
authors.lastname: Badilescu
authors.forename: R B
authors.initials: RB
authors.lastname: de Alencastro
authors.forename: H
authors.initials: H
authors.lastname: Le-Thanh
authors.forename: G
authors.initials: G
authors.lastname: Richer
authors.forename: C
authors.initials: C
authors.lastname: Sandorfy
authors.forename: P P
authors.initials: PP
authors.lastname: Vaudreuil
authors.forename: D
authors.initials: D
authors.lastname: Vocelle
mesh_terms: D005583:Fourier Analysis; D005615:Freezing; D008962:Models, Theoretical; D012168:Retinal Pigments; D012176:Retinoids; D012545:Schiff Bases; D012996:Solutions; D013055:Spectrophotometry, Infrared / Q000379:methods
chemical_list: D012168:Retinal Pigments; D012176:Retinoids; D012545:Schiff Bases; D012996:Solutions; C003299:N-retinylidene-n-butylamine