title: Deuterium isotope effect on 13C chemical shifts of tetrabutylammonium salts of Schiff bases amino acids.
abstract: Deuterium isotope effects on 13C chemical shift of tetrabutylammonium salts of Schiff bases, derivatives of amino acids (glycine, L-alanine, L-phenylalanine, L-valine, L-leucine, L-isoleucine and L-methionine) and various ortho-hydroxyaldehydes in CDCl3 have been measured. The results have shown that the tetrabutylammonium salts of the Schiff bases amino acids, being derivatives of 2-hydroxynaphthaldehyde and 3,5-dibromosalicylaldehyde, exist in the NH-form, while in the derivatives of salicylaldehyde and 5-bromosalicylaldehyde a proton transfer takes place. The interactions between COO- and NH groups stabilize the proton-transferred form through a bifurcated intramolecular hydrogen bond.
authors.affiliation: Institute of Chemistry and Environmental Protection, Szczecin University of Technology, Al. Piastów 42, 70-065 Szczecin, Poland. zroz@ps.pl
authors.forename: Z
authors.initials: Z
authors.lastname: Rozwadowski
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D000596:Amino Acids / Q000737:chemistry*; D001547:Benzaldehydes / Q000737:chemistry*; D002247:Carbon Isotopes / Q000032:analysis; D003903:Deuterium / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D009281:Naphthalenes / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012492:Salts / Q000737:chemistry; D012545:Schiff Bases / Q000737:chemistry
chemical_list: C482304:2-hydroxynaphthaldehyde; D000447:Aldehydes; D000596:Amino Acids; D001547:Benzaldehydes; D002247:Carbon Isotopes; D009281:Naphthalenes; D000644:Quaternary Ammonium Compounds; D012492:Salts; D012545:Schiff Bases; C032892:3,5-dibromosalicylaldehyde; D003903:Deuterium; C009405:tetrabutylammonium