Magnetic Resonance in Chemistry 2006-09-01

Deuterium isotope effect on 13C chemical shifts of tetrabutylammonium salts of Schiff bases amino acids.

Z Rozwadowski

Index: Magn. Reson. Chem. 44(9) , 881-6, (2006)

Full Text: HTML

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.Copyright (c) 2006 John Wiley & Sons, Ltd.