Nuclear Magnetic Resonance: Structure of the Amino Group I

Abstract

Line widths and second moments of the proton magnetic resonance absorption line of ten amines, amides, and amino acids have been measured. It is shown that hydrogen bonds in the amides and amino acids strongly affect the structure. New evidence for the existence of glycine in the dipolar form in the solid state is presented. The N–H bond distances in urea and glycine are calculated from observed second moments and are found to be 1.077±0.007 A and 1.074±0.014 A, respectively. The bond angles of the amino group are assumed tetrahedral in both cases in making the calculation.