13C NMR Spectroscopic Studies of Intra- and Intermolecular Interactions of Amino Acid Derivatives and Peptide Derivatives in Solutions.

¹³C NMR spectroscopic investigations were conducted for various amino acid derivatives and peptides. It was observed that ¹³C NMR chemical shifts of the carbonyl carbons are correlated with the solvent polarities, but the extent depends on the structures. The size of the functional groups and inter- and intra-molecular hydrogen bonding appear to be the major contributors for this tendency [ABSTRACT FROM AUTHOR]