The “hydrazinoturn” hydrogen bonding network in hydrazinopeptides and aza-β3-peptides as probed by an AIM topological analysis of the electronic density

This paper follows a previous publication [Salaün, A., et al., Conformation of Nα-substituted hydrazino acetamides in CDCl3, the precious help of the analysis of Δδ between amidic hydrogens, and correlation to the conformation of Aza-β3-peptides. J. Org. Chem. 71 (2006) 150-158] where the so called “hydrazinoturn” hydrogen bond network is assessed in aza-β3-peptides, as modeled by selected representative hydrazinoacetamides, on the basis of proton NMR. In this paper, DFT theoretical calculations at the B3LYP/6-311G++(d,p) level of theory are described in order to shed light on the intramolecular hydrogen bond network of the same molecules. The analysis is carried on by means of the AIM topological analysis of the electronic density.