Study On The Construction And Structure Of Aromatic Nipoid Peptides Based On Intermolecular Hydrogen Bond And π - π Stacking

In this dissertation, a series of hybrid short peptides consisting of aromatic amide segments and aliphatic amide (such as β-alanine, γ-propalanine, etc.) units were designed and synthesized. Following that we have studied their hydrogen bonding pattern through XRD, NMR, and so on.The target molecules mainly can be divided into two categories.The first category molecules were comprised of 4-acetamido benzoic acid (or 4-isobutyl amido benzoic acid) unit and several amino acid segments. The results of the data of single crystal of target molecules revealed that the π-π stacking interaction was existed in part of the target molecules. Furthermore, a regular extensive structure was formed under the conjunct induction of intermolecular hydrogen bonding and π-π stacking interaction, which was further demonstrated by NMR titration and dilution experiments.The second category molecules were comprised of pentafluorobenzoic acid unit and amino acid segments. The results of the data of single crystal of target molecules revealed that a unitary, regular extensive structure were formed under the conjunct induction of intermolecular hydrogen bonding and the strong π-π stacking interaction.The systemic study on the interactions of two categories of molecules helped to get two conclusions. The first was that, the strength of π-π stacking interaction mainly due to the electron-matching of molecules. Traditionally, a strong π-π stacking interaction existed between a electron-rich phenyl group and the electron-short phenyl group. The second was that, the structure of two molecules must be favorable. Favorable structure, complete with matched electron property would strengthen the π-π stacking interaction a lot, that meant a chance of significant regulation and control on the hydrogen bonding pattern. Consequently, the establishment of the extensive structure conjunctly induced by intermolecular hydrogen bonding and π-π stacking interaction provided the theoretical support as well as the practical feasibility for the construction of β-sheet of peptidomimetics.