Silver complexes of peptidomimetic polyazapyridinophanes. The influence of the bonding cavity size and the nature of side chains

Abstract

Several peptidomimetic macrocycles containing a pyridine spacer and ring sizes ranging from 15 to 17 have been efficiently synthesized starting from valine and phenylalanine. The complexes formed have been investigated by potentiometry and NMR. Log K values show that phenylalanine derivatives are consistently more stable than valine derivatives , whilst macrocycles with ring sizes of 16 members are the most appropriate for the complexation. The NMR data, in combination with molecular modeling, allow rationalization of the structure of the complexes formed and the participation of the aromatic rings from the side chain of phenylalanine in pi-Ag+ interactions to be discarded.

Copper(ii) complexes of macrocyclic and open-chain pseudopeptidic ligands: synthesis, characterization and interaction with dicarboxylates

“…This particular amino acid was selected because some phenylalanine-derived receptors have been shown to be better hosts for cations than those obtained from valine. 15 In view of the multiple and important roles played by dicarboxylate anions in living systems, 16 we also studied the interaction of the obtained Cu(II) complexes with a series of dicarboxylates with similar structures and of high biological interest, such as malate and aspartate.…”

The Determination of Protonation Constants of Peptidomimetic Cyclophanes in Binary Methanol-Water Mixtures

“…All investigated linear and cyclophane ligands were synthesized according to the procedures previously described [ 14 – 16 ] as well as the pyridinophane derivatives [ 17 ]. The tetraethylammonium perchlorate was commercial sample (Fluka) of electrochemical grade.…”

Anion‐Templated Syntheses of Pseudopeptidic Macrocycles

“…However, anion templation is still in its infancy, as it is restricted to inorganic spherical species in most cases 4. Recently, we synthesized and studied new pseudopeptidic macrocycles5 with interesting properties as organogelators,6 molecular receptors,7 chemosensors,8 or molecular devices 9. During this ongoing research, we envisioned the preparation of larger structures to increase the size and complexity of the substrates within the molecular recognition event.…”