Synthesis and Dimerization Properties of Cup‐ and Bowl‐shaped Cyclic Trilactams

Abstract

Two chiral trilactams, cup-shaped (À )-1 and bowlshaped (À )-2, were synthesized. Single crystal X-ray analysis revealed that (À )-1 formed dimer structure by the formation of three NH···O type complementary hydrogen bonds at three amide moieties. The equilibrium constant (K eq ) and kinetic parameters~H°and~S°of the dimer formation phenomenon of (À )-1 were determined by variable temperature proton NMR. Further binding energy calculation on both (À )-1 and (À )-2 dimers confirmed the more favourable formation of (À )-1 dimer than (À )-2 dimer, explaining the significant solubility difference of the two against the less polar solvent, such as CHCl 3 . Trilactam (À )-1 afforded coordination polymer by complexation with Zn 2 + , keeping the capsule-like structure.

The long-awaited synthesis and self-assembly of a small rigid C3-symmetric trilactam

“…5–8 One simple motif that is commonly found in these molecules is the amide group. 9–11 Herein we report the first synthesis, characterization, and solid-state self-assembly of a remarkably small molecule containing three amide groups, trilactam 1 (Fig. 1), which was first proposed and modelled as a scaffold for supramolecular structures in 1993 12 and has been the target of synthetic efforts from several research groups at the latest since 1971.…”