2025/07/07 by Cole D. Stearns, Ajeet Kumar, Ion Ghiviriga +3 · 1 voice
Chemistry · Materials Science · #Supramolecular Chemistry and Complexes #Supramolecular Self-Assembly in Materials #Synthesis and Properties of Aromatic Compounds
paper · doi:10.1021/jacs.5c05543
openalex publication_date 2025/07/07 · openalex created_date 2025/10/10 · openalex updated_date 2026/06/15
[2.2]Paracyclophanes ( [2 . 2]pCps ), with their intimately spaced arene decks, have been used to study intermolecular charge-transfer effects in chromophores and for applications in photoredox chemistry and organic electronics. In 2016, we reported the synthesis and characterization of the first [2.2]pCp -tetracarboxamide ( [2.2]pCpTA ), envisaged as a covalently fixed supramolecular dimer of 2,5-dimethylterephthalamides. Demonstrated here is the idea that mixed-amide [ n . n ]pCpMTA s can be used to emulate stereoelectronic effects in alternating supramolecular copolymers. As exemplars, we report mixed-deck pseudo - ortho and pseudo - meta [2.2]pCpMTA monomers, each furnished with pairs of C - and N -centered amides arrayed in distinct substitution patterns. Programmable transannular H-bonding pairs dictate both small-molecule conformations and specific amide sequencing in emergent supramolecular assemblies. Variable-concentration and variable-temperature spectroscopy, X-ray crystallography, and density functional theory (DFT) data have been obtained that relate H-bonding geometry, elongation constant ( K e ), assembly mechanism, and dipolar effects to the realization of unique structural control in amide-based supramolecular polymers. Characterization of the [2.2]pCpMTA monomers and their self-assembly behavior more broadly shows how stereoelectronic engineering either encourages or dissuades supramolecular polymerization, insight that can be applied beyond cyclophane-based architectures.