Year: 2026
Type: preprint
Abstract: Encoding prescribed topologies in rigid conjugated frameworks offers a route to tuning electronic properties but is constrained by severe geometric strain. We synthesized and isolated Möbius kekulene, a compact, all-benzenoid double-stranded counterpart of planar kekulene. Its synthesis was enabled by strain-trajectory programming, in which precursor connectivity is designed to control strain accumulation during cyclization. Comparison of two precursors revealed contrasting strain trajectories: MCP1 concentrated the torsional deformation into an inaccessible late-stage closure, whereasMCP2 accommodated deformation progressively, reducing the largest strain increment and affording Möbius kekulene 1. Crystallography confirms a singly twisted topology with a calculated strain energy of 73.9 kcal/mol per twist, highest among reported Möbius π-systems. Despite pronounced distortion, 1 retains a Clar-type localized electronic structure analogous to planar kekulene, with local aromaticity progressively perturbed toward the twist region. These results establish strain-trajectory programming as a design principle for accessing highly constrained molecular topologies.
Source: ChemRxiv
Authors: Mingxin He, Yong Ni
Institution: Southern University of Science and Technology
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
Award: G3825297942
OpenAlex ID: W7220894987