Mechanically Coupled Supramolecular Scissors Govern Photomechanical and Elastic Responses in Molecular Crystals
Journal
Angewandte Chemie International Edition
ISSN
1433-7851
1521-3773
Date Issued
2026-09-07
Author(s)
Tsai, Shu‐Huan
Li, Shu‐Li
Chang, Yu‐Chen
Manoharan, Deepak
Su, Chuan‐Jie
Wang, Chih‐Hsuan
Liu, Yi‐Hung
Abstract
Mechanically responsive molecular crystals offer a powerful platform for transducing molecular motion into macroscopic mechanical work, yet molecular-level understanding of how crystal structures govern molecular motion and, consequently, mechanical behavior remains limited. A notable example is the anthracene-pentiptycene-semifluorinated alkyl crystal 1-F4, recently reported to exhibit large elastic bending (ε ≈ 12%) and >15% photoinduced crystal expansion without fracture. Here, we investigate a homologous crystal series (1-Fn, n = 2, 3, 4, and 6) and reveal a mechanically coupled supramolecular scissoring motion that governs their diverse mechanical responses. The balance between scissor stretchability and compressibility, tuned by semifluorinated alkyl substituents, dictates the deformation mode, elasticity, and crystal integrity. An optimally balanced scissor state in 1-F4 enables exceptional elastic and photomechanical deformation while preserving crystal integrity, whereas fully-extended (1-F2), over-contracted (1-F6), or mechanically unbalanced (1-F3) scissor states lead to brittle failure or explosive photosalient behavior. These results establish a direct structure−motion−property relationship within this homologous series, demonstrating that key mechanical properties, including deformation mode and elastic limit, are encoded in the initial scissor geometry within the crystal packing arrangement.
Subjects
mechanical properties
photodimerization
photosalient effect
supramolecular scissor
tongue-and-groove joints
Publisher
Wiley
Type
journal article