Subtle differences in interlayer energetics dictate facet-dependent elastic and plastic flexibility in a molecular crystal
Abstract
Mechanically flexible molecular crystals hold promise for emerging functional materials such as optoelectronics and piezoelectrics. Here, we report a rare example of facet-dependent elastic and plastic bending in a molecular crystal. Synchrotron micro-focused X-ray diffraction mapping (µ-XRD) and X-ray quantum crystallography (QCr) reveal distinct domain-level structural changes during plastic versus elastic deformation and variations in intermolecular interactions across the slip planes that govern these distinct mechanical responses. Potential energy densities evaluated at the interaction regions from QCr models, along with the subtle difference in interlayer binding energies (ΔE = 2.2 kJ mol-1) reveal more robust interactions that underpin the elastically bending facet. µ-XRD mapping uncovers the atomistic origin of elastic deformation in terms of molecular reorientation (Δθ = 0.38°) and packing density gradients in the bent region, whereas plastic deformation proceeds via irreversible molecular slippage, quantified by a 5-fold increase in crystal mosaicity (from 0.06° to 0.30°). These findings correlate subtle electron-density and energetic features with the domain-level changes underlying this rare phenomenon.
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BibTeX
@misc{rahman2026subtle,
title = {{Subtle differences in interlayer energetics dictate facet-dependent elastic and plastic flexibility in a molecular crystal}},
author = {Atiqur Rahman and Ravi Teja Malisetty and Amit K. Pradhan and Aditya K. Prajapati and Vivian G. Shang and John C. McMurtrie and Jack K. Clegg and Sajesh P. Thomas},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15008881/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008881/v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Subtle differences in interlayer energetics dictate facet-dependent elastic and plastic flexibility in a molecular crystal
AU - Atiqur Rahman
AU - Ravi Teja Malisetty
AU - Amit K. Pradhan
AU - Aditya K. Prajapati
AU - Vivian G. Shang
AU - John C. McMurtrie
AU - Jack K. Clegg
AU - Sajesh P. Thomas
PY - 2026
DA - 2026/09/15
PB - ChemRxiv
DO - 10.26434/chemrxiv.15008881/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008881/v1
AB - Mechanically flexible molecular crystals hold promise for emerging functional materials such as optoelectronics and piezoelectrics. Here, we report a rare example of facet-dependent elastic and plastic bending in a molecular crystal. Synchrotron micro-focused X-ray diffraction mapping (µ-XRD) and X-ray quantum crystallography (QCr) reveal distinct domain-level structural changes during plastic versus elastic deformation and variations in intermolecular interactions across the slip planes that govern these distinct mechanical responses. Potential energy densities evaluated at the interaction regions from QCr models, along with the subtle difference in interlayer binding energies (ΔE = 2.2 kJ mol-1) reveal more robust interactions that underpin the elastically bending facet. µ-XRD mapping uncovers the atomistic origin of elastic deformation in terms of molecular reorientation (Δθ = 0.38°) and packing density gradients in the bent region, whereas plastic deformation proceeds via irreversible molecular slippage, quantified by a 5-fold increase in crystal mosaicity (from 0.06° to 0.30°). These findings correlate subtle electron-density and energetic features with the domain-level changes underlying this rare phenomenon.
ER -