Fast and Slow Motions Drive Elusive Polymorphic Transitions in a Naphthalene-Diimide Crystal
- 1Department of Chemistry ‘‘Giacomo Ciamician, University of Bologna, via Piero Gobetti 85, Bologna, Italy, 40129
Abstract
Thermally induced solid-state polymorphic transitions in an n-hexyl-functionalized naphthalenediimide organic semiconductor (NDI-C6) are investigated using atomistic molecular dynamics (MD) simulations. NDI-C6 exhibits two stable polymorphs: the α phase at room temperature and the γ phase at higher temperatures. The MD simulations reproduce the structural stability of both phases and provide a refined description of their unit-cell parameters and side-chain conformations, which have been only partially resolved experimentally. The α-to-γ transition proceeds through a sequential, non-concerted two-step mechanism. An initial fast (sub-nanosecond) process involves the collective rearrangement of the NDI cores, followed by a slow process (>100 ns) characterized by side-chain extension. These results provide an atomistic picture of polymorphism in NDI-C6 and establish a robust computational protocol for investigating labile phase transitions in the broader class of NDIbased n-type soft organic semiconductors.
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BibTeX
@misc{severi2026fast,
title = {{Fast and Slow Motions Drive Elusive Polymorphic Transitions in a Naphthalene-Diimide Crystal}},
author = {Marco Severi and Giulia Dall’Aglio and Daniele Fazzi},
howpublished = {ChemRxiv},
year = {2026},
month = aug,
doi = {10.26434/chemrxiv.15008060/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008060/v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Fast and Slow Motions Drive Elusive Polymorphic Transitions in a Naphthalene-Diimide Crystal
AU - Marco Severi
AU - Giulia Dall’Aglio
AU - Daniele Fazzi
PY - 2026
DA - 2026/08/31
PB - ChemRxiv
DO - 10.26434/chemrxiv.15008060/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008060/v1
AB - Thermally induced solid-state polymorphic transitions in an n-hexyl-functionalized naphthalenediimide organic semiconductor (NDI-C6) are investigated using atomistic molecular dynamics (MD) simulations. NDI-C6 exhibits two stable polymorphs: the α phase at room temperature and the γ phase at higher temperatures. The MD simulations reproduce the structural stability of both phases and provide a refined description of their unit-cell parameters and side-chain conformations, which have been only partially resolved experimentally. The α-to-γ transition proceeds through a sequential, non-concerted two-step mechanism. An initial fast (sub-nanosecond) process involves the collective rearrangement of the NDI cores, followed by a slow process (>100 ns) characterized by side-chain extension. These results provide an atomistic picture of polymorphism in NDI-C6 and establish a robust computational protocol for investigating labile phase transitions in the broader class of NDIbased n-type soft organic semiconductors.
ER -