Reticulating Local Dynamics in Three-Dimensional Covalent Organic Frameworks
Abstract
In covalent organic frameworks (COFs), the geometry of the building units predetermines the structure of the framework, yet comparable design principles relating the COF linkers to the local motions that govern guest adsorption and diffusion as well as mechanical response have remained beyond reach. Here, we combine synchrotron X-ray pair distribution function (PDF) analysis with molecular dynamics (MD) simulations accelerated by machine learning interatomic potentials to resolve and compare the local dynamics of two three-dimensional imine-linked COFs, chosen to differ in the geometry and rigidity of one of their two building units. Both are constructed from the same 4-connected square planar linker, $4,4',4'',4'''−(pyrene−1,3,6,8−tetrayl)tetraaniline (PyTTA), reticulated with the 12−connected nanographene hexakis[3,5−bis(p−formylphenyl)−4,6−dimethoxyphenyl]hexabenzocoronene to give COF−412, [(HBC−LA_{12})(PyTTA)_3]_{\mathit{imine}}, and with the 6−connected triptycene 2,3,6,7,14,15−hexakis(4−formylphenyl)triptycene to give COF−564, [(Trip−CHO)_2(PyTTA)_3]_{\mathit{imine}}$. The PDF-MD approach resolves the amplitude, the time scale, and the spatial extent of the motion of all COF linkers, separating the limited libration of the fused aromatic cores from the larger reorientational tilts of the pendant aryl rings they carry and from the translation of whole linkers within the net. The simulations further reveal that exchanging the nanographene- for the triptycene-based linker tunes the equilibrium tilt and the positional probability density of PyTTA, raising the tilt amplitude of its linker partner, and, notably, strengthens the coupling between the translations of neighbouring linkers. This approach provides a blueprint for understanding local dynamical properties in COFs, and shows them to be selectable through the choice of building unit and amenable to design.
Related
- Local Structure and Dynamics of Three-Dimensional Covalent Organic Frameworks
- Chiroptical Nonlinearity Found in Covalent Organic Frameworks
- Molecular Curvature Enables Tubular π-Stacked Pathways in Three-Dimensional Conductive Metal-Organic Frameworks
- Layered spin-crossover metal-organic frameworks for light-induced control of two-dimensional quantum materials
- An encoded asymmetric ligand for metal-selective topological assembly of two-dimensional metal-organic frameworks
BibTeX
@misc{tavani2026reticulating,
title = {{Reticulating Local Dynamics in Three-Dimensional Covalent Organic Frameworks}},
author = {Francesco Tavani and Saber Mirzaei and M. Saeed Mirzaei and Jian Yin and Yen-Hsu Lin and Caden Myers and Cheng-Hung Lin and AM Milinda Abeykoon and Simon J. L. Billinge and Omar M. Yaghi},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.24418},
eprint = {2610.24418},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.24418},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Reticulating Local Dynamics in Three-Dimensional Covalent Organic Frameworks
AU - Francesco Tavani
AU - Saber Mirzaei
AU - M. Saeed Mirzaei
AU - Jian Yin
AU - Yen-Hsu Lin
AU - Caden Myers
AU - Cheng-Hung Lin
AU - AM Milinda Abeykoon
AU - Simon J. L. Billinge
AU - Omar M. Yaghi
PY - 2026
DA - 2026/10/25
PB - arXiv
DO - 10.48550/arxiv.2610.24418
UR - https://arxiv.org/abs/2610.24418
AB - In covalent organic frameworks (COFs), the geometry of the building units predetermines the structure of the framework, yet comparable design principles relating the COF linkers to the local motions that govern guest adsorption and diffusion as well as mechanical response have remained beyond reach. Here, we combine synchrotron X-ray pair distribution function (PDF) analysis with molecular dynamics (MD) simulations accelerated by machine learning interatomic potentials to resolve and compare the local dynamics of two three-dimensional imine-linked COFs, chosen to differ in the geometry and rigidity of one of their two building units. Both are constructed from the same 4-connected square planar linker, $4,4',4'',4'''−(pyrene−1,3,6,8−tetrayl)tetraaniline (PyTTA), reticulated with the 12−connected nanographene hexakis[3,5−bis(p−formylphenyl)−4,6−dimethoxyphenyl]hexabenzocoronene to give COF−412, [(HBC−LA_{12})(PyTTA)_3]_{\mathit{imine}}, and with the 6−connected triptycene 2,3,6,7,14,15−hexakis(4−formylphenyl)triptycene to give COF−564, [(Trip−CHO)_2(PyTTA)_3]_{\mathit{imine}}$. The PDF-MD approach resolves the amplitude, the time scale, and the spatial extent of the motion of all COF linkers, separating the limited libration of the fused aromatic cores from the larger reorientational tilts of the pendant aryl rings they carry and from the translation of whole linkers within the net. The simulations further reveal that exchanging the nanographene- for the triptycene-based linker tunes the equilibrium tilt and the positional probability density of PyTTA, raising the tilt amplitude of its linker partner, and, notably, strengthens the coupling between the translations of neighbouring linkers. This approach provides a blueprint for understanding local dynamical properties in COFs, and shows them to be selectable through the choice of building unit and amenable to design.
ER -