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oai:figshare.com:article/34034170 2026-09-30T17:12:04Z category_1 category_4 category_915 category_873 category_39 category_135 portal_63 item_type_6 month_year_09_2026

Structure–Dynamics-Property Relationship Reveals the Origin of Porous Integrity in Imine-Linked Covalent Organic Frameworks William B. Stoll (21412963) Johanna Kölbel (11919024) Alonso Acosta Vera (25144939) Sameeha Sultana (25144942) William Archacki (25144945) Khai-Nghi Truong (3367049) Irin E. Aby (25144948) Brandon R. Barnett (1565590) Luca Catalano (1460302) Agnes E. Thorarinsdottir (6615830) Michael T. Ruggiero (4378540) Biophysics Biochemistry Physical Sciences not elsewhere classified Chemical Sciences not elsewhere classified Ecology Computational Biology remains largely unexplored property relationship reveals dimensional electron diffraction planar linker conformations frequency vibrational spectroscopy frequency raman spectroscopy bent linker conformation mode analysis reproduces multiwell torsional potential covalent organic frameworks quantify linker flexibility chemically related cofs local mode analysis negligible gas uptake favoring collapsed packing 2 </ sub structure – dynamics local amine flexibility frequency lattice dynamics linker flexibility frequency dynamics lattice dynamics phase local mode decomposition torsional softness packing constraints based frameworks amine torsions flexible cofs crystal structure cofs ). therefore linked support guest structural integrity results demonstrate responsive structures relative trend principles calculations preserving near porous materials porous integrity key determinant interpenetrated framework increasingly recognized comparatively stiff combining three Molecular flexibility encoded in low-frequency lattice dynamics is increasingly recognized as a key determinant of the properties of porous materials, particularly metal–organic frameworks, but remains largely unexplored in covalent organic frameworks (COFs). Here, we establish a structure–dynamics–property relationship for chemically related COFs by combining three-dimensional electron diffraction, low-frequency vibrational spectroscopy, and first-principles calculations. Using 3D electron diffraction, we determined the crystal structure of the collapsed reduced framework COF-300-AR, revealing a bent linker conformation. Terahertz and low-frequency Raman spectroscopy, together with solid-state density functional theory and local mode analysis, resolve the lattice dynamics of contracted COF-300-H₂O, COF-320A, and collapsed COF-300-AR and quantify linker flexibility through imine/amine torsions. Normal-mode decomposition and torsional potential energy surfaces show that these coordinates are comparatively stiff in the imine-based frameworks, preserving near-planar linker conformations that support guest-responsive structures. In contrast, COF-300-AR exhibits a shallower, multiwell torsional potential that enables bent linker conformations, favoring collapsed packing. Gas-phase local-mode analysis reproduces this relative trend in torsional softness, suggesting that linker flexibility can be screened before a crystal structure is available. The negligible gas uptake of COF-300-AR is therefore linked to the coupling of local amine flexibility with packing constraints in the interpenetrated framework. More broadly, these results demonstrate how low-frequency dynamics can identify molecular coordinates governing the structural integrity and porosity in flexible COFs. 2026-09-30T00:00:00Z Text Journal contribution 10.1021/jacs.6c14616.s003 https://figshare.com/articles/journal_contribution/Structure_Dynamics-Property_Relationship_Reveals_the_Origin_of_Porous_Integrity_in_Imine-Linked_Covalent_Organic_Frameworks/34034170 CC BY-NC 4.0