Home >
News > Rapid Synthesis of Single-Crystal Covalent Organic Framework with Controllable Crystal Habits
Rapid Synthesis of Single-Crystal Covalent Organic Framework with Controllable Crystal Habits
Summary:
The authors from Beijing National Laboratory for Molecular Sciences & ICAS, China: developed a scalable acetal/CH₃COOH protocol to rapidly grow single-crystal COF-300 with controllable habits (sub-μm–300 µm, tetragonal-dipyramid to spindle), achieving laboratory SC-XRD resolution down to 0.79 Å and providing a platform for COF facet-engineering.
Background:
1. Industry problem & status: Traditional single-crystal COF-300 needs 30 days and gives ≤60 µm crystals; fast protocols (CF₃COOH) remain limited in size/shape control and facet engineering is rare.
2. This work: proposed replacing aldehyde with acetal precursor + pure CH₃COOH (80 °C) to create homogeneous nucleation; crystals reach 60 µm in 1 h, 120 µm in 48 h, 300 µm in 30 d with tunable habits.
Research Content:
1. Synthesis: TPADA (terephthalaldehydebis(diethylacetal)) + TAM in 1,4-dioxane, 0.1–7 mL CH₃COOH, 10–160 µL aniline (or H₂O), 80 °C, 48 h; single-crystal COF-300 harvested in 81–89 % yield.
2. Characterizations:
1) PXRD – tetragonal I41/a, a = b = 26.5565(16) Å, c = 7.4431(5) Å; water-exchange shrinks to a = b = 19.6219(10) Å.
2) SEM – spindle/dipyramid/prism habits, largest 120 µm; CV < 15 % for narrow size distribution.
3) VT-FT-IR – ν(O–H···N) 3257 cm⁻¹, reversible dehydration/rehydration; ¹³C NMR imine C shifts 158→159 ppm.
3. Application: Demonstrated as benchmark sc-COF for laboratory SXRD structure determination; 2D TAPB-COF (µm rhombi) also obtained.
4. Mechanism: Acetal slowly releases aldehyde → homogeneous supersaturation; compatible aromatic amines (pKa 3.3–5.3) cap [010] face, decouple nucleation/growth; ML model (KELM-BES) accurately maps acid/aniline dosage → crystal size/shape.
Outlook:
The work delivers a general, rapid (1 h) and green (water-tunable) route to large, facet-engineered single-crystal COFs, advancing real-time crystallization mechanistic studies and structure-property investigations.
Rapid Synthesis of Single-Crystal Covalent Organic Framework with Controllable Crystal Habits
Authors: Wenqiang Gao, Ziao Chen, Jiaxin Hong, YinYue Zhang, Zhao Yang, Minghui Liu, Xinyu Wang, Shengcong Shang, Zewen You, Zhihao Shao, Jichen Dong, Yunlong Guo, Jianyi Chen, Yunqi Liu
DOI: 10.1021/jacs.5c01638
Link: https://pubs.acs.org/doi/10.1021/jacs.5c01638
The above review is for academic progress sharing. For any errors or copyright issues, please contact us for correction or removal.
