TY - JOUR
T1 - Hydrolytic Stability of Boronate Ester-Linked Covalent Organic Frameworks
AU - Li, Huifang
AU - Li, Haoyuan
AU - Dai, Qingqing
AU - Li, Hong
AU - Brédas, Jean Luc
N1 - Funding Information:
The work at Georgia Tech was supported by the Army Research Office Multidisciplinary University Research Initiative (MURI) program under grant no. W911NF‐15‐1‐0447 as well as by the Army Research Office grant no. W911NF‐17‐1‐0339. The work at KAUST was supported by internal funding from King Abdullah University of Science and Technology; the authors are grateful to the KAUST IT Research Computing Team and Supercomputing Laboratory for providing outstanding assistance as well as computational and storage resources. H.F.L. thanks the National Natural Science Foundation of China (21403037) for funding.
Publisher Copyright:
© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2018/2/1
Y1 - 2018/2/1
N2 - The stability of covalent organic frameworks (COFs) is essential to their applications. However, the common boronate ester-linked COFs are susceptible to attack by nucleophiles (such as water molecules) at the electron-deficient boron sites. To provide an understanding of the hydrolytic stability of the representative boronate ester-linked COF-5 and of the associated hydrolysis mechanisms, density functional theory (DFT) calculations were performed to characterize the hydrolysis reactions of the molecule formed by the condensation of 1,4-phenylenebis(boronic acid) (PBBA) and 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) monomers; two cases were considered, one dealing with the freestanding molecule and the other with the molecule interacting with COF layers. It was found that the boronate ester (B–O) bond dissociation, which requires one H2O molecule, has a relatively high energy barrier of 22.3 kcal mol−1. However, the presence of an additional H2O molecule significantly accelerates hydrolysis by reducing the energy barrier by a factor of 3. Importantly, the hydrolysis of boronate ester bonds situated in a COF environment follows reaction pathways that are different and have increased energy barriers. These results point to an enhanced hydrolytic stability of COF-5 crystals.
AB - The stability of covalent organic frameworks (COFs) is essential to their applications. However, the common boronate ester-linked COFs are susceptible to attack by nucleophiles (such as water molecules) at the electron-deficient boron sites. To provide an understanding of the hydrolytic stability of the representative boronate ester-linked COF-5 and of the associated hydrolysis mechanisms, density functional theory (DFT) calculations were performed to characterize the hydrolysis reactions of the molecule formed by the condensation of 1,4-phenylenebis(boronic acid) (PBBA) and 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) monomers; two cases were considered, one dealing with the freestanding molecule and the other with the molecule interacting with COF layers. It was found that the boronate ester (B–O) bond dissociation, which requires one H2O molecule, has a relatively high energy barrier of 22.3 kcal mol−1. However, the presence of an additional H2O molecule significantly accelerates hydrolysis by reducing the energy barrier by a factor of 3. Importantly, the hydrolysis of boronate ester bonds situated in a COF environment follows reaction pathways that are different and have increased energy barriers. These results point to an enhanced hydrolytic stability of COF-5 crystals.
KW - boronic ester linkage
KW - covalent organic frameworks
KW - density functional theory
KW - hydrolytic reactions
KW - potential energy surface
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U2 - 10.1002/adts.201700015
DO - 10.1002/adts.201700015
M3 - Article
AN - SCOPUS:85082944688
SN - 2513-0390
VL - 1
JO - Advanced Theory and Simulations
JF - Advanced Theory and Simulations
IS - 2
M1 - 1700015
ER -