Stewart David, Antypov Dmytro, Dyer Matthew S, Pitcher Michael J, Katsoulidis Alexandros P, Chater Philip A, Blanc Frédéric, Rosseinsky Matthew J
Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK.
Diamond Light Source, Harwell Campus, Didcot, Oxfordshire, OX11 0DE, UK.
Nat Commun. 2017 Oct 24;8(1):1102. doi: 10.1038/s41467-017-01423-5.
Covalent organic frameworks (COFs) are network polymers with long-range positional order whose properties can be tuned using the isoreticular chemistry approach. Making COFs from strong bonds is challenging because irreversible rapid formation of the network produces amorphous materials with locked-in disorder. Reversibility in bond formation is essential to generate ordered networks, as it allows the error-checking that permits the network to crystallise, and so candidate network-forming chemistries such as amide that are irreversible under conventional low temperature bond-forming conditions have been underexplored. Here we show that we can prepare two- and three-dimensional covalent amide frameworks (CAFs) by devitrification of amorphous polyamide network polymers using high-temperature and high-pressure reaction conditions. In this way we have accessed reversible amide bond formation that allows crystalline order to develop. This strategy permits the direct synthesis of practically irreversible ordered amide networks that are stable thermally and under both strong acidic and basic hydrolytic conditions.
共价有机框架(COFs)是具有长程位置有序性的网络聚合物,其性质可通过等规化学方法进行调控。利用强键制备COFs具有挑战性,因为网络的不可逆快速形成会产生具有锁定无序性的无定形材料。键形成的可逆性对于生成有序网络至关重要,因为它允许进行错误检查,从而使网络能够结晶,因此,诸如酰胺等在传统低温键形成条件下不可逆的候选网络形成化学方法尚未得到充分探索。在这里,我们表明,我们可以通过使用高温高压反应条件使无定形聚酰胺网络聚合物失透,来制备二维和三维共价酰胺框架(CAFs)。通过这种方式,我们实现了可逆的酰胺键形成,从而使晶体有序性得以发展。这种策略允许直接合成在热、强酸性和碱性水解条件下均稳定的几乎不可逆的有序酰胺网络。