Suzuki Mitsuharu, Miura Masashi, Ohkubo Enzo, Karimata Haru, Aizawa Naoya, Yamada Hiroko, Nakayama Ken-Ichi
Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan.
J Am Chem Soc. 2023 Feb 8;145(5):3008-3015. doi: 10.1021/jacs.2c11520. Epub 2023 Jan 29.
The diversity and complexity of covalent organic frameworks (COFs) can be largely increased by incorporating multiple types of monomers with different topologies or sizes. However, an increase in the number of monomer types significantly complicates the COF formation process. Accordingly, much remains unclear regarding the viability of monomer combinations for ternary or higher-arity COFs. Herein, we show that, through an extensive examination of 12 two-nodes-one-linker ([2 + 1]) combinations, monomer-set viability is determined primarily by the conformational strain originating from disordered monomer arrangements, rather than other factors such as the difference in COF formation kinetics between monomers. When monomers cannot accommodate the strain associated with the formation of a locally disordered, yet crystalline framework, the corresponding [2 + 1] condensation yields a mixture of different COFs or an amorphous polymer. We also demonstrate that a node-linker pair that does not form a binary COF can be integrated to generate a single-phase framework upon addition of a small amount of the third component. These results will clarify the factors behind the successful formation of multicomponent COFs and refine their design by enabling accurate differentiation between allowed and disallowed monomer combinations.
通过引入多种具有不同拓扑结构或尺寸的单体，共价有机框架（COF）的多样性和复杂性可以得到大幅提高。然而，单体类型数量的增加会显著使COF的形成过程变得复杂。因此，关于三元或更高元COF的单体组合的可行性，仍有许多尚不清楚的地方。在此，我们表明，通过对12种双节点单连接体（[2 + 1]）组合进行广泛研究，单体组合的可行性主要由无序单体排列产生的构象应变决定，而非其他因素，如单体之间COF形成动力学的差异。当单体无法承受与形成局部无序但结晶的框架相关的应变时，相应的[2 + 1]缩合会产生不同COF的混合物或无定形聚合物。我们还证明，在添加少量第三种组分后，不能形成二元COF的节点 - 连接体对可以整合生成单相框架。这些结果将阐明多组分COF成功形成背后的因素，并通过准确区分允许和不允许的单体组合来优化其设计。
