Tan Hao, Zhao Xiang, Du Liting, Wang Bufeng, Huang Yongliang, Gu Yupeng, Lu Zhiyong
College of Mechanics and Materials, Hohai University, No. 8 Focheng West Road, Nanjing, 211100, China.
Advanced Analysis and Testing Center, Nanjing Forestry University, No. 159 Longpan Road, Nanjing, 210037, China.
Small. 2024 Jan;20(3):e2305881. doi: 10.1002/smll.202305881. Epub 2023 Sep 5.
Core-shell metal-organic frameworks (MOF@MOF) are promising materials with sophisticated structures that cannot only enhance the properties of MOFs but also endow them with new functions. The growth of isotopic lcore-shell MOFs is mostly limited to inconvenient stepwise seeding strategies with strict requirements, and by far one-pot synthesis is still of great challenge due to the interference of different components. Through two pairs of isoreticular MOFs, it reveals that the structural incompatibility is a prerequisite for the formation of MOFs@MOFs by one-pot synthesis, as illustrated by PMOF-3@HHU-9. It further unveils that the adaptability of the shell-MOF is a more key factor for nucleation kinetic control. MOFs with flexible linkers has comparably slower nucleation than MOFs with rigid linkers (forming PMOF-3@NJU-Bai21), and structural-flexible MOFs built by flexible linkers show the lowest nucleation and the most adaptability (affording NJU-Bai21@HHU-9). This degree of adaptability variation controls the sequence and further facilitates the synthesis of a first triple-layered core-shell MOF (PMOF-3@NJU-Bai21@HHU-9) by one-pot synthesis. The insight gained from this study will aid in the rational design and synthesis of other multi-shelled structures by one-pot synthesis and the further expansion of their applications.
核壳金属有机框架材料（MOF@MOF）是具有复杂结构的有前景的材料，不仅可以增强金属有机框架材料（MOF）的性能，还能赋予它们新的功能。同位素核壳MOF的生长大多局限于不方便的分步播种策略，且要求严格，到目前为止，由于不同组分的干扰，一锅法合成仍然极具挑战性。通过两对同构MOF，研究表明结构不相容性是通过一锅法合成MOF@MOF的先决条件，如PMOF-3@HHU-9所示。研究还进一步揭示，壳层MOF的适应性是控制成核动力学的更关键因素。具有柔性连接体的MOF的成核速度比具有刚性连接体的MOF慢（形成PMOF-3@NJU-Bai21），由柔性连接体构建的结构柔性MOF的成核速度最低且适应性最强（得到NJU-Bai21@HHU-9）。这种适应性变化程度控制了顺序，并进一步促进了通过一锅法合成首个三层核壳MOF（PMOF-3@NJU-Bai21@HHU-9）。从这项研究中获得的见解将有助于通过一锅法合理设计和合成其他多壳结构，并进一步扩展其应用。
