24. Hierarchical Organic Microspheres from Diverse Molecular Building Blocks

Y. Li, L. Fan, X. Xu, Y. Sun, W. Wang, B. Li, S. Veroneau, P. Ji*

Microspherical structures find broad application in chemistry and materials science, including in separations and purifications, energy storage and conversion, organic and biocatalysis, and as artificial and bioactive scaffolds. Despite this utility, the systematic diversification of their morphology and function remains hindered by the limited range of their molecular building blocks. Drawing upon the design principles of reticular synthesis, where diverse organic molecules generate varied porous frameworks, we show herein how analogous microspherical structures can be generated under mild conditions. The assembly of simple organic molecules into microspherical structures with advanced morphologies represents a grand challenge. Beginning with a partially condensed Schiff base which self-assembles into a hierarchical organic microsphere, we systematically synthesized sixteen microspheres from diverse molecular building blocks. We subsequently explicate the mechanism of hierarchical assembly through which these hierarchical organic microspheres are produced, isolating the initial monomer, intermediate substructures, and eventual microspheres. Furthermore, the open cavities present on the surfaces of these constructs provided distinctive adsorptive properties, which we harnessed for the immobilization of enzymes and bacteriophages. Holistically, these hierarchical organic microspheres provide an approach for designing multi-functional superstructures with advanced morphologies derived from simple organic molecules, revealing an extended length scale for reticular synthesis.

微球结构在化学和材料科学中有着广泛的应用，包括分离和纯化、能量存储和转换、有机和生物催化以及作为人工和生物活性支架。尽管有这种用途，但由于分子结构块的范围有限，其形态和功能的系统多样化仍然有限。借鉴网格合成化学的设计原理，其中不同的有机分子产生不同的多孔框架，我们在此展示了如何在温和条件下生成类似的微球结构。将简单的有机分子组装成具有高级形态的微球结构是一项巨大的挑战。从部分缩合的席夫碱开始，它可以自组装成一个多级有机微球，我们系统地合成了来自不同分子结构块的十六个微球。随后，我们阐明了生产这些多级有机微球的分层组装机制，分离了初始单体、中间亚结构和最终的微球。此外，这些结构表面的开放空腔具有独特的吸附特性，我们利用这种特性来固定酶和噬菌体。总体而言，这些多级有机微球提供了一种设计源自简单有机分子的多功能超结构的设计策略，拓宽了网格合成化学。