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Crystalline porous frameworks, such as covalent organic frameworks (COFs), metal–organic frameworks (MOFs), and hydrogen-bonded organic frameworks (HOFs), have demonstrated exceptional potential in diverse applications, including gas adsorption/separation, catalysis, sensing, electronic devices, etc. However, the building blocks for constructing ordered frameworks are typically limited to multisubstituted aromatic small molecules, and uncontrolled interpenetration has remained a long-standing challenge in the field. Shape-persistent macrocycles and molecular cages have garnered significant attention in supramolecular chemistry and materials science due to their unique structures and novel properties. Using such preporous shape-persistent 2D macrocycles or 3D cages as building blocks to construct extended networks is particularly appealing. This macrocycle-to-framework/cage-to-framework hierarchical assembly approach not only mitigates the issue of interpenetration but also enables the integration of diverse properties in an emergent fashion. Since our demonstration of the first organic cage framework (OCF) in 2011 and the first macrocycle-based ionic COFs (ICOFs) in 2015, substantial advancements have been made over the past decade. In this Account, we will summarize our contributions to the development of crystalline porous frameworks, consisting of shape-persistent macrocycles and molecular cages as preporous building blocks, via hierarchical dynamic covalent assembly. We will begin by reviewing representative design strategies and the synthesis of shape-persistent macrocycles and molecular cages from small molecule-based primary building blocks, emphasizing the critical role of dynamic covalent chemistry (DCvC). Next, we will discuss the further assembly of preporous macrocycle/cage-based secondary building blocks into extended frameworks, followed by an overview of their properties and applications. Finally, we will highlight the current challenges and future directions for this hierarchical assembly approach in the synthesis of crystalline porous frameworks. This Account offers valuable insights into the design and synthesis of functional porous frameworks, contributing to the advancement of this important field.
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Hydrogen bonded frameworks: smart materials used smartly
Hydrogen-bonded frameworks (HBFs) have been studied for decades owing to their fascinating and diverse architectures, always with an eye toward the role of hydrogen bonding in their design as well as their utility in various applications. This review addresses recent advances in HBFs that illustrate their versatility and utility stemming from their unique attributes compared with other classes of molecular frameworks. Guanidinium organosulfonate hydrogen-bonded frameworks, pioneered in our lab and one of the most extensive and versatile collections of HBFs, are used to illustrate molecular design concepts and the principle of architectural isomerism that expands access to a greater structural landscape. Recognizing the growing role of computation in materials design, from ab initio methods to machine learning, this review also touches on their emerging use in the design and synthesis of HBFs. The growth of the HBF arsenal promises continuing innovations, with applications ranging from electronic materials and chemical separations to gas adsorption and catalysis.
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- Award ID(s):
- 2002964
- PAR ID:
- 10321747
- Date Published:
- Journal Name:
- Molecular Systems Design & Engineering
- Volume:
- 6
- Issue:
- 10
- ISSN:
- 2058-9689
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/d1me00055a
