Covalent Organic Frameworks: Organic Chemistry Extended into Two and Three Dimensions

Covalent organic frameworks are constructed by covalently linking organic molecules into crystalline 2D and 3D networks. Their architectural and chemical stability, coupled with their porosity, has allowed them to be used as starting materials and products of molecular organic reactions. Increasingly sophisticated structural and chemical design strategies have enabled the synthesis of complex 3D, 2D, and 1D (weaving) structures from geometrically predefined building blocks. Like small molecules, these materials allow for precise spatial organization of chemical functionalities but do so at length scales ranging from a few angstroms to several microns.