Porous coordination polymers/metal-organic frameworks

Coordination polymers are constructed from metal ions and bridging ligands that assemble to form infinite frameworks with long-range structural ordering (Fig. 1A). Coordination bonds play an important role in the construction of these extended structures and other weak chemical bonds, such as hydrogen bonds and van der Waals interactions, also play a role. Coordination frameworks can be controlled by modifying the geometries of the components, drawing parallels between this type of synthetic strategy, and building blocks. Generally, the coordination polymer (CP) formation process automatically proceeds and is therefore referred to as a self-assembly process. Crystalline CPs, in particular, are widely utilized because their structures can be exclusively determined by X-ray crystallographic methods. Moreover, their unique network motifs and structural diversity enable physical and chemical properties ranging from magnetism and conductivity to optical properties.^1–4 The size and geometry of the components that control the topology and spatial dimensionality of the networks and the functionality of the ligands determine the strength of the coordination bonds, resulting in thermally and chemically stable frameworks. Weakly coordinating anions influence the local coordination structure of metal ions and the overall framework structure and are thus regarded as framework regulators. In particular, protic solvent molecules are involved in hydrogen bonding linkages in frameworks, forming a complementary linking network. In comparison to assemblies of discrete metal complexes, infinite CPs benefit from (i) the construction of stable frameworks (e.g., zeolites and activated carbons), which leads to microporous functions; (ii) a desirable arrangement of metal ions with spins, which....