Heterometallic cages: synthesis and applications

Abstract

The general methods used for synthesizing heterometallic cages are described. The intrinsic properties and applications of these cages as host–guest systems and catalysts are also examined.

High-order layered self-assembled multicavity metal–-organic capsules and anti-cooperative host–multi-guest chemistry

“…2–5 A very diverse library of supramolecular architectures with well-defined shapes and sizes has been created, and pioneering contributions include metallo-macrocycles, 6–8 platonic polyhedra, 9–11 metal–organic cages, 12–14 intricate molecule knots 15–17 and so on. 18–20 Highly sophisticated structures, such as the DNA double helix and virus capsid structure, can be constructed via supramolecular self-assembly in nature. However, the level of size and complexity of most artificial metal–organic supramolecular architectures employed to date lags far behind that of nature.…”

“…However, the level of size and complexity of most artificial metal–organic supramolecular architectures employed to date lags far behind that of nature. Although remaining a formidable challenge, there are still creative efforts focused on developing construction strategies of complicated metal–organic supramolecules, such as low-symmetry metal–organic cages, 19–21 interlocked molecular assemblies, 22–25 giant metal-based supramolecules 13,26 and so on. 7,27…”

Giant Expanded Porous Metallo-Hexagons

“…Over the past few decades, there has been a rapid expansion in the construction of giant structures through molecular self-assembly as a bottom-up approach . Among them, metal–ligand coordination has been regarded as one of the most effective methods. − Ligands based on N-donor units like pyridine, bipyridine, terpyridine, and related compounds have been employed to coordinate with various metal ions to create discrete supramolecular complexes (SCCs) such as 2D polygons and 3D polyhedrons with precisely controlled sizes and shapes. − Pioneers in the field, including Lehn, Stang, Raymond, Fujita, Newkome, and other researchers, have made impressive advancements in the elegant synthesis of intricate molecular structures such as square grid, Star of David, hexagonal fractal, and various polygons. − These discrete architectures can achieve outstanding complexity and functionality in areas such as sensors, magnetic materials, catalysis, and molecular electronics due to their controllable intensive metal centers. Despite advancements, challenges persist in the formation of highly complex metallocycles, especially in assembly systems involving multiple components, − including issues like self-sorting, ligand distortion, and the poor solubility of assembled products. , …”

Stepwise construction of a metallocatenane based on non-labile bis(terpyridine)-CdII complexes

“…For multicomponent coordination-driven self-assembly, 7 avoiding the formation of misconnected structures or structural isomers becomes increasingly challenging as the number and type of building blocks increase. Therefore, metalloligand strategies 8 are commonly employed to reduce the possibility of forming undesired products. In this approach, metalloligands are constructed stepwise using kinetically inert coordination bonds, which are then treated with labile metal ions to generate the targeted architectures.…”