Inner and Outer Beauty

Abstract

Symmetry and pattern are precious forms of beauty that can be appreciated on both the macroscopic and molecular scales. Crystallographers have long appreciated the intimate connections between symmetry and molecular structure, reflected in their appreciation for the artwork of Escher. This admiration has been applied in the design of highly symmetrical coordination compounds. Two classes of materials are discussed: extended coordination arrays and discrete supramolecular assemblies. Extended coordination polymers have been implemented in gas separation and storage due to the remarkably porosity of these materials, aided by the ability to design ever-larger inner spaces within these frameworks. In the case of discrete symmetrical structures, defined inner and outer space present a unique aesthetic and chemical environment. The consequent host-guest chemistry and applications in catalysis are discussed.

Dynamic covalent synthesis of aryleneethynylene cages through alkyne metathesis: dimer, tetramer, or interlocked complex?

“…The size and shape complementarity of building blocks are usually considered to be critical for the assembly of supramolecules. 31 , 32 , 36 – 39 In general, the angular disposition of connection sites of building blocks determines the topology, whereas the size of building blocks determines the physical dimension of the assembly product. As ethynylene bonds are linear, closely resembling metal–ligand dative bonds, a tenable view is that they share similar geometrical requirements for building blocks when employed in the assembly of discrete molecules.…”

Mechanochemistry of supramolecules

“…Nature displays innumerable and beautiful creations [67–68] which include highly complex self-assembled structures made from smaller building blocks by using weak or non-covalent interactions [69–70]. Therefore, the supramolecular approach [71] and systems chemistry [1,72] are considered as the fastest growing areas of chemical research during the last couple of decades [73–74].…”