Evolution of Metallomacrocycles From Macrocycles
In this chapter, we introduce the evolution process of self-assembled metallomacrocycles from covalent macrocycles. During the past decades, a large number of covalent macrocycles, such as cryptands, cyclodextrins, calixarenes, cucurbiturils, and pillararenes, have been successfully synthesized, some of which have wide applications in molecular recognition, catalysis, and supramolecular self-assembly. However, some of these covalent macrocycles suffer from time-consuming synthetic procedures, low yields, and difficult modification. The use of coordination-driven self-assembly provides a controllable and highly efficient synthetic strategy for the construction of discrete supramolecular metallomacrocycles with well-defined shapes and sizes. In this chapter we describe the work of Stang, Fujita, Mirkin, Cotton, and others who have independently exploited novel coordination-based strategies for the self-assembly of discrete metallomacrocycles. In addition, we discuss the characterization of self-assembled metallomacrocycles by using mass spectrometry and X-ray measurement.