Metallacycles, metallacages, and their aggregate/optical behavior

Abstract Since the first metallacycle was prepared by Verkade in 1983, various metallacycles and metallacages with controllable nanoscale shapes and sizes have been created by modular design and synthesis, showing unique properties that enable applications in catalysis, sensors, and biomedicine. Everything from their photophysical properties to their antitumor activities and catalysis was found to be influenced by their suprastructures. Thus, it is necessary and helpful to develop a systematic understanding of the relationships among the micro/nanostructures, the resultant photophysical/chemical properties, and the corresponding applications. In this review, we summarized the latest progress in this area in approximately the past 5 years.