Photocatalysis in Supramolecular Fluorescent Metallacycles and Metallacages

Abstract

The utilization of photocatalytic techniques for achieving light‐to‐fuel conversion is a promising way to ease the shortage of energy and degradation of the ecological environment. Fluorescent metallacycles and metallacages have drawn considerable attention and have been used in widespread fields due to easy preparation and their abundant functionality including photocatalysis. This review covers recent advances in photocatalysis in discrete supramolecular fluorescent metallacycles and metallacages. The developments in the utilization of the metallacycles skeletons and the effect of fluorescence‐resonance energy transfer for photocatalysis are discussed. Furthermore, the use of the ligands decorated by organic chromophores or redox metal sites in metallacages as photocatalysts and their ability to encapsulate appropriate catalytic cofactors for photocatalysis are summarized. For the sake of brevity, macrocycles and cages with inorganic coordination complexes such as ruthenium complexes and iridium complexes are not included in this minireview.

Subphthalocyanine capsules: molecular reactors for photoredox transformations of fullerenes

“…3 The combination of the two fields, that is the formation of coordination cages by selfassembly of chromophores with photosensitizing abilities, offers powerful possibilities since it provides a local concentration of photoactive units surrounding a bound guest in a way that would not be possible in solution under normal conditions, affording an antenna effect in which excitation energy from several sources is directed to a single reaction site. Although there are examples in the literature of "antenna" cages performing as photocatalysts, 4,5 most of them are focused on the production of hydrogen or the generation of reactive oxygen species, but the realization of more complex photoredox transformations remains largely unexplored. The development of chemical reactions under photoredox catalysis is a central research field that has allowed to overcome issues, such as decomposition or the lack of control over the reaction, associated with the direct excitation of organic substrates with high energy UV-light.…”

Supramolecular Coordination Cages for Artificial Photosynthesis and Synthetic Photocatalysis

“…Additionally, the photophysical properties undergo changes when the PSs are placed in close and constraint proximity, which have recently been reviewed. 196 In this section, our discussion will focus on the application of these systems in organic photoredox catalysis. 4.3.1.…”

Switchable metallacycles and metallacages

“…Metallacycles have attracted much attention in recent years because they exhibit various shapes, sizes and coordination geometries, which are determined by their central metal ions, design and number of building blocks. [49][50][51] With their versatile structures and inherent dynamic and reversible nature, switchable metallacycles are expected to be promising platforms that provide controllability in optical switching, guest capture/release and catalysis efficiency; as a result, switchable metallacycles have potential application in molecular logic gates, drug delivery systems, biological materials, etc.…”