Insight into functionalized-macrocycles-guided supramolecular photocatalysis

Abstract

Due to the unique characteristics of macrocycles (e.g., the ease of modification, hydrophobic cavities, and specific guest recognition), they can provide a suitable environment to realize photocatalysis via noncovalent interactions with different substrates. In this minireview, we emphasized the photochemical transformation and catalytic reactivity of different guests based on the binding with various macrocyclic hosts as well as on the role of macrocyclic-hosts-assisted hybrid materials in energy transfer. To keep the clarity of this review, the macrocycles are categorized into the most commonly used supramolecular hosts, including crown ethers, cyclodextrins, cucurbiturils, calixarenes, and pillararenes. This minireview not only summarizes the role that macrocycles play in photocatalytic reactions but also clarifies the photocatalytic mechanisms. Finally, the future research efforts and new pathways to apply macrocycles and supramolecular hybrid materials in photocatalysis are also discussed.

Reactivity and selectivity modulation within a molecular assembly: recent examples from photochemistry

“…In a different scenario, β-cyclodextrins were employed in the last two decades as chiral molecular hosts for the efficient photocyclodimerization of anthracenecarboxylic acid 75 (AC). A lot of work has been done employing these molecules [ 57 ], and one of the latest examples on this field was reported in 2019 by Inoue and co-workers [ 58 ]. In this publication, a new class of cyclodextrin (CD) dimers 77 were designed where a sulphur atom connects two different saccharide units (Scheme 21 ).…”

A Photosensitive Cationic Macrocycle Based on Triphenylamine as Photocatalysts for Selective Photooxidation of Phosphines, Styrenes, and Hydroazobenzenes

“…Since the first macrocycle crown ether was synthesized by Pederson in 1967, there has been significant progress in the production of fully synthesized macrocycles that offer structural specificity, great selectivity, and host–guest complexation. Up to now, a wide range of macrocycles including cyclodextrins, calixarenes, cucurbiturils, pillararenes, and cyclotriveratrylenes, are documented and have garnered growing interest due to their intriguing structures and versatile functionalities. − These macrocycles have a variety of features and uses, including as molecular recognition, gas storage, mass transportation, and electronics. − Among the many applications of macrocyclic molecules, macrocyclic supramolecular catalysis has gradually attracted extensive attention in recent years, in which several macrocycle and cage compounds with cavities have been utilized as supramolecular catalysts to enable otherwise unfavorable transformations. − However, in these macrocyclic supramolecular catalytic systems, the catalytic process generally happens through the interaction between the substrate and the macrocyclic molecule rather than directly using the macrocyclic molecule as the catalyst. In addition, the commonly employed macrocycles such as crown ethers, cucurbiturils, and cyclodextrins are either transparent to spectroscopy or exhibit low absorption in the UV–vis range.…”

Tetraphenylethylene-embedded pillar[5]arene-based orthogonal self-assembly for efficient photocatalysis in water

“…To fabricate a successful FRET system, the following key points need to be considered, i) the acceptor absorption spectrum should have good overlapping with the donor emission spectrum; ii) the distance between the donor and an acceptor should be within 10 nm; iii) dipoles of the donor and acceptor molecules must be adopted constructively vicinity to each other [ 9 ]. These fundamental criteria provide a wonderful approach for the construction of supramolecular photocatalytic systems by self-assembly strategies [ 10 – 11 ].…”