In this Review, we highlight cucurbituril-based host–guest assemblies demonstrating fluorescence (singlet–singlet, FRET) and phosphorescence (triplet–singlet, TS-FRET) resonance energy transfer. We overview the achievements and challenges as well as discuss current and future applications of the cucurbituril-based energy transfer systems.

Abstract

Supramolecular systems demonstrating resonance energy transfer have recently became a topical area on the borderline of supramolecular chemistry, photochemistry, photophysics and biology. The modularity of supramolecular interactions is a prerequisite for fine tuning of optical properties, which is difficult to achieve by other means. As a component of such systems, cucurbit[n]uril (CB[n]) macrocycles can play a wide spectrum of roles from anchoring of FRET pairs and modulation of the optical output to providing biocompatibility of FRET stains for cell imaging. The aim of this Review is to outline the development of the CB[n]-based systems with fluorescence (FRET) and phosphorescence (TS-FRET) energy transfer and to highlight achievements, challenges and perspectives of this fascinating combination of a classical photophysical process and a classical supramolecular host. Particular attention in this Review is given to the current and potential applications of the reviewed systems.