Corrole Chemistry and Applications

Corroles are contracted tetrapyrrolic macrocycles distinguished by a 19 π-electron conjugated core and three meso carbon bridges. Their unique electronic structure confers high redox flexibility, strong absorption in the visible region and the ability to stabilise a wide array of metal ions. Complexation with transition or main-group metals yields metallocorroles that exhibit rich photophysical and catalytic behaviours. In catalysis, corrole complexes have been developed as electrocatalysts for oxygen reduction, hydrogen evolution and small-molecule activation, benefitting from tuneable redox potentials and ligand noninnocence. In materials science, surface-adsorbed corroles display switchable spin states and Kondo physics, opening routes to molecular spintronics. In the biomedical arena, water-soluble and lipophilic metallocorroles serve as photosensitisers for photodynamic therapy and as platforms for targeted drug delivery, leveraging efficient singlet oxygen generation and favourable bioavailability. Advances in synthetic methodologies and substituent design have expanded the scope of accessible corrole derivatives, allowing precise control over metal–ligand interactions, axial coordination and supramolecular assembly. This versatility has established corroles as a bridge between fundamental coordination chemistry and real-world applications in energy conversion, information technologies and healthcare.

Research from Nature Portfolio

Recent studies have demonstrated that adsorption of fused-ring copper corroles on gold surfaces can be used to modulate molecular spin states through alteration of metal–ligand π-interactions, yielding sharp Kondo resonances and controllable spin distributions suitable for molecular spintronic devices. Elsewhere, the development of cell-penetrating protein–corrole nanoparticles has enabled efficient encapsulation of lipophilic metallocorroles, achieving enhanced uptake in cancer cells, prolonged intracellular retention and selective localisation within organelles, thereby improving theranostic potential. In parallel, exploration of iridium(III) triarylcorrole derivatives with varied axial ligands has shown that, despite low near-infrared phosphorescence yields, these complexes can sensitise singlet oxygen formation effectively, suggesting their promise as photosensitisers in photodynamic therapy when equipped with targeting groups.

Corrole Chemistry and Applications publication trend

The graph below shows the total number of articles in corrole chemistry and applications across all publications each year (not limited to Nature Index journals).

Technical terms

Corrole: A tetrapyrrolic macrocycle with a 19 π-electron conjugated ring system, analogous to porphyrins but contracted.

Metallocorrole: A coordination complex in which a corrole ligand binds a metal centre, often producing distinct redox and photophysical properties.

Macrocycle: A large cyclic molecule characterised by multiple repeating units, often providing a rigid framework for metal coordination.

Noninnocent ligand: A ligand that can undergo redox changes or delocalise electron density, participating actively in the electronic structure of the complex.

Oxygen reduction reaction: An electrochemical process in which molecular oxygen is reduced to water or peroxide, critical to fuel cells and metal–air batteries.

Photodynamic therapy: A minimally invasive treatment that employs a photosensitiser activated by light to generate cytotoxic reactive oxygen species for selective cell eradication.

References

1. Modulation of the molecular spintronic properties of adsorbed copper corroles. Nature Communications (2015).
2. Cell-Penetrating Protein/Corrole Nanoparticles. Scientific Reports (2019).
3. Iridium Corroles Exhibit Weak Near-Infrared Phosphorescence but Efficiently Sensitize Singlet Oxygen Formation. Scientific Reports (2020).
4. Tuning ORR selectivity of π-conjugated cobalt corroles from 2e- to 4e-. Materials Today Catalysis (2024).
5. Amphiphilic Rhenium-Oxo Corroles as a New Class of Sensitizers for Photodynamic Therapy. ACS Omega (2020).