Encapsulation-Led Adsorption of Neutral Dyes and Complete Photodegradation of Cationic Dyes and Antipsychotic Drugs by Lanthanide-Based Macrocycles

Molecular architectures offering large cavities can accommodate guest molecules,while their compositional engineering allows tunability of the band gap to support photocatalysisusing visible light. In this work, two lanthanide (Ln)-based macrocycles, synthesized using a cobalt-based metalloligand and offering large rectangular cavities, exhibited selective adsorption of neutraldyes over both anionic and cationic dyes. Both Ln macrocycles illustrated completephotodegradation of cationic dyes using visible light without the use of any oxidant. Both Lnmacrocycles exhibited complete photodegradation of not only cationic dyes but also a fewphenothiazine-based antipsychotic drugs. Photocatalysis involved the generation of reactive oxygenspecies (ROS), which was corroborated with the band gap of two Ln macrocycles. These resultswere supported by radical scavenger studies and the quantitative estimation of superoxide andhydroxyl radicals. Complete photodegradation of both dyes and drugs was confirmed by spectralstudies, while the generation of CO2and N2gases was established by gas chromatography.Importantly, Ln macrocycles were able to distinguish between the neutral dyes that werequantitatively adsorbed and the cationic dyes/drugs that were completely photodegraded.

Automated summary

This study demonstrates the complete photodegradation of neutral dyes and certain antipsychotic drugs using two lanthanide-based macrocycles synthesized with a cobalt-based metalloligand. The photocatalysis process involves the generation of reactive oxygen species and is supported by the band gap of the macrocycles.