Construction of supramolecular linear polymers based on pyridinium modified anthraquinone and cucurbit[8]uril for visible-light-induced valorization of lignin models†

Abstract

How to achieve selective cleavage of C–C bonds in lignin or lignin model compounds to obtain high yields and high selectivity of valuable aromatic products remains a challenge. In this study, we have designed and synthesized a supramolecular polymer (Bamvp–CB[8]) based on anthraquinone through host–guest interactions between the methylated vinylpyridine salt substituted anthraquinone derivative (Bamvp) and cucurbit[8]uril (CB[8]) in aqueous solution, which not only self-assembled into cross-linked spherical nanoparticles with fluorescence enhancement but also greatly improved the generation capacity of singlet oxygen (¹O₂) and superoxide anion radicals (O₂˙⁻) in water. Compared with anthraquinone molecules, the supramolecular polymer Bamvp–CB[8] exhibits excellent photocatalytic activity, and can be used as an efficient photocatalyst for selective cleavage of C–C bonds in lignin models to obtain benzoic acids and phenols with high efficiency, low catalyst loading and good functional group tolerance, highlighting its great potential for photocatalysis application through a supramolecular polymer strategy.