Construction of a novel tetraphenylethylene-based supramolecular dimer for improving the generation of reactive oxygen species and photocatalytic performance

Using supramolecular strategies to improve the generation of reactive oxygen species is a practical and environmentally friendly method, but it is also a difficult undertaking. In this study, we created and produced a vinylpyridine-modified tetraphenylethylene derivative TPE-Py-I, which has excellent solubility in water and has the ability to construct supramolecular dimers (2TPE-Py-I@CB[8]) in an aqueous solution through host-guest interaction with cucurbit[8]uril (CB[8]). The supramolecular dimer demonstrated a remarkable aggregation-induced emission response, with the fluorescence progressively intensifying upon the introduction of CB[8]. Meanwhile, the formation of supramolecular dimer also greatly improved the intersystem crossing effect of the molecular assembly system, so that the generation ability of reactive oxygen species including singlet oxygen (1O2) and superoxide anion radical (O2•-) were enhanced, which provided a basis for its application as an excellent supramolecular photosensitizer in photocatalytic organic reactions. To our delight, 2TPE-Py-I@CB[8] exhibits excellent photocatalytic properties, making it suitable for both phosphine photooxidation and cross-dehydrogenative coupling reactions. This work provides a non-covalent strategy for the development of supramolecular dimer photosensitizers and broadens its application in the field of photocatalytic organic conversion.