Synthesis and host-guest chemistry of a thiophene-extended pillar[6]arene: toward applications in nitroaromatics removal and cell imaging.

Over the past decade, significant progress has been made in the study of pillar [n]arenes; however, the development of their analogs remains underexplored, offering new opportunities for the discovery of functional materials. In this work, a luminescent thiophene-extended pillar [6]arene (TPExP6) featuring a π-rich cavity was designed and synthesized from 2,5-dibromothiophene and (4-formylphenyl)boronic acid via a five-step procedure with an overall yield of approximately 9.8%. This molecule combines an extended π-conjugated cavity with strong intrinsic emission, enabling it not only to form stable host-guest complexes with nitrobenzene derivatives for the effective removal of persistent nitroaromatic pollutants from water but also to be applied in tumor cell imaging. This achievement substantially advances the application of macrocyclic compounds in environmental protection and biomedical materials.