A Self‐Assembled Palladium(II) Barrel for Binding of Fullerenes and Photosensitization Ability of the Fullerene‐Encapsulated Barrel

Abstract

Fullerene extracts obtained from fullerene soot lack their real application due to their poor solubility in common solvents and difficulty in purification. Encapsulation of these extracts in a suitable host is an important approach to address these issues. We present a new Pd6 barrel (1), which is composed of three 1,4-dihydropyrrolo[3,2-b]pyrrole panels, clipped through six cis-PdII acceptors. Large open windows and cavity make it an efficient host for a large guest. Favorable interactions between the ligand and fullerene (C60 and C70) allows the barrel to encapsulate fullerene efficiently. Thorough investigation reveals that barrel 1 has a stronger binding affinity towards C70 over C60, resulting in the predominant extraction of C70 from a mixture of the two. Finally, the fullerene encapsulated barrels C60⊂1 and C70⊂1 were found to be efficient for visible-light-induced singlet oxygen generation. Such preferential binding of C70 and photosensitizing ability of C60⊂1 and C70⊂1 are noteworthy.