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

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 Pd 6 barrel ( 1 ), which is composed of three 1,4‐dihydropyrrolo[3,2‐b]pyrrole panels, clipped through six cis ‐Pd II acceptors. Large open windows and cavity make it an efficient host for a large guest. Favorable interactions between the ligand and fullerene (C 60 and C 70 ) allows the barrel to encapsulate fullerene efficiently. Thorough investigation reveals that barrel 1 has a stronger binding affinity towards C 70 over C 60 , resulting in the predominant extraction of C 70 from a mixture of the two. Finally, the fullerene encapsulated barrels C 60 ⊂ 1 and C 70 ⊂ 1 were found to be efficient for visible‐light‐induced singlet oxygen generation. Such preferential binding of C 70 and photosensitizing ability of C 60 ⊂ 1 and C 70 ⊂ 1 are noteworthy.