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