Supramolecular Subphthalocyanine Cage as Catalytic Container for the Functionalization of Fullerenes in Water

Abstract

Herein we report the first example of a supramolecular cage that works as a catalytic molecular reactor to perform transformations over fullerenes in aqueous medium. Taking advantage of the ability of metallo-organic Pd(II)-subphthalocyanine (SubPc) capsules to form stable host:guest complexes with C₆₀ , we have prepared a water-soluble cage that provides a hydrophobic environment for conducting cycloadditions over encapsulated C₆₀ , namely, Diels-Alder reactions with anthracene. Indeed, the presence of catalytic amounts of SubPc cage dissolved in water promotes co-encapsulation of insoluble C₆₀ and anthracene substrates, allowing the reaction to occur inside the cavity under mild conditions. The lower stability of the host:guest complex with the resulting C₆₀ cycloadduct facilitates its displacement by pristine C₆₀ , which grants catalytic turnover. Moreover, bis-addition compounds are regioselectively formed inside the cage when using excess anthracene.

Keywords: Catalysis; Fullerene; Metallosupramolecular; Subphthalocyanine; Water.