Synthesis and Characterization of Positively Charged Pentacationic [60]Fullerene Monoadducts for Antimicrobial Photodynamic Inactivation

Abstract

We designed and synthesized two analogous pentacationic [60]fullerenyl monoadducts, C[subscript 60](>ME[subscript 1]N[subscript 6]+C[subscript 3]) (1) and C[subscript 60](>ME[subscript 3]N[subscript 6]+C[subscript 3]) (2), with variation of the methoxyethyleneglycol length. Each of these derivatives bears a well-defined number of cationic charges aimed to enhance and control their ability to target pathogenic Gram-positive and Gram-negative bacterial cells for allowing photodynamic inactivation. The synthesis was achieved by the use of a common synthon of pentacationic N,N′,N,N,N,N-hexapropyl-hexa(aminoethyl)amine arm (C[subscript 3]N[subscript 6]+) having six attached propyl groups, instead of methyl or ethyl groups, to provide a well-balanced hydrophobicity–hydrophilicity character to pentacationic precursor intermediates and better compatibility with the highly hydrophobic C[subscript 60] cage moiety. We demonstrated two plausible synthetic routes for the preparation of 1 and 2 with the product characterization via various spectroscopic methods.