Clicked BODIPY‐Fullerene‐Peptide Assemblies: Studies of Electron Transfer Processes in Self‐Assembled Monolayers on Gold Surfaces

Abstract

AbstractTwo BODIPY‐C60‐peptide assemblies were synthesized by CuAAC reactions of BODIPY‐C60 dyads and a helical peptide functionalized with a terminal alkyne group and an azide group, respectively. The helical peptide within these assemblies was functionalized at its other end by a disulfide group, allowing formation of self‐assembled monolayers (SAMs) on gold surfaces. Characterizations of these SAMs, as well as those of reference molecules (BODIPY‐C60‐alkyl, C60‐peptide and BODIPY‐peptide), were carried out by PM‐IRRAS and cyclic voltammetry. BODIPY‐C60‐peptide SAMs are more densely packed than BODIPY‐C60‐alkyl and BODIPY‐peptide based SAMs. These findings were attributed to the rigid peptide helical conformation along with peptide‐peptide and C60‐C60 interactions within the monolayers. However, less dense monolayers were obtained with the target assemblies compared to the C60‐peptide, as the BODIPY entity likely disrupts organization within the monolayers. Finally, electron transfer kinetics measurements by ultra‐fast electrochemistry experiments demonstrated that the helical peptide is a better electron mediator in comparison to alkyl chains. This property was exploited along with those of the BODIPY‐C60 dyads in a photo‐current generation experiment by converting the resulting excited and/or charge separated states from photo‐illumination of the dyad into electrical energy.