Fulleropyrrolidines with orthogonally flexible substituents - Synthesis and electrochemical properties

A large series of disubstituted fulleropyrrolidines was synthesized and analyzed by cyclic voltammetry. The three main groups of target compounds differ by a flexible N-chain, while their further diversity was achieved by the introduction of various rigid, aryl substituents at the pyrrolidine carbon. Some dialkyl analogues were also designed for comparison, A standard [3+2]-cycloaddition of in situ generated azomethine ylides to C-60 afforded a variety of disubstituted fulleropyrrolidines. Furthermore, a set of dumbbell-shaped di(fulleropyrrolidine) derivatives containing rigid fumaryl or isophthaloyl diamide platform was prepared with the aim of investigating a long-range effect of the second fulleropyrrolidine moiety on their electrochemical properties. All compounds were fully characterized by comparative analysis of spectral data, while examination of electrochemical properties was performed on representative samples, distinguished by main structural subunits. All compounds expressed quite similar electron-accepting ability, lower than C-60, but higher in comparison to structurally similar N-methylfulleropyrrolidine.