Molecular modelling of fullerene–porphyrin dyads

Abstract

Computational studies have been performed on a variety of C60–porphyrin dyads, a class of donor–acceptor materials which have been a subject of considerable attention in recent years. Molecular modelling studies were carried out to clarify the relationship between molecular topology and experimentally determined rates of intramolecular electron and energy transfer in these systems. The systems studied include doubly linked cyclophane-like C60–porphyrin dyads, where structural variations were made computationally on the porphyrin and linker portions, as well as dyads with flexible polyether and rigid steroid linkers. The molecular modelling studies involved building and minimising structures of the various fullerene–porphyrin dyads, followed by molecular dynamics to find the equilibrium and lowest energy conformations. The study confirmed that attractive van der Waals interactions between porphyrin and C60 moieties cause these dyads to adopt unusual conformations in which these groups are in close proximity, often in orientations which are not readily predictable from conventional structural representations. The implications of these computational data for the design of fullerene–porphyrin dyads with specific properties in the context of electron and energy transfer processes are discussed.