Energy and Electron Transfer Dynamics within a Series of Perylene Diimide/Cyclophane Systems

Artificial
photosynthetic systems for solar energy conversion exploit
both covalent and supramolecular chemistry to produce favorable arrangements
of light-harvesting and redox-active chromophores in space. An understanding
of the interplay between key processes for photosynthesis, namely
light-harvesting, energy transfer, and photoinduced charge separation
and the design of novel, self-assembling components capable of these
processes are imperative for the realization of multifunctional integrated
systems. We report our investigations on the potential of extended
tetracationic cyclophane/perylene diimide systems as components for
artificial photosynthetic applications. We show how the selection
of appropriate heterocycles, as extending units, allows for tuning
of the electron accumulation and photophysical properties of the extended
tetracationic cyclophanes. Spectroscopic techniques confirm energy
transfer between the extended tetracationic cyclophanes and perylene
diimide is ultrafast and quantitative, while the heterocycle specifically
influences the energy transfer related parameters and the acceptor
excited state.