Towards molecular scale devices based on controlled intramolecular interactions

In this paper we propose to use intramolecular electronic energy transfer as a way of connecting between logical operations that are implemented on different molecules. We have already shown that the rate of through-bond-mediated intramolecular singlet–singlet electronic energy transfer (EET) in certain rigid bichromophoric molecules is five orders of magnitude higher than that observed in flexibly linked systems containing the same donor–acceptor chromophores, for which through space EET via exchange interaction is dominant. This is the first direct evidence that the rigidity of the interchromophore bridge is significant for promoting through-bond bridge-mediated intramolecular EET. One problem associated with the above schemes is that it will be very difficult to cascade these elements as is needed for computing. This may be done by utilizing proton transfer rather than electron or energy transfer as the basic switching process.