Pushing around electrons: towards 2-D and 3-D molecular switches.

In the new age of molecular electronics there has been a great deal of speculation about ways to control the passage of electrons through organic-based wires using electro- or photo-active switches. However, the next stage development is envisaged as the added sophistication of directionality so that electron migration can be switched into 2 and 3 dimensions. This short tutorial review will set out how this realisation may be achieved and highlight examples where the idea of directionality in electron transfer has been put into practice.