oa The Development of Molecular Wires

The concluding part of this paper on the use of ruthenium(II) and osmium(II) polypyridyl complexes, as molecular sized terminal subunits that are linked together by polyyne bridges functioning as molecular girders to retain the stereochemical rigidity, deals with the process of electron transfer between the subunits and considers the benefits conferred by the use of polyyne bridges. The ruthenium and osmium complexes have properties which aid the selective promotion of an electron from the metal to the bridging ligand, together with amenable absorption and emission spectral profiles, and facile oxidation-reduction processes. This makes them promising candidates for vectorial electron transfer. Future work to extend the lengths of the linkages, to ensure unidirectional and longrange electron tunnelling, and to anchor the wires to supports is discussed. These are the necessary requirements for the development of molecular wiring made from these materials for future use with molecular-scale electronic devices.