Higher-dimensional and Functional Molecular Wires: Toward Molecular Circuits

Our recent work on organometallic molecular devices, which should lead to development of molecular circuit, is reviewed. The initial work on organometallic molecular wires consisting of two redox-active organometallic termini connected by π-conjugated linkers has been followed by the work on higher dimensional and functional systems. The higher dimensional systems serve as junctions of molecular circuits and involve polynuclear complexes, where the redox-active centers are connected by the ethylene, benzene and hexaarylbenzene (HAB) derivatives. It is notable that the HAB system exhibits toroidal delocalization through π-π interaction among the peripheral aromatic rings. For the functional systems we have developed molecular variable resistor based on attachment/detachment of the dicobalt fragments to the alkyne-based molecular wire and molecular switch containing the photochromic dithienylethene bridges. The preparative methods of the organometallic molecular devices and the evaluation methods of their wire-like performance are also briefly described.