Electrical and optical effects in molecular nanoscopic-sized building blocks

A biomimetic strategy is used to bridge the gap from the molecular scale to the microscale. Dendritic, conformationally rigid ruthenium(II)polypyridyl complexes have been synthesized to form a set of nanometer-sized building blocks (NBBs) (1.6-5.0 nm) with discrete 'tertiary' structures. We postulate that thin films constructed from NBBs with differing tertiary structures will form ordered arrays with differing 'quaternary' structures and, presumably, differing electronic properties. Experimental studies show that thin films of these molecules are conductive, display electric field-modulated conductivity, and enhanced conductivity upon visible irradiation. Significantly, changes in the molecule's overall shape (tertiary structure) have a measurable effect on the electrical properties of the films prepared from them. Importantly, these NBBs are chemically robust and structurally tunable. We intend to exploit these properties as well as their newly discovered electronic, optical, and, potentially even, chiro-optical properties so as to provide a new, added dimension in molecular electronics and chiral optical devices.