Combining one-, two- and three-dimensional polyphenylene nanostructures

Abstract

The achievement of a true nanotechnology is regarded as one of the Holy Grails of modern science. To achieve this will require the construction by synthesis or self-assembly of complex functional nanoarchitectures. Such structures might contain combinations of one-, two-, and three-dimensional phenylene nanostructures. In this paper we provide an overview of recent progress in the synthesis and characterisation of new materials containing various combinations of one-, two-, and three-dimensional phenylene structural units. Though synthetically driven the ultimate aim of this work is to design and prepare new functional materials for use in electronic or other devices. Control of their optical and electronic properties by synthetic design and the evaluation of their potential for electronic applications are thus key features of our work. A vital aspect of this is the control of the supramolecular order of the materials in the solid state, by regulation of their intermolecular interactions. The attachment of bulky three-dimensional phenylene dendrimers to one-dimensional conjugated polyphenylenes or two-dimensional discotic graphite molecules enables the control of their intermolecular interactions and thus of their optical and electronic properties, with potential importance for their application in electronic devices. Linking two-dimensional graphite units together into linear and non-linear chains provides a new way to control the self-assembly of discotic materials and thus opens a way towards more new complex superstructures. Another way is demonstrated to combine elements of one- and two-dimensional polyphenylenes by the synthesis of graphite ribbons. Finally partial cyclodehydrogenation of polyphenylene dendrimers has been used to produce three-dimensional arrays of two-dimensional graphenes. Such materials have potential applications in lithium and hydrogen storage. Taken together these results present a useful step in the development of the complex architectures necessary for a true nanotechnology.