1- , 2-, and 3-dimensional polyphenylenes--from molecular wires to functionalised nanoparticles

Polyphenylenes, ranging from one-dimensional wire-like conjugated polymers to two-dimensional disc-shaped polyaromatic hydrocarbons and three-dimensional sphere-like dendrimers, have been prepared using methods that allow synthetic control of their molecular and supramolecular order in order to optimise their physical, especially optical and electrical, properties. 1D-conjugated polymers can be used as emitting materials in LEDs, with their colours tuned so as to give emission across the whole visible spectrum. Their supramolecular order can be manipulated by attachment of bulky sidechains to suppress aggregation, and by formation of rod-coil block copolymers. 2D polycyclic aromatic hydrocarbons form stable columnar mesophases with high charge carrier mobilities. Their size, shape, and substitution patterns can be altered so as to maximise their intra- and intercolumnar order. 3D polyphenylene dendrimers can be prepared in ways that enable control of their shape, and their surfaces can be selectively functionalised in ways that permit them to act as functionalised nanoparticles.