Pyridine-capped, oligomeric (o-phenyleneethynylene)s.

The synthesis, optical properties, and solid-state structures of a series of o-(aryleneethynylene) oligomers containing three to seven aryl units is described. The main chain in all examples is composed of between one and five 4,5-dimethoxybenzene rings which are capped on each end by 2-pyridyl rings. These oligomers demonstrate pH-dependent emission and absorption spectra. Single crystals were obtained from the aryleneethynylenes containing three to five arene rings. These single crystals were investigated by X-ray diffraction.