Synthesis and characterization of novel para- and meta-phenylenevinylene derivatives: Fine tuning of the electronic and optical properties of conjugated materials

We report the synthesis of novel phenylenevinylene derivatives that allow for the introduction of meta versus para connections on the phenylene rings, as well as the incorporation of nitrogen atoms within the conjugated backbone and the attachment of electroactive substituents. We assess the impact of the various derivatization schemes on the electronic and optical properties by means of gas-phase ultraviolet photoelectron spectroscopy (UPS) and optical absorption and emission measurements; the evolution of the experimental data is further supported by the results of quantum-chemical calculations. We demonstrate that the electronic and optical properties of phenylenevinylene chains, and by extension those of many conjugated materials, can be tuned over a large energy range by a tailored design of the molecular structures.