Synthesis of low band gap polymers - a challenge for organic chemists

Abstract

Stable intrinsic semiconductors, which exhibit conductivities of 0.1 S/cm without any doping process can be easily prepared by using our “shish-kebab” approach. Hereby stacked transition metal macrocycles [MacM(L)] n with M e.g. Fe, Ru, Os and Mac = phthalocyanine (Pc) or 2,3-naphthalocyanine (2,3-Nc) are used. The bridging ligands (L) are special heteroaromatic systems, e.g. s-tetrazine (tz), substituted tetrazines, triazine (tri), substituted trizines, but also special organic dinitriles, e.g. tetrafluoroterephthalic acid dinitrile, fumarodinitrile, dicyanoacetylene, and dicyane. We report about the preparation and the characterization of the corresponding transition metal complexes [MacM(L)] n. The intrinsic conductivities of all these compounds are a result of the low oxidation potential of the bridging ligands and due to the low lying LUMO in the corresponding bridged systems [MacM(L)] n. The electrical and physical properties, especially the UV- and Möβbauer spectra (for the corresponding iron compounds) for the bridged macrocyclic metal complexes are discussed in respect to the intrinsic semiconducting properties of these compounds.