π‐Conjugated 2,2′:6′,2″‐Bis(terpyridines): Systematical Tuning of the Optical Properties by Variation of the Linkage between the Terpyridines and the π‐Conjugated System

Abstract 2,2′:6′,2″‐Terpyridines bearing well‐defined π‐conjugated substituents at the 4′‐position are known to exhibit interesting electronic and optical properties. The systematic variation of both the spacer unit and the linker in conjugated bis(terpyridines) has resulted in a library of π‐conjugated systems, enabling the study of the structure–property relationships of these materials. We have proven the Huisgen 1,3‐dipolar cycloaddition reaction to be a versatile tool for connecting conjugated systems, even though the conjugation is hindered by the introduced triazole moiety. All the terpyridine derivatives were fully characterized by 1 H and 13 C NMR spectroscopy, UV/Vis absorption and emission measurements as well as MALDI‐TOF MS. Thin films of the materials were produced by spin‐coating and subsequently characterized. Because tuning of the band gap of the materials over a wide range is possible, quantum yields of up to 85 % and extinction coefficients of around 100000 M –1 cm –1 could be observed, the compounds might be promising candidates for the design of new functional supramolecular materials.