Exploration of the electronic structure of dendrimerlike acetylene-bridged oligothiophenes by correlating Raman spectroscopy, electrochemistry, and theory

Physical and theoretical methods were used to investigate a series of radial thiphene-based structures consisting of a central benzene or thiophene ring surrounded by acetylene-bridged terthienyl arms. It was found using Fourier transform Raman spectroscopy of the neutral solids that the terthiophene arms are weakly coupled across the core. It was suggested that the phenomenon occurred due to the cross-conjugation or meta-conjugation that prevented full delocalization. Further insight into the charge delocalization of the oxidized species was provided by Raman spectroelectrochemistry and quantum chemical calculations.