Synthesis and characterization of new derivatives of azulene,including experimental and theoretical studies of electronic and spectroscopic behavior

Four new azulene derivatives featuring two π‐conjugated and sulfur terminated rigid side arms in the 1,3‐positions of the azulene core were designed, synthesized, and characterized. The syntheses were carried out on the basis of a palladium cross‐coupling procedure in the key reaction step. The crystal structures of the target compound 3 and of the intermediate compounds 7 and 9 have been studied. Supporting density functional theory calculations reveal insights into the electronic properties of the particular azulenes. The comparison of measured UV–Vis, infrared, and Raman data to calculated values allowed assignment of major spectral features to the particular structural differences of the new compounds and comparison to plain azulene. Cyclic voltammetry measurements were performed showing the redox characteristics of the new azulene derivatives. Copyright © 2012 John Wiley & Sons, Ltd.