RESUMO
Invited for this month's cover are the three collaborating groups from the University of Stuttgart and the Fraunhofer Institute for Applied Polymer Research in Potsdam, both from Germany as well as the University of Windsor, Canada. The cover picture shows the shift of frontier orbital energies and symmetries upon excitation with light for three different chromophore lengths. Read the full text of the article at 10.1002/cplu.201300308.
RESUMO
Three series of rigidified tri-, penta- and heptamethine merocyanine dyes were synthesised. A piperidyl moiety was chosen as the electron-donating substituent while the electron-accepting group was varied from ketones to malononitriles and cyanoacetates. The structures of the compounds in the solid state and in solution were elucidated by X-ray diffraction and NMR spectroscopy, respectively, while optical properties were investigated by absorption and emission spectroscopy. As a general trend, the acceptor properties decrease in the series malononitrile>cyanoacetate>ketone based on the analysis of their solvatochromic behaviour. The experimental results were further supported by calculations at the B3LYP 6-311+G(d) level of theory.
