Modulating structure and properties in organic chromophores: influence of azulene as a building block
The properties of isomeric azulene derivatives, substituted through the 5-membered ring, were examined using a combination of experimentation and theoretical calculations for a series of well-defined electroactive oligomers. The substitution pattern was shown to dramatically influence solid-state, electronic, and optical properties of the oligomers with acid-responsive materials only being observed when the azulenium cation could be directly stabilized by substituents on the 5-membered ring. In addition, the absorption maxima and optical band-gaps of the azulenium cations can be tuned by the substitution position of the azulene ring by the chromophore.
Additional Information© The Royal Society of Chemistry 2014. Received 2nd June 2014, Accepted 1st July 2014. First published on 16th July 2014. This work was partially supported by DOE Basic Energy Science under award DE-SC0005414 (M.M., M.L.C., M.J.R. and C.J.H.), the NSF PREM program between UCSB and UTEP (DMR-1205302) (N.D.T., M.L.C., and C.J.H.) and the MRSEC Program of the NSF under award no. DMR-1121053 (M.M., S.K., M.J.R., and C.J.H.). M.M. thanks the JSPS Research Fellowships for Young Scientists and also thanks Dr Kei Murata (Tokyo Institute of Technology) and Dr Akiko Inagaki (Tokyo Metropolitan University) for the helpful discussions on DFT calculation.
Supplemental Material - c4sc01623h1.pdf