Synthesis and Characterization of C₆₀ Dyads with Highly Photoactive Dicyanoethylenylated Diphenylaminofluorene Chromophore Antenna

Abstract

We designed and synthesized a novel class of highly photoactive C₆₀(> CPAF-C_n) nanostructures for their potential uses as photonic materials, using CPAF-C_n chromophore as the light-harvesting antenna. It is a part of our research effort on developing C₆₀(> DPAF-C_n)-based nonlinear photonic organics. We extended the structural modification by chemical conversion of the keto group in C₆₀(> DPAF-C_n) compound to a 1,1-dicyanoethylenyl moiety with stronger electron-withdrawing ability that resulted in a largely increased electronic polarization of the chromophore conjugate. Structural characterization of several C₆₀(> CPAF-C_n) containing variable alkyl sidechains was made by various spectroscopic methods. Interestingly, the chemical modification leads to a large bathochromic shift of the major absorption band of C₆₀(> CPAF-C_n) in the visible spectrum up to 600 nm and extending the photoresponsive capability of C₆₀–DCE–DPAF nanostructures to longer red wavelengths than the parent C₆₀(> DPAF-C_n) materials.

Keywords:

• C₆₀ dyads
• diphenylaminofluorene
• photoactive antenna
• photonic fullerenyl nanomaterials

Acknowledgments

We thank Air Force Office of Scientific Research for funding under the contract number FA9550-05-1-0154.