Various triflate (TfO–), tetrafluoroborate (BF4–), and perchlorate (ClO4–) salts of (E)-9-(3-(4-(diphenylamino)phenyl)allylidene)-9H-carbazol-9-ium chromophores, asymmetrical streptocyanine blue dyes, were synthesized, and their structures and photochemical and electrochemical properties were characterized. Displaying a… Click to show full abstract
Various triflate (TfO–), tetrafluoroborate (BF4–), and perchlorate (ClO4–) salts of (E)-9-(3-(4-(diphenylamino)phenyl)allylidene)-9H-carbazol-9-ium chromophores, asymmetrical streptocyanine blue dyes, were synthesized, and their structures and photochemical and electrochemical properties were characterized. Displaying a high absorption band in the wavelength range 620–640 nm in acidified benzonitrile, the dyes provide an intense absorption at longer wavelength thanks to their oxidized π-conjugated systems. The π-electronic structure underwent twisting and bending, counteracting the electron-donating/withdrawing induction of its different substituents with a propensity to cancel its dipole moment and HOMO–LUMO charge-transfer coefficient. Zeta potential measurements of colloidal suspensions of sensitized TiO2 anatase nanoparticles outlined the difference in electric behavior of the organic ionic pairs at the surface of the nanoparticles: The noncoordinating or coordinating characters of the counterions wer...
               
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