Joint spectroscopic and theoretical investigation of cationic cyanine dye Astrazon Orange-R: solvent viscosity controlled relaxation of excited states

Abstract

In this paper, the first study of cationic cyanine dye Astrazon Orange-R by combined spectroscopic and theoretical investigation is presented. It is shown that molecular modeling of Astrazon Orange-R is in very good agreement with experiment, allowing us to gain insight into its complicated photophysics. A solvent viscosity controlled relaxation of excited states, involving cyanine isomerization, is also outlined.

Spectroscopic Studies of the Interactions between a Cationic Cyanine Dye and a Synthetic Phyllosilicate: From Photophysics to Hybrid Materials

“…However, in a 2 g·L –1 clay solution, the decay emission signal was dominated by a 3 ns fluorescence lifetime. This lifetime value of 3 ns is the attended value in the case of a very viscous solvent as described in ref and very close to the natural radiative lifetimes of AO-R measured in ref . As a conclusion, it seems that the electrostatic interaction between the cationic dye and the clay surface are strong enough to prevent the deactivation of the excited emissive state by the ultrafast isomerization of the dye in its excited state.…”

“…The four first orthogonal kinetics (KOP 1–4) of the experiments, in pure water and in the presence of the synthetic phyllosilicate, are displayed in Figure . In pure water, the best fits of the KOP required a sum of two exponential decay functions and a step function with time constants of 2.54 ± 0.15 and 11.54 ± 0.20 ps, as described in ref , whereas the sum of the three exponential decay functions and a step function was necessary to reproduce the kinetics in the presence of the Laponite nanoparticles with lifetimes of 0.482 ± 0.02, 17.41 ± 0.75, and 417 ± 33 ps.…”

“…Femtosecond pump–probe measurements were performed on a CDP Corp ExciPro system, the femtosecond laser excitation wavelength was adjusted to 590 nm with an optical parametric amplifier as described elsewhere. A pump–probe cross-correlation under 200 fs was obtained . AO-R was purchased from TCI; its structure was checked by NMR, and it was used as received (see Scheme ).…”

“…In the present work, we studied the modification of the photophysics of a cationic cyanine dye, Astrazon orange R (AO-R), by Laponite nanoplatelets. Indeed, AO-R exhibits complex photophysics involving isomerization in the excited state . This ultrafast isomerization process, which is responsible for the quenching of the AO-R singlet excited state, is controlled by solvent viscosity.…”

On the interaction of triarylmethane dye crystal violet with LAPONITE® clay: using mineral nanoparticles to control the dye photophysics

“…Femtosecond pump-probe measurements were performed on a CDP corp Excipro system, the femtosecond laser excitation wavelength was adjusted to 590 nm with a pump-probe crosscorrelation about 200 fs as described elsewhere. 49 Crystal violet was purchased from Sigma-Aldrich, its structure was checked by NMR, and used as received. LAPONITE s RD was obtained from BYK Additives & Instruments former Rockwood additives.…”