Fast photoprocesses in a symmetric indotricarbocyanine dye (HITC) in solutions

Abstract

UDC 535.34Spectral-kinetic and photochemical properties of HITC dye with iodide and perchlorate counterions have been studied in environments where the dye molecules exist in different ionic forms. In ethanol, the dye molecules exist as free ions; in dichlorobenzene, as contact ion pairs. Superfast transformation of non-stationary spectra in an HITC dye bleaching band is found. The observed effects are interpreted within the framework of concepts on "burning out" a notch in the contour of a non-uniformly widened vibronic band of S 0 → S 1 -absorption. Qualitative differences in recorded absorption spectra from the dye excited electronic states for weakly and highly polar solvents are found. It is shown that the observed differences are caused by superfast charge transfer in the contact ion pairs that results in the formation of free radicals.

Reactive species involved in the regioselective photooxidation of heptamethine cyanines

“…We have chosen 1 , which represents the simplest heptamethine indocyanine, as a model system for our efforts. 24 To accurately measure yields of reactions run at low micromolar concentrations, we employed triplicate HPLC analysis calibrated using standard curves generated from independently prepared standards of previously known 2 and 6 (see ESI † ). Exposing a solution of 1 (50% MeCN/H 2 O, 20 μM) to modest fluence (20 mW cm –2 ) of 740 nm light for 2 hours produces 2 and 6 in 57% and 12% yields, respectively ( Fig.…”

Sensitive Naked Eye Detection of Hydrogen Sulfide and Nitric Oxide by Aza-BODIPY Dyes in Aqueous Medium

“…The fluorescence properties of the derivatives 3a – 3c were investigated in different solvents and exhibited a similar shift as that of absorption spectra due to the changes in the substitution as shown in Figure B. The azido aza-BODIPY 3a showed an emission maximum at 750 nm with a quantum yield of ∼0.07 (indotricarbocyanine dye was used as the reference, Φ F = 0.28) . Similarly, the amino derivative 3b showed the fluorescence maximum at 815 nm with a quantum yield of 0.02 (IR-125 was used as the reference, Φ F = 0.13). ,− In contrast, the dimethylamino derivative 3c exhibited a large Stokes shift with an emission maximum at 945 nm.…”

“…The azido aza-BODIPY 3a showed an emission maximum at 750 nm with a quantum yield of ∼0.07 (indotricarbocyanine dye was used as the reference, Φ F = 0.28). 57 Similarly, the amino derivative 3b showed the fluorescence maximum at 815 nm with a quantum yield of 0.02 (IR-125 was used as the reference, Φ F = 0.13). 19,58−60 In contrast, the dimethylamino derivative 3c exhibited a large Stokes shift with an emission maximum at 945 nm.…”

Temperature-dependent shape-responsive fluorescent nanospheres for image-guided drug delivery

“…HITC (1,3,3,1′,3′,3′- h examethyl-2,2′- i ndo t ricarbo c yanin) is a polymethine Cy7 type dye soluble in a variety of media and often studied as a model fluorescent compound, 20–23 laser dye, 23 precursor to optical materials 24 and a contrast agent in biological applications. 25 As a typical cyanine dye, HITC showed absorption-fluorescence sensitivity to the environment, including spectral shifts (Fig.…”