Photodegradation Processes of Cyanine Dyes in the Film State Induced by Singlet Molecular Oxygen

Abstract

Photodegradation processes of carbocyanine dyes spin-coated on a polycarbonate plate were studied by steadystate photolysis and near-IR emission spectroscopy. The efficiency of the whole photodegradation caused by molecular oxygen directly and/or indirectly was found to strongly depend on both substituents on the 1 and 1′ positions and the counterion. Singlet molecular oxygen ( 1 ∆g) produced at the interface between the dye thin film and a polycarbonate plate was detected by near-IR emission spectroscopy. Its yield did not depend on substituents on the 1 and 1′ positions but on the counterion. The relative reactivity of carbocyanine dyes in the film state with the singlet molecular oxygen was estimated by exploiting a perinaphthenone thin film as a singlet molecular oxygen generator. The reactivity strongly depended on both substituents on the 1 and 1′ positions and the counterion.

Pyrophthalones as Blue Wavelength Absorbers in Thermoplastic Media

“…peroxy radicals) formed by the photoexcitation of dyes upon excitation to higher excited electronic states in a polar environment (26–28) or (2) degradation by reaction with 1 O 2 , produced by sensitization of ground state triplet oxygen via an organic dye or other absorber (26–28). Several teams of researchers have investigated the lifetimes, mechanisms of generation, physical quenching and chemical quenching of singlet molecular oxygen in homogeneous polymer matrices (29), as well as cyanine (30) and merocyanine (31) dye‐doped in thin films. To better understand the mechanism of degradation for PyP in polycarbonate, we employed three different classes of additives: radical scavengers, triplet quenchers and SOS to unravel the plausible mechanisms of photodegradation.…”

Pentamethine cyanine located in mitochondria: relationship between photostability and excited state lifetime

“…自从1856年Williams [1] 发现"豆粉"蓝菁染料以来, 由于此类染料具有吸收波长范围可调(540~1000 nm)、 摩尔消光系数大、吸收及发射光谱范围可调、合成 容易等优点, 被广泛应用于生物荧光分析 [2,3] 及荧光 成像 [4,5] . 虽然目前菁染料应用面较广, 但普遍存在光 化学不稳定的缺点, 特别是近红外菁染料, 如五甲川 (Cy5)、七甲川染料(Cy7)的光稳定性较差, 成为限制 其产业大规模应用的不利因素 [6,7] . 因此, 研究和提高 菁染料的光稳定性具有重要的理论和现实意义.…”

Fluoromodules: Fluorescent Dye-Protein Complexes for Genetically Encodable Labels

“…36 Although we have not verified this for DIR, it is known that cyanine photobleaching can occur at least partly through oxidative attack by singlet oxygen (generated by the fraction of the dye excited state that intersystem crosses to the triplet state). 35,37 The new fluorogen, α-CN-DIR, bound to the promiscuous FAP K7 (K D = 60 nM and ϕ f = 0.16), so new FAPs were not needed. As expected, the α-CN-DIR/K7 fluoromodule was approximately eightfold more photostable than the parent DIR/K7 fluoromodule.…”