The photochemistry of triarylmethane dyes bound to polyelectrolytes: photoinduced electron transfer involving bound dye monomers and dimers

Jones, Guilford; Oh, Churl; Goswami, Kisholoy

doi:10.1016/1010-6030(91)85007-4

Cited by 30 publications

(16 citation statements)

References 38 publications

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“…Intersystem crossing (ISC) to a long lived triplet excited state may account for the 2.6% energy discrepancy. Enhanced quantum efficiency for intersystem crossing (F5sc) has been noted before for a dye bound to a macromolecule as compared with the unbound dye (Bellin and Yankus, 1968;Jones et al, 1991). Our observations of a slightly increased fluorescence efficiency and the decreased heat yield for MG-BSA (compared with MG) is consistent with the suggestion of a decreased internal conversion rate constant.…”

Section: Discussionsupporting

confidence: 90%

The efficiency of malachite green, free and protein bound, as a photon-to-heat converter

Indig¹,

Jay²,

Grabowski³

1992

Biophysical Journal

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Dye assisted laser inactivation of proteins has been found to be a methodology that can achieve high selectivity. Despite the fact that the methodology is successful, knowledge of the detailed inactivation mechanism would allow full optimization of this technique. Here, pulsed-laser photoacoustic calorimetry is used to study the photophysical properties, principally the heat release behavior, of protein bound malachite green. We found that when bound to bovine serum albumin the dye is a good photon-to-heat converter, but approximately 2.6% of the absorbed photon energy (lambda(exc) = 624 nm) is not released as heat in less than 10 mus. This observation suggests that a mechanism other than simple heat-induced inactivation may be the principle process; a long lived excited triplet state of malachite green (or species derived from it) is postulated to play a major role.

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Section: Discussionsupporting

confidence: 90%

The efficiency of malachite green, free and protein bound, as a photon-to-heat converter

Indig¹,

Jay²,

Grabowski³

1992

Biophysical Journal

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“…It is observed that on addition of surfactants (studied in this paper) there is an increase in absorbance along with a minor bathochromic shift in the first absorption band ∼2–3 nm in the aqueous micellar environment indicating that the polarity in the vicinity of the probe is slightly lower than that of the pure aqueous form. − Addition of SDS causes a minor enhancement in both bands with a small red shift in the 329 nm band. A similar change was observed for triarylmethane (TPM) dyes bound to polyelectrolytes . Similarly, a minor enhancement was observed in CTAB and TX-100.…”

Section: Resultssupporting

confidence: 70%

“…A similar change was observed for triarylmethane (TPM) dyes bound to polyelectrolytes. 44 Similarly, a minor enhancement was observed in CTAB and TX-100.…”

Section: Resultsmentioning

confidence: 89%

Experimental and Quantum Chemical Calculations of Imidazolium Appended Naphthalene Hybrid in Different Biomimicking Aqueous Interfaces

et al. 2016

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The effect of solvent polarity and micellar headgroup on a newly designed imidazolium based ionic liquid (IL) conjugated with naphthalene, 1,2-dimethyl-3-((6-(octyloxy)naphthalen-2-yl)methyl)-1H-imidazol-3-ium chloride (IN-O8-Cl), was studied using steady state and time-resolved fluorescence techniques. We observed that the dipole moment in the excited state is remarkably higher than the ground state. The effect of micellar surface charge on the photophysics of IN-O8-Cl in aqueous phase at room temperature was investigated. Formation of premicellar aggregates in sodium dodecylsulfate (SDS) was perceived; further the microenvironment of IN-O8-Cl was examined using steady-state fluorescence spectroscopy. Micropolarity of the micellar environment of SDS was found to be lower than that of cetyltrimethylammonium bromide (CTAB) and triton X-100 (TX100) following the order SDS < TX-100 < CTAB. The binding constant (Kb) and edge excitation red shift (EERS) from the emission maximum suggest that the probe binds strongly to the micelles. Multiexponential behavior was observed in time-resolved fluorescence lifetime studies in all micellar environments. We have observed an increase in rotational correlation time as we move from pure aqueous phase to solution containing surfactants of different head charge. Varieties of spectral parameters were used to justify the region in which the probe is present. The experimentally obtained dipole moment data were justified and explained by the DFT calculations of the electronic properties of IN-O8-Cl molecules in gas phase and in selected solvents.

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“…For species free in solution, the relative importance of the type I and II reactions depends on the respective reaction rates, k I and k II , and the concentrations of substrate and oxygen. In complex biological systems the noncovalent binding of photosensitizers to proteins, nucleic acids, and other biological substrates is likely to be a widespread phenomenon. − When the ground-state photosensitizer is physically attached to a substrate, the variables regulating the competition between reaction type I and type II are no longer those that occur for free species. The type I mechanism becomes much more competitive, especially when the excited photosensitizer is bound to a macromolecular domain that, for topological reasons, offers some protection against diffusional oxygen quenching. , The binding of photosensitizers to biopolymers has other important consequences.…”

Section: Introductionmentioning

confidence: 99%

“…Within the framework of host−guest complexes the dynamics of separation of the primary photochemical products are altered, and thus reaction paths not observed for species free in solution may become more competitive in restricted reaction spaces. The photophysical and photochemical properties of photosensitizers also may be greatly affected by the nature of the microenvironment in which they are accommodated in the biopolymer, − and because diffusion no longer precedes the interaction of the excited photosensitizer with the substrate, short-lived excited singlet states are more likely to engage in the photosensitization process.…”

Section: Introductionmentioning

confidence: 99%

Effect of BSA Binding on Photophysical and Photochemical Properties of Triarylmethane Dyes

1998

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We have employed a combination of steady-state and time-resolved spectroscopic techniques to explore the effect of protein binding on the photophysical and photochemical properties of three triarylmethane dyes: ethyl violet, crystal violet, and malachite green. Our results indicate that the binding sites of bovine serum albumin (BSA) are very efficient in preventing fast nonradiative relaxation processes that occur via rotational motion of the aromatic rings of these triarylmethanes. As a result, remarkable enhancements in fluorescence quantum yield and lifetime, intersystem crossing efficiency, and photoreactivity are observed upon protein binding. The 532 nm laser-induced photobleaching of ethyl violet noncovalently bound to BSA yields leuco ethyl violet and 4,4′-bis(diethylamino)benzophenone as reaction products. The former was more prominent in nitrogen-purged samples and the latter in air-equilibrated samples. The time-resolved transient spectra of the ethyl violet complex show superimposed elements of the spectroscopic signatures of both ethyl violet triplet and the semireduced dye radical. Based on the nature of the reaction photoproducts and transient intermediates, the first step of the bleaching process is postulated to be an electron or hydrogen atom transfer from the protein to the dye moiety. An analogous reaction mechanism was observed for protein-bound crystal violet.

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The photochemistry of triarylmethane dyes bound to polyelectrolytes: photoinduced electron transfer involving bound dye monomers and dimers

Cited by 30 publications

References 38 publications

The efficiency of malachite green, free and protein bound, as a photon-to-heat converter

The efficiency of malachite green, free and protein bound, as a photon-to-heat converter

Experimental and Quantum Chemical Calculations of Imidazolium Appended Naphthalene Hybrid in Different Biomimicking Aqueous Interfaces

Effect of BSA Binding on Photophysical and Photochemical Properties of Triarylmethane Dyes

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