Unusual photobehavior of benzophenone triplets in hexafluoroisopropanol. Inversion of the triplet character of benzophenone

Lewandowska-Andrałojć, Anna; Hug, Gordon L.; Hörner, Gerald; Pędziński, Tomasz; Marciniak, Bronisław

doi:10.1016/j.jphotochem.2012.06.010

Cited by 10 publications

(9 citation statements)

References 44 publications

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“…For Aβ 16–22 -BP 20 , we were unable to observe the carbonyl n →π* transition (for which λ max typically falls in the range 330–350) 46 that generates the reactive intermediate (BP triplet). This absence is explained by some unusual solvent effects, which were the subject of a recent report by Lewandowska-Andralojc et al ( 47 ) HFIP induces a blue shift of the weak n →π* absorption, causing it to become hidden under the tail of the strong aromatic π→π* absorption (see Supplementary Figure ESI 5 ). Although the authors were unable to determine the precise position of λ max when the HFIP content was above 80% (v/v), they were still able to observe a proportion of BP’s n →π* triplet spectroscopically when the sample was irradiated at 340 nm.…”

Section: Resultsmentioning

confidence: 96%

Analysis of Amyloid Nanostructures Using Photo-cross-linking: In Situ Comparison of Three Widely Used Photo-cross-linkers

et al. 2014

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Photoinduced cross-linking (PIC) has become a powerful tool in chemical biology for the identification and mapping of stable or transient interactions between biomacromolecules and their (unknown) ligands. However, the value of PIC for in vitro and in vivo structural proteomics can be realized only if cross-linking reports accurately on biomacromolecule secondary, tertiary, and quaternary structures with residue-specific resolution. Progress in this area requires rigorous and comparative studies of PIC reagents, but despite widespread use of PIC, these have rarely been performed. The use of PIC to report reliably on noncovalent structure is therefore limited, and its potentials have yet to be fully realized. In the present study, we compared the abilities of three probes, phenyl trifluoromethyldiazirine (TFMD), benzophenone (BP), and phenylazide (PA), to record structural information within a biomolecular complex. For this purpose, we employed a self-assembled amyloid-like peptide nanostructure as a tightly and specifically packed model environment in which to photolyze the reagents. Information about PIC products was gathered using mass spectrometry and ion mobility spectrometry, and the data were interpreted using a mechanism-oriented approach. While all three PIC groups appeared to generate information within the packed peptide environment, the data highlight technical limitations of BP and PA. On the other hand, TFMD displayed accuracy and generated straightforward results. Thus TFMD, with its robust and rapid photochemistry, was shown to be an ideal probe for cross-linking of peptide nanostructures. The implications of our findings for detailed analyses of complex systems, including those that are transiently populated, are discussed.

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Section: Resultsmentioning

confidence: 96%

Analysis of Amyloid Nanostructures Using Photo-cross-linking: In Situ Comparison of Three Widely Used Photo-cross-linkers

et al. 2014

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“…The impact of the solute−solvent-specific interaction on the ET driving force and the quenching kinetics was indicated in our earlier studies of 3 BP quenching in a series of protic and nonprotic solvents. 7,8 In that previous work, the driving force was ascribed to one or both of the ET reactants, 3 BP (predominantly) and anisole (secondarily), being H-bonded to the solvent. Good accordance with the experiment, obtained here, shows that in a highly nonideal solution such as the BP− anisole−ACN−H 2 O system, a similar basis for the quenching dynamics is operative.…”

Section: Bp By Anisole In Acn−h 2 O Mixturesmentioning

confidence: 99%

“…In qualitative terms, two quenching mechanisms (CT and ET) have been operating in two-component solvent mixtures of a nonprotic (ACN) and a protic constituent (hexafluoro-2-propanol). 8 Competition between full ET and polarization (CT) of the reaction partners is omnipresent in photochemistry. It is discussed in some detail both for singlet-born 9 and triplet-born 10 quenching reactions.…”

Section: Introductionmentioning

confidence: 99%

“…This mechanistic branching was correlated with the state of solvation of the excited ketone that greatly differs in nonprotic media such as neat acetonitrile (ACN) or dichloromethane on the one hand or trifluoroethanol on the other. In qualitative terms, two quenching mechanisms (CT and ET) have been operating in two-component solvent mixtures of a nonprotic (ACN) and a protic constituent (hexafluoro-2-propanol) . Competition between full ET and polarization (CT) of the reaction partners is omnipresent in photochemistry.…”

Section: Introductionmentioning

confidence: 99%

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Water-Triggered Photoinduced Electron Transfer in Acetonitrile–Water Binary Solvent. Solvent Microstructure-Tuned Reactivity of Hydrophobic Solutes

Lewandowska-Andrałojć

Hug

Marciniak

et al. 2020

J. Phys. Chem. B

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The solvent-composition dependence of quenching triplet states of benzophenone ( 3 BP) by anisole in acetonitrile–water (ACN–H 2 O) mixtures was investigated by laser flash photolysis over the water mole fraction ( x w ) increasing from 0 to 0.92. Single exponential decay of 3 BP was observed over the whole composition range. The quenching rate constant consistently increased with the water content but increased far more rapidly with x w > 0.7. The water-triggered electron-transfer (ET) mechanism was confirmed by a steeply growing quantum yield of the benzophenone ketyl radical anion, escaping back-ET when the partial water volume exceeded the acetonitrile one. The water-content influence on the 3 BP quenching rate was described by a kinetic model accounting for the microheterogeneous structure of the ACN–H 2 O mixtures and the very different solubility of the reactants in the solvent components. According to the model, the ET mechanism occurs at a rate constant of 1.46 × 10 9 M –1 s –1 and is presumably assisted by the ACN–H 2 O hydrogen-bonding interaction.

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“…The excited triplet state of Bz has been well-studied, and its characteristic transient absorption peak is approximately 520 nm [15]. The characteristic absorption of 3 Tan I ⁄ is at 630 nm.…”

Section: Energy Transfer From 3 Bz * To Tan Imentioning

confidence: 99%

The triplet state of tanshinone I and its synergic effect on the phototherapy of cancer cells with curcumin

Zhang

Jiang

et al. 2015

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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Unusual photobehavior of benzophenone triplets in hexafluoroisopropanol. Inversion of the triplet character of benzophenone

Cited by 10 publications

References 44 publications

Analysis of Amyloid Nanostructures Using Photo-cross-linking: In Situ Comparison of Three Widely Used Photo-cross-linkers

Analysis of Amyloid Nanostructures Using Photo-cross-linking: In Situ Comparison of Three Widely Used Photo-cross-linkers

Water-Triggered Photoinduced Electron Transfer in Acetonitrile–Water Binary Solvent. Solvent Microstructure-Tuned Reactivity of Hydrophobic Solutes

The triplet state of tanshinone I and its synergic effect on the phototherapy of cancer cells with curcumin

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