We present a compilation of spectral parameters associated with triplet–triplet absorption organic molecules in condensed media. The wavelengths maximum absorbance and the corresponding extinction coefficients, where known, have been critically evaluated. Other data, for example, lifetimes, energies energy transfer rates, relevant to triplet states these are included by way comments but not subjected similar scrutiny. Work gas phase has omitted, as theoretical studies. provide an...

Adsorption of a cationic dye, cresyl violet, on SnO2 and SiO2 nanoclusters nanocrystalline thin films results in the formation H-aggregates. These dyes are photochemically electrochemically active extend photoresponse large bandgap semiconductors such as SnO2. Photocurrent generation dye capped has been demonstrated with visible light excitation. A photon-to-photocurrent efficiency around 1% observed at 510 nm. Back electron transfer between photoinjected oxidized sensitizer plays an...

The pathogenesis of Alzheimer's disease is strongly associated with the formation and deposition β-amyloid peptide (βAP) in brain. This contains a methionine (Met) residue C-terminal domain, which important for its neurotoxicity propensity to reduce transition metals form reactive oxygen species. Theoretical studies have proposed βAP Met radical cations as intermediates, but no experimental evidence regard reactivity these species available, largely due insolubility peptide. To define...

A global least-squares technique is developed to assist in the critical evaluation of data consisting large sets measurements. The particularly designed handle where many measurements are relative linearization procedure used reduce inherently nonlinear problem a traditional multivariate linear regression. here evaluate extinction coefficients, ε’s, triplet–triplet absorption (TTA) spectra organic molecules condensed phases. previous assumption, that there no solvent effects on TTA spectra,...

The rate constants for the quenching of excited states metal ions and complexes in homogeneous fluid solution are reported this compilation. Values kq dynamic, collisional processes between species quenchers have been critically evaluated, presented with following information, among others, from original publications, when available: description medium, temperature at which was determined, experimental method, range quencher concentration used, lifetime state absence quencher, activation...

We succeeded in establishing for the first time a conclusive spectroscopic signature reduced single-wall carbon nanotubes (SWNT), which evolves from electron donor−acceptor interactions between SWNT and electron-donating π-extended tetrathiafulvalene (exTTF). In particular, π−π were employed to anchor donor surface of SWNT. New conduction band electrons, injected photoexcited exTTF, shift transitions that are associated with van Hove singularities lower energies.

Radiation chemical methods were used to investigate the reactions of glycine anions, H2NCH2CO2- (Gly-), with •OH, (CH3)2C•OH, and •CH3 radicals. A major most significant product from all these processes is CO2. Pulse-radiolysis revealed that initial step in •OH-induced mechanism oxidation amino group, producing +H2N•-CH2-CO2- HN•-CH2-CO2- yields 63% 37%, respectively. The radical cation, +H2N•-CH2-CO2-, suffers fast (≤100 ns) fragmentation into CO2 + •CH2NH2. other primary radical,...

A description is given of how multiple time scales are incorporated into a new computer program for running pulse-radiolysis experiments on linear accelerator. For any kinetic trace, the data can be presented ten distinct scales. The algorithms doing this presented. utility procedure illustrated with radiolysis bromide solutions. traces discussed in terms formation BrOH− adduct and its approach to equilibrium Br−2. second example, dipeptide Met–Met, illustrates ease simultaneously...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXT4-Carboxybenzophenone-sensitized photooxidation of sulfur-containing amino acids. Nanosecond laser flash photolysis and pulse radiolysis studiesKrzysztof Bobrowski, Bronislaw Marciniak, Gordon L. HugCite this: J. Am. Chem. Soc. 1992, 114, 26, 10279–10288Publication Date (Print):December 1, 1992Publication History Published online1 May 2002Published inissue 1 December...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTQuenching of triplet states aromatic ketones by sulfur-containing amino acids in solution. Evidence for electron transferBronislaw Marciniak, Krzysztof Bobrowski, and Gordon L. HugCite this: J. Phys. Chem. 1993, 97, 46, 11937–11943Publication Date (Print):November 1, 1993Publication History Published online1 May 2002Published inissue 1 November 1993https://pubs.acs.org/doi/10.1021/j100148a015https://doi.org/10.1021/j100148a015research-articleACS...

We have prepared three isomeric donor-acceptor systems, in which two phthalocyanine (Pc) units been attached to the 1-,5- (1a), 1-,8- (1b), or 2-,6- (1c) positions of a central anthraquinone (AQ) moiety, leading packed (1b) extended (1a and 1c) topologies. The electronic interactions between donor acceptor ground state excited states studied by different electrochemical photophysical techniques. Due markedly topologies, we able modify these at intramolecular level and, proper choice solvent...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotoprocesses in diphenylpolyenes. 2. Excited-state interactions with stable free radicalsS. K. Chattopadhyay, P. Das, and G. L. HugCite this: J. Am. Chem. Soc. 1983, 105, 20, 6205–6210Publication Date (Print):September 1, 1983Publication History Published online1 May 2002Published inissue 1 September 1983https://pubs.acs.org/doi/10.1021/ja00358a002https://doi.org/10.1021/ja00358a002research-articleACS PublicationsRequest reuse permissionsArticle...

An asymmetrically substituted mono-amino Zn(<sc>ii</sc>) phthalocyanine exhibits an unexpected tendency to form emissive H-type dimers and higher order aggregates.

In the course of 266 nm nanosecond laser flash photolysis carbazole (CBL) in acetonitrile, we discovered a new transient absorption band centered at 360 that has been heretofore unreported despite numerous reports on similar topics. To put some limits possible transients responsible for this and thus to solve mechanism CBL photolysis, employed strategy selectively blocking active sites by various modifications structure. This was supported use solvent effect triplet quenching molecular...

Abstract

The heteroaromatic thiols (imidazole, oxazole, and thiazole derivatives) were investigated in regard to their abilities function as co-initiators free-radical photopolymerizations induced by camphorquinone isopropylthioxanthone. As shown the kinetic data, these are efficient with activities comparable aromatic amines. They quenched triplet states of isopropylthioxanthone rate constants determined be on order 109 108 M-1 s-1, respectively. results suggested that rates polymerization a...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotoprocesses in diphenylpolyenes. Oxygen and heavy-atom enhancement of triplet yieldsS. K. Chattopadhyay, P. Das, G. L. HugCite this: J. Am. Chem. Soc. 1982, 104, 17, 4507–4514Publication Date (Print):August 1, 1982Publication History Published online1 May 2002Published inissue 1 August 1982https://pubs.acs.org/doi/10.1021/ja00381a001https://doi.org/10.1021/ja00381a001research-articleACS PublicationsRequest reuse permissionsArticle...

The recent study on the •OH-induced oxidation of calmodulin, a regulatory "calcium sensor" protein containing nine methionine (Met) residues, has supported first experimental evidence in for formation S∴N three-electron bonded radical complexes involving sulfur atom residue and amide groups adjacent peptide bonds. To characterize reactions oxidized residues proteins multiple more detail, current study, small model cyclic dipeptide, c-(l-Met−l-Met), was by •OH radicals generated via pulse...

The mechanism of photoinduced electron transfer between sulfur-containing alcohols and the 4-carboxybenzophenone (CB) triplet state in aqueous solution was investigated using laser flash photolysis steady-state techniques. Bimolecular rate constants for quenching CB by five hydroxyalkyl sulfides, 2-(methylthio)ethanol (2-MTE), 2,2'-dihydroxydiethyl sulfide (2,2'-DHE), 3-(methylthio)propanol (3-MTP), 3,3'-dihydroxydipropyl (3,3'-DHP), 4-(methylthio)butanol (4-MTB), with varying numbers OH...

Neighboring group participation was investigated in the •OH-induced oxidation of S-methylglutathione aqueous solutions. Nanosecond pulse radiolysis used to obtain spectra reaction intermediates and their kinetics. Depending on pH, concentration S-methylglutathione, irradiation leads different transients. The transients observed were an intramolecularly bonded [>S∴NH2]+ intermediate, intermolecularly S∴S-bonded radical cation, α-(alkylthio)alkyl radicals, α-amino-alkyl-type radical,...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTemperature dependence of the lifetimes excited benzyl and other arylmethyl radicalsDan. Meisel, Paritosh K. Das, Gordon L. Hug, Kankan. Bhattacharyya, Richard W. FessendenCite this: J. Am. Chem. Soc. 1986, 108, 16, 4706–4710Publication Date (Print):August 1, 1986Publication History Published online1 May 2002Published inissue 1 August 1986https://doi.org/10.1021/ja00276a004RIGHTS & PERMISSIONSArticle Views269Altmetric-Citations49LEARN ABOUT THESE...

To investigate neighboring amide participation in thioether oxidation, which may be relevant to brain oxidative stress accompanying beta-amyloid peptide aggregation, conformationally constrained methylthionorbornyl derivatives with amido moieties were synthesized and characterized, including an X-ray crystallographic study of one them. Electrochemical oxidation these compounds, studied by cyclic voltammetry, revealed that their peak potentials less positive for those compounds group was...

Noncovalent nanohybrids between meso-(p-hydroxyphenyl)porphyrin (TPPH) and graphene oxide (GO) sheets were studied as a function of pH. The overall charge the TPPH molecule changes negative (−4), neutral, positive (+2) depending on pH solution. Results Fourier transform infrared spectroscopy, thermogravimetric analysis, elemental analysis confirm successful noncovalent functionalization GO with TPPH. We applied number methods to probe ground-state well excited-state interaction components...