RSC - Photochem. Photobiol. Sci. latest articles

Photochemistry and photophysics of the endoperoxide of mesodiphenylhelianthrene: a contribution to the localization of the S1([small pi][sigma]) state of aromatic endoperoxides

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05382A, Paper

Reinhard Schmidt
Excitation of the S₁([small pi]*[sigma]*) state of the non-fluorescent endoperoxide MDHPO produces quantitatively by O-O bond rupture a biradical, the precursor of the strongly fluorescent diepoxide MDHDO and of ground state MDHPO.
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A computational model for previtamin D3 production in skin

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05295D, Paper

Merve Meinhardt-Wollweber, Ronald Krebs
We introduce a computational model predicting UV derived vitamin D production in human skin. The effect of variations in the different input parameters are shown and discussed to give an idea of the capabilities of the model.
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Oxidatively generated damage to DNA at 5-methylcytosine mispairs

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05379A, Paper

Joshy Joseph, Gary B. Schuster
5-Methylcytosine (C_m) in DNA sequences containing C_m-A or C_m-T mismatches behaves like "thymine" in one electron oxidation induced modifications. The reactivity of C_m is attributed to the efficient generation of the 5-methyl radical by a Proton Coupled Electron Transfer (PCET) mechanism.
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Small change in structure leads to large difference in protein photocleavage: two porphyrins bearing rhodanine-based pendants

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05352G, Paper

Guo-Yu Jiang, Wan-Hua Lei, Qian-Xiong Zhou, Yuan-Jun Hou, Xue-Song Wang
The presence of a COOH group renders RhDCOOH-TPP less hydrophobic in character and leads to additional interactions toward BSA, which leads to a significant increase of the ¹O₂ quantum yield upon BSA binding and effective BSA photocleavage. In contrast, RhD-TPP is inactive in the photocleavage of BSA.
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The donor-acceptor biphenyl platform: A versatile chromophore for the engineering of highly efficient two-photon sensitive photoremovable protecting groups

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05360H, Paper

Alexandre Specht, Frederic Bolze, Loic Donato, Cyril Herbivo, Sebastien Charon, David Warther, Sylvestre Gug, Jean-Francois Nicoud, Maurice Goeldner
Different photoremovable protecting groups in the o-nitrobenzyl, phenacyl, and 2-(o-nitrophenyl)propyl series with a donor-acceptor biphenyl backbone were investigated in order to develop efficient two-photon sensitive photoremovable protecting groups.
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Aromatic aldols and 1,5-diketones as optimized fragrance photocages

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05286E, Paper

Axel G. Griesbeck, Olga Hinze, Helmut Gorner, Ursula Huchel, Christian Kropf, Uta Sundermeier, Thomas Gerke
Aromatic aldols and 1,5-diketones with abstractable [gamma]-hydrogen atoms are highly photoactive cage molecules for the release of fragrance compounds (aldehydes and Michael ketones, respectively). By tuning the properties of the chromophores, [small delta]-damascone cages were developed for selective release of fragrances under air and solar irradiation. The intermediates of the Norrish II process were observed by laser transient absorption spectroscopy.
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Photochemical investigation of the IR absorption bands of molecular oxygen in organic and aqueous environment

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05350K, Paper

A. A Krasnovsky, A. S. Kozlov, Ya. V. Roumbal
Absorbance of dissolved oxygen molecules corresponding to the weak IR absorption maxima at 765, 1073 and 1273 nm has been estimated in air-saturated solvents using the photooxygenation rates of the ¹O₂ traps upon direct excitation of O₂ by IR diode lasers.
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Reaction of the m-THPC triplet state with the antioxidant Trolox and the anesthetic Propofol: Modulation of photosensitization mechanisms relevant to photodynamic therapy?

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05354C, Paper

O. Friaa, P. Maillard, D. Brault
Antioxidants may affect the outcome of photodynamic therapy (PDT) through the inactivation of reactive oxygen species or reaction with the photosensitizer triplet state.
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Effects of visible and UV light on the characteristics and properties of crude oil-in-water (O/W) emulsions

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05275J, Paper

Homer C. Genuino, Dayton T. Horvath, Cecil K. King'ondu, George E. Hoag, John B. Collins, Steven L. Suib
Prudhoe Bay and South Louisiana crude oil-in-water emulsions were prepared, characterized, and exposed to both visible and UV light irradiation. The unique changes in physico-chemical properties of these emulsions as a result of photodegradation were investigated.
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Direct aerobic photo-oxidative syntheses of aromatic methyl esters from methyl aromatics using anthraquinone-2,3-dicarboxylic acid as organophotocatalyst

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05387J, Communication

Norihiro Tada, Yuki Ikebata, Tomoya Nobuta, Shin-ichi Hirashima, Tsuyoshi Miura, Akichika Itoh
This paper reports a useful method for facile direct syntheses of aromatic methyl esters from methyl aromatics by aerobic photo-oxidation using anthraquinone-2,3-dicarboxylic acid as an organophotocatalyst.
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Characterization and reactivity of photodimers of dihydroneopterin and dihydrobiopterin

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05363B, Paper

Mariana Vignoni, Carolina Lorente, Franco M. Cabrerizo, Rosa Erra-Balsells, Esther Oliveros, Andres H. Thomas
The photodimerization of 7,8-dihydrobiopterin and 7,8-dihydroneopterin upon UV-A irradiation yields two main isomeric dimers containing an azacyclobutane ring. The dimers undergo a retro [2 + 2]-cycloaddition in the dark.
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Spectral, photophysical and photochemical properties of tetra- and octaglycosylated zinc phthalocyanines

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05348A, Paper

Zafar Iqbal, Nkosiphile Masilela, Tebello Nyokong, Alexey Lyubimtsev, Michael Hanack, Thomas Ziegler
Zinc phthalocyanines substituted with glucose and galactose moieties show high triplet quantum yields ranging from 0.68 to 0.88 and long triplet lifetimes which range from 100 to 430 [small mu ]s.
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Structural volume changes upon triplet formation of water-soluble porphyrins depend on the resonant effect of the substituents

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05368C, Paper

Mikalai M. Kruk, Silvia E. Braslavsky
The contractions determined upon production of the triplet state in water-soluble porphyrins with para substituents in the meso phenyl groups correlate with the substituent Hammett resonant [sigma]_R constants.
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Ketonization of enols in aqueous solution: is carbon protonation always rate-determining?

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05369A, Paper

Anna Paola Pelliccioli, Peter Sebej, Jakob Wirz
The answer to the title question is: No! The rate-determining step for ketonization of the (E)-enol of o-methylacetophenone up to pH 11 is ionization of the hydroxyl group.
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Environmental polarity estimation in living cells by use of quinoxaline-based full-colored solvatochromic fluorophore PQX and its derivatives

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05337C, Paper

Kentaro Kudo, Atsuya Momotake, Junko K. Tanaka, Yoshihiro Miwa, Tatsuo Arai
Site-dependent fluorescence spectra were observed in HEp-2 cells after staining with PQX, which indicated less polarity at the Golgi body and more polarity around the cell periphery.
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[small pi]-Cation interactions as the origin of the weak absorption at 532 nm observed in tryptophan-containing polypeptides

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05341A, Paper

O. A. Roveri, S. E. Braslavsky
A weak light absorption at 532 nm, well detected by LIOAS, was observed with acid solutions of tryptophan and neutral solution of tryptophan containing polypeptides and proteins: this is a spectral manifestation of [small pi]-cation interactions.
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Bis-semiquinone (bi-radical) formation by photoinduced proton coupled electron transfer in covalently linked catechol-quinone systems: Aviram's hemiquinones revisited

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05378K, Paper

Nguyen Van Anh, Rene M. Williams
"Bi-radical state caught in the act". Transient absorption spectroscopy of the hydrogen-bonded donor (blue)-acceptor (red) system shows the fingerprint of a long-lived (300 ns to 18 [small mu ]s) bi-radical state. Charge transfer interactions and two conformations are present. These molecules played a role in the genesis of molecular electronics.
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Differential interactions of a biological photosensitizer with liposome membranes having varying surface charges

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05346B, Paper

Bijan Kumar Paul, Nikhil Guchhait
Electrostatic interactions plays a key role in the differential interaction of the potent cancer cell photosensitizer harmane (HM) with liposome membranes of varying surface charges. Photophysics, prototropic transformation equilibrium and dynamics of the drug are differentially modulated within the two lipids DMPC and DMPG.
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Cobalt bis(dicarbollide) versus closo-dodecaborate in boronated chlorin e6 conjugates: implications for photodynamic and boron-neutron capture therapy

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05237G, Paper

Anastasija V. Efremenko, Anastasija A. Ignatova, Alena A. Borsheva, Mikhail A. Grin, Vladimir I. Bregadze, Igor B. Sivaev, Andrey F. Mironov, Alexey V. Feofanov
A conjugate with cobalt bis(dicarbollide) is promising for BNCT and fluorescence diagnostics of cancer. A conjugate with closo-dodecaborate is suitable for PDT and BNCT.
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Externally sensitized deprotection of PPG-masked carbonyls as a spatial proximity probe in photoamplified detection of binding events

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05326H, Paper

Tiffany P. Gustafson, Greg A. Metzel, Andrei G. Kutateladze
Externally sensitized fragmentation in dithiane PPG-protected carbonyls is adopted for detection and amplification of binding events, which trigger massive self-amplified release of benzophenone from its masked state, simultaneously quenching the fluorescence.
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Multi-domain GFP-like proteins from two species of marine hydrozoans

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C1PP05238A, Paper

Marguerite E. Hunt, Chintan K. Modi, Galina V. Aglyamova, D. V. S. Ravikant, Eli Meyer, Mikhail V. Matz
Jellyfish on fire: the fiery orange fluorescence of this anthoathecate jellyfish is due to a protein named Ember, which consists of four concatenated GFP-like domains.
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Photoactivatable fluorophores and techniques for biological imaging applications

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05342J, Perspective

Wen-hong Li, Genhua Zheng
Photoactivatable fluorophores (PAFs) are powerful imaging probes for biological research. We review recent developments in this field, emphasizing on a novel class of caged coumarins with numerous outstanding properties ideally suitable for live cell imaging.
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Photorelease of tyrosine from [small alpha]-carboxy-6-nitroveratryl ([small alpha]CNV) derivatives

Photochem. Photobiol. Sci., 2012, Advance Article
DOI: 10.1039/C2PP05320A, Paper

Alexander G. Russell, Matthew J. Sadler, Helen J. Laidlaw, Agustin Gutierrez-Loriente, Christopher W. Wharton, David Carteau, Dario M. Bassani, John S. Snaith
[small alpha]-Carboxy-6-nitroveratryl ([small alpha]CNV) tyrosine ethers undergo rapid photolysis above 300 nm to release the free phenol. N-Fmoc derivatives suitable for incorporation of caged tyrosine into peptides are described.
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