نتایج جستجو برای: photochemical oxidation

تعداد نتایج: 126898  

2014
Simon B. Lang Kathryn M. O’Nele Jon A. Tunge

A combination of photoredox and palladium catalysis has been employed to facilitate the room temperature decarboxylative allylation of recalcitrant α-amino and phenylacetic allyl esters. This operationally simple process produces CO2 as the only byproduct and provides direct access to allylated alkanes. After photochemical oxidation, the carboxylate undergoes radical decarboxylation to site-spe...

Journal: :Journal of photochemistry and photobiology. B, Biology 2002
H D Burrows M Canle L J A Santaballa S Steenken

The photodegradation of pesticides is reviewed, with particular reference to the studies that describe the mechanisms of the processes involved, the nature of reactive intermediates and final products. Potential use of photochemical processes in advanced oxidation methods for water treatment is also discussed. Processes considered include direct photolysis leading to homolysis or heterolysis of...

2016
Han Bao Robert L. Burnap

Photosynthetic water oxidation is catalyzed by the Mn4CaO5 cluster of photosystem II. The assembly of the Mn4O5Ca requires light and involves a sequential process called photoactivation. This process harnesses the charge-separation of the photochemical reaction center and the coordination environment provided by the amino acid side chains of the protein to oxidize and organize the incoming mang...

Journal: :Chemistry 2015
Takashi Nakazono Alexander R Parent Ken Sakai

Enabling the production of solar fuels on a global scale through artificial photosynthesis requires the development of water oxidation catalysts with significantly improved stability. The stability of photosystems is often reduced owing to attack by singlet oxygen, which is produced during light harvesting. Here, we report photochemical water oxidation by CoFPS, a fluorinated Co-porphyrin desig...

Journal: :Dalton transactions 2014
Ivan P Pozdnyakov Alexey A Melnikov Nikolai Tkachenko Sergey V Chekalin Helge Lemmetyinen Victor F Plyusnin

Photochemical reactions with the participation of iron(iii) carboxylates are important for environmental photochemistry and have a great potential of application in water purification (advanced oxidation processes, photo-Fenton and Fenton-like processes). In spite of this, information about excited states and primary intermediates in the photochemistry of Fe(iii) complexes with carboxylic acids...

2008
Renyi Zhang

Nonmethane hydrocarbons (NMHCs) play an important role in the atmosphere. Photochemical oxidation of hydrocarbons leads to ozone (O3), organic acid, and carbon dioxide (CO2) production, with major implications for local and regional air quality, acid deposition, and the greenhouse effect. In addition, emissions of atmospheric NMHCs lead to an increased aerosol loading, which has major implicati...

Journal: :Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology 2015
Haingo L Andriampanarivo Martin Köhler Juan López Gejo Thomas Betzwieser Benny C Y Poon Po Lock Yue Solofonirina D Ravelomanantsoa André M Braun

Thiophene was taken as a model compound for investigations on the efficiency of a continuous process of the vacuum-ultraviolet- (VUV-) photochemically initiated oxidation and mineralization of sulfur containing organic compounds in the gas phase. In the presence of molecular oxygen, atomic oxygen and ozone were photochemically generated and are assumed to initiate or participate in the (thermal...

Journal: :Biochimica et biophysica acta 2000
C Tommos G T Babcock

The photosynthetic processes that lead to water oxidation involve an evolution in time from photon dynamics to photochemically-driven electron transfer to coupled electron/proton chemistry. The redox-active tyrosine, Y(Z), is the component at which the proton currents necessary for water oxidation are switched on. The thermodynamic and kinetic implications of this function for Y(Z) are discusse...

1995
William P. L. Carter John A. Pierce Dongmin Luo Irina L. Malkina

The effects of 26 individual volatile organic compounds (VOCs) on ozone formation, NO oxidation, and OH radical levels were measured by adding them to reactive organic gas (ROG) NOx air environmental chamber irradiations representing a simplified model photochemical smog system. These experiments had relatively low ROG/NOx ratios to represent conditions where ozone formation is most sensitive t...

Journal: :Dalton transactions 2017
Anton A Shushakov Ivan P Pozdnyakov Vjacheslav P Grivin Victor F Plyusnin Danila B Vasilchenko Andrei V Zadesenets Alexei A Melnikov Sergey V Chekalin Evgeni M Glebov

Diazide diamino complexes of Pt(iv) are considered as prospective prodrugs in oxygen-free photodynamic therapy (PDT). Primary photophysical and photochemical processes for cis,trans,cis-[Pt(N3)2(OH)2(NH3)2] and trans,trans,trans-[Pt(N3)2(OH)2(NH3)2] complexes were studied by means of stationary photolysis, nanosecond laser flash photolysis and ultrafast kinetic spectroscopy. The process of phot...

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