نتایج جستجو برای: photochemical forming

تعداد نتایج: 124842  

Journal: :Molecules 2010
Miroslav Sisa Susan L Bonnet Daneel Ferreira Jan H Van der Westhuizen

Flavonoids and their photochemical transformations play an important role in biological processes in nature. Synthetic photochemistry allows access to molecules that cannot be obtained via more conventional methods. This review covers all published synthetic photochemical transformations of the different classes of flavonoids. It is first comprehensive review on the photochemistry of flavonoids.

Journal: :Trends in microbiology 1999
A Verméglio P Joliot

Functional and ultrastructural studies have indicated that the components of the photosynthetic apparatus of Rhodobacter sphaeroides are highly organized. This organization favors rapid electron transfer that is unimpeded by reactant diffusion. The light-harvesting complexes only partially surround the photochemical reaction center, which ensures an efficient shuttling of quinones between the p...

2016
Daryl Staveness Irene Bosque Corey R. J. Stephenson

Harnessing visible light as the driving force for chemical transformations generally offers a more environmentally friendly alternative compared with classical synthetic methodology. The transition metal-based photocatalysts commonly employed in photoredox catalysis absorb efficiently in the visible spectrum, unlike most organic substrates, allowing for orthogonal excitation. The subsequent exc...

2003
S. M. Saunders M. J. Pilling

Kinetic and mechanistic data relevant to the tropospheric degradation of volatile organic compounds (VOC), and the production of secondary pollutants, have previously been used to define a protocol which underpinned the construction of a near-explicit Master Chemical Mechanism. In this paper, an update to the previous protocol is presented, which has been used to define degradation schemes for ...

2017
Ryan D. McCulla William S. Jenks

Atomic oxygen O(3P) is a potent oxidant that has been well-studied in the gas phase. However, exploration of its reactivity in the condensed organic phase has been hampered by the lack of an appropriate source. Dibenzothiophene-S-oxide (DBTO) and related derivatives have been promoted as photochemical O(3P) sources but suffer from low quantum yields. Photolysis of dibenzoselenophene-Se-oxide (D...

2007
G.

Photochemical reactions have been examined in relation with the physical properties of the solid polymeric matrix in which they are carried out. Three main reaction types are considered: (i) photocrosslinking reactions resulting from cyclodimerization of unsaturated groups and from the decomposition of photolabile groups into very reactive species, e.g. nitrenes from azides; (ii) photoisomeriza...

2002

Photochemical smog IS a complex m1xture of chemiCals, some harmless. others h1ghly react1ve and poten11ally dangerous for plants, an1mats and humans. The main consmuents of photochemical smog are ozone (0.,) and nitrogen diox1de (N0 2). Although ozone is widely cons1dered the chTef indicator of photochemical smog, Ollrogen diox1de IS an important pollutant in 11s own right, alfecllng human and ...

Journal: :علوم گیاهان زراعی ایران 0
ایمان نادعلی فرزاد پاک نژاد فواد مرادی محمد نصری علیرضا پازوکی

to evaluate the effects of methanol and drought stress on chlorophyll fluorescence parameters, chlorophyll and relative water content in sugar beet, a study was conducted in 2008 in maahdasht (karaj, iran). aqueous solutions of 0 (control), 7, 14, 21, 28, 35% (v/v) methanol with each solution containing 0.2% glycine and a second factor, namely drought stress (irrigation after 70% depletion of a...

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