نتایج جستجو برای: photochemistry

تعداد نتایج: 3515  

2016
Stevan W. Djuric Charles W. Hutchins Nari N. Talaty

This review covers recent advances in the implementation of enabling chemistry technologies into the drug discovery process. Areas covered include parallel synthesis chemistry, high-throughput experimentation, automated synthesis and purification methods, flow chemistry methodology including photochemistry, electrochemistry, and the handling of "dangerous" reagents. Also featured are advances i...

Journal: :Angewandte Chemie 2014
Philipp J Gritsch Christian Leitner Magnus Pfaffenbach Tanja Gaich

Investigations of excited-state redox processes have an exceptional impact on the field of organic photochemistry and its application to the synthesis of complex target molecules. In such a photochemical process a single-electron transfer takes place to produce ion-radical intermediates, if the reduction and oxidation potentials, as well as excited-state energies of electron donors and acceptor...

Journal: :Philosophical transactions. Series A, Mathematical, physical, and engineering sciences 2013
Zhanyong Li Scott J Burya Claudia Turro Kim R Dunbar

The new complex [Rh2(phen)2(CH3CN)6](BF4)4 (1) was synthesized and characterized in solution and its crystal structure was determined. Irradiation of 1 with visible light (λirr>590 nm) in water results in the release of two equatorial CH3CN ligands, CH3CNeq, as well as in the formation of mononuclear radical Rh(II) fragments stemming from the homolytic photocleavage of the metal-metal bond. The...

2005
Hari Nair Michael E. Summers Charles E. Miller Yuk L. Yung

The existence of methane in the martian atmosphere may be an indicator of subsurface life. Biological processes are known to fractionate the common isotopologues of methane, and hence measuring these isotopic ratios may yield constraints on the nature of the methane source. Any measurement of the isotopic ratios of atmospheric methane must consider the additional fractionation due to photochemi...

Journal: :The Journal of chemical physics 2012
Dietrich Menzel

This is a personal account of the development of the title subject which is the broader field encompassing surface photochemistry. It describes the early times when the main interest centered on desorption induced by slow electrons, follows its evolution in experiment (use of synchrotron radiation and connections to electron spectroscopies; use of lasers) and mechanisms, and briefly mentions th...

2016
C. M. Anderson R. E. Samuelson Y. L. Yung J. L. McLain

We propose that C4N2 ice clouds observed in Titan’s springtime polar stratosphere arise due to solid-state photochemistry occurring within extant ice cloud particles of HCN-HC3N mixtures. This formation process resembles the halogen-induced ice particle surface chemistry that leads to condensed nitric acid trihydrate (NAT) particles and ozone depletion in Earth’s polar stratosphere. As our anal...

2004
Yvan Fracheboud

Each quantum of light absorbed by a chlorophyll molecule rises an electron from the ground state to an excited state. Upon de-excitation from a chlorophyll a molecule from excited state 1 to ground state, a small proportion (3-5% in vivo) of the excitation energy is dissipated as red fluorescence. The indicator function of chlorophyll fluorescence arises from the fact that fluorescence emission...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2002
Nicholas J Turro

Supramolecular organic photochemistry, a field concerned with the interaction of light with supramolecular assemblies of organic molecules, has been inspired by the remarkable structural and dynamic features of guest@host chemistry, particularly as exemplified by enzymes. Exemplars of supramolecular organic photochemistry from soft-matter hosts (micelles) and hard-matter hosts (porous solids) a...

Journal: :Journal of General Physiology 1920

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