By means of a technique of corona excited supersonic expansion coupled with a pinhole-type glass nozzle, we generated vibronically excited but jet-cooled benzyl-type radicals from precursor 2-chloro-4-fluorotoluene seeded in a large amount of inert carrier gas He. From an analysis of the visible vibronic emission spectrum, we found evidence of the formation of the 2-chloro-4-fluorobenzyl and 4-fluorobenzyl radicals. A possible pathway for the formation of these benzyl-type radicals is herein proposed. Also, the electronic energy in the D(1) → D(0) transition and the vibrational mode frequencies of the 2-chloro-4-fluorobenzyl radical in the ground electronic state were accurately determined, for the first time, by comparison with ab initio calculations and the known vibrational data of the precursor.
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http://dx.doi.org/10.1063/1.4708808 | DOI Listing |
Chemistry
March 2018
Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489, Berlin, Germany.
Native chemical ligation (NCL) is an invaluable tool in the total chemical synthesis of proteins. Ligation auxiliaries overcome the requirement for cysteine. However, the reported auxiliaries remained limited to glycine-containing ligation sites and the acidic conditions applied for cleavage of the typically applied N-benzyl-type linkages promote side reactions.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2015
Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin (Germany).
Native chemical ligation enables the chemical synthesis of proteins. Previously, thiol-containing auxiliary groups have been used to extend the reaction scope beyond N-terminal cysteine residues. However, the N-benzyl-type auxiliaries used so far result in rather low reaction rates.
View Article and Find Full Text PDFPhys Chem Chem Phys
November 2015
State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
Laccase catalyzes the oxidation of natural phenols and thereby is believed to initialize reactions in lignification and delignification. Numerous phenolic mediators have also been applied in laccase-mediator systems. However, reaction details after the primary O-H rupture of phenols remain obscure.
View Article and Find Full Text PDFRadiat Environ Biophys
May 2015
Department of Physics, Faculty of Art and Science, Balikesir University, 10145, Cagis, Balikesir, Turkey,
The structural and kinetic features of the radiation-induced radicals of benzoic acid and its sodium and potassium salts were investigated using electron paramagnetic resonance (EPR) spectroscopy. Two main different radicals were found to be responsible for the measured spectra of the irradiated samples. It is concluded that these two radicals have a structure similar to that of cyclohexadienyl-type (CHD) and benzyl-type (BNZ) radicals.
View Article and Find Full Text PDFChemistry
July 2014
UMR 6226 ISCR, Chimie et Photonique Moléculaires, Université de Rennes 1, 35042 Rennes (France).
Covalent Si-C grafting of a silatrane cage to a carbon-based interface provides a truly conjugated benzyl-type system in which the 3 c-4 e orbital of the silatrane interacts with the macroscopic π-type substituent (graphite Csp2 network) through hyperconjugation. This process, studied by voltammetry, EIS, FTIR, SEM and DFT modeling, allows one to build carbon-based conducting interfaces with electronically conjugated molecular extensions. Non-conjugated covalent grafting of an alkyl silatrane moiety provides chemically stable functional interfaces that have good promise for electrochemically-driven applications, for example, electrochemical spin-writing.
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