نتایج جستجو برای: halogen

تعداد نتایج: 4763  

Journal: :Chemical science 2013
David C Powers Matthew B Chambers Thomas S Teets Noémie Elgrishi Bryce L Anderson Daniel G Nocera

Halogen photoelimination is a critical step in HX-splitting photocatalysis. Herein, we report the photoreduction of a pair of valence-isomeric dirhodium phosphazane complexes, and suggest that a common intermediate is accessed in the photochemistry of both mixed-valent and valence-symmetric complexes. The results of these investigations suggest that halogen photoelimination proceeds by two sequ...

Journal: :Physical chemistry chemical physics : PCCP 2012
Nan Gao Wei Tao Zheng Qing Jiang

The electronic structures and band gaps of silicene (the Si analogue of graphene) adsorbed with halogen elements are studied using the density functional theory based screened exchange local density approximation method. It is found that the band gaps of silicene adsorbed with F, Cl, Br and I have a nonmonotonic change as the periodic number of the halogen elements increases. This is attributed...

In the 1- (4-fluorophenyl) -2,3-dihydro-1 H-naphto- [1 and 2-e] [1 and 3] oxazine-3-n, there are 4 rings, respectively, rings from the side attached to the halogen They are named C, B, A, and D. Calculations and studies show that the amount of aromatics in the halogen-ring A in all cases has the highest number. In the B loop, the predicted aromatism level is zero, and in the ring C and D, relat...

Journal: :JOURNAL OF THE ILLUMINATING ENGINEERING INSTITUTE OF JAPAN 2004

2007
Pierangelo Metrangolo Franck Meyer Tullio Pilati Giuseppe Resnati

The reaction of 2-amino-ethanol and iodo-penta-fluoro-benzene in the presence of K(2)CO(3) gave the title compound, C(8)H(6)F(4)INO, in high yield. The structure is characterized by double layers of mol-ecules linked by O-H⋯O and N-H⋯O hydrogen bonds, and linear C-I⋯F [I⋯F = 3.049 (2) Å] and bent C-I⋯I [I⋯I = 3.9388 (7) Å] inter-actions between pairs of nearly parallel iodo-tetra-fluoro-phenyl ...

Journal: :Acta crystallographica. Section C, Structural chemistry 2015
Kulsoom Kamal Hardesh K Maurya Atul Gupta Prema G Vasudev

The revived interest in halogen bonding as a tool in pharmaceutical cocrystals and drug design has indicated that cyano-halogen interactions could play an important role. The crystal structures of four closely related δ-keto esters, which differ only in the substitution at a single C atom (by H, OMe, Cl and Br), are compared, namely ethyl 2-cyano-5-oxo-5-phenyl-3-(piperidin-1-yl)pent-2-enoate, ...

Journal: :American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics 2010
Siddik Malkoç Tancan Uysal Serdar Uşümez Eren Işman Asli Baysal

INTRODUCTION In this in-vitro study, we evaluated the temperature changes in the pulp chamber during bracket bonding using 4 different light sources. METHODS Eighty intact extracted maxillary central incisors were used. The teeth were divided into 4 groups of 20 teeth each. Brackets (Mini Twin, Dentaurum, Ispringen, Germany) were bonded with Transbond XT (3M Unitek, Monrovia, Calif) adhesive ...

Journal: :Acta biochimica Polonica 2016
Jarosław Poznański Maria Winiewska Honorata Czapinska Anna Poznańska David Shugar

Analysis of 664 known structures of protein kinase complexes with halogenated ligands revealed 424 short contacts between a halogen atom and a potential protein X-bond acceptor, the topology and geometry of which were analyzed according to the type of a halogen atom (X = Cl, Br, I) and a putative protein X-bond acceptor. Among 236 identified halogen bonds, the most represented ones are directed...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2016
Kimberly M Parker William A Mitch

Although halogen radicals are recognized to form as products of hydroxyl radical ((•)OH) scavenging by halides, their contribution to the phototransformation of marine organic compounds has received little attention. We demonstrate that, relative to freshwater conditions, seawater halides can increase photodegradation rates of domoic acid, a marine algal toxin, and dimethyl sulfide, a volatile ...

Journal: :Molecules 2017
Yi Yang Joseph J Pignatello

Halide ions are ubiquitous in natural waters and wastewaters. Halogens play an important and complex role in environmental photochemical processes and in reactions taking place during photochemical water treatment. While inert to solar wavelengths, halides can be converted into radical and non-radical reactive halogen species (RHS) by sensitized photolysis and by reactions with secondary reacti...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید