نتایج جستجو برای: halogen

تعداد نتایج: 4763  

2016
Anna-Carin C. Carlsson Krenare Mehmeti Martin Uhrbom Alavi Karim Michele Bedin Rakesh Puttreddy Roland Kleinmaier Alexei A. Neverov Bijan Nekoueishahraki Jürgen Gräfenstein Kari Rissanen Máté Erdélyi

We have investigated the influence of electron density on the three-center [N-I-N](+) halogen bond. A series of [bis(pyridine)iodine](+) and [1,2-bis((pyridine-2-ylethynyl)benzene)iodine](+) BF4(-) complexes substituted with electron withdrawing and donating functionalities in the para-position of their pyridine nitrogen were synthesized and studied by spectroscopic and computational methods. T...

Journal: :Chemical & pharmaceutical bulletin 2015
Kenichi Murai Daisuke Endo Norihito Kawashita Tatsuya Takagi Hiromichi Fujioka

A halogen-induced oxidative rearrangement of N,O-ketals prepared from cyclobutanones, leading to pyrrolidone derivatives, is developed. The reaction proceeds via an iminium ether intermediate and, depending on the reaction medium, two types of pyrrolidone derivative, containing a halogen atom or hydroxyl group, can be obtained.

Journal: :Chemical communications 2014
Yinjie Chen Haifeng Yu Lanying Zhang Huai Yang Yunfeng Lu

A series of photoresponsive halogen-bonded liquid crystals (LCs) were successfully constructed using molecular halogen and azopyridine compounds, which show interesting properties of photoinduced phase transition upon UV irradiation. In addition, bromine-bonded LCs were first obtained with high mesophase stability.

Journal: :Current opinion in chemical biology 1998
A Butler

The nature of the oxidized halogen intermediate in vanadium bromoperoxidase has recently been shown to depend on the nature of the organic substrate. For example, in the presence of indoles, vanadium bromoperoxidase does not release a freely diffusible oxidized halogen intermediate (such as HOBr+/-BR2+/-Br3-). Regioselective investigations are, therefore, now feasible.

Journal: :Dalton transactions 2011
Christer B Aakeröy Abhijeet S Sinha Prashant D Chopade John Desper

A series of four bifunctional ligands based on β-diketonate moieties bearing methyl (2), chloro (3), bromo (4) and iodo (5) substituents and their corresponding Cu(II) complexes have been synthesized and crystallographically characterized in order to explore the possibility of using halogen bonds for the directed assembly of predictable architectures in coordination chemistry. The four ligands ...

Journal: :Angewandte Chemie International Edition 2020

Journal: :European journal of orthodontics 2004
A P Pettemerides M Sherriff A J Ireland

The purpose of this study was to compare the effectiveness of a plasma arc lamp with a conventional tungsten quartz halogen lamp in orthodontic bonding. Twenty consecutive patients had their brackets bonded either with Transbond XT (n = 10) or Fuji Ortho LC (n = 10). In total, 352 teeth were bonded, 176 in each group. Using a randomized cross-mouth control study design, where diagonally opposit...

Journal: :Physical chemistry chemical physics : PCCP 2015
Ibon Alkorta José Elguero Otilia Mó Manuel Yáñez Janet E Del Bene

Ab initio MP2/aug'-cc-pVTZ calculations have been carried out to investigate the structures, binding energies, and bonding characteristics of binary complexes HFBe:FCl, R2Be:FCl, and FCl:N-base, and of ternary complexes HFBe:FCl:N-base and R2Be:FCl:N-base for R = H, F, Cl; N-base = NH3, NHCH2, NCH. Dramatic synergistic cooperative effects have been found between the Be···F beryllium bonds and t...

2016
Yisu Li Binbin Guo Zhijian Xu Bo Li Tingting Cai Xinben Zhang Yuqi Yu Heyao Wang Jiye Shi Weiliang Zhu

Drug repositioning has been attracting increasingly attention for its advantages of reducing costs and risks. Statistics showed that around one quarter of the marketed drugs are organohalogens. However, no study has been reported, to the best of our knowledge, to aim at efficiently repositioning organohalogen drugs, which may be attributed to the lack of accurate halogen bonding scoring functio...

Journal: :Topics in current chemistry 2015
Michal H Kolář Palanisamy Deepa Haresh Ajani Adam Pecina Pavel Hobza

The nature of halogen bonding in 128 complexes was investigated using advanced quantum mechanical calculations. First, isolated halogen donors were studied and their σ-holes were described in terms of size and magnitude. Later, both partners in the complex were considered and their interaction was described in terms of DFT-SAPT decomposition. The whole set of complexes under study was split int...

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