نتایج جستجو برای: halogen bond

تعداد نتایج: 74365  

2015
Christina Hettstedt Peter Mayer Konstantin Karaghiosoff

Halogen bonding is currently a widely discussed topic in the literature. In the last 15 years an increasing number of reviews (approximately 50) have been published on this subject. This type of intermolecular interaction was discovered about two centuries ago but was investigated in detail only in the last few years (for detailed mechanism and the theory of halogen bonding see ref. 2–6). Halog...

Journal: :journal of dentistry, tehran university of medical sciences 0
sm. abtahi z. khamverdy

statement of the problem: various methods such as light emitting diode (led) have been used to enhance the polymerization of resin-based orthodontic adhesives. there is a lack of information on the advantages and disadvantages of different light curing systems. purpose: the aim of this study was to compare the effect of led and halogen light curing systems on the shear bond strength of orthodon...

Journal: :Organic & biomolecular chemistry 2016
Josué M Silla Matheus P Freitas

Halogen bonds are defined as interactions between halogens and a Lewis base in which the halogen (X) acts as the electrophilic species, and is typically explained by the presence of a σ-hole at the end of the C-X bond. Despite the important role of the halogen bond in intermolecularly interacting species, e.g. in acid-base reactions, enzyme inhibition and the supramolecular architecture, this i...

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: :The journal of physical chemistry. A 2010
Kelling J Donald Bernard K Wittmaack Chad Crigger

Halogen bonding between halide sites (in substituted organic molecules or inorganic halides) and Lewis bases is a rapidly progressing area of exploration. Investigations of this phenomenon have improved our understanding of weak intermolecular interactions and suggested new possibilities in supramolecular chemistry and crystal engineering. The capacity for halogen bonding is investigated at the...

Journal: :Organic and Biomolecular Chemistry 2021

A Mukaiyama aldol reaction can be catalyzed by bidentate halogen bond donors with very high efficiency. The halogenated catalysts were stable over multiple consecutive runs, which supports the halogen-bond-based mode of catalysis.

2016
Timothy A. Barendt Sean W. Robinson Paul D. Beer

Two bistable halogen and hydrogen bonding-naphthalene diimide [2]rotaxanes have been prepared and the system incorporating a halogen bond donor anion recognition site is demonstrated to exhibit superior anion induced translational motion of the macrocyclic wheel component relative to the hydrogen bonding analogue. Proton NMR spectroscopy is used to estimate the percentage occupancies of the mac...

Journal: :journal of dentistry, tehran university of medical sciences 0
m. hashem-hoseini assistant professor, department of orthodontics, school of dentistry, tehran university of medical s h. mahmood-hashemi orthodontist, dental research center, tehran university of medical sciences, tehran, iran f. soltan-moradi laser research center, atomic energy organization of iran t. hooshmand assistant professor, department of dental materials, school of dentistry, tehran university of medic i. haririan associate professor, department of pharmaceutics, school of pharmacy, tehran university of medical s j. chalipa assistant professor, department of orthodontics, school of dentistry, tehran university of medical s

objective: nowadays light-cured composites are used widely by orthodontists to bond brackets. as these composites require 20-40 seconds time per tooth to be light cured, more chair-time in needed compared to self-cured composites. in recent years, the argon laser and plasma arc lights have been introduced in dentistry to reduce this curing time. the purpose of this study was to compare bond str...

Journal: :Journal of Biological Chemistry 1968

Journal: :Acta crystallographica. Section C, Structural chemistry 2017
Chideraa I Nwachukwu Nathan P Bowling Eric Bosch

Halogen bonding is a well-established and intensively studied intermolecular interaction that has also been used in the preparation of functional materials. While polyfluoroiodo- and polyfluorobromobenzenes have been widely used as aromatic halogen-bond donors, there have been very few studies of iodoimidazoles with regard to halogen bonding. We describe here the X-ray structures of three iodoi...

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