نتایج جستجو برای: halogen

تعداد نتایج: 4763  

Journal: :Molecules 2017
Fabiola Zapata Sergio J Benítez-Benítez Paula Sabater Antonio Caballero Pedro Molina

Most of the halogen bonding receptors for anions described use halogen bonding binding sites solely in the anion recognition process; only a few examples report the study of anion receptors in which the halogen bonding interaction has been used in combination with any other non-covalent interaction. With the aims to extend the knowledge in the behaviour of this kind of mixed receptors, we repor...

2013
Arri Priimagi Gabriella Cavallo Pierangelo Metrangolo Giuseppe Resnati

Halogen bonding is an emerging noncovalent interaction for constructing supramolecular assemblies. Though similar to the more familiar hydrogen bonding, four primary differences between these two interactions make halogen bonding a unique tool for molecular recognition and the design of functional materials. First, halogen bonds tend to be much more directional than (single) hydrogen bonds. Sec...

2014
Pierangelo Metrangolo Giuseppe Resnati

Cl/Br/I alternative substitutions in a series of dihalophenols indicate that type I and type II halogen···halogen contacts have different chemical nature. Only the latter ones qualify as true halogen bonds, according to the recent IUPAC definition.

Journal: :Physical chemistry chemical physics : PCCP 2016
Juan Crugeiras Ana Ríos

Ab initio MP2(full)/aug-cc-pVTZ calculations have been carried out to investigate the halogen transfer between haloamines and ammonia. The results show that the formation of a halogen bond complex between ammonia and the protonated N-haloamine is a preliminary step in the halogen transfer process. The complexation energies, optimized geometries, topology of electron density and potential energy...

Journal: :Chemical communications 2015
Fanny Frausto Zachary C Smith Terry E Haas Samuel W Thomas

Diphenylacetylene (tolan) derivatives with self-complementary aryl halides and halogen bond-accepting nitriles form 2D bricklayer packing motifs when halogen bonding occurs. When halogen bonding is absent, as occurred with fluorinated aryl bromides, the molecules adopt other packing motifs. These results suggest halogen bonding is potentially useful for producing rarely observed 2D bricklayer m...

Journal: :physical chemistry research 2014
mohammad solimannejad elahe bayatmanesh mehdi esrafili

mp2 calculations with cc-pvtz basis set were used to analyze intermolecular interactions in f3cx···yli···nccn and f3cx···nccn···liy triads (x = cl, br; y = cn, nc) which are connected via halogen and lithium bonds. those complexes with the role of liy as halogen acceptor and lithium donor show cooperativity with energy values ranging between -1.97 and -2.92 kj mol-1. those complexes with simult...

2016
Shuiqin Jiang Lujia Zhang Dongbin Cui Zhiqiang Yao Bei Gao Jinping Lin Dongzhi Wei

The use of halogen bond is widespread in drug discovery, design, and clinical trials, but is overlooked in drug biosynthesis. Here, the role of halogen bond in the nitrilase-catalyzed synthesis of ortho-, meta-, and para-chlorophenylacetic acid was investigated. Different distributions of halogen bond induced changes of substrate binding conformation and affected substrate selectivity. By engin...

ژورنال: حیات 2011
رحیمی‌نیا, طاهره, رحیمی‌کیان, فاطمه, مدرس, مریم, مهران, عباس, نیرومنش, شیرین,

Background & Aim: The Non Stress Test (NST) is a main assessment tool for fetal wellbeing however, it has a high rate of false-positive results. External stimulation with halogen light has been recommended to aid in provoking fetal response, decreasing false-positive results and promoting the test. This study aimed to assess the effect of halogen light stimulation on nonreactive pattern of NST....

     The effects of substituents on the symmetry and the nature of halogen bonds in [N∙∙∙X∙∙∙N]+-type systems are presented for the YC5H4N∙∙∙X∙∙∙NC5H5 (Y = NO2, CN, H, CH3, OCH3, OH, NH2, X = Cl, Br, I) complexes. Some structural parameters, energy data and electronic properties were explored with...

2016
William Kretz

It is known that halogen bonding is supported by so-called sigma holes on halides that interact with bases, but what are the limits of that interaction? How does the interaction depend on the group to which the halogen atom is bonded? To answer these questions, complexes of the form MH3X---Y (where M=C, Si, Ge, Sn, Pb; X= F, Cl, Br, I and Y are Lewis bases) were optimized and their energetics a...

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