نتایج جستجو برای: chirality

تعداد نتایج: 12872  

2003
Howard D. Flack Jack D. Dunitz

An extensive study and analysis of the concepts, classification, presentation, and nomenclature of chirality and lack of chirality in crystal structures and their constituents is presented. Oriented crystal structures are classified. The chirality rules for existence of molecular crystal structures are examined and the relation to segmentation and latent symmetry highlighted. The nomenclature o...

Journal: :iranian journal of pharmaceutical research 0
gabriel hancu university of medicine and pharmacy targu mures, faculty of pharmacy, department of pharmaceutical chemistry anca cârje university of medicine and pharmacy targu mures, faculty of pharmacy, department of analytical chemistry ileana iuga university of medicine and pharmacy, faculty of pharmacy, department of pharmaceutical chemistry ibolya fülöp university of medicine and pharmacy targu mures, faculty of pharmacy, department of toxicology and biofarmacy zoltán istvan szabó university of medicine and pharmacy targu mures, faculty of pharmacy, department of pharmaceutical chemistry

carvedilol is administered as a racemic mixture of the r(+)- and s(-)-enantiomers, although it was demonstrated that the two enantiomers exhibit different pharmacological effects and stereoselective pharmacokinetics. the aim of this study was the evaluation of several native and derivatized cyclodextrines as chiral selectors for the separation of carvedilol enantiomers. stereoselective interact...

Journal: :Chemical Society reviews 2005
Santiago Alvarez Pere Alemany David Avnir

The definition of the continuous chirality measure(CCM) is provided and its applications are summarized in this tutorial review, with special emphasis on the field of transition metal complexes. The CCM approach, developed in recent years, provides a quantitative parameter that evaluates the degree of chirality of a given molecule. Many quantitative structural correlations with chirality have b...

Journal: :CVGIP: Image Understanding 1991
Yacov Hel-Or Shmuel Peleg David Avnir

Many natural shapes are chiral (or handed). Our hands, for example, have a righthand version and a left-hand version, the two types being mirror images of each other. Molecules are also classi ed according to their chirality, which determines their chemical characteristics. Glucose, for example, is sweet only in one chirality, while it is tasteless in the other. The notion of chirality for two ...

Journal: :Journal of theoretical biology 2005
Wei Li Shuo-Xing Dou Peng-Ye Wang

In eukaryote nucleosome, DNA wraps around a histone octamer in a left-handed way. We study the process of chirality formation of nucleosome with Brownian dynamics simulation. We model the histone octamer with a quantitatively adjustable chirality: left-handed, right-handed or non-chiral, and simulate the dynamical wrapping process of a DNA molecule on it. We find that the chirality of a nucleos...

2004
Shmuel Peleg Hagit Zabrodsky

Many natural shapes have chirality (or handedness): for instance our hands have a right-hand version and a left-hand version, the two types being mirror images of each other. In chemistq, for example, molecules and crystals are classified as having chirality D or L. Interaction between molecules is dependent on their chirality, and chirality may determine chemical characteristics. For instance,...

Journal: :Chirality 2003
Salvatore Capozziello Alessandra Lattanzi

Chirality is of primary importance in many areas of chemistry and has been extensively investigated since its discovery. We introduce here a description of central chirality for tetrahedral molecules using a geometrical approach based on complex numbers. According to this representation, for a molecule having n chiral centers it is possible to define an "index of chirality chi." Consequently, a...

2017
Peng-Peng Wang Shang-Jie Yu Alexander O Govorov Min Ouyang

Cooperative chirality phenomena extensively exist in biomolecular and organic systems via intra- and inter-molecular interactions, but study of inorganic materials has been lacking. Here we report, experimentally and theoretically, cooperative chirality in colloidal cinnabar mercury sulfide nanocrystals that originates from chirality interplay between the crystallographic lattice and geometric ...

2017
Ting Chen Shu-Ying Li Dong Wang Li-Jun Wan

Noncovalently introducing stereogenic information is a promising approach to embed chirality in achiral molecular systems. However, the interplay of the noncovalently introduced chirality with the intrinsic chirality of molecules or molecular aggregations has rarely been addressed. We report a competitive chiral expression of the noncovalent interaction-mediated chirality induction and the intr...

2018
Wei Zhang Yin Zhao Lu Yin

To date, liquid crystal chirality, mechanophysical chirality, circularly polarized photon chirality, gelation and chiral solvation are all feasible candidates to generate optically active polymers and supramolecular chirality when employing achiral molecules as start‐ ing substances. Among this, chiral‐solvation‐induced chirality is one of the dominant methods for construction of chirality from...

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