نتایج جستجو برای: chiral stability

تعداد نتایج: 336584  

1997
Tamás S. Biró Carsten Greiner

Utilizing the Langevin equation for the linear σ-model we investigate the effect of friction and white noise on the evolution and stability of collective pionic fields in energetic heavy ion collisions. We find that the smaller the volume, the more stable transverse (pionic) fluctuations become on a homogeneous disoriented chiral field background (the average transverse mass 〈mt 〉 increases). O...

2017
Marco Russo Paolo Lo Meo

Polarimetry was used to investigate the binding abilities of a chiral calix[4]resorcinarene derivative, bearing L-proline subunits, towards a set of suitably selected organic guests. The simultaneous formation of 1:1 and 2:1 host-guest inclusion complexes was observed in several cases, depending on both the charge status of the host and the structure of the guest. Thus, the use of the polarimet...

Journal: :The Journal of organic chemistry 2006
Alexandre Martinez Catherine Hemmert Christophe Loup Guillaume Barré Bernard Meunier

We describe a general synthetic strategy for the preparation of a series of macrocyclic chiral manganese(III) salen complexes. The developed reaction pathway allows the modulation of the different key groups, namely, the chiral diimine, the bulky substituents in positions 3 and 3', and the linker used in the macrocyclization of the Schiff base. The different complexes presented here illustrate ...

Journal: :Dalton transactions 2016
Susanne Striegler Jessica B Pickens

The coordination between N-p-methylbenzyl-d-galactonoamidine, a putative transition state analogue of the hydrolyis of glycosidic bonds, and symmetric and chiral binuclear copper(ii) complexes was characterized by spectroscopic titration, isothermal titration calorimetry, circular dichroism spectroscopy, and DFT calculations to elucidate the binding sites in the carbohydrate upon coordination t...

2012
C. A. Dominguez

Next to leading order corrections to the SU(3) × SU(3) Gell-Mann-Oakes-Renner relation (GMOR) are obtained using weighted QCD Finite Energy Sum Rules (FESR) involving the pseudoscalar current correlator. Two types of integration kernels in the FESR are used to suppress the contribution of the kaon radial excitations to the hadronic spectral function, one with local and the other with global con...

2016
Honghua Jia Fan Huang Zhen Gao Chao Zhong Hua Zhou Min Jiang Ping Wei

ω-Transaminase (ω-TA) as a kind of important biocatalyst is widely used in preparation of chiral intermediates. In this paper, a magnetic PVA-Fe3O4 nanoparticles was prepared and employed on immobilization of ω-TA to reduce the cost, increase reusability and enhance stability. The prepared magnetic PVA-Fe3O4 nanoparticles were characterized by transmission electron microscope (TEM), X-ray diffr...

A new chromatographic procedure was proposed for the separation of propranolol (PRN) enantiomers based upon enantioselective chiral ligand-exchange chromatography. The separation was carried out on a short C8 column leading to considerably short separation time. L-alanine and Cu2+ were applied as chiral selector and central bivalent complexing ion, respectively. It was found that the kind of co...

F. Salahi K. Jadidi M. Hamzelooian M. J. Taghizadeh

An efficient, one-pot, four-component procedure for the synthesis of a small library of new chiral spiro- oxindolopyrrolidines with high regio-, diastereo- (>99:1 dr), and enantioselectivity (up to 80% ee) is described. In this process, the regio- and stereochemical 1,3-dipolar cycloaddition of azomethine ylides, which were generated insitu by the reaction of isatin derivatives and sarcosin,wit...

2003
Mukesh C. Gohel

Introduction Chiral molecules exist in a pair of stereoisomers (enantiomers). If a plane of polarized light is passed through a sample of each enantiomer, one will rotate the light to the left (levorotatory or (-)-enantiomer or R-form),and the other will rotate the light to the right (dextrorotatory or (+)-enantiomer or Sform). Rotation of light will not be observed if the light is passed throu...

Journal: :Angewandte Chemie 2022

Abstract We report the synthesis of a [20]cyclophenacene‐type cyclophenylene‐naphthylene (CPN) belt and enantioselective chiral‐type CPN belts (up to >99 % ee ) by cationic rhodium(I)‐catalyzed intramolecular [2+2+2] cycloaddition naphthalene‐embedded cyclic polyynes. The depth‐expanded was also attempted, but final unsuccessful. Theoretical calculations clarified that reactivity depends on ...

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