Fibril stability in solutions of twisted -sheet peptides: a new kind of micellization in chiral systems

2000 ◽  
Vol 17 (3) ◽  
pp. 481-497 ◽  
Author(s):  
I.A. Nyrkova ◽  
A.N. Semenov ◽  
A. Aggeli ◽  
N. Boden
Keyword(s):  
Chiral Systems

Discovery of new electro-optic effects in chiral systems

1997 ◽  
Author(s):  
Rui-Fang Shi ◽  
S. Yamada ◽  
O. Zamani-Khamiri ◽  
Anthony F. Garito
Keyword(s):  
Electro Optic ◽  
Chiral Systems

Metalloporphyrin catalysts for organic synthesis

2004 ◽  
Vol 08 (09) ◽  
pp. 1166-1171 ◽  
Author(s):  
Gérard Simonneaux ◽  
Pietro Tagliatesta
Keyword(s):  
Organic Synthesis ◽  
Enantiomeric Excess ◽  
Catalytic Reactions ◽  
Terminal Alkynes ◽  
Asymmetric Oxidation ◽  
Carbene Transfer ◽  
Catalytic Asymmetric ◽  
Chiral Systems ◽  
Metalloporphyrin Catalysts

Novel chiral systems for the catalytic asymmetric oxidation and cyclopropanation of olefins based on metalloporphyrins containing iron, ruthenium and manganese, have been recently introduced. High catalyst turnover numbers and sometimes high enantiomeric excess were observed. New catalytic reactions with metalloporphyrins have recently been reported; these are the olefination of aldehydes and cyclotrimerization of terminal alkynes. Dendrimers and polymers containing metalloporphyrins, have also been found to be efficient catalysts for oxidation and carbene transfer.

Regioselective formation of the quinazoline moiety on the upper rim of calix[4]arene as a route to inherently chiral systems

2020 ◽  
Vol 44 (16) ◽  
pp. 6490-6500
Author(s):  
M. Tlustý ◽  
H. Dvořáková ◽  
J. Čejka ◽  
M. Kohout ◽  
P. Lhoták
Keyword(s):  
Inherently Chiral ◽  
Chiral Systems ◽  
Upper Rim ◽  
Inherently Chiral Calixarenes

N-acyl aminocalix[4]arenes were cyclized with nitriles to afford the expected quinazolines only in the case of para-substituted series. This strategy represents a new route to inherently chiral calixarenes potentially useful as fluorescent receptors.

scholarly journals Localized molecular orbitals for calculation and analysis of vibrational Raman optical activity

2018 ◽  
Vol 20 (45) ◽  
pp. 28751-28758 ◽  
Author(s):  
Sandra Luber
Keyword(s):  
Optical Activity ◽  
Molecular Orbitals ◽  
Localized Molecular Orbitals ◽  
Raman Optical Activity ◽  
Chiral Systems ◽  
Spectroscopic Signatures ◽  
Insight Into ◽  
The Way

First calculations of vibrational Raman optical activity based on localized molecular orbitals are presented, which pave the way for novel insight into spectroscopic signatures of chiral systems.

scholarly journals Theoretical Calculations on the Mechanism of Enantioselective Copper(I)-Catalyzed Addition of Enynes to Ketones

Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 359 ◽  
Author(s):  
Hanwei Li ◽  
Mingliang Luo ◽  
Guohong Tao ◽  
Song Qin
Keyword(s):  
Density Functional Theory ◽  
Steric Hindrance ◽  
Phenyl Ring ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Dft Method ◽  
Catalytic Cycle ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Chiral Systems

Computational investigations on the bisphospholanoethane (BPE)-ligated Cu-catalyzed enantioselective addition of enynes to ketones were performed with the density functional theory (DFT) method. Two BPE-mesitylcopper (CuMes) catalysts, BPE-CuMes and (S,S)-Ph-BPE–CuMes, were employed to probe the reaction mechanism with the emphasis on stereoselectivity. The calculations on the BPE-CuMes system indicate that the active metallized enyne intermediate acts as the catalyst for the catalytic cycle. The catalytic cycle involves two steps: (1) ketone addition to the alkene moiety of the metallized enyne; and (2) metallization of the enyne followed by the release of product with the recovery of the active metallized enyne intermediate. The first step accounts for the distribution of the products, and therefore is the stereo-controlling step in chiral systems. In the chiral (S,S)-Ph-BPE–CuMes system, the steric hindrance is vital for the distribution of products and responsible for the stereoselectivity of this reaction. The steric hindrance between the phenyl ring of the two substrates and groups at the chiral centers in the ligand skeleton is identified as the original of the stereoselectivity for the titled reaction.

Theory and Simulation of Texture Transformations in Chiral Systems: Applications to Biological Fibrous Composites

2001 ◽  
Vol 709 ◽  
Author(s):  
Gino De Luca ◽  
Alejandro D. Rey
Keyword(s):  
Three Dimensional ◽  
Front Propagation ◽  
Fibrous Composites ◽  
Propagation Process ◽  
Chiral Nematic ◽  
New Information ◽  
Biological Structures ◽  
Planar Film ◽  
Chiral Systems ◽  
Gennes Theory

ABSTRACTNumerous studies [1-3] have shown that chiral biological structures share common properties with liquids crystals, in particular a tendency to assemble in three-dimensional lattices very similar to that of chiral nematics. Biological fibrous composites are usually found in planar (film) and cylindrical (fibber) twist geometries. In this work, the formation process of the planar twist architecture is numerically investigated using a mesoscopic model based on the Landau-de Gennes theory of chiral nematic liquid crystals. The simulations and visualizations of the computed textures provide new information on some of the principles that govern the formation of chiral biological structures. It is found that a defect-free planar twist architecture arises from a chiral front propagation process with a fully relaxed wake.

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