نتایج جستجو برای: chiral forms

تعداد نتایج: 305620  

2015
Yuliya Kirillova Nataliya Boyarskaya Andrey Dezhenkov Mariya Tankevich Ivan Prokhorov Anna Varizhuk Sergei Eremin Dmitry Esipov Igor Smirnov Galina Pozmogova Maxim Antopolsky

New polyanionic modifications of polyamide nucleic acid mimics were obtained. Thymine decamers were synthesized from respective chiral α- and γ-monomers, and their enantiomeric purity was assessed. Here, we present the decamer synthesis, purification and characterization by MALDI-TOF mass spectrometry and an investigation of the hybridization properties of the decamers. We show that the modifie...

1999
W. Bietenholz

It was shown recently by I. Horváth that lattice fermions obeying the standard form of the Ginsparg-Wilson relation cannot be ultralocal. However, there are more general forms of the Ginsparg-Wilson relation, which also guarantee the physical chiral properties, but which are not covered by Horváth’s consideration. Here we extend his proof to a much larger class of Ginsparg-Wilson fermions, demo...

2013
Jie Gao Hongyan Wang Liangru Yang Yongmei Xiao Pu Mao

In the title compound, C34H28N2S2, the central imidazole ring (r.m.s. deviation = 0.0015 Å) forms dihedral angles of 55.7 (3), 17.94 (11) and 86.27 (11)°, respectively, with the mean planes of the attached thienyl and two phenyl substituents. The thienyl ring shows ring-flip disorder [occupancy ratio = 0.647 (2):0.353 (2)]. The chiral centre maintains the S configuration of the l-phenyl-alanino...

Stereoisograms of octahedral complexes are classified into five types (type I--typeV) under the action of the corresponding RS-stereoisomeric group. Their enumeration is accomplished in a type-itemized fashion, where Fujita's proligand method developed originally for combinatorial enumeration under point groups (S. Fujita, Theor. Chem. Acc., 113, 73--79 (2005)) is extended to meet the requireme...

شکری, علی اصغر, یزدی, الهه,

In recent years, due to electron transport properties of nanostructures based on carbon nanotubes, a lot of attention to design electronic devices in the field of nanotechnology has attracted. There are three types of carbon nanotubes in zigzag, armchair and chiral (asymmetrical) forms. Since the types of armchair are electrically conductive, by a combination with a metal such as zinc can be ac...

1998
Y. Takimoto H. Igarashi H. Kurokawa T. Fujiwara

Locality is analyzed for Toda field theories by noting novel chiral description in the conventional nonchiral formalism. It is shown that the canonicity of the interacting to free field mapping described by the classical solution is automatically guaranteed by the locality. Quantum Toda theories are investigated by applying the method of free field quantization. We give Toda exponential operato...

2012
Ferenc Fülöp Miklós Hollósi Elemér Vass Gábor Szilvágyi Andreja Jakas Ilona Laczkó

There are two principal forms of vibrational optical activity (VOA), an IR form referred to as vibrational circular dichroism (VCD) and Raman form known as Raman optical activity (ROA). This paper reports examples of the application of VCD spectroscopy for the determination of the absolute configuration and conformation of chiral molecules, e.g. cyclic -lactams. VCD spectroscopy can be applied...

2009
David S. Sholl Andrew J. Gellman

A ny object that cannot be superimposed upon its mirror image is said to be chiral, and the two mirror image forms are called enantiomers. A person’s left and right hands are one familiar macroscopic example of chiral objects. Chirality is of immense interest in chemistry, because many organic molecules are chiral. Any atom in a molecule that is tetrahedrally bonded to four different functional...

Journal: :Physical chemistry chemical physics : PCCP 2011
Donald G Fraser Daniel Fitz T Jakschitz Bernd M Rode

Smectite clays are hydrated layer silicates that, like micas, occur naturally in abundance. Importantly, they have readily modifiable interlayer spaces that provide excellent sites for nanochemistry. Vermiculite is one such smectite clay and in the presence of small chain-length alkyl-NH(3)Cl ions forms sensitive, 1-D ordered model clay systems with expandable nano-pore inter-layer regions. The...

2004

The manner in which biologically active molecules, such as proteins, peptides, etc. bind to surfaces is of relevance due to a number of applications such as the development of biosensors and biocompatible materials. The structure, conformation and local order of these molecules upon adsorption influence their interaction with further incoming species and the process of molecular recognition. Ma...

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