Search results for "Chiral"
showing 10 items of 752 documents
Supramolecular chirality and symmetry breaking of fluoride complexes of achiral foldamers
2017
Aromatic oligoamide foldamers containing a central pyridine-2,6-dicarbonyl motif are partially preorganized to favor the binding of fluoride anions. In the solid state, the foldamer-fluoride complexes form achiral, polar and chiral crystal structures depending on the chemical structure of the foldamer. One of the six foldamers studied here, a C2v symmetrical foldamer (1), formed repeatedly chiral crystal structures when crystallized with tetra-butylammonium fluoride, showing supramolecular bulk chirality and symmetry breaking in crystallization.
Dynamical Casimir-Polder interaction between a chiral molecule and a surface
2016
We develop a dynamical approach to study the Casimir-Polder force between a initially bare molecule and a magnetodielectric body at finite temperature. Switching on the interaction between the molecule and the field at a particular time, we study the resulting temporal evolution of the Casimir-Polder interaction. The dynamical self-dressing of the molecule and its population-induced dynamics are accounted for and discussed. In particular, we find that the Casimir-Polder force between a chiral molecule and a perfect mirror oscillates in time with a frequency related to the molecular transition frequency, and converges to the static result for large times.
Catalytic Enantioselective Conjugate Alkynylation of β-Aryl-β-trifluoromethyl Enones Constructing Propargylic All-Carbon Quaternary Stereogenic Cente…
2016
The enantioselective conjugate alkynylation of β-aryl-β-trifluoromethyl enones has been carried out using terminal alkynes and diethylzinc in the presence of 3,3'-bis(perfluorophenyl)BINOL as the chiral ligand to give the corresponding ketones bearing a trifluoromethylated propargylic quaternary stereocenter with fair to good enantioselectivities. Enones bearing a bulky 2-naphthyl attached to the carbonyl group provided the best enantioselectivities. The synthetic applicability of the resulting products has been demonstrated with their iodocyclization to form 4H-pyrans.
Enantioseparations with polysaccharide-based chiral stationary phases in HPLC. Application to the enantioselective evaluation of the biodegradability…
2023
The chiral nature of living systems has obvious implications for the biologically active compounds that interact with them. At the molecular level, chirality represents an intrinsic property of the essential building blocks of life, such as amino acids and sugars, and therefore, of peptides, proteins, enzymes, carbohydrates, nucleosides and a number of alkaloids and hormones. As a consequence, processes mediated by biological systems are stereochemistry-sensitive, and a pair of enantiomers can have different effects on living organisms. The scientific community has been studying the implications of chirality for life for more than a century. Today, it is still a topic of active research and…
Meson–meson and meson–baryon interactions in a chiral non-perturbative approach
1998
A qualitative account of the meson-meson and meson-baryon interactions using chiral Lagrangians and the inverse amplitude method in coupled channels is done. The method, imposing exact unitarity, proves to be a very useful tool to extend the information contained in the chiral Lagrangians at energies beyond the realm of applicability of chiral perturbation theory. Oset Baguena, Eulogio, Eulogio.Oset@ific.uv.es
Chiral symmetry in the KḰ and kn systems
1996
In this talk we present teh results of recent developments in the aplication of Chiral perturbation theory to the KḰ system and to de K+N →KNπ reaction close to threshosd. In the first case, we study the decay channels of the a0 and f0 mesons assumed to be made largely from KḰ. In the second case comparison is made with the present data. A qualitative agreement with experiment is both in found cases. Oset Baguena, Eulogio, Eulogio.Oset@ific.uv.es, Nieves Pamplona, Juan Miguel, Juan.M.Nieves@ific.uv.es
Chiral Low-Energy Constants: Status and Prospects
2007
7 pages.-- PACS nrs.: 11.15.Pg, 12.38.-t, 12.39.Fe.-- ISI Article Identifier: 000252187200017.-- ArXiv pre-print available at: http://arxiv.org/abs/0710.4405
Chiral symmetry andπ-πscattering in the covariant spectator theory
2014
The π-π scattering amplitude calculated with a model for the quark-antiquark interaction in the framework of the Covariant Spectator Theory (CST) is shown to satisfy the Adler zero constraint imposed by chiral symmetry. The CST formalism is established in Minkowski space and our calculations are performed in momentum space. We prove that the axial-vector Ward-Takahashi identity is satisfied by our model. Then we show that, similarly to what happens within the Bethe-Salpeter formalism, application of the axial-vector Ward Takahashi identity to the CST π-π scattering amplitude allows us to sum the intermediate quark-quark interactions to all orders. Thus, the Adler self-consistency zero for π…
A SU(4) circle times O(3) scheme for nonstrange baryons
2007
4 pages, 3 tables.-- PACS nrs.: 12.39.Jh, 14.20.-c, 14.20.Gk.-- ISI Article Identifier: 000245667300027.-- ArXiv pre-print available at: http://arxiv.org/abs/hep-ph/0610257
Theoretical Simulations on Electric Properties of CNT-Me and GNR-Me Interconnects Using Effective Media Approach
2011
Abstract To overcome disadvantages of nowadays microtechnology, a further miniaturization of electronic devices, high integration level as well as increase of both operation frequencies and power density is required, including the use of adequate materials and innovative chip interconnects. Due to their unique physical properties, especially due to a ballistic (without losses) mechanism of conductivity, carbon nanotubes (CNTs) and graphene nanoribbons (GNRs) attract a permanently growing technological interest, for example, as promising candidates for nanointerconnects in a high-speed electronics.