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Dihedral angle

About: Dihedral angle is a research topic. Over the lifetime, 15718 publications have been published within this topic receiving 174904 citations.


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Journal ArticleDOI
TL;DR: Three compounds that bear two axially chiral bridged binaphthyl units were developed as photodynamic chiral dopants for nematic liquid crystals by inducing a change in the dihedral angle that led to an inversion of the handedness of the helices.
Abstract: A good turn: Three compounds that bear two axially chiral bridged binaphthyl units were developed as photodynamic chiral dopants for nematic liquid crystals. For compounds with suitable bridge lengths, a change in the dihedral angle induced a switch of the binaphthyl units from the cisoid to the transoid form upon UV irradiation, which led to an inversion of the handedness of the helices.

117 citations

Journal ArticleDOI
TL;DR: The solution conformation of the ribonuclease barnase has been determined by using 1H nuclear magnetic resonance (NMR) spectroscopy as mentioned in this paper, using 853 interproton distance restraints obtained from analyses of two-dimensional nuclear Overhauser spectra, 72 phi and 53 chi 1 torsion angle restraints and 17 hydrogen-bond distance restraints.
Abstract: The solution conformation of the ribonuclease barnase has been determined by using 1H nuclear magnetic resonance (NMR) spectroscopy. The 20 structures were calculated by using 853 interproton distance restraints obtained from analyses of two-dimensional nuclear Overhauser spectra, 72 phi and 53 chi 1 torsion angle restraints, and 17 hydrogen-bond distance restraints. The calculated structures contain two alpha-helices (residues 6-18 and 26-34) and a five-stranded antiparallel beta-sheet (residues 50-55, 70-75, 85-91, 94-101, and 105-108). The core of the protein is formed by the packing of one of the alpha-helices (residues 6-18) onto the beta-sheet. The average RMS deviation between the calculated structures and the mean structure is 1.11 A for the backbone atoms and 1.75 A for all atoms. The protein is least well-defined in the N-terminal region and in three large loops. When these regions are excluded, the average RMS deviation between the calculated structures and the mean structure for residues 5-34, 50-56, 71-76, 85-109 is 0.62 A for the backbone atoms and 1.0 A for all atoms. The NMR-derived structure has been compared with the crystal structure of barnase [Mauguen et al. (1982) Nature (London) 297, 162-164].

116 citations

Journal ArticleDOI
TL;DR: In this paper, an extension to the configurational-bias Monte Carlo method is presented which allows for the efficient conformational sampling of the interior segments of chain molecules whose interactions include strong bonded terms (governing bond stretching, bond angle bending and dihedral angle rotation).
Abstract: An extension to the configurational-bias Monte Carlo method is presented which allows for the efficient conformational sampling of the interior segments of chain molecules whose interactions include strong bonded terms (governing bond stretching, bond angle bending, and dihedral angle rotation). The ability to regrow interior segments overcomes the limitations of conventional configurational-bias methods (where the regrowth is always directed to a free chain end) and now allows for the simulation of chain systems with low concentrations of chain ends, that is, higher molecular weights, networks, or cyclic structures. As previously proposed by Dijkstra et al. [J. Chem. Phys. 1994, 101, 3179] for lattice polymers and by Vendruscolo [J. Chem. Phys. 1997, 106, 2970] for freely jointed polymers, an additional biasing (closing) probability is used that guides the bead-by-bead configurational-bias regrowth of interior segments toward its desired fixed target. However, while the previous methods are limited to ch...

115 citations

Journal ArticleDOI
TL;DR: In this paper, the texture, distribution, and infiltration tendency of a quartz-albite melt in equilibrium with a synthetic, texturally-equilibrated quartzite was examined in a series of distribution and infiltration experiments at 1,250° C and 8 kbar hydrostatic pressure.
Abstract: The texture, distribution, and infiltration tendency of a quartz-albite melt in equilibrium with a synthetic, texturally-equilibrated quartzite was examined in a series of distribution and infiltration experiments at 1,250° C and 8 kbar hydrostatic pressure. Wetting angle measurements from melt distribution experiments show a dihedral angle (θ) of 60 degrees, implying a quartz/quartz interfacial energy approximately 1.7 times the quartz/melt value. Because of this specific relationship between interfacial energies, the system can achieve its lowest surface free energy state with the melt either in pools or along grain edge intersections, possibly forming some interconnected channels. Stability of melt in pockets and along grain edge intersections was observed in a fourteen-day, dispersed-melt experiment, yet melt pools failed to disperse into the quartzite during infiltration experiments. Comparison of the observed dihedral angle with previously measured surface energy values for the melt and quartz shows excellent agreement, and also demonstrates that an aggregate of randomly orientated anisotropic grains acts approximately isotropically.

114 citations

Journal ArticleDOI
15 Mar 1989
TL;DR: In this article, the possibility of molecular switching was investigated theoretically on a model system in which two redox active sites are connected by 4,4′-bipyridine, and the electronic coupling between these sites was determined by two methods: theimer splitting method and the effective Hamiltonian method.
Abstract: The possibility of molecular switching is investigated theoretically on a model system in which two redox active sites are connected by 4,4′-bipyridine. The electronic coupling between these sites is determined by two methods: the “dimer splitting” method and the effective Hamiltonian method. The pathways for electronic coupling are analyzed and computed for all dihedral angles between the pyridine cycles. It is found that the π-π coupling dominates the electronic interaction for most angle values. However, in strictly perpendicular conformation, the electronic interaction does not vanish, due to the existence of crossed σ-π interactions.

114 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023203
2022473
2021160
2020195
2019193
2018216