Topic
Dihedral angle
About: Dihedral angle is a research topic. Over the lifetime, 15718 publications have been published within this topic receiving 174904 citations.
Papers published on a yearly basis
Papers
More filters
Patent•
01 Oct 1974
TL;DR: An electro-mechanical sign which alternatively exhibits two different kinds of information, for example clock or sign display information, on two respective faces of several adjacent dihedral angles as mentioned in this paper.
Abstract: An electro-mechanical sign which alternatively exhibits two different kinds of information, for example clock or sign display information, on two respective faces of several adjacent dihedral angles.
39 citations
TL;DR: A calixarene complex with tetragonal Mn(II 2Gd(III)2 tetranuclear units was synthesized in solvothermal conditions, where the addition of a small amount of water was crucial for the formation of the target compound.
Abstract: A calixarene complex with tetragonal MnII2GdIII2 tetranuclear units was synthesized in solvothermal conditions, where the addition of a small amount of water was crucial for the formation of the target compound. In the structure, two tail-to-tail p-tert-butylthiacalixarenes are located in a C-shaped mode with a dihedral angle of 14.29° but not in the conventional antiparallel arrangement and form a sandwich-like subunit with an in-between Mn2Gd2 unit. Both calixarenes assume similar cone shapes of C2v symmetry but are pinched to different extents. The extended structure is constructed by supramolecular stacking of the sandwich-like units with the interstices filled by the solvent. The magnetic property of the title compound has been examined.
39 citations
TL;DR: The use of 1H and 13C NMR spectroscopy is reported to study the fluctuations in conformation of the anti-bacterial drug trimethoprim when it is bound to its "target," dihydrofolate reductase.
Abstract: The conformation of a small molecule in its binding site on a protein is a major factor in the specificity of the interaction between them. In this paper, we report the use of 1H and 13C NMR spectroscopy to study the fluctuations in conformation of the anti-bacterial drug trimethoprim when it is bound to its "target," dihydrofolate reductase. 13C relaxation measurements reveal dihedral angle changes of +/- 25 degrees to +/- 35 degrees on the subnanosecond time scale, while 13C line-shape analysis demonstrates dihedral angle changes of at least +/- 65 degrees on the millisecond time scale. 1H NMR shows that a specific hydrogen bond between the inhibitor and enzyme, which is believed to make an important contribution to binding, makes and breaks rapidly at room temperature.
39 citations
TL;DR: In this paper, the relative grain boundary energy increases with tilt angle up to about 20 degrees and then remains relatively constant with increasing angle, which is explained by segregation of point defects to the boundary.
Abstract: Relative energies of symmetrical [001] tilt boundaries in nickel oxide bicrystals were determined from the dihedral angle at the groove root with a surface profilometer. At 1535°C in air, the relative grain boundary energy increases with tilt angle up to about 20 degrees and then remains relatively constant with increasing angle. A strong temperature dependence of boundary energy is explained by segregation of point defects to the boundary. Grooving kinetics are controlled by volume diffusion of nickel, and a theoretical discussion of mass transport in nonstoichio-metric solids is given, predicting this behavior under certain conditions.
39 citations
TL;DR: Ab initio calculations using restricted Hartree-Fock, second-order Møller-Plesset perturbation theory (MP2), density-functional theory (DFT), and coupled-cluster methods have been done to obtain the torsional potential-energy profile of the aza-aromatic molecule 4,4'-bipyridine.
Abstract: Ab initio calculations using restricted Hartree-Fock, second-order Moller-Plesset perturbation theory (MP2), density-functional theory (DFT), and coupled-cluster methods have been done to obtain the torsional potential-energy profile of the aza-aromatic molecule 4,4'-bipyridine. The torsional potential is evaluated adiabatically by fixing the normalized sum of the dihedral angles through the C-C inter-ring bond at several values along the torsional path and relaxing the remaining degrees of freedom. Previous discrepancies between MP2 and DFT internal rotation barrier heights are removed, and seen to be mostly due to the underestimation of the dispersion energy in the coplanar conformer by MP2 when using relatively small basis sets. The calculations indicate that the barrier height between the twisted global minimum and the 0 degrees conformer is around 1.5-1.8 kcal mol-1 while that corresponding to the 90 degrees one is about 2.0-2.2 kcal mol-1. This same relative energy ordering of the coplanar and perpendicular conformers was experimentally derived from nuclear magnetic resonance (NMR) measurements of 1H dipolar couplings on 4,4'-bipyridine solutions in a nematic liquid crystal, although the barrier heights are much lower than those estimated from NMR experiments in the gas phase. The DFT infrared spectrum and zero-point vibrational energy corrections to the torsional energy profile have also been calculated, the latter having a small influence on the torsional potential-energy profiles.
39 citations