Topic
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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TL;DR: The topography of the β-turn was investigated in this paper using 146 examples of βturns reported in the literature and common topographical features were observed across a wide variety of β turn types, including the spatial relationship between the entry and exit peptide bonds and the relative orientations of the intervening sidechains.
111 citations
TL;DR: It is shown that MD simulations of reasonable duration can describe the main characteristics of the peptide-TiO(2) surface interaction in solution, at least on a short time scale.
Abstract: Ab initio periodic calculations and classical molecular dynamics (MD) simulations were performed to investigate the adsorption mode of alanine and a number of short peptides, in particular two peptides, alanine-glutamic acid and alanine-lysine, taken as model systems for the ionic self-complementary oligopeptide EAK16-II, onto TiO(2) (110) rutile surface, and their conformational characteristics upon adsorption. The atomistic description of the rutile surface and its interactions with water and peptide molecules were based on ab initio calculations, the TIP3P water model, the AMBER force field, and available parameters. By comparison with ab initio calculations, it is shown that MD simulations of reasonable duration can describe the main characteristics of the peptide-TiO(2) surface interaction in solution, at least on a short time scale. Atom-atom radial distribution functions, atom-surface distances, backbone and side chain dihedral angle distributions, and peptide-surface interaction energies have been analyzed. Once adsorbed onto the TiO(2) rutile surface by a bidentate interaction of both carboxyl oxygens with two adjacent Ti atoms, the small peptide studied showed a clear propensity to remain there and undergo relatively limited hinge-bending motions.
111 citations
TL;DR: In this article, the effect of variation of structural factors on the spin exchange interaction between copper(II) centers in dialkoxo-bridged dinuclear copper complexes were studied by the ab initio MO method with UHF formalism.
Abstract: The effect of variation of structural factors on the spin-exchange interaction between copper(II) centers in dialkoxo-bridged dinuclear copper complexes were studied by the ab initio MO method with UHF formalism. The calculations were performed on di-μ-methoxotetraamminedicopper(II). The J-values were obtained as functions of Cu–O–Cu angle, dihedral angle between two coordination planes, planarity of bonds on the bridging oxygens, tetrahedral distortion of coordination planes, and the tilt of O–C bond from the O–O axis. The results demonstrated that the Cu–O–Cu angle most effectively affect the J-value but the other factors are less effective.
111 citations
TL;DR: The ferromagnetic exchange coupling is discussed using DFT calculations on model compounds that have shown a countercomplementary effect of the hydroxo and acetate bridges.
Abstract: The structural and magnetic data of the trinuclear compound [Cu3(L)2(CH3COO)2(OH)2(dmf)2] (HL = N-(2-methylpyridyl)toluensulfonylamide) are reported. The compound crystallizes in the monoclinic system, space group P2(1)/n (no. 14), with a = 11.6482(6) A, b = 13.5772(6) A, c = 13.5306(7) A, alpha = 90 degrees, beta = 92.859(5) degrees, gamma = 90 degrees, and Z = 2. The three copper atoms form an exact linear arrangement. Neighboring coppers are connected by a hydroxo bridge and a bidentate syn-syn carboxylato group. The coordination spheres of the terminal copper atoms are square pyramidal with a dmf molecule as the apical ligand. The central copper has a regular square planar geometry. The mixed bridging by a hydroxide oxygen atom and a bidentate carboxylato group leads to a noncoplanarity of the adjacent basal coordination planes with a dihedral angle of 51.96(9) degrees. Susceptibility measurements (2-300 K) reveal a strong ferromagnetic coupling, J = 93(6) cm-1, in the mixed-bridged moiety leading to a quartet ground state that is confirmed by the EPR spectra. The ferromagnetic exchange coupling is discussed using DFT calculations on model compounds that have shown a countercomplementary effect of the hydroxo and acetate bridges.
111 citations
TL;DR: In this paper, the vibrational frequencies of biphenyl and its 4,4'-dihalogen derivatives have been computed for various values of the dihedral angle between the two rings.
111 citations