scispace - formally typeset
Search or ask a question
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
More filters
Journal ArticleDOI
TL;DR: In this article, 4-cyanobenzylideneamino antipyrine (CBAP) has been synthesized and characterized by elemental analysis, FT-IR, UV-VIS and X-ray single crystal diffraction techniques.
Abstract: 4-(4-cyanobenzylideneamino)antipyrine (CBAP) has been synthesized and characterized by elemental analysis, FT-IR, UV-VIS and X-ray single crystal diffraction techniques. Crystallographic study reveals that the compound adopts trans configuration about the Schiff base imine double bond. The substituted p-cyanophenyl ring indirectly linked to the pyrazoline ring by the C=N double bond is almost coplanar with the pyrazole ring, whereas the phenyl ring directly attached to the pyrazoline ring forms an effective dihedral angle. Density functional calculations have been carried out to optimize and to characterize the title compound by using B3LYP method at 6-31G(d) basis set. The calculated results show that the optimized geometry can well reproduce the crystal structural parameters and the theoretical vibrational frequencies show good agreement with experimental values. On the basis of theoretical vibrational analyses, the thermodynamic properties (standard heat capacities, standard entropies, and standard ent...

108 citations

Journal ArticleDOI
TL;DR: A new penalty function for use in restrained molecular dynamics simulations which allows experimental J-coupling information to be enforced as a time-averaged, rather than instantaneous, quantity is described.
Abstract: We describe a new penalty function for use in restrained molecular dynamics simulations which allows experimental J-coupling information to be enforced as a time-averaged, rather than instantaneous, quantity. The pseudo-energy term has been formulated in terms of a calculated J value (a measured quantity) rather than the relevant dihedral angle (a derived quantity). This accounts for the distinct non-linearity of the coupling constant with respect to either Cartesian coordinates or dihedral angles. Example simulations of the cyclic decapeptide antamanide show the procedure's ability to enforce experimental restraints while exploring a large region of conformational space and producing a relatively small disturbance of the physical force field.

108 citations

Journal ArticleDOI
Chang Seop Hong1, Youngkyu Do1
TL;DR: Ferromagnetic coupling between metal centers and end-to-end coordination of the azido bridges were found together for the first time in the one-dimensional nickel(II) compound [Ni(5-methylpyrazole)4(N3)]n] as mentioned in this paper.
Abstract: Ferromagnetic coupling between metal centers and end-to-end coordination of the azido bridges were found together for the first time in the one-dimensional nickel(II) compound [{Ni(5-methylpyrazole)4(N3)}n](ClO4)n⋅n H2O (1; the structure in the unit cell is shown). The ferromagnetic coupling involving spin canting occurs between the two crystallographically distinct types of magnetic centers in 1 owing to a large Ni-N3-Ni torsion angle of 75.7° and a dihedral angle of 60.6° between two types of NiN4 least-squares planes.

108 citations

Journal ArticleDOI
TL;DR: The calculations give a tight family of structures in the region Tyr2 to Phe4, all containing a type VI turn with an unusual disposition of the aromatic rings of Tyr and Phe, which stack against the proline ring.

108 citations

Journal ArticleDOI
TL;DR: In this paper, a proposed intramolecular hydrogen bond in the 2−haloethanols has been investigated with analysis of the microwave spectra of 2−chloroethanol and 2−bromo-ethanol, for each moledule, only a form gauche about the CC bond has been observed.
Abstract: A proposed intramolecular hydrogen bond in the 2‐haloethanols has been investigated with analysis of the microwave spectra of 2‐chloroethanol and 2‐bromoethanol. For each moledule, only a form gauche about the CC bond has been observed. For the chloro compound nine isotopic species have been studied to yield the molecular coordinates of the chlorine, oxygen, hydroxyl hydrogen, and carbon atoms, and thus a molecular structure. For bromoethanol a molecular structure has been found based upon the coordinates of the bromine and hydroxyl hydrogen atoms. Principal structural conclusions are that, of the probable rotameric forms, the lowest energy form is the one allowing close approach of hydrogen and halogen—namely, the gauche–gauche for dihedral angles (CCX) (COH) close to 60°. The O–H bond length in chloroethanol is 1.008 A, about 5% longer than in ethanol. The H···X distance is ∼ 0.5 A less than the sum of the atom van der Waals radii for X = Cl, Br. The O···X distance is approximately equal to the sum of t...

107 citations


Network Information
Related Topics (5)
Hydrogen bond
57.7K papers, 1.3M citations
88% related
Crystal structure
100.9K papers, 1.5M citations
85% related
Ligand
67.7K papers, 1.3M citations
80% related
Molecule
52.4K papers, 1.2M citations
79% related
Intramolecular force
41.6K papers, 772.2K citations
77% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023203
2022473
2021160
2020195
2019193
2018216