1,129 research outputs found
(E)-N′-(2-FurylmethylÂene)benzoÂhydrazide
In the title compound, C12H10N2O2, the dihedral angle between the benzene and furan rings is 52.54 (7)°. In the crystal, interÂmolecular N—H⋯O hydrogen bonds and C—H⋯π interÂactions link the molÂecules
(E)-N′-[1-(4-BromoÂphenÂyl)ethylÂidene]-2-hydroxyÂbenzohydrazide
In the title compound, C15H13BrN2O2, the two aromatic rings form a dihedral angle of 7.9 (1)° and an intraÂmolecular N—H⋯O hydrogen bond influences the molÂecular conformation. In the crystal, interÂmolecular O—H⋯O hydrogen bonds link the molÂecules into chains propagated in [001]. The crystal packing exhibits also π–π interÂactions, which pair molÂecules into centrosymmetric dimers with short interÂmolecular distances of 3.671 (4) Å between the centroids of aromatic rings
N′-(2-ChloroÂbenzylÂidene)benzoÂhydrazide
The asymmetric unit of the title compound, C14H11ClN2O, contains two independent molÂecules. In one molÂecule, the two aromatic rings form a dihedral angle of 45.94 (16)°, while in the second molÂecule this angle is 58.48 (16)°. In the crystal, interÂmolecular N—H⋯O hydrogen bonds link the molÂecules into two crystallographically independent sets of chains propagating along [001]
Cosmological constraints on holographic dark energy models under the energy conditions
We study the holographic and agegraphic dark energy models without
interaction using the latest observational Hubble parameter data (OHD), the
Union2.1 compilation of type Ia supernovae (SNIa), and the energy conditions.
Scenarios of dark energy are distinguished by the cut-off of cosmic age,
conformal time, and event horizon. The best-fit value of matter density for the
three scenarios almost steadily located at by the joint
constraint. For the agegraphic models, they can be recovered to the standard
cosmological model when the constant which presents the fraction of dark
energy approaches to infinity. Absence of upper limit of by the joint
constraint demonstrates the recovery possibility. Using the fitted result, we
also reconstruct the current equation of state of dark energy at different
scenarios, respectively. Employing the model criteria
, we find that conformal time model is the worst,
but they can not be distinguished clearly. Comparing with the observational
constraints, we find that SEC is fulfilled at redshift with confidence level. We also find that NEC gives a meaningful
constraint for the event horizon cut-off model, especially compared with OHD
only. We note that the energy condition maybe could play an important role in
the interacting models because of different degeneracy between and
constant .Comment: 8 pages, 4 figures, accepted for publication in PR
1-(2-HyÂdroxyÂbenzoÂyl)thioÂsemicarbazide hemihydrate
The asymmetric unit of the title compound, C8H9N3O2S·0.5H2O, contains two thiosemicarbazide molÂecules with the short distance of 3.521 (3) Å between the centroids of the benzene rings, and one water molÂecule. In the two independent molÂecules, the benzene rings and the thioÂsemicarbazone fragments are twisted at 9.2 (3) and 18.5 (3)°. An extensive three-dimensional hydrogen-bonding network, formed by interÂmolecular N—H⋯O, N—H⋯S and O—H⋯O hydrogen bonds, consolidates the crystal packing
N′-(2-HyÂdroxy-1,2-diphenylÂethylÂidene)benzohydrazide
In the title compound, C21H18N2O2, the amino group is involved in an intraÂmolecular N—H⋯O hydrogen bond. The rings make dihedral angles of 37.9 (2), 64.4 (2) and 83.6 (2)°. In the crystal, interÂmolecular O—H⋯N and O—H⋯O hydrogen bonds link the molÂecules into chains running along [100]
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