(E)-N′-[1-(4-Bromo­phen­yl)ethyl­idene]-2-hydroxy­benzohydrazide

In the title compound, C15H13BrN2O2, the two aromatic rings form a dihedral angle of 7.9 (1)° and an intra­molecular N—H⋯O hydrogen bond influences the mol­ecular conformation. In the crystal, inter­molecular O—H⋯O hydrogen bonds link the mol­ecules into chains propagated in [001]. The crystal packing exhibits also π–π inter­actions, which pair mol­ecules into centrosymmetric dimers with short inter­molecular distances of 3.671 (4) Å between the centroids of aromatic rings

(E)-N′-(2-Furylmethyl­ene)benzo­hydrazide

In the title compound, C12H10N2O2, the dihedral angle between the benzene and furan rings is 52.54 (7)°. In the crystal, inter­molecular N—H⋯O hydrogen bonds and C—H⋯π inter­actions link the mol­ecules

N′-(2-Chloro­benzyl­idene)benzo­hydrazide

The asymmetric unit of the title compound, C14H11ClN2O, contains two independent mol­ecules. In one mol­ecule, the two aromatic rings form a dihedral angle of 45.94 (16)°, while in the second mol­ecule this angle is 58.48 (16)°. In the crystal, inter­molecular N—H⋯O hydrogen bonds link the mol­ecules 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 $\Omega_{m0}=0.26$ by the joint constraint. For the agegraphic models, they can be recovered to the standard cosmological model when the constant $c$ which presents the fraction of dark energy approaches to infinity. Absence of upper limit of $c$ 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 $\chi^2_{\textrm{min}}/dof$, 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 $0.2 \lesssim z \lesssim 0.3$ with $1\sigma$ 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 $\Omega_m$ and constant $c$.Comment: 8 pages, 4 figures, accepted for publication in PR

1-(2-Hy­droxy­benzo­yl)thio­semicarbazide hemihydrate

The asymmetric unit of the title compound, C8H9N3O2S·0.5H2O, contains two thiosemicarbazide mol­ecules with the short distance of 3.521 (3) Å between the centroids of the benzene rings, and one water mol­ecule. In the two independent mol­ecules, the benzene rings and the thio­semicarbazone fragments are twisted at 9.2 (3) and 18.5 (3)°. An extensive three-dimensional hydrogen-bonding network, formed by inter­molecular N—H⋯O, N—H⋯S and O—H⋯O hydrogen bonds, consolidates the crystal packing

N′-(2-Hy­droxy-1,2-diphenyl­ethyl­idene)benzohydrazide

In the title compound, C21H18N2O2, the amino group is involved in an intra­molecular N—H⋯O hydrogen bond. The rings make dihedral angles of 37.9 (2), 64.4 (2) and 83.6 (2)°. In the crystal, inter­molecular O—H⋯N and O—H⋯O hydrogen bonds link the mol­ecules into chains running along [100]