Structural,spectroscopic and first‐principles studies of new aminocoumarin derivatives

The new aminocoumarin derivatives 3‐[1‐(3‐hydroxyanilino)ethylidene]‐3H‐chromene‐2,4‐dione, ( 1 ), 3‐[1‐(4‐hydroxyanilino)ethylidene]‐3H‐chromene‐2,4‐dione, ( 2 ), and 3‐[1‐(2‐hydroxyanilino)ethylidene]‐3H‐chromene‐2,4‐dione, ( 3 ), all C₁₇H₁₃NO₄, were synthesized by reacting an equimolar amount of 3‐acetyl‐4‐hydroxycoumarin and the corresponding aminophenol in absolute ethanol. Structural and spectroscopic analysis of these phases revealed that derivatives ( 1 ) and ( 2 ) are isomers of previously reported ( 3 ) [Brahmia et al. (2013). Acta Cryst. E 69 , o1296]. The crystal structures of meta derivative ( 1 ) and para derivative ( 2 ) were ab initio determined from powder X‐ray diffraction data using the direct‐space approach. Both ( 1 ) and ( 2 ) adopt the orthorhombic space group P2₁2₁2₁. These isomers show hydrogen bonds and rich π–π stacking, together with π…H interactions, which are built by conjugated systems of coumarin and phenol rings. In the crystalline lattice, the packing of ( 1 ) and ( 3 ) are mainly stabilized through O—H…O hydrogen bonding between neighbouring coumarin molecules, while hydrogen bonds between coumarin and water molecules build the stable crystal structure of derivative ( 2 ). A big similarity in the skeletons of the IR spectra of these isomers was noticed. Derivative ( 2 ) exhibits two weak bands which were not present in the spectra of the other two derivatives, at 2370 and 2948 cm^?1, which can be assigned to the O—H vibrations of the solvent (H₂O) trapped in the structure of ( 2 ). These aminocoumarin derivatives display absorption maxima in the visible region, attributed to π–π delocalization involving the whole electronic system of the compounds with a considerable charge‐transfer character originating from the aminophenyl ring and pointing towards the coumarin system which is characterized by a high electron‐accepting character. Additionally, the isolated molecular ground‐state geometries were optimized at the PBE0/TZP level and the electronic properties, molecular electrostatic potential and Hirshfeld charges were determined.     

H2-broadening,shifting and mixing coefficients of the doublets in the ν2 and ν4 bands of PH3 at room temperature

The broadening, shifting and mixing coefficients of the doublet spectral lines in the ν₂ and ν₄ bands of PH₃ perturbed by H₂ have been determined at room temperature. Indeed, the collisional spectroscopic parameters: intensities, line widths, line shifts and line mixing parameters, are all grouped together in the collisional relaxation matrix. To analyse the collisional process and physical effects on spectra of phosphine (PH₃), we have used the measurements carried out using a tunable diode-laser spectrometer in the ν₂ and ν₄ bands of PH₃ perturbed by hydrogen (H₂) at room temperature. The recorded spectra are fitted by the Voigt profile and the speed-dependent uncorrelated hard collision model of Rautian and Sobelman. These profiles are developed in the studies of isolated lines and are modified to account for the line mixing effects in the overlapping lines. The line widths, line shifts and line mixing parameters are given for six A₁ and A₂ doublet lines with quantum numbers K = 3n,?(n = 1,?2, …) and overlapped by collisional broadening at pressures of less than 50 mbar.     

General decay for a coupled Lamé system of nonlinear viscoelastic equations

In this paper, we consider a coupled Lamé system of nonlinear viscoelastic equations with general source terms. Under some suitable conditions on the initial data and the relaxation functions, we prove an asymptotic stability result of global solution taking into account that the kernel is not necessarily decreasing. This work generalizes and improves earlier results in the literature.     

Tail product-limit process for truncated data with application to extreme value index estimation

A weighted Gaussian approximation to tail product-limit process for Pareto-like distributions of randomly right-truncated data is provided and a new consistent and asymptotically normal estimator of the extreme value index is introduced. A simulation study is carried out to evaluate the finite sample behavior of the proposed estimator and compare it to that recently proposed by Gardes and Stupfler (TEST 24, 207–227, 2015). Also, a new approach of estimating extreme quantiles, under random right truncation, is derived and applied to a real dataset of lifetimes of automobile brake pads.     

Synthesis,spectroscopic and antibacterial investigations of new hydroxy ethers and heterocyclic coumarin derivatives

The reactions between oligoethylene glycol diglycidyl ethers 2a‐c with both 7‐hydroxy‐4‐methyl‐2H‐chromen‐2‐one and 4‐hydroxy‐2H‐chromen‐2‐one lead to new hydroxy ethers 3 and 4 containing coumarin moieties in good yield. The synthesis of 3‐(3‐(dimethylamino)acryloyl)‐4‐hydroxy‐2H‐chromen‐2‐one 5 and new heterocyclic compounds 4‐hydroxy‐3‐(1H‐pyrazol‐3‐yl)‐2H‐chromen‐2‐one 6a , 4‐hydroxy‐3‐(1‐phenylpyrazol‐3‐yl)‐2H‐chromen‐2‐one 6b and 4‐hydroxy‐3‐(isoxazol‐3‐yl)‐2H‐chromen‐2‐one 6c is also described. All compounds were characterized by ¹H NMR, ¹³C{¹H} NMR, 2D‐¹H‐¹³C HMBC, 2D‐¹H NOESY NMR, IR, and MS spectroscopy. Additionally, the antibacterial activity of the new products containing coumarin moiety was evaluated. This activity is clearly dependent on the chemical structure of compounds.     

Purification of pediocin PA-1 by immunoaffinity chromatography

A one-step purification procedure for purifying pediocin PA-1, a class IIa bacteriocin produced by Pediococcus acidilactici UL5, was developed based on column immunoaffinity chromatography with specific antipediocin PA-1 polyclonal antibodies coupled to cyanogen bromide-activated SepharoseTM. About 13.3 microg/mL purified pediocin PA-1 was obtained from 15 mL P. acidilactici UL5 culture supernatant, as measured by enzyme-linked immunosorbent assay. The specific activity and average recovery of the eluted pediocin PA-1 were about 6602 AU/mg and 53.3%, respectively. This is the first report of successful purification of pediocin PA-1 by immunoaffinity using pediocin PA-1-specific polyclonal antibodies.     

Extension of the non-uniform warping theory to an orthotropic composite beam

This Note proposes an extension to composite section of the non-uniform (out-of-plane) warping beam theory recently established for homogeneous and isotropic beam by R. El Fatmi (C. R. Mecanique 335 (2007) 467–474). For the present work, which constitutes a first step of this extension, the cross-section is assumed to be symmetric and made by orthotropic materials; however, Poisson's effects (called here in-plane warping) are also taken into account. Closed form results are given for the structural behavior of the composite beam and for the expressions of the 3D stresses; these ones, easy to compare with 3D Saint Venant stresses, make clear the additional contribution of the new internal forces induced by the non-uniformity of the (in and out) warpings. As first numerical applications, results on torsion and shear-bending of a cantilever sandwich beam are presented.     

Full potential study of the elastic, electronic, and optical properties of spinels MgIn2S4 and CdIn2S4 under pressure effect

The structural, elastic, electronic, and optical properties of cubic spinel MgIn₂S₄ and CdIn₂S₄ compounds have been calculated using a full relativistic version of the full-potential linearized-augmented plane wave with the mixed basis FP/APW+lo method. The exchange and correlation potential is treated by the generalized-gradient approximation (GGA). Moreover, the Engel-Vosko GGA formalism is also applied to optimize the corresponding potential for band structure calculations. The ground state properties, including the lattice constants, the internal parameter, the bulk modulus, and the pressure derivative of the bulk modulus are in reasonable agreement with the available data. Using the total energy-strain technique, we have determined the full set of first-order elastic constants C_ij and their pressure dependence, which have not been calculated or measured yet. The shear modulus, Young’s modulus, and Poisson’s ratio are calculated for polycrystalline XIn₂S₄ aggregates. The Debye temperature is estimated from the average sound velocity. Electronic band structures show a direct band gap (Г-Г) for MgIn₂S₄ and an indirect band gap (K-Г) for CdIn₂S₄. The calculated band gaps with EVGGA show a significant improvement over the GGA. The optical constants, including the dielectric function ε(ω), the refractive index n(ω), the reflectivity R(ω), and the energy loss function L(ω) were calculated for radiation up to 30 eV.     

Molecular docking study on β-cyclodextrin Interactions of metobromuron and [3-(p-bromophenyl)-1-methoxy-1-methylurea]

The inclusion process involving β-cyclodextrin (β-cyclodextrin-CD) and phenylurea herbicide metobromuron (MB) has been investigated by using the MM+, PM3, B3LYP, HF, ONIOM2 and NBO methods. The binding and complexation energies for both orientations considered in this research are reported. The geometry of the most stable complex shows that the aromatic ring is deeply self-included inside the hydrophobic cavity of β-CD also an intermolecular hydrogen bond is established between host and guest molecules. This suggests that hydrophobic effect and hydrogen bond play an important role in the complexation process. The statistical thermodynamic calculations by PM3 demonstrate that 1:1?MB/β-CD complex is favored by a negative enthalpy change. Moreover, NBO calculations proved also that are a very useful means to quantify the interaction energies of the hydrogen bonds.     

Effect of humidity and UV-assistance on the preparation of erbium doped alumina by aerosol MOCVD process

The effect of deposition temperature, relative humidity of carrier gas and UV-assistance on the growth of Erbium-doped aluminium oxide films has been studied. The films were prepared from aluminium acetylacetonate (Al(C₅H₇O₂)₃) and erbium (III) Tris(2,2,6,6-tetramethyl-3,5-heptanedionate) (Er(TMHD)₃) by UV and aerosol-assisted metal-organic chemical vapour deposition, using air with controlled humidity as carrier gas. Amorphous transparent films were deposited between 350 and 460 °C. It was observed that UV assistance allows a large decrease down to 5 kJ/mol of the activation energy of the deposition reaction for deposition temperatures lower than 420 °C. More over, depositing under high air humidity induced higher deposition rate, lower level of organic contamination and higher film density. Under these conditions Er-doped aluminium oxide films with a refractive index value of 1.71 were obtained at 460 °C.