Classical chemical sciences
A clean, simple, highly efficient and eco-friendly benign method for the synthesis of 1, 8-dioxo-octahydroxanthene derivatives utilizing novel bronsted acidic ionic liquid; L-Pyrrolidine-2-carboxylic acid sulfate (LPCAS) as reagent been reported. Distinguishing features of the methodology are excellent yield of products in shorter reaction time, cleaner reaction profile, environmentally friendly nature and the use of inexpensive reagent.
Keywords: 1,8-dioxooctahydroxanthenes, L-pyrrolidine-2-carboxylic acid sulfate (LPCAS), eco-friendly, solvent free, ionic liqud
In crystal of 1,8-bis(4-fluorobenzoyl)naphthalene-2,7-diyl dibenzoate, C38H22O6F2, the phenyl rings of benzoyloxy groups and the naphthalene ring demonstrate largely disproportionate interplanar angles [38.97(7)° and 52.62(6)°] different from those between 4-fluorobenzoyl group and the naphthalene ring core [71.24(5)° and 78.85(6)°]. One of two benzoyloxy groups has three effective intramolecular interactions [(benzoyloxy)C–H(o-)···O(benzoyloxy), (naphthalene)C–H(6-)···O=C(benzoyloxy), and (benzoyloxy)C–H(o-)···π(4-fluorobenzoyl) hydrogen bonds] and the other has no intramolecular interactions. In crystal, the molecules of identical enantiomeric isomer are unidirectionarly arranged along the b axis through (4-fluorobenzoyl)C–H(m-)···O=C(4-fluorobenzoyl) hydrogen bonding interactions forming columnar structure. Moreover, a column is connected with the mirror imaged column composed of the opposite enantiomeric isomers into centrosymmetric dimer aggregates by three types of complementary interactions, i.e., (benzoyloxy)C–H(m-)···F, (4-fluorobenzoyl)C–H(m-)···π(4-fluorobenzoyl), and (4-fluorobenzoyl)C–H(m-)···π(benzoyloxy) hydrogen bondings. The tubular structures thus formed are stacked parallel to the ac plane via (benzoyloxy)C–H(p-)…F, (benzoyloxy)C–H(m-)…(benzoyloxy), (naphthalene)C–H(6-)…O=C(4-fluorobenzoyl), and (4-fluorobenzoyl)C–H(o-)…O=C(benzoyloxy) hydrogen bonds. In homologous compound, a fluoro group-free derivative for title compound, the enantiomeric isomer and the opposite enantiomeric counterpart isomer are alternately arranged in a head-to-tail fashion through (benzoyl)C–H(p-)…O=C(benzoyl) hydrogen bonds along b-axis. The zigzagged columns are aligned along a-axis with inversion center to form a sheet structure. However, there are no effective non-covalent bonding interactions between the zigzagged columns. In other words, the molecular packing structure of the homologous compound is governed by solely one strong (benzoyl)C–H(p-)…O=C(benzoyl) hydrogen bonds, contrary to the organization of supramolecular architecture in title compound ascribed to cooperative unidirectional (4-fluorobenzoyl)C–H(m-)…O=C(4-fluorobenzoyl) hydrogen bonds and bidirectional (benzoyloxy)C–H(m-/p-)…F hydrogen bonds.
Keywords: non-coplanarly accumulated aromatic rings; non-classical hydrogen bonds; C–H···F hydrogen bonds; C–H···O=C hydrogen bonds.
An efficient methodology has been developed by which a series of new 2-indolylmethylene-linked compounds can be readily synthesized by thermal Knoevenagel condensation of 3-methylindole-2-carboxaldehyde and cyclic active methylene compounds under catalyst- and solvent-free conditions.
Keywords: Knoevenagel condensation, 3-methylindole-2-aldehyde, cyclic active methylene compounds, catalyst- and solvent-free reaction
Materials and environmental chemistry
The synthesis of the steroidal imidazole and nickel molybdate based composite membrane is described. The fabricated composite material was characterized by using FT-IR, XRD, PSA and SEM and has been investigated for its functional, diffusive, structural, electrical and optical properties. The SEM showed that membrane has random non-preferential orientation with no visible cracks and appeared to be composed of dense and loose aggregation of small particles. No impurity peak was observed in the XRD pattern showing the single phase composite formation. The IR spectra showed the characteristic absorption peaks of different functional groups present in the composite. It was observed that real impedance decreased with the increase in frequency while AC conductivity gradually increased with the increase in frequency of applied AC due to hopping phenomenon. It was also confirmed that with the increase in frequency, the dielectric constant decreased and became almost constant at high frequencies for both compositions. The UV-vis spectrum of the synthesized composite indicate band gap energy of about 3.1 eV showing a weak blue shift compared to 4.6 eV for the bulk. Due to their optical and electrical properties, nano phase composite is promising candidate for use as selectivity of different cations.
Keywords: Steroidal imidazole, Band gap, Conductivity, Impedance, SEM
Results of the effect of concentrated light energy in a xenon high-flux optical furnace on transformation of boron nitride (BN) and boron (B) powders in a flow of nitrogen are presented. Raman, Auger Electron (AES), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning and transmission electron microscopes (SEM and TEM), and the measurement of band gap using transmittance technique have been employed for investigation of the properties of produced nanostructures. According Raman, AES and FTIR study the surface of all prepared nano powders is composed of BN. XRD disclosed pure amorphous boron inside particle. Gradient transformation pure boron to BN in the framework of one particle as well as layered nanostructure was observed by TEM study. Dependence of a square of the optical absorption coefficient for a deposited BN film versus the photon energy of incident light has confirmed a gradient and layered nature of the prepared BN nanostructures.
Keywords: Light heating, powder, Boron, Boron nitride, gradient and layered nanostructures.
The inhibition effect of grieseofulvin against the mild steel corrosion in 1 M HCl solution has been investigated by potentiodynamic polarization measurements, electrochemical impedance spectroscopy (EIS) and quantum chemical methods. It was found thatgrieseofulvin acts as a good mild steel corrosion inhibitor in the acid solution at temperature ranging from 298-328 K. The potentiodynamic polarization study reveals that grieseofulvin acts as mixed type inhibitor. The adsorption of grieseofulvin on mild steel follows the Langmuir adsorption isotherm. Scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS) studies established that grieseofulvin formed a protective layer on the surface of mild steel.
Keywords: adsorption; mild steel; corrosion inhibitor; grieseofulvin
Chemical and biological aspects of life
Result of research of quantitative characteristics of biochemical composition of fruits of 30 taxons of 3 Vacciniaceae species (such as V. corymbosum L. (highbush blueberry), V. vitis-idaea L. (lingonberry) and Oxycoccus macrocarpus (Ait.) Pers. (cranberry)) inter-specific distinctions of a degree of stability of its separate components to complex influence of meteorological factors are revealed by 32 parameters (traits) describing the contents in fruits of some organic acids, carbohydrates, phenolic compounds, terpenoids and major mineral elements are presented. The cultivars possessing by the greatest and accordingly by the least levels of dependence on abiotic factors are identified
Keywords: Biochemical composition, genotypic variability, highbush blueberry (V. corymbosum L.), lingonberry (V. vitis-idaea L.), cranberry (Oxycoccus macrocarpus (Ait.) Pers.).
Hypothalamic proline-rich peptide-1 (PRP-1), a neurosecretory cytokine appeared to be involved in the multiple mechanisms of cardioprotection. Dose-dependent effects of PRP-1 (4 and 8 μg) were studied in an open-chest model of myocardial ischemia-reperfusion injury (IRI). Adult male Sprague-Dawley rats underwent 40-minute left anterior descending coronary artery occlusion, under isoflurane anesthesia followed by 2 and/or 24 h of reperfusion. Groups treated with PRP-1 were compared to control. It has been revealed that the efficient dose of PRP-1 can restore in a time-dependent manner the contractile activity of the myocardium and suppress the both inflammation and necrosis via amelioration of oxidative stress in the cardiac tissues therethrough contributing to the in vivo reduction of myocardial infarct volume and an improvement the cardiac hemodynamics and coronary circulation. New studies are needed to ascertain a beneficial effect of PRP-1 in humans and its future clinic use for the myocardial IRI treatment
Keywords: Hypothalamic proline-rich peptide-1; cardiac output; ischemia-reperfusion; myeloperoxidase; myocardial infarction; neutrophils