Classical chemical sciences
The title compound, C23H16N2O2Cl crystallizes in the triclinic space group P-1 with unit cell parameters a=7.1747(7), b=9.5663(7), c=13.8456(11)Å, α= 97.174(6), β= 97.910(7), γ=98.781(7), Z= 2. The benzimidazol ring is almost perpendicular to the chlorophenyl ring with dihedral angle 88.1(8)º. There are no significant interaction between the molecules except weak C-H-O intramolecular hydrogen bonding. In the benzimidazole ring the five and six membered rings are almost planner with very small deviation. Packing diagram of the given crystal system represent the layer arrangement of the molecules and within the layer the pair of the molecules are reversibly oriented along the b-axis.
Keywords: Benzimidazole; crystal structure; Direct method; intramolecular hydrogen bond
The processes of electromagnetic radiation of radio-waves range in electrochemical systems are the matter of consideration in the present study. Two potentials, constant potential and low variable potential (with amplitude of 10 mV) are applied simultaneously in these systems to the metal-solution interface. The aim of the present work is: investigation of the adsorption processes in electrochemical systems by radio-spectroscopic method. The adsorption processes of the organic molecules are of great importance for creation of optochemotronic sensors, for electrochemiluminescence and various other processes. The analytical expressions for coordinates and rate of particles in such system are received. Moreover, expressions for vector-potential of the electromagnetic radiation of the system, which is connected with this motion, are also considered. The main outcome is existence of nonlinear, quadratic dependence between the signal of the electromagnetic radiation of the radio-wave range U and amplitude of a variable potential E, which is applied to the interface. The same dependence exist in electrochemical systems, where there is no current. Obtained theoretical results are used for the analysis of the experimental data, which was received for adsorption-desorption of aliphatic alcohols. Although there is no charge transfer between the alcohol molecules and electrode during the adsorption, quadratic dependence between U and E is investigated for all peaks on desorption SHS(second harmonic signal) - curves of butanol-1, butanol-2, hexanol, pentanol and isoamyl molecules on mercury electrode. For different concentrations of alcohols, different frequencies and values of the amplitude of variable potential were applied. Experimental results confirm the accuracy of proposed theoretical model.
Keywords: Electrochemical system; radio-waves; electromagnetic radiation; nonlinear phenomenon; aliphatic alcohols; adsorption
The title compound, 2-amino-4-(4-fluorophenyl)-7,7-dimethyl-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile (C21H24FN3O3), crystallizes in the monoclinic space group C2/c with unit cell parameters: a=31.342(3), b= 9.3481(9), c= 15.9051(11) Ǻ, β= 118.687(9)º, Z = 8. The crystal structure was solved by direct methods and refined by full-matrix least-squares procedures to a final R-value of 0.0588 for 2776 observed reflections. The fused cyclohexene and pyran rings adopt sofa and boat conformations, respectively. The four essentially planar atoms (C1/C2/C5/C6) of pyran ring (maximum deviation = 0.0878Å for C2) form a dihedral angle of 87.85(7)º with the benzene ring and is almost coplanar with the mean plane of the cyclohexene ring [dihedral angle = 7.23(7)º]. In the crystal, molecules are connected into inversion dimers via pairs of N-H…N hydrogen bonds and these dimers are further linked by N-H…O hydrogen bonds into a twodimensional network.
Keywords: Crystal structure; direct methods; conformations; C-H…O, N-H…N and N-H…O intra- and intermolecular interactions; crystallographic dimers; substituted tetrahydro-4H-chromene-3-carbonitrile
Little is known about ozonides and their decomposition notwithstanding the growing interest for these compounds in medicinal chemistry or as intermediates in chemical synthesis. Using the Van Krevelen’s group increment approach we have calculated the theoretical decomposition enthalpies of a series of olefins ozonation products adopting the simple assumption that the ozonides decompose into aldehydes and carboxylic acids but also by-products of ozonation like polyozonides, bis-peroxides and polycarbonyloxide decompose into the same products. It was found that all the homologous series of 1-olefin ozonides decompose with a ΔHdec = -267 kJ mol-1 and considering the other by-products the decomposition range of the entire crude ozonation mixture of 1-olefins is given by ΔHdec = -272±20 kJ mol-1. For the homologous series of symmetrical olefins of the type R-CH=CH-R the canonical ozonides with 1,2,4-trioxolane ring decompose with ΔHdec = -298 kJ mol-1 while considering the other by-products the decomposition range of the entire crude ozonation mixture of symmetric olefins is given by ΔHdec = -288±10 kJ mol-1. Asymmetric olefins of the type R-CH=CH-R’ with R ≠ R’can be represented by the monounsaturated fatty acids series or by the methyl and the ethyl esters of fatty acids. Also for this homologous series the canonical ozonides with 1,2,4-trioxolane ring decompose with ΔHdec = -298 kJ mol-1 while considering the other by-products the decomposition range of the entire crude ozonation mixture of symmetric olefins is given by ΔHdec = -288±10 kJ mol-1.
Keywords: Ozonides; Thermochemical Calculations; Group Increments; Decomposition Enthalpy
Materials and environmental chemistry
Keywords: Cd(II) removal; 2,5-hexanedione bis(salicyloylhydrazone); natural water; flotation; spectrophotometry
Strontium carbonate architectures assembled from nanorods are successfully synthesized at room temperature and screw capped method at 100 C. Our experiments show that the protocol followed for the synthesis of SrCO3 as well as the concentration of various gums used, play an important role in the size and morphology of SrCO3. Here in, we obtained aragonite type nanorod aggregates with unusual morphologies via transformation of metal carbonates at different conditions using natural gums as additives. A rational mechanism based on the oriented self-assembly of SrCO3 nuclei is proposed for the formed architectures. The crystals undergo an interesting morphology changes and have been well characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Thermogravimetric Analysis (TGA) and Fourier Transform Infrared spectroscopy (FT-IR) techniques. This method is simple, low-cost and environmentally friendly route for the synthesis of SrCO3 architectures with altogether different morphologies.
Keywords: natural gums; screw capped; self assembly; architectures; SrCO3
Safe drinking water is a severe problem in many parts of the various countries including India a fast developing country. Authors have used some low-cost materials and their products as one of the best adsorbents for the removal of fluoride from water mainly used for drinking and other domestic purposes. Results are appreciable to be applied in large scale purposes.
Keywords: Fluoride, removal, resins, saw-dust, water analysis, drinking water purification
Industrial and engineering chemistry
ZigBee-style networks began to be conceived around 1999, when many installers realized that both Wi-Fi and Bluetooth were going to be unsuitable for some industrial applications. In particular, many engineers saw a need for self-organizing ad-hoc digital radio networks. The real need for mesh has been cast in doubt since that, in particular as mesh is largely absent in the market. ZigBee protocols are intended for embedded applications requiring low data rates and low power consumption. The resulting network will use very small amounts of power — individual devices must have a battery life of at least two years to pass ZigBee certification. Typical application areas include: automation, advanced temperature control, safety and security, wireless sensor networks, industrial control-embedded sensing. ZigBee devices find applications in corrosion monitoring also such as corrosion fatigue, strain in concrete structures and linear polarization resistance sensors.
Keywords: ZigBee devices; corrosion monitoring; corrosion fatigue; strain in concrete structures; linear polarization resistance sensor