Structure–reactivity relationships of alkyl α‐hydroxymethacrylate derivatives

A series of alkyl α‐hydroxymethacrylate derivatives with various secondary functionalities (ether, ester, carbonate, and carbamate) and terminal groups (alkyl, cyano, oxetane, cyclic carbonate, phenyl and morpholine) were synthesized to investigate the effect of intermolecular interactions, H‐bonding, π–π interactions, and dipole moment on monomer reactivity. All of the monomers except one ester and one ether derivative are novel. The polymerization rates, determined by using photo‐DSC, showed the average trend (aromatic carbamate > hydroxyl > ester > carbonate ～ aliphatic carbamate ～ ether), with several exceptions due to the differences in terminal groups. There is a correlation between the chemical shift differences of the double bond carbons, the calculated dipole moments, and the reactivities only for nonhydrogen bonded monomers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

The Internal Bremsstrahlung Accompanying the β-Decay from 185W

The internal bremsstrahlung (IB) spectrum accompanying the β-decay from ¹⁸⁵W radionuclide has been measured. The obtained spectrum was analyzed into its constituting gamma lines taking into account all the proper corrections. The analyzed spectrum was compared with those theoretically calculated. The experimental results for the IB probability were found to be in good agreement with theoretical calculations especially with the shape corrected modified KUB theory of Nilsson up to 357.7 keV.     

On Tauberian theorems for (<Emphasis Type="Italic">A,k</Emphasis>) summability method

Let (u _n ) be a sequence of real numbers. In this paper we introduce some Tauberian conditions in terms of regularly generated sequences for (A, k) summability method.     

Synthesis,crystal structure and catalytic activity for H2O2 disproportionation of the manganese(II) coordination polymer {[Mn(O2C(CF2)8CO2)(phen)2]H2O}n (phen = 1,10-phenanthroline)

The title polymeric complex {[Mn(O₂C(CF₂)₈CO₂)(phen)₂]H₂O}_n was synthesized through the reaction of 1,10-phenanthroline, perfluorosebacic acid and MnCO₃ · H₂O. The molecular structure was characterized by X-ray diffraction, elemental analysis, thermal gravimetry, IR and UV–Vis spectroscopy and its catalytic activity has been studied. X-ray structure analysis shows that each Mn(II) ion is octahedrally coordinated by two bidentate phenanthroline ligands and the carboxylate oxygen atoms from two symmetry related perfluorosebacate ligands, which are coordinated in cisoid positions. The structure consists of polymeric chains, with the perfluorosebacato ligand bridging the Mn(II) ions in a monodentate fashion. Crystallographic characterization shows a supramolecular structure involving hydrogen bonds, π–π and π-ring interactions. The catalytic results indicated that the complex has reasonably good activity towards the disproportionation of hydrogen peroxide into water and dioxygen in methanol and it does not exhibit saturation kinetics with the substrate. The initial reaction rates and their temperature and base dependencies were investigated by monitoring the dioxygen evolution. Kinetic studies revealed a first-order dependence on the catalyst concentration. Activation parameters have been calculated at 301 K.     

Backtracking and exchange of information: Methods to enhance a beam search algorithm for assembly line scheduling

Beam search (BS) is used as a heuristic to solve various combinatorial optimization problems, ranging from scheduling to assembly line balancing. In this paper, we develop a backtracking and an exchange-of-information (EOI) procedure to enhance the traditional beam search method. The backtracking enables us to return to previous solution states in the search process with the expectation of obtaining better solutions. The EOI is used to transfer information accumulated in a beam to other beams to yield improved solutions.     

Homo‐ and heteropolynuclear copper(II) complexes containing a new diimine–dioxime ligand and 1,10‐phenanthroline: synthesis,characterization, solvent‐extraction studies,catalase‐like functions and DNA cleavage abilities

A series of homo‐, heterodinuclear and homotrinuclear copper(II) complexes containing a new Schiff base ligand and 1,10‐phenanthroline were synthesized. Based on results of elemental analyses, FTIR, ¹H‐ and ¹³C‐NMR spectra, conductivity measurements and magnetic susceptibility measurements, the complexes had general compositions {[Cu(L)(H₂O)M(phen)₂](ClO₄)₂ [M = Cu(II), Mn(II), Co(II)]} and {[Cu₃(L)₂(H₂O)₂](ClO₄)₂}. The metal:L:phen ratio is 2:1:2 for the dinuclear copper(II) complexes and the metal:L ratio was 3:2 for the trinuclear copper(II) complex. The liquid–liquid extraction of various transition metal cations [Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Pb(II), Cd(II), Hg(II)] from the aqueous phase to the organic phase was carried out using the diimine–dioxime ligand. It was concluded that the ligand can effectively be used in solvent extraction of copper(II) from the aqueous phase to the organic phase. Furthermore, catalytic activitiy of the complexes for the disproportionation of hydrogen peroxide was also investigated in the presence of imidazole. Dinuclear copper(II)–manganese(II) complex has some similarity to manganese catalase in structure and activity. The interaction between these complexes and DNA has also been investigated by agarose gel electrophoresis; we found that the homo‐ and heterodinuclear copper complexes can cleave supercoiled pBR322 DNA to nicked and linear forms in the presence of H₂O₂. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis of 3,3′-methylenebis(4-hydroxyquinolin-2(1H)-ones) of prospective anti-COVID-19 drugs

Molecular Diversity - During formylation of 2-quinolones by DMF/Et3N mixture, the unexpected 3,3′-methylenebis(4-hydroxyquinolin-2(1H)-ones) were formed. The discussed mechanism was proved as...     

ChemInform Abstract: Structure,Ionization, and Fragmentation of Hydrogenated Aluminoboron Clusters: Al2B2H2n (n = 0—6).

Energetic and structural stability of Al₂B₂H_2n (n = 0—6) clusters is investigated by DFT calculations and a stochastic search algorithm.     

Investigation of the structural properties of annealed CdIn2Te4/CdS thin film solar cells produced by the electron-beam evaporation (e-beam) technique

Thin film CdIn₂Te₄/CdS solar cells were deposited onto the ITO-coated glass substrate by electron beam evaporation (e-beam) technique, and the the effect of annealing on their structural properties is studied. The annealing was performed under nitrogen atmosphere for 1 h. The manufactured solar cells were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDAX) analysis. Crystallite size (D), inter-planer distance (d) and lattice constant (a) values were calculated for the thin film solar cell from XRD data. Annealed samples display well defined XRD patterns with three diffraction peaks. We observed increased peak intensity in the annealed films. EDAX analysis showed that only CdIn₂Te₄ is present in absorber layer and CdS is found in the window layer, but no impurity atoms are present the structure. It is observed that surface roughness of the annealed films incresed, according to SEM images. The I–V characteristics show that the current is increased for annealed thin films solar cells.

     

Oxalic acid removal from wastewater using multi-walled carbon nanotubes: Kinetic and equilibrium analysis

Oxalic acid adsorption from aqueous solution is studied in this work. Multi-walled carbon nanotubes (MWCNT) were used as an adsorbent. The investigated adsorption variables are equilibrium time, initial acid concentration, and temperature. The experimental results were presented using equilibrium isotherm and kinetic models. The used equilibrium models are Langmuir, Freundlich, and Temkin adsorption isotherms. And the kinetic models are Elovich, Lagergren pseudo-first-order and pseudo-second-order kinetic models. The thermodynamics studies were carried out at three different temperatures: 278, 298, and 318 K. Langmuir isotherm was the best fitted equilibrium model for the experimental data. The all applied kinetic models fitted the data suitably.