New copper(II) complexes produced by the template reaction of acetoacetic-2-pyridylamide and amino-aliphatic alcohols

The template condensation of acetoacetic-2-pyridylamide with amino aliphatic alcohols such as 2-aminoethanol (HL1) and 3-amino propanol (HL2) in the presence of copper(II) ions gave octahedral complexes, which have been characterized by elemental analyses, u.v.-vis. and i.r. spectra, conductivity, d.t.a, magnetic and e.s.r. measurements. The molar conductance in DMF indicate that the complexes are non-ionic in character. The e.s.r. spectra of solid complexes (2) and (5) at room temperature indicate axial type symmetry (dx2-y2) with covalent bond character.     

UV-vis, IR and 1H NMR spectroscopic studies of some mono- and bis-azo-compounds based on 2,7-dihydroxynaphthalene and aniline derivatives

The absorption spectra of mono- and bis-azo-derivatives obtained by coupling the diazonium salts of aromatic amines and 2,7-dihydroxynaphthalene have been studied in six organic solvents. The different absorption bands have been assigned and the effect of solvents on the charge transfer band is also discussed. The diagnostic IR spectral bands and 1H NMR signals are assigned and discussed in relation to molecular structure. Also, semi-empirical molecular orbital calculations using the atom superposition and electron delocalization molecular orbital (ASED-MO) theory have been performed to investigate the molecular and electronic structures of these compounds. According to these calculations, an intramolecular hydrogen bonding is essential for stabilization of such molecules.     

Glycosidases of turnip leaf tissues

Four myrosinase (β-thioglucosidase EC. 3.2.3.1) and seven disaccharase (β-fructofuranosidase, EC. 3.2.1.26) isoenzymes were isolated from turnip leaves. The most active enzymes were isolated in pure form. Myrosinase and disaccharase mol wt was 62.0 × 10³ and 69.5 × 10³ dalton, respectively, on the basis of gel filtration on Sephadex G-200. Myrosinase pH profile showed high activity between pH 5 and 7 with the optimum at pH 5.5. The purified enzyme was heat-stable for 60 min at 30°C with only loss of 24% of activity. Its activity is strongly inhibited (100%) by Pb²⁺, Ba²⁺, Cu²⁺ and Ca²⁺ ions, and activated (70%) by EDTA at 0.04M. The pure enzyme failed to hydrolyze amylose, glycogen, lactose, maltose, and sucrose. TheK _m andV _max values of myrosinase using sinigrin as specific substrate was 0.045 mM and 2.5 U, respectively. The maximal activity of disaccharase enzyme was obtained at pH 4–5 and 35–37°C. The enzyme was heat-stable at 30°C for 30 min with only 10% loss of its activity. Its activity is strongly activated (70–240%) by Ca²⁺, Ba²⁺, Cu²⁺, and EDTA at 0.01M. The enzyme activity is specific to the disaccharide sucrose and failed to hydrolyze other disaccharides (maltose and lactose). TheK _m andV _max of disaccharase were 0.123 mM and 3.33 U, respectively.     

Polymer-Mercury Coated Screen-Printed Sensors for Electrochemical Stripping Analysis of Heavy Metals

In the perspective of in-field stripping analysis of heavy metals, the use and disposal of toxic mercury solutions (necessary to plate a mercury film on a carbon electrode surface) presents a problem. The aim of this work was the development of mercury coated screen-printed electrodes previously prepared in the lab and ready to use in-field. Thus some commercially available polymers like Nafion®, Eastman Kodak AQ29®, and Methocel® were investigated as mercury entrapping systems for electrochemical stripping analysis of heavy metals. Screen-printed disposable cells with a silver pseudo-reference electrode, a graphite counter electrode, and a graphite working electrode were used. To modify the sensor, the polymer solution was cast onto the carbon working electrode surface. Detection limits of 0.8 and 1 μg/L were obtained for lead and cadmium respectively. Since Methocel® based electrodes showed the best performance, they were used for the analysis of real samples. The results were compared with those obtained using a classical thin mercury film electrode and ICP spectroscopy.

All the experiments reported here were performed in un-deareated solutions as required for in-field analysis.     

Comparative Study of Surface Functionalization of Hydroxyapatite by One‐pot Grafting of Organophosphonates Species

The ability to graft apatite surface by specific ligand fields creates powerful new technology applications. Thus, grafted organophosphonate can provide an effective route to modify the surface properties of apatite materials. The ability to decorate the apatite surface with the desired functionality requires covalent attachment to solid interface; most commonly achieved using organophosphonate self‐assembly. The current study shows that various phosphonates can react with calcium ions and control the formation of the porous apatite with high surface areas as well as the porosity. The structural and surface properties are given some importance in this review.     

Band formation in a CPLC subjected to rectilinear oscillatory shear

The response of a homeotropically aligned columnar phasmidic liquid crystal (CPLC) to rectilinear oscillatory shear was investigated for frequencies between 10^-2 and 100 Hz and cell thicknesses between 20 and 100 μm. At threshold shear amplitude, we observed a spatial pattern consisting of stationary bands, perpendicular to the direction of shear and localized in the bulk of the columnar sample. For fixed thickness and at threshold shear amplitude, we observed band structure for several frequencies corresponding to integer harmonics ν_o, 2ν_o, 3ν_o. We interpret the obtained results in terms of curvature walls that evolve gradually, according to the amplitude, to characteristic developable domain walls of the columnar phase.     

Structural studies and anticancer activity of a novel (N6O4) macrocyclic ligand and its Cu(II) complexes

A novel (N6O4) macrocyclic ligand (L) and its Cu(II) complexes have been prepared and characterized by elemental analysis, spectral, thermal (TG/DTG), magnetic, and conductivity measurements. Quantum chemical calculations have also been carried out at B3LYP/6-31+G(d,p) to study the structure of the ligand and one of its complexes. The results show a novel macrocyclic ligand with potential amide oxygen atom, amide and amine nitrogen atoms available for coordination. Distorted square pyramidal ([Cu(L)Cl]Cl·2.5H2O (1), [Cu(L)NO3]NO(3)·3.5H2O (2), and [Cu(L)Br]Br·3H2O (4) and octahedral ([Cu(L)(OAc)2]·5H2O (3)) geometries were proposed. The EPR data of 1, 2, and 4 indicate d1x2(-y)2 ground state of Cu(II) ion with a considerable exchange interaction. The measured cytotoxicity for L and its complexes (1, 2) against three tumor cell lines showed that coordination improves the antitumor activity of the ligand; IC50 for breast cancer cells are ≈8.5, 3, and 4 μg/mL for L and complexes (1) and (2), respectively.