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Volume 5, No. 3, September 2010, Ramadan 1431 H

Articles

 

 

Synthesis and Solid-State Structure Analyses of a Thia-Bridged Diquinolinium Acetate Compound

The proton-transfer compound of thia-bridged dinitrodiphenyldiquinoline 4 with acetic acid was obtained through crystallization of compound 3 from acetic acid. Solid-state structure of 4 was determined by single-crystal X-ray diffraction. Compound 4 was ionic, with proton transfer occurring from one acetic acid hydroxy group to the aromatic nitrogen of one of the pyridine moiety leaving the other one unprotonated. The versatile supramolecular self-assembly of 4 was carefully investigated and presented in term of crystal engineering and host-guest chemistry.

 

 

N. M. Alghezawi, S. F. Alshahateet*, R. Bishop

JJC, 2010, 5(3), 211-220

Asymmetric Addition of Diethyl Zinc to Benzaldehyde Catalyzed by Chiral Diamine Ligand and Ti-diamine Modified Complex Derived from D-mannitol

Modified procedure for preparation of chiral: 3,4-Diazido-1, 2:5, 6-di-O-isopropylidene-D-mannitol from the corresponding bismesylate and new chiral ligand: 3, 4-diamino-1, 2:5, 6-O-isopropylidene-D-mannitol was described.  The application of both diamine and Ti-diamine complex as catalysts in enantioselective addition of diethyl zinc to prochiral benzaldehyde was described. High enantioselectivity up to 93% e.e. was achieved. The standard analytical measurements including optical activity of the diazide, diamine and the determination of optical purity of the resulting alcohol were reported.

 

 

Abdullah M. A. Al Majid*, Hassan M. A. Al-Hazimi, Mohammed B. Al-Shammery

JJC, 2010, 5(3), 221-230

Bis(Alkyne) Copper(I) Trifluoracetate: Synthesis, Characterization, and Solid-State Structure

                The synthesis, properties and solid structure of heterobimetallic {[Ti](µ-s,p-CºCSiMe3)2}CuO2CCF3 ([Ti] = (h5-C5H4SiMe3)2Ti) is discussed. The thermal induced decomposition of the title compound is reported.

 

 

Mohammed A. Al-Anber, Bernhard Walfort and Heinrich Lang*

JJC, 2010, 5(3), 231-238

Synthesis of VO (IV) Complexes and Study of their
 Liquid Crystalline Behavior

The synthesis and characterization of new homologous series of VO(IV) complexes derived from 4 (4 – Chloro benzoyloxy) – 2 – hydroxyl benzylidine – 4 – alkoxy aniline (where the alkoxy chain is OCnH2n+1 and n=1-7, 9,10)are reported. The liquid crystalline properties and phase transitions were studied using polarized hot stage optical microscopy and differential scanning calorimetry (DSC) for the ligands and their complexes.

 

 

Uhood J. AL–Hamdani* and Maan abd Al-diem

JJC, 2010, 5(3), 239-252

Surface Characterization, Isotherm Modeling and Thermodynamics of Zn(II) Adsorption onto Modified Corncob

Investigations were conducted to study the adsorption behavior of Zn(II) ions on a low-cost adsorbent. The natural corncob (NCC) was citric acid modified to enhance its adsorption ability. The physical and chemical properties of the modified corncob (MCC) such as surface area, surface functional groups and surface charge determine the adsorption characteristics of the material. The surface areas of NCC and MCC were determined to be 13 m2 /g and 9 m2 /g, respectively. The values for the pHPZC of the NC and MCC were found to be 5.8 and 3.6, respectively. The effect of various parameters such as pH of the medium, adsorbent dose, initial Zn(II) concentration and temperature were examined. The equilibrium adsorption data were modeled by Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm equations. The constants of each isotherm model were evaluated. The presented values of the normalized standard deviation (∆q) indicate that the Freundlich isotherm provide the best correlation between experimental and predicted data with the lowest value of ∆q equal to 3.4 % and appears to be the best fit model for the present Zn(II) adsorption studies. The obtained value for the mean energy of adsorption (Eads = 10.8 kJ mol-1), shows that the interaction between Zn(II) ions and MCC proceeded principally by ion exchange at all temperatures. The optimum conditions for the maximum Zn(II) adsorption capacity (qm= 26.3 mg g-1 ) by MCC were pH 5.0±0.1, adsorbent dose 1.0 g, temperature 318 K, and initial Zn(II) concentration 250 mg L-1. The sorption process was found to be endothermic in nature ( ∆H : 70.7 kJ mol-1), with increase in entropy ( ∆S : 292.2 J mol-1 K-1). The negative value of Gibbs free energy, ∆G indicates that the adsorption occurs via a spontaneous process. The increase in -∆G from 16.7 to 21.9 kJ mol-1 with increase of temperature from 298 K to 318 K indicates that the adsorption of Zn(II) onto MCC is more favorable at higher temperatures. The results show that MCC , which has a very low economical value, may be used effectively in removal of Zn(II) from aqueous solution.

 

 

Atef S. Alzaydien

JJC, 2010, 5(3), 253-270

Oxygen Nonstoichiometry and Defect Structure Analysis of
Sr- and Fe-Substituted LaCoO3

The point defect model equilibrium presented here for La1-xSrxCo1-yFeyO3-d system using the nonstoichiometry data is based on the presence of two oxidation states of cobalt ions, Co4+ and Co3+, that are populated in various proportions depending on temperature, partial pressure of oxygen and Sr or Co content. It allows us to interpret the thermogravimetric data, the electrical behavior and calculate some thermodynamic quantities of the defect formation reaction of this material.

 

 

Malika Diafi, Kaltoum Adaika, Mahmoud Omari*

JJC, 2010, 5(3), 271-282

Changes of Anode Materials during Extended Cycling of
Lithium Ion Batteries

Experimental data on lithium ion batteries with LiCoO2 as cathode and SSG (a modified natural graphite) as anode showing good uniformity, high capacity and good cycling behavior are reported. Three cells were cycled for 500, 1060 and 1600 cycles, the changes of the graphitic an­ode material were investigated by X-ray diffraction, scanning electronic microscopy, X-ray photoelec­tron spectroscopy, electrochemical impedance spectroscopy, cyclic voltammetry and capac­ity measurements in order to identify the mechanism of capacity fading of these lithium ion batteries. During cycling, the graph­itic structure is very stable and evidently does not change. However, the electrolyte solution continu­ously reacts with the anode material during cycling and the thickness of the surface film on the an­ode material increases with cycling, which leads to a change of the surface composition, increase of charge transfer resistance and decrease of the height of redox peaks in cyclic voltammograms. The comparison of the capacity fading of the anode material and the complete lithium ion batteries shows clearly that the an­ode mainly contributes to capacity fading of lithium ion batteries due to reactions of electrolyte solution constituents with the anode material during cycling. These results provide valuable clues for manufacturing lithium ion batter­ies with improved cycling behavior.

 

H.P. Zhang, L.J. Fu, Y.P. Wu*, R. Holze*

JJC, 2010, 5(3), 283-290

Use of Iron (III) Chloride for the Sensitive and Selective Assay of Etamsylate in Pharmaceuticals

The first method (method A) is based on the reaction of ETM with ferric chloride in DMF medium to form a colored species with a λmax at 655 nm. The second method (method B) is based on the oxidative coupling reaction involving ETM, 3-methyl-2-benzothiazolinone hydrazone (MBTH) and ferric chloride in the presence of sodium acetate which yielded a bright pink colored chromogen with λmax.at 520 nm. 

 

 

Kanakapura Basavaiah Vinay, Hosakere Doddarevanna Revanasiddappa, Okram Zenita Devi and Kanakapura Basavaiah*

JJC, 2010, 5(3), 291-305

Characterization of Colouring Matters by HPLC-DAD and Colour Measurements, Preparation of Lake Pigments with Ararat kermes (Porphyrophora hameli Brand)

In this work, the lake pigments aluminium, tin, iron, aluminium-calcium, tin-calcium and iron-calcium ararat kermes were obtained by means of KAl(SO4)2.12H2O (alum), SnCl2.2H2O, FeSO4.7H2O and Ca(NO3)2.4H2O solutions from Ararat kermes (Porphyrophora hameli Brand) dye insects. A reversed phase high performance liquid chromatography (HPLC) with diode-array detection (DAD) method was utilized for the identification of red anthraquinone dyes present in the lake pigments. The extraction of dyes from the lake pigments was carried out with HCl / MeOH / H2O (2:1:1; v/v/v) solution. HPLC analysis shows that carminic acid and flavokermesic acid were identified in the acid hydrolysed Ararat kermes extract (1), the non - hydrolysed Ararat kermes extract, aluminium - ararat kermes lake pigment, aluminium - calcium - ararat kermes lake pigment. CIELAB values of the lake pigments were measured.  

 

Ozan Deveoglu*, Emıne Torgan, Recep Karadag

JJC, 2010, 5(3), 307-315