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Volume 8, No. 2, June 2013, Shaa'ban 1434 H

Articles

 

 

Synthesis of New Azacrown Ether Schiff-Bases and their Complexes with C60

 

 

Shehadeh Mizyed*, Rana Kiwan and Deeb Marji

JJC, 2013, 8(2), 71-78

Spectrophotometric Determination of Paracetamol by Reduction of
18-Molybdo-2-Phosphate Heteropoly Anion

 

 

Mohammed Khair E.A. Al-Shwaiyat

JJC, 2013, 8(2), 79-89

Solid Phase Extraction of Copper, Cadmium and Lead using Amberlite XAD-4 Resin Functionalized with 2-Hydroxybenzaldehyde Thiosemicarbazone and its Application on Green Tea Leaves

Amberlite XAD resins have attracted much attention of researchers in the last few years for their capability to accommodate important chelating groups.  The modified resins act as solid phase extractants (SPE) for pre-concentration and determination of environmentally important metal ions. A new chelating resin; XAD-4 functionalized with 2-hydroxybenzaldehyde thiosemicarbazone was synthesized and studied for solid phase extraction of Cu2+, Cd2+, and Pb2+ from aqueous media and subsequent determination by GFAAS. Application of the developed SPE to the determination of the three metal ions in tea leave digests provided acceptable concentration values. The optimum values for pH, flow rate, acid concentration, tolerance limit for foreign electrolytes, detection limits, limits of quantification, maximum adsorption capacity and sorption half time (t1/2) were evaluated. The methodology involving the modified resin exhibited a high preconcentration factor and low relative standard deviation for determination of Cu2+, Cd2+, and Pb2+. The extraction medium is highly stable and is reusable after slight conditioning.

 

 

Didarul A. Chowdhury, Md. Ikram ul Hoque*, Zeenath Fardous

JJC, 2013, 8(2), 90-102

Visible Spectrophotometric Determination of Ganciclovir in its Pharmaceutical Formulations using Quinalizarin Reagent

A simple, rapid and sensitive spectrophotometric method for the determination of Ganciclovir was developed. The method is based on the proton transfer reaction of drug with quinalizarin reagent in aqueous solution to form violet product which shows maximum absorbance at 560 nm. Beer's law was obeyed in the concentration range   1-20 g.mL-1 with an average recovery (accuracy) of 99.02% and precision (RSD) of less than 2.0%. The molar absorbtivity was 8.93x103 l.mol-1.cm-1 with LOD of 0.21 g.mL-1 and LOQ of 0.71 g.mL-1. The proposed method was further applied to the determination of the drug in pharmaceutical formulations as an injection and capsule and the results were comparable with the certified values of pharmaceutical formulations.

 

 

Usra I.S. Al-Neaimy*  and  Amal M. S.Al-Delymi*

JJC, 2013, 8(2), 103-112

C-C Bond Cleavage in Aromatic Molecules; Benzene, Toluene and Naphthalene

 

Muthana Shanshal* and Mustafa M. Muala

JJC, 2013, 8(2), 113-124

On the Factors Affecting H-bonding: a CCSD(T)//B3LYP Study on Malonaldehyde Cation-Radical

Among the factors that may affect H-bond strength, the effect of the molecular ionization has not received any considerable attention. Here, malonaldehyde and its cation-radical as models were studied using DFT (B3LYP) and ab-initio theories (HF, MP2, and CCSD(T)). Based on establishing a comparison with the CCSD(T)/CBS energy barrier (from literature), we have found that the CCSD(T)/D95(d,p)//B3LYP/6-31G(d,p) computational protocol can be used as a reference for evaluating performance of the B3LYP and the MP2 methods on this model. In this computational organic chemistry study several aspects were investigated, they are: structures, energies, natural population analysis (NPA) charges, intramolecular charge transfer (delocalization) energies, and atoms in molecule (AIM) electron densities with regard to the H-bonding. The results indicate that loss of an electron can cause considerable effects on the various electronic structure aspects and the details are presented and discussed. All the aspects confirm that ionizing the molecule disturbs the electron density distribution in the HOMO orbital and makes the two oxygen atoms, relatively, electron deficient centers which consequently weakens both the H1-O1 bond and the O2/H1-O1 H-bond. The details of this investigation are new addition to the hydrogen bond theory. Other types of molecular models and computational protocols are of interest for future investigations.

 

 

Tareq Irshaidat

JJC, 2013, 8(2), 125-137