International Journal of Chemical Research

Number 1, 2013

140-143
COMPLEXES OF ZN(II) AND CD(II) WITH 1-(FURAN-2-YLMETHYLENE)UREA AND N-(PROPAN-2-YLIDENE)BENZOHYDRAZIDE

Authors: EMMANUEL S.A., THOMAS S.A., IDRIS S.O., IYUN J.F.

Abstract

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Complexes of Zn(II) and Cd(II) with 1-(furan-2-ylmethylene)urea (A) and N-(propan-2-ylidene)benzohydrazide (B) have been synthesized and characterized by IR, UV/Vis spectroscopy, powdered X-ray diffractometry, scanning electron microscopy, conductivity, elemental study and solubility study. The ligands were also characterized by HNMR spectroscopy. The result showed that the ligands acted as bidentate donors coordinating through the azomethine nitrogen and the carbonyl oxygen. The elemental analysis indicates that the complexes of Zn and Cd with A precipitated as ML1 types complex while complexes of B with Zn precipitated as an ML2 type complex. The complex of Cd with B however the not precipitate from solution. The conductivity study also indicates that the complexes A are electrolytes while B complex is a non-electrolyte.

144-152
MERCAPTOBENZOTHIAZOLE-ON-GOLD ORGANIC PHASE BIOSENSOR SYSTEMS: 2. ENHANCED CARBAMATE PESTICIDE DETERMINATION

Authors: SOMERSET V., BAKER P., IWUOHA E.

Abstract

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In this paper the results for the construction of a gold/mercaptobenzothiazole/polyaniline/ acetylcholinesterase/polyvinylacetate (Au/MBT/PANI/AChE/PVAc) thick-film biosensor for the determination of certain carbamate pesticide solutions in selected aqueous organic solvent solutions are reported. AChE biosensors are designed to complement the classical analytical methods of pesticide detection. The Au/MBT/PANI/AChE/PVAc electrocatalytic biosensor device was constructed by encapsulating acetylcholinesterase (AChE) enzyme in the PANI polymer composite, followed by the coating of poly(vinyl acetate) (PVAc) on top to secure the biosensor film from disintegration in the organic solvents evaluated. The electroactive substrate called acetylthiocholine (ATCh) was employed to provide the movement of electrons in the amperometric biosensor. The voltammetric results have shown that the current shifts more anodically as the Au/MBT/PANI/AChE/PVAc biosensor responded to successive acetylthiocholine (ATCh) substrate addition under anaerobic conditions in 0.1 M phosphate buffer, KCl (pH 7.2) solution and aqueous organic solvent solutions. For the Au/MBT/PANI/AChE/PVAc biosensor, various performance and stability parameters were evaluated. These factors include the optimal enzyme loading, effect of pH, long-term stability of the biosensor, temperature stability of the biosensor, the effect of polar organic solvents, and the effect of non-polar organic solvents on the amperometric behavior of the biosensor. The biosensor constructed in this study offered a reasonable linear range between 0.25 to 3.45 nM for the detection of carbofuran, aldicarb and dioxacarb pesticide solutions. The detection limits for the individual carbamate pesticides were 0.249 nM for carbofuran, followed by 1.209 nM for aldicarb and 1.572 nM for dioxacarb.

153-158
AN IMPROVED SYNTHESIS OF 2-(PYRID-2΄-YL)-1,10-PHENANTHROLINE TRIDENTATE TERPYRIDYL LIGAND

Authors: ZIBASERESHT R., KARIMI P., MOHIT-AZAR S., AMIRLOO M.R., AZIMI M.

Abstract

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An improved multistep synthetic route for preparation of a tridentate terpyridyl ligand, 2-(pyrid-2Î„-yl)-1,10-phenanthroline, has been reported. In the first step, a Skraup quinoline synthesis using m-toluidine and glycerol was employed. The mixture of 5- and 7-methylquinoline which was obtained was selectively nitrated at 8-carbon position of the 7- derivative. The methyl group in 7-methyl-8-nitroquinoline was then oxidized to an aldehyde followed by a reduction of the nitro group to an amine group. The last step involved a FriedlÃ¤nder condensation of the amino aldehyde with 2-acetylpyridine to obtain the final product with overall high yield. All products were fully characterized.