VOLUME 12, NO1, MAR 1990

Preparation Characterisation and Light Absorption Spectrophotometry of Copper (II) and Nickel(lI) Complexes of Some Fluorinated Tetradentate Ketoamine Schiff Bases

Copper(II) and nickel(II) complexes of tetradentate ketoamine Schiff bases bis(tri­Ouoroacetylmesityloxide) ethylenediimine (H2F3AM2en), bis(triOuoroacetylmesityloxide) propylenediimine (H2F3AM2pn), bis (triOuoroacetylmesityloxide) d-stilbenediimine (dl­H2F3AM2S) and bis(triOuoroacetylmestiyloxide) meso-stilbenediimine (meso- H2F3AM2S) are prepared and IR, lH_NMR and mass spectra of the reagents are recorded. Ultraviolet and visible spectra of the reagents and metal complexes are recorded in methanol, acetone, chloroform and n-hexane and possible assignment of the different bands is suggested.read more

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A G BHATTI ,M Y KHUHAWAR ,

Oxidation of Nickel(lI) and Copper(II) Macrocyclic Complexes by Chlorine Radical Anions and Monochlorocobalt(lII)Ions

Strong oxidants such as chlorine rad-ical anions' and mORochlorocobalt(III) ions are generated by flash photolysis. Oxidation of nickel(IIrand copper (II) tetraazamacrocyclic com­plexes are reported. The nickel(III) and copper(III) complexes are stable in st·rongly acidic aqueous solutions. Axial coordination of chloride stabilizes the copper(IlI) state of copper mac­rocyclic complexes; while nickel(III) state are stabilized at low chloride ion consentration. Thus, an outer-sphere electron- transfer mechanism was propose

M A KHALIFA ,

Separation of the Molecular Motion of a Diatomic Molecule

An attempt is made to show in a straightfOlward way how a body-fixed (BF) frame of reference may be constructed for a diatomic molecule such that rotational and translational motions could be described as motions of the BF frame and internal (vibrational and electronic) motions could be described with respect to the BF frame. A diatomic molecule is a special case which we do not need to impose any condition, such as the Eckart's conditions, on the BF frame. The correct form of the total angular momentum operators is derived quantum mechanically. The Hougen-Watson isomorphic Hamiltonian is rederived. For conformity, the method is developed in strict analogy to the first author's previous works, with the necessary variations for the diatomic molecule. read more

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A MAGHARI ,R ISLAMPOUR ,

Spectrophotometric Determination of Cyanide by Silica Supported Tris(pentane-2,4-dionato) Iron(lII) Reagent

A fast and accurate spectrophotometric method has been investigated for the quan­titative evaluation of free cyanide ions in the concentration range of 25 ppb by using silica sup­ported tris(pentane-2,4-dionato )iron(II1)column.read more

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A AHMAD ,M MAZHAR ,G AGSHAN ,S IKRAM ,S ALI ,

Kinetic Alterations in Michaelis - Menten Parameters of Human Erythrocyte Acetyl¬cho linesterase in Splenomegally

A huge elevation in the Michaelis-Menten parameters (aKm, avm) of the human erythrocyte acetylcholine esterase (AChE.Ec.3.1.1.7) in splenomegally were obseIVed. 76 blood samples were assayed from the hospitalized patients compared with ltIe 'normal blood samples as control. Time course effect of the disease upto six months were also obseIVed. Attempts have been made to suggest possible interpretations for the change observed.read more

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S F MABOOD ,Z M KHAN ,H ULLAH ,

Spectrophotometric Determination of Aspirin in Pharmaceutical Formulations by Oxidation with Potassium Dichromate

A simple and rapid spectrophotometric method for determination of aspirin is described. The method is based on oxidationof aspirin with dichromate ions. Absorbance of Chromium(III) produced was measured at 582 nln. The method is employed for the determina­tion of aspirin in drug samples. The results have been compared with those reported on the samples.read more

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T A AWAN ,J ANWAR ,

The Separation of Copper (II) Nickel(lI) and Palladium (II) Complexes of New Tetradentate SchitTBases Using Normal Phase HPLC

The copper and nickel complexes of tetradentate ligands bis(salicylaldehyde) phenylpropylenediimine (H2SAzPP) and bis-( o-hydroxylacetophenone )phenylpropylenediimine (HzHAzPP) and copper(II), nickel(II) and palladium(II) complexes of bis (benzoylacetone) phenylethylenediimine (HillAzPE) and bis( o-hydroxyacetophenone) phenylethylenediimine (HzHAzPE) have been prepared and their structure is elucidated using IR, UV, IH NMR and mass spectroscopic techniques. The metal complexes are less sensitive for spectrophotometric determination of metal ions, but show high value of molar absorptivities in UV regions, which enabled to use UV -detector with HPLC system for separation of copper and nickel, and copper, nickel palladium complexes at ng levels. The separation is achieved on 25Ox4mm column packed with Licrosorb Si 100, 5# using isocratic elution with mixture of chloroform-n-hexane. Detection was achieved within 290-310 nm using UV detector, linear calibration range were found in the ng levels and detection limits at sub ng levels of metal ions.read more

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A K TALPUR ,G O KHASKHELI ,M Y KHUHAWAR ,

Solvent Extraction of Vanadium (IV) and Vanadium (V) with Di-o- tolylhydrogenphosphate in Benzene

The extractions of V(IV) and V(V) from acidic sulphate-acetate media with di-o-tolyl­hydrogenphosphate (HDTP or HzAz) in benzene have been investigated as functions of various experimental parameters. Reactions for extractions of V(IV) and V(V) have been proposed via chelation and solvation respectively. Temperature dependence data give the apparent enthalpy change (6H) for the reactions as -29.65 kJ/mol (below 50°C) and -26.78 kJ/mol for V(V) and V (IV) respectively. The loading capacities of HDTP for V(IV) and V(V) are found to be 6g1100g HDTP and 3.6g1100g HDTP respectively. The value of the extraction equilibrium consta.nt for the extraction of V(IV) has been calculated to be log Kex = 1.19. The diluent effect has al

R K BISWAS ,D A BEGUM ,M R ALI ,S S U NOOR ,

Determination of Chloride by Gas-Phase Molecular Adsorption Spectrometry.com

Chloride in the range of 0.1 to 0.5 mg is determined by gas-phase molecular absorp­tion spectrometry. Chloride samples were quantitatively oxidized by successive addition of potas­sium persulphate solution and sulphuric acid. The released chlorine gas was swept in stream of nitrogen through a long-path optical cell where its absorption was measured at 330 nm. Various parame ters concerning the determination have been investigated and chloride content in a num­ber of samples was determined by the described procedure.read more

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M I FAROOQI ,O VASEEM ,J ANWAR ,A RAFIQ ,

Some New Chromogenic Reagents for Copper (I) and Iron(lI)j Pyridyl-Substituted Pyrazine and Quinoxaline Compounds

Fifteen new pyridyl-substituted pyrazine ligands have been synthesized and their IR and mass spectra are recorded. The ligands containing ethyl, methyl or phenyl groups adjacent to donor nitrogen atoms in aromatic pyridyl or pyrazine rings react only with copper(I), but the reagen ts 2,3-b is(2' -pyridyl) -5 -phenyl-5 ,6-dihydropyrazin e( III) ,2,3-bis(2' - pyridyl)-5 - P henyl-6­methyl-5,6-dihydropyrazine(V), 2,5-diphenyl-3-(2' -pyridyl)-5,6-dihydropyrazine(IX) and 2,3­bis(2' -pyridyl)-5-phenylpyrazine(XI) react with copper(I) an iron(II) to for coloured compouns. Their reactions have been studied spectrophotometrically and the effects of methyl, ethyl and phenyl groups substitution on the reactions towards copper(I) and iron(II) have been inves­tigated in terms of solution stability, molar absorptivity and wavelength of maximum absorbance.Finally the reagent bis 2,3-(6-methylpyridyl)J-5,5,6,6-tetramethyl-5,6- dihydropyrazine(II) proved to be better chromogenic reagent for copper, have been applied for the spectrophotometric determination of copper in water samples and human head hairs.read more

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G O KHASKHELI ,M Y KHUHAWAR ,