VOLUME 10, NO2, JUN 1988

IONIZATION-POTENTIALS AND ELECTRON-AFFINITIES OF ORGANIC-MOLECULES FROM ELECTRONIC CHARGE-TRANSFER SPECTRA

Molecular complexes of N-dimethyl benzylidene aniline derivatives (as electron donors) with some aromatic nitro compounds (as acceptors) have been prepared and investigated by electronic absorption spectra. The ionization potentials of the donors are determined from the electronic absorption spec­tra of the solid CT complexes. The electron affinity of some acceptors are also evaluated. read more

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M GABER ,M A EL MORSI ,M A EL GHAFAR ,

PREPARATION AND REACTIONS OF 5H-1,2-DITHIEPIN-5-THIONES

A new series of 5.!:!.-1.2-dithiepin-5-thiones were prepared from the reaction of 1.5-diarylpent-l-yne-3.5-diones and phosphorus pentasulfide. Some reactions of these dithiepins were studied and the structure of the parent compounds as well as all the products was confirmed from their spectral characteristics.read more

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I E S EL KHOLY ,M G MAREI ,M M MISHRIKEY ,

IODINE ADDUCTS WITH PHOSPHINE DERIVATIVES IN ACETONITRILE AS SOLVENT

The phosphine derivati-ves having general formulae; R P, R RP and R PX 322(where R = aryl or substituted aryl group, R = alkyl or alkoxy group and X = halogen) react with iodine to form 2:1, 1:1 and 1:2 addition compounds in solution. The solvent acetonitrile, exerts an ionising affect on the adducts formed. The interactions are s tudi ed by conductometri c and spectroscopi c methods. In presence of excess of phosphine derivative concentration, forma­tion of iodide ions takes place.2 Rip + 12 (R2RP)2I2 (R2RP)2I+ + I and R2RP + 12 R/PI2 R2RPI+ + I . The reaction involves the formation of an equilibrium system predomi­nantly lying towards the right side. When excess of iodine is present, tri­iodide ions are formed: The spectroscopic results complement the results obtained by conductometric measurements.read more

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A MUHAMMAD ,

SOME REACTIONS WITH ALPHA,BETA-UNSATURATED ACYL ISOTHIOCYANATES

Nucleophilic addition reactions of CL,8 -unsaturated acyl isothio­cyanates with aromatic and heteroaromatic amines have been studied. Compound 12 was also prepared which afforded pyrazolo [l,5-a]-s-triazine, coumarine and pyrazolo [l,5-c]-as-triazine derivatives on treatment with 5% potassium hydroxide, salicylaldehyde and diazotis~d aminopyrazole respectively.read more

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N M ABED ,A G A ELAGAMEY ,A F A HARB ,

POTENTIOMETRIC DETERMINATION OF DISSOCIATION-CONSTANTS OF DITHIODIGLYCOLIC ACID IN AQUEOUS AND AQUA-ORGANIC MEDIA AT DIFFERENT TEMPERATURE AND IONIC STRENGTHS

The pKa1 and pKa2 values relating to the dissociation of Dithiodigly­colic acid have been determined at different temperatures 20°. 30° and 40°C and ionic strengths 0.1. 0.2. 0.5 and 1.0 M KN03 in aqueous media and also in aqua-organic solvents. viz. DMSO. DMF. acetonitrile. isopropanol. ethanol and methanol by employing Albert Serjeant method as refined by Noyes and Irving Rosotti method. From the variation of pK 1 and pK 2 with temperature.The values of free energy. enthalpy and entropy of dissociation are also evaluated and discussed.read more

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R S SAXENA ,S SHARMA ,K K SAXENA ,

DETERMINATION OF SHAHRIGH COAL WITH HNO3 AND THE DETERMINATION OF TRACE-ELEMENTS IN THE ACID-EXTRACTS

Shahrigh coal was extracted with HN03 for different durations of time end with acid of different concentrations. The extracts were analysed for trace elements by atomic absorption spectrophotometer. Iron was found to be present in highest quantity whereas Mn in lowest quantity in the HN03 extracts. Duration of time and concentration of acid have positive effects on the extraction of trace elements, which were however not very significant in most of the cases. Percentage extractions of trace elements within diffe­rent duration of time and with acid of different concentration have also been calculated.read more

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M I MOHAMMAD ,M A KHAN ,

QUANTITATIVE-DETERMINATION OF CERTAIN CATIONS BY PAPER-CHROMATOGRAPHY

Qualitative and quantitative analysis of iron, zinc, cobalt, copper and nickel using paper chromatography is reported. Qual i tative analysi s was done by measuring Rf values of these metal cations whereas the quantitative estimation was done by colour comparison technique using Lovibond Tintometer.read more

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A MAJEED ,M S KHAN ,M ZULFIQAR ,A RASHID ,

REACTIONS OF SOME OXIDIZING-AGENTS WITH POTASSIUM OXALATE IN MOLTEN LINO3 - KNO3 EUTECTIC

few reactions of K2S207, KMn04, Ce(S04)2 and FeC13 with K2C204 in molten alkali metal nitrate eutectic were investigated. The products were characterized by elemental analysis, thermogravimetric and x-ray powder difraction techniques. Potassium pyrosulphate reacted with the melt to form sulphate and nitryl (N02-) ions. Later N02- is reduced by oxalate ion giving N02 and CO2. Potassium permanganate was reduced by oxalate ion to form a mixed valence oxide ion, Mn30g4- and CO2• Cerium (IV) sulphate and iron (III) chloride were simply reduced to Ce(llI) and Fe(lI) ions through one electron transfer by oxalate ion. Their oxalates were separated from the melt and characterized.When excess of oxalic acid was reacted with K2Cr207 or K2Cr04, it produced a well known oxalate complex, K3 [Cr(C204)3]. read more

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M R MALIK ,N AHMAD ,M ZULFIQAR ,

SPECTROSCOPIC STUDIES OF NICOTINIC HYDRAZIDE AND ITS ARYLIDENE DERIVATIVES

The electronic absorption spectra, in different solvents as well as in buffer solutions, ir spectra and IH nmr spectra of nicotinic hydrazide and its arylidene derivatives are investigated. The important bands are assigned to the corresponding molecular vibrations and discussed in relation to molecular structure.read more

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M H A KADER ,H Y F EL BARADIE ,M GABER ,R M ISSA ,

MOLECULAR-COMPLEXES OF SOME TETRAVALENT TIN-COMPOUNDS

Reactions of the following tin(IV) salts: dirrethyltin dichloride, diphenyltin dichloride and tin tetrachloride with a variety of nitrogen and oxygen donating ligands were studied. Besides the physical properties the partial ir-spectral features, the thermal and electrolytic behaviour of the formed complexes are reported. An attempt was made to compare between the complexes of the three considered salts.read more

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W S HEGAZI ,S HESSIN ,M A WASEEF ,