Selectivity and thermodynamic characteristics of doubly charged cations on zirconium titanate from aqueous and alcoholic solutions

The ion-exchange isotherms of Ni²⁺/H⁺ and Co²⁺/H⁺ have been determined with a solution of 0.1 ionic strength for both forward and backward reactions at 25^°C by a batch technique. The thermodynamic equilibrium constants for the exchange process have been calculated using the Gains and Thomas equation. The preference Ni²⁺>Co²⁺ has been shown. The ion exchange selectivity for exchange of Ni²⁺ and Co²⁺ ions with hydrogen ions on zirconium titanate has been investigated as a function of [HCl] from aqueous and 25% of methanol and/or ethanol solutions. The values of the thermodynamic functions for the studied systems have been reported. This revised version was published online in July 2006 with corrections to the Cover Date.     

Reaction of 4-aryl-1,2,4-triazines with hydrazine

The action of hydrazine on 3,5-dioxo-4-aryl-2,3,4,5-tetrahydro-1,2,4-triazines gave 4-amino-3,5-dixo-2,3,4,5-tetrahydro-1,2,4-triazines. The intermediates of this reaction were isolated and shown to be α-ketoacidhydra-zide 4-arylsemicarbazones and not the α-ketoanilidecarbohydrazones. The realtive rates of cyclization of the latter isomeric derivatives provide a support for a proposed intermediates which were not isolated in the reaction of 3-mercapto and 3-methylmercapto-4-aryl-5-oxo-4,5-dihydro-1,2,4-triazines with hydrazine.     

Substituted iron selenocarboxylate complexes CpFe(CO)(EPh3)SeCOR (E = P,As, Sb)

Photolytic substitutions of iron selenocarboxylate complexes CpFe(CO)₂SeCOR with triphenylphosphine, triphenylarsine or triphenylantimony (EPh₃) gave exclusively the monosubstituted complexes CpFe(CO)(EPh₃)SeCOR [R = 3,5-C₆H₃(NO₂)₂ (1), 4-C₆H₄NO₂ (2), Ph (3), 2-C₆H₄Me (4), and E = P (a), As (b), Sb (c)] in high yields.     

Liquid natural rubber (LNR) as a compatibiliser in NR/LLDPE blends—II: the effects of electron-beam (EB) irradiation

Electron-beam (EB) irradiation technique has been used to improve the properties of 60/40 blends of NR/LLDPE in the presence of compatibilisers such as LNR-6 and LNR-16. Improvement in the physical properties of the blend correspond with the increase in the interactions created by EB irradiation as measured by gel content. For this blend ratio, the radiation dose of 200 kGy is found to be optimum. While LNR-6 shows some complimentary effects when it is used together with EB irradiation technique; LNR-16, however, causes an imperfection effect in the blend. The crosslinking process that takes place as a result of EB irradiation occurs at the expense of crystalline arrangement of the semi-crystalline LLDPE. For the morphological fixation purposes EB irradiation technique is found to be very effective.     

Synthetic studies of organodi-π-cyclopentadienyl- titanium (III) derivatives

Two synthetic routes to compounds of the type π-Cp₂Ti^IIIR (R=CH₃, CH₂Si(CH₃)₃, C₆F₅) have been investigated: (a) chemical reduction of π-Cp₂Ti^IV(R)Cl by zinc or aluminum metal in tetrahydrofuran, and (b) conventional organometallic syntheses using organo-lithium or -magnesium reagents and [π-Cp₂Ti^IIICl]₂. The preferred route is via an organolithium reagent, since chemical reduction gives a mixture of products. Green, monomeric complexes (R = CH₂Si(CH₃)₃, C₆F₅) were isolated and characterised. From the reaction of π-Cp₂Ti^IVCl₂ and trimethylsilylmethyllithium in a 1/1 ratio, π-CpTi^IV [CH₂Si(CH₃)₃]₃ was obtained. Unlike π-Cp₂Ti^IIIC₆F₅, π-Cp₂Ti^IIICH₂Si(CH₃)₃ does not form a blue complex with molecular nitrogen.     

Synthesis and reactions of 2-[α-(3,4-disubstituted phenacyl)-p-substituted styryl]-4H-3,1-benzoxazin-4-ones

Science Department, Faculty of Teachers, P.O.Box 2313, Al Hasa, 31982, Saudi Arabia Faculty of Engineering, Ain Shames University, EgyptChemistry Department, Faculty of Science, Ain Shames University, Egypt     

Ligational,thermal, corrosion inhibition and antimicrobial properties of salicylidinebenzenesulphonylhydrazone

Summary Complexes of Cu^II, Co^II, Ni^II, Cd^II, Zn^II and Hg^II with salicylidinebenzenesulphonylhydrazone (HSBS) have been prepared and characterized by elemental analyses, molar conductivities, magnetic moments, spectral (visible, i.r., n.m.r.) and thermal (d.t.a., t.g., d.t.g.) measurements. The magnetic and spectral studies confirm that the Ni^II complex is square, whereas the Co^II complex is tetrahedral. The molar conductivities for the complexes lie in the non-electrolyte range. The corrosion inhibition of aluminium using HSBS was studied by chemical and electrochemical methods. Also, the antimicrobial activities of HSBS and its complexes have been investigated.     

Determination of phenothiazines by charge-transfer complex formation with chloranilic acid

A rapid and sensitive spectrophotometrc method has been developed for the microdetermination of some phenothiazine derivatives as the pure substances and in different dosage forms. The method depends on the formation of stable donor-acceptor complexes between phenothiazines and chloranilic acid in an acetonitrile-2-propanol solvent mixture. The resulting intensely purple chloranilic acid radical anion possesses a characteristic absorption maximum at 515 nm. Beer's law is obeyed over the concentration ranges 1-6, 1-10 and 5-30 mug ml for prochlorperazine dimaleate, trifluoperazine dihydrochloride and thiethylperazine dihydrochloride, with apparent molar absorptivities of 7.76 x 10(4), 1.95 x 10(4) and 6.64 x 10(3) 1. mole(-1).cm(-1), respectively. Statistical comparison of the results with those of an official method shows excellent agreement and indicates no significant difference in precision.     

(Dibenzyl sulfoxide‐κO)bis(1,3‐diphenylpropane‐1,3‐dionato‐κ2O,O′)dioxouranium(VI)

In the title compound, [UO₂(C₁₅H₁₁O₂)₂(C₁₄H₁₄OS)], the U^VI atom is coordinated by seven O atoms in a distorted pentagonal–bipyramidal geometry. Both di­phenyl­propane‐1,3‐dionate systems are nearly planar. The sulfoxide moiety is in a distorted tetrahedral geometry, while its two aromatic rings are nearly orthogonal to one another. The crystal packing is stabilized by two bifurcated hydrogen‐bonding interactions involving both uranyl O atoms.     

Mass spectral fragmentation patterns of heterocycles. VII . Reinvestigation of fundamental processes in phenothiazines

Electron impact induced fragmentation patterns of simple phenothiazines have been reinvestigated using metastable ion studies, exact mass measurements and deuterated derivatives. Secondary fragmentation processes involving ions m/e 198, 171, 167, 166, 154, 140 and 139 have been clarified. Mechanisms for the release of sulfur (SH· and CSH·) nitrogen (HCN and H₂CN·) containing fragments from phenothiazine molecular ion are proposed based on the deuterium content of the daughter ions obtained from 1,9-dideutenophenothiazine. A revised mechanism for the expulsion of ketene from 10-acetylphenothiazine is suggested based on the fragmentation pattern of the 1,9-dideuterioderivative. The composition of m/e 140 was determined by high resolution measurement to be C₁₀H₆N and not C₁₁H₇ as previously reported.