Charge transfer complexes of methylnaphthalene derivatives with TCNE in CCl4.

The spectrophotometric and thermodynamic properties of different substituted methylnaphthalenes charge transfer (CT) complexes with tetracyanoethylene have been studied in carbon tetrachloride. The spectral characteristics of the CT bands have also been discussed in relation to the positions of methyl groups. The formation constants and the spectral properties of the complexes are markedly affected with the substitution position of the methyl groups. The ionization potentials of the donors are determined.     

Spectral and magnetic properties of phenylazo-6-aminouracil complexes

Complexes of Co(II), Ni(II) and Cu(II) with substituted phenylazo-6-aminouracils containing (-H, p-OH, p-CH(3), p-OCH(3) p-COOH) have been synthesized and characterized by elemental analysis, magnetic measurements and spectral measurements (IR, UV-Vis, ESR). Infrared spectra assigned the fundamental bands of the major groups, O-H, N-H, C-H, C=O, C=N, N=N, C-N and C-O (nu, delta and gamma modes of vibrations). The absence of nu(OH) and the appearance of nu(C=O) in the infrared spectra of the free ligands of 5-(p-tolyl and p-anisylazo)-6-aminouracil, assigned the keto structure, whereas in cases of 5-(phenyl, p-hydroxyphenyl and p-carboxyphenylazo)-6-aminouracil ligands, the data showed strong nu(OH) and nu(C=O) bands to assign keto-enol tautomerisms. The modes of interactions between the ligands and the metals were discussed, where oxygen and nitrogen atoms (of amino-amide groups) are involved in chelation. The azo group was not involved in chelation for all the prepared complexes except those of copper complexes derived from 5-(phenyl, p-tolyl, p-hydroxyphenyl and p-carboxyphenylazo)-6-aminouracils. The room temperature effective magnetic moment values, the Nujol mull spectra and ESR proved that all the prepared complexes were of octahedral geometry, except the nickel complex derived from 5-(phenylazo)-6-aminouracil and cobalt complex derived from 5-(p-carboxy-phenylazo)-6-aminouracil were square planar.     

Utilization of charge-transfer complexation in the spectrophotometric determination of some monosaccharides through their osazone intermediates

Monosaccharide osazones are utilized in the spectrophotometric determination of their parent compounds though charge-transfer complexation with two-electron acceptor reagents. The molar combining ratio and the optimum complexation conditions have been studied. The method has been used to analyse for glucose and fructose and in determining blood glucose.     

Stereoselective access to the versatile 4-aminohex-5-ene-1,2,3-triol pattern

We developed a stereocontrolled route allowing potential access to the eight isomers of 4-benzylaminohex-5-ene-1,2,3-triol in two or four steps and ca. 50% yield from readily available chiral nonracemic cis- or trans-alpha,beta-epoxyimine precursors. A new (NH(4))(2)CO(3)-based carboxylation/intramolecular cyclization sequence allowed regio- and stereocontrolled C-3 epoxide opening while neat C-2 hydrolysis was ensured by simple aqueous acidic treatment.     

Indirect determination of pilocarpine by atomic absorption spectrometry

Atomic absorption spectroscopic (AAS) method for microdetermination of pilocarpine alkaloid has been developed. The procedure is based upon the measurement of mercuric content of pilocarpine complex. The experimental conditions as well as the molar ratio were thoroughly studied. The percentage recovery of pilocarpine was found to be (99.15 ± 0.79). The proposed method was applied on pharmaceutical formulations and the results were satisfactory and in good agreement with that given by the official one.     

Asymmetric hydrogenation of trisubstituted N-acetyl enamides derived from 2-tetralones using ruthenium-SYNPHOS catalysts: a practical synthetic approach to the preparation of β3-adrenergic agonist SR58611A

The asymmetric hydrogenation of various trisubstituted enamides derived from 2-tetralones under mild reaction conditions using Ru-SYNPHOS catalysts is reported. This practical and clean method gives access to several chiral 2-aminotetralins derivatives in high isolated yields and enantiomeric excesses up to 95% depending on the substitution pattern of the aromatic ring and the nature of the amide moiety. In addition, the usefulness of the current method is demonstrated via a practical synthetic approach to the enantiomerically pure SR58611A compound, a potent and selective β₃-adrenergic receptor agonist.     

Modelling and numerical simulation of high strength fibre reinforced concrete corbels

In the present study, new constitutive models for high strength steel fibre reinforced concrete (HSSFRC) have been formulated by means of a regression analysis of many experimental data (from literature) by using SPSS-statistical program. This proposed constitutive models have been employed for formulating the material finite element models to study the behaviour of HSSFRC corbels.     

Microdetermination of cinchona alkaloids by atomic absorption spectroscopy

A sensitive and rapid microdetermination method has been developed for the determination of cinchona alkaloids via their mercury complex. Different parameters of the procedure have been thoroughly studied. The percentage recoveries for quinine, quinidine, cinchonine and cinchonidine were found to be 98.97 ±0.62, 99.06 ± 0.62, 98.90 ± 0.74, respectively. The results obtained are favourably compared to the official ones. The method is characterised by its specificity, accuracy and good precision.     

Synthesis,thermal and electrical studies on solvated oxovanadium(IV) complexes with schiff bases derived from aromatic diamines and 2-hydroxy-1-naphthaldehyde

Summary Solvated oxovanadium(IV) complexes of Schiff bases derived from aromatic diamines and 2-hydroxy-1-naphthaldehyde have been prepared from ethanolic medium. The elemental analyses reveal that the complexes have the ratio 1:1, 2:2 and 1:2 (ligand:metal) composition which are nonelectrolyte inDMF. The coordination number six (octahedral geometry) is proposed for the complexes prepared. This is based on the results of IR, electronic and EPR spectra. TGA as well as DTA studies and the electrical properties and (I–V) characteristics for the metal complexes were investigated.

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Synthese und thermische bzw. elektrochemische Untersuchungen an solvatisierten Oxovanadium(IV)-Komplexen mit Schiff-Basen aus aromatischen Diaminen und 2-Hydroxy-1-naphthaldehyd

Zusammenfassung Die im Titel genannten Komplexe wurden in ethanolischem Medium hergestellt. Sie sind inDMF Nichtelektrolyte und haben laut Elementaranalyse die Zusammensetzung Ligand:Metall=1:1, 2:2 und 1:2. Basierend auf IR-, UV- und EPR-Spektren wird die Koordinationszahl 6 (oktahedrale Geometrie) vorgeschlagen. Es wurden TGA- und DTA-Studien durchgeführt und das elektrochemische Verhalten der Metallkomplexe untersucht.