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991.
M. R. Mahmoud S. A. Ibrahim N. M. Ismail 《Monatshefte für Chemie / Chemical Monthly》1985,116(2):167-175
Co(II), Ni(II) and Cu(II) complexes of some bifunctional arylidene-o-phenylenediamineSchiff bases have been prepared. Formation, stoichiometry and stability of the complexes have been tested in solution using electronic spectral measurements. Characterization of the complexes has been accomplished primarily by elemental analysis, molar conductance as well as electronic and IR spectral measurements. It is concluded that theo,o-hydroxy derivative (L
1) acts as a bivalent ONNO tetradentate ligand while the molecules of the other derivatives (L
2-L
5) are coordinated to the metal ions as bidentate NN ligands. The Cu(II)-L
1 complex is suggested to possess a tetrahedral geometry whereas the other complexes are suggested to exhibit a distarted octahedral geometry. The different bands observed in the electronic spectra of the complexes inDMF solutions have been assigned to the -*,L M CT and d-d electronic transitions.
Untersuchungen zur Charakterisierung einiger zwei- und vierzähniger bifunktionellerSchiffbasen-Komplexe mit Co(II), Ni(II) und Cu(II)
Zusammenfassung Es wurden die Co(II)-, Ni(II)- und Cu(II)-Komplexe einiger bifunktioneller Aryliden-o-phenylendiamin-Schiffbasen hergestellt. Unter Verwendung elektronenspektroskopischer Methoden wurde die Bildung, Stöchiometrie und Stabilität der Komplexe in Lösung untersucht. Die Charakterisierung erfolgte mittels Elementaranalysen, Leitfähigkeitsmessungen und Elektronen- bzw. IR-Spektroskopie. Es wird darauf geschlossen, daß daso,o-HydroxyderivatL 1 als bivalenter vierzähniger ONNO Ligand wirkt, während die anderen Derivate (L 2-L 5) als zweizähnige NN Liganden an die Metallionen koordiniert sind. Für den Cu(II)-L 1 Komplex wird eine tetraedrische Geometrie vorgeschlagen, währenddessen die anderen Komplexe eine verzerrte octaedrische Geometrie aufweisen. Die in den Elektronenspektren der Komplexe inDMF-Lösung auftretenden Banden werden den -*,L M CT und d-d Elektronenübergängen zugeordnet.相似文献
992.
A. A. T. Ramadan M. A. El-Behairy A. I. Ismail M. M. Mahmoud 《Monatshefte für Chemie / Chemical Monthly》1994,125(11):1171-1182
Summary Proton-ligand formation constants ofDCPT and metal-ligand formation constants of its complexes with Fe(II) and Fe(III) have been determined potentiometrically at 10, 20, 30, and 40°C in 75% (v/v) dioxane-water at 0.10M ionic strength (KNO3). The thermodynamic parameters G, H, and S have also been evaluated. The possibility of formingM(HL),M(HL)2, andM(HL)3 species was substantiated from potentiometric and electronic absorption measurements. The values of the stability constants logK
M(HL), log
, and log
derived from the spectrophotometric method are in good agreement with those obtained from potentiometric data. The use ofDCPT as an analytical reagent for the spectrophotometric determination of iron is discussed. The solid complexes have been characterized by chemical analysis and magnetic susceptibility, IR, NMR, and electronic spectral data.
Synthese und Eigenschaften von Eisen(II)- und Eisen(III)-Komplexen mit 3-(,-Dicarboxy-n-propylidene-hydrazino)-5,6-diphenyl-1,2,4-triazin (DCPT)
Zusammenfassung Die Bildungskonstanten sowohl vonDCPT als auch seiner Komplexe mit Fe(II) und Fe(III) wurden bei 10, 20, 30 und 40°C in Dioxan-Wasser (75% (v/v)) bei einer lonenstärke von 0.1M KNO3 potentiometrisch bestimmt. Zusätzlich wurden die thermodynamischen Parameter G, H und S ermittelt. Die Wahrscheinlichkeit des Auftretens von Komplexen der ArtM(HL),M(HL)2 undM(HL)3 wurde mittels potentiometrischer und absorptionsspektroskopischer Messungen erhärtet. Nach beiden Methoden ermittelte Stabilitätkonstanten stimmen gut überein. Die Verwendung vonDCPT als analytisches Reagens zur spektrophotometrischen Eisenbestimmung wird diskutiert. Die Komplexe konnten in Substanz hergestellt werden und wurden durch chemische Analyse und über ihre magnetischen und spektroskopischen Eigenschaften charakterisiert.相似文献
993.
A simple, rapid, and reliable method is given for determination of As(III) based on arsenite reduction of alcoholic iodine and titration of the equivalent iodide with Hg(II) using silver amalgam as the indicator electrode. Arsenite reduction is applied to the estimation of lead in minium, manganese in duralumin, chromium in zinc chromate, and vanadium and chromium in ilmenite, the excess of arsenite being determined by the same method used for As(III). The endpoints are accurately determined with very satisfactory potential breaks. 相似文献
994.
Three new vic-dioxime ligands, [N-(ethyl-4-amino-1-piperidine carboxylate)-phenylglyoxime (L1H2), N-(ethyl-4-amino-1-piperidine carboxylate)-glyoxime (L2H2), and N,N′-bis(ethyl-4-amino-1-piperidine carboxylate)-glyoxime (L3H2)], and their Co(II) with Cu(II) metal complexes, were synthesized for the first time. Mononuclear complexes of these ligands
with a 1:2 metal-ligand ratio were prepared with Co(II) and Cu(II) salts. The BF2+-capped Co(II) and mononuclear complexes of the vic-dioxime were prepared for [Co(L1·BF2)2] and [Co(L2·BF2)2]. The ligands act in a polydentate fashion bonding through nitrogen atoms in the presence of a base, as do most vic-dioximes. The cobalt(II) and copper(II) complexes are non-electrolytes as shown by their molar conductivities (ΛM) in DMF. The structures of the ligands and complexes were determined by elemental analyses, FT-i.r., u.v.–vis., 1H- and 13C-n.m.r. spectra, magnetic susceptibility measurements, and molar conductivity. The comparative electrochemical studies show
that the stabilities of the reduced or oxidized species and the electrode potentials of the complexes are affected by the
substituents attached on the oxime moieties of the complexes. 相似文献
995.
Four novel 3-alkyl(aryl)-4-(4-methoxycarbonylbenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (2) were synthesized by the reactions of 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (1) with methyl 4-formylbenzoate and characterized by elemental analyses and IR, 1H NMR, 13C NMR and UV spectral data. In addition, isotropic 1H and 13C nuclear magnetic shielding constants of 2 were obtained by the gauge-including-atomic-orbital (GIAO) method at the B3LYP density functional level. The geometry of each compound was optimized using the 6-311G basis set. 相似文献
996.
A simple reversed-phase column liquid chromatographic method for the determination of cis and trans isomers of monocrotophos (MCP) using a C18 column, aqueous acetonitrile as eluent and UV detection at 218 nm was developed. The method was used for quality assurance and to study the relative stabilities of cis and trans isomers in technical products of MCP. 相似文献
997.
Ismail I. Fasfous Mustafa M. El‐Abadelah Salim S. Sabri 《Journal of heterocyclic chemistry》2002,39(1):225-227
The synthesis of new pyrazolo[4,3‐c]β‐carbolines ( 8a,b ) is achieved by condensation of the appropriate aldehyde with 3‐(4‐amino‐1,3‐dimethylpyrazol‐5‐yl)indole ( 4 ) under Pictet‐Spengler reaction conditions. Regioselective cyclization occurred at the usual indole C‐2 position as evidenced from the 1H‐and 13C nmr spectra of 8a,b which lack the pyrrolic H‐2 signal, present in 4 (δ 7.26, 1H, d, Jch‐NH = 2‐5 Hz). 相似文献
998.
Coordination modes of multidentate azodye ligand derived from 4,4′‐methylenedianiline towards some transition metal ions: Synthesis,spectral characterization,thermal investigation and biological activity 下载免费PDF全文
Nine new azodye metal complexes of Mn(II), Co(II), Ni(II), Cu(II), Cr(III), Fe(III), Ru(III), Hf(IV) and Zr(IV) ions have been prepared via the reaction of 5,5′‐((1E,1′E)‐(methylenebis(1,4‐phenylene))bis(diazene‐2,1‐diyl))bis(6‐hydroxy‐2‐thioxo‐2,3‐dihydropyrimidin‐4(5H)‐one) (H4L) with the corresponding metal salts affording sandwich (1 L:1 M), mononuclear (2 L:1 M), binuclear (1 L,2 M) and tetranuclear (1 L,4 M) complexes. Elemental analyses, spectral methods, magnetic moment measurements and thermal studies were utilized to confirm the mode of bonding and geometrical structure for the ligand and its metal complexes. Infrared spectral data show that the H4L ligand chelates with some metal ions in keto–enol–thione or keto–thione manner. It behaves in a neutral/dibasic tetradentate fashion in sandwich and binuclear complexes. Also, it acts as a neutral bidentate moiety in the Cr(III) complex. The spectra reveal that azo group participates in chelation in all complexes. Octahedral geometry was suggested for all chelates but the Cu(II) complex with square planar geometry. The thermal stability and decomposition of the compounds were studied, the data showing that the thermal decomposition ended with metal or metal oxide mixed with carbon as final product. The electron spin resonance spectrum of the Cu(II) complex demonstrates that the free electron is located in the ( ) orbital. Measurements of biological activity against human cell lines Hep‐G2 and MCF‐7 reveal that the Cu(II) complex has a higher cytotoxicity in comparison to the free ligand and other metal complexes, with IC50 values of 6.10 and 5.2 μg ml?1, respectively, while the ligand has anti‐tumour activity relative to some of the investigated metal complexes. 相似文献
999.
G. M. Abou-Elenien N. A. Ismail A. A. Magd Eldin 《Monatshefte für Chemie / Chemical Monthly》1992,123(12):1117-1124
Summary Differently substituted 5-arylidene-2-thiohydantoins (2a–f) were studied electrochemically in benzonitrile with 0.1M tetra-n-butylammonium-perchlorate as supporting electrolyte using DC-, cyclic voltammetry (CV), coulometry and controlled potential electrolysis (CPE). These compounds are oxidized in a one two-electron transfer process or in irreversible two successive one-electron processes to the corresponding diradical, which simaltaneously reacts with the solvent to regenerate the starting species. On the other hand the reduction products are the 5-arylidene-4-imidazolidinone-2-thiols.
Voltammetrische Untersuchungen einiger substituierter 5-Aryliden-2-thiohydantoine in nichtwäßrigem Medium
Zusammenfassung Es wurden verschieden substituierte 5-Aryliden-2-thiohydantoine (2a–f) in Benzonitril mit 0.1M Tetra-n-butylammoniumperchlorat als Leitsalz elektrochemisch untersucht, wobei DC-, Cyclische Voltammetry (CV), Coulometrie und kontrollierte-Potential-Elektrolyse (CPE) eingesetzt wurden. Die Verbindungen wurden entweder in einem Zweielektronen-Transferprozeß oder in zwei irreversiblen Prozessen aufeinanderfolgender Einelektronen-Stufen zum entsprechenden Diradikal oxidiert, welches simultan mit dem Solvens unter Regenerierung der Startspezies reagiert. Andererseits sind die Reduktionsprodukte die 5-Aryliden-4-imidazolidinon-2-thiole.相似文献
1000.
Metal phthalocyanines (M = Cu, Ni, Co) 3-5 bearing four 16-membered diazadithia macrocycles at the peripheral positions were prepared. Detosylation with concentrated sulfuric acid afforded products containing both sulfonated groups on the aromatic rings of the macrocyclic substituents which are excellently soluble in water and donor sites for binding four CuII ions to give a pentanuclear complex. 相似文献