Rhodium(III), palladium(II) and platinum(II) complexes of Bis(o-aminobenzenesulfonyl)ethylenediamine

New complexes of the formulae K₃[RhL ₃]·2 H₂O, [PdL]·H₂O and [M(LH₂)Cl₂] [whereM = Pd, Pt andLH₂ = bis(o-aminobenzenesulfonyl)ethylenediamine] have been prepared and characterized by conductivity measurements, thermogravimetric analysis, X-ray powder patterns and IR, Ligand Field and¹H-NMR spectroscopy.

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Rhodium(III), Palladium(II)- und Platin(II)-Komplexe mit Bis(o-aminobenzolosulfonyl)ethylendiamin (Kurze Mitteilung)

Zusammenfassung Neue Komplexe der allgemeinen Formeln K₃[RhL ₃]·2H₂O, [PdL]·H₂O und [M(LH₂)Cl₂] mitM = Pd, Pt undLH₂ = Bis(o-aminobenzolosulfonyl)ethylendiamin wurden dargestellt und mit Konduktionsmessungen, thermogravimetrischen Analysen, Röntgenstrukturanalysen, IR, Ligandfeld- und¹H-NMR-Spektroskopie charakterisiert.

     

Synthesis and characterization of metal complexes of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Ru(III), Rh(III) and Pd(II) with derivatives of 1,3,4-thiadiazole-2,5-dithiol as new ligands

The synthesis of some new transition metal complexes with 1,3,4-thiadiazole-2,5-dithiol derivatives (L₁ and L₂) as new ligands is reported. Each complex was prepared by the reaction of the ligands with the appropriate metal salts (CrCl₃, MnCl₂·4H₂O, FeCl₃, CoCl₂·6H₂O, NiCl₂·6H₂O, CuCl₂·2H₂O, RuCl₃, RhCl₃ and PdCl₂). Elemental micro analysis (C.H.N.), UV–Visible spectroscopy, ¹H NMR, infrared (IR) spectroscopy, atomic absorption, magnetic susceptibility, continuous variation method and molar conductance techniques were used to characterize the structural formulae of these chelate complexes.     

Deprotonated and non-deprotonated cobalt(II) complexes of the bis-amide tetradentate ligand N,N′-(dipicolyl)-1,8-naphthylene diamine. Three different modes of coordination by the ligand

The preparation and some properties of the cobalt(II) complexes Co(LH₂)Cl₂·2H₂O, Co(LH₂(NCS)₂ and CoL·H₂O (whereLH₂=N,N-(dipicolyl)-1,8-naphthylenediamine) are reported. On the basis of magnetic moments, visible reflectance and IR data, the structure is proposed to be pseudo-octahedral for Co(LH₂)Cl₂·2 H₂O, pseudo-tetrahedral for Co(LH₂)(NCS)₂ and square planar for CoL·H₂O.

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Deprotonierte und Nicht-deprotonierte Co(II)-Komplexe des vierzähnigen Bisamid-Liganden N,N-(Dipicolyl)-1,8-naphthyldiamin. Drei verschiedene Koordinationstypen

Zusammenfassung Es werden die Darstellung und einige Eigenschaften der Kobalt(II)-Komplexe Co(LH₂)Cl₂·2 H₂O, Co(LH₂)(NCS)₂ und CoL·H₂O [LH₂=N,N-(dipicolyl)-1,8-naphthylendiamin] diskutiert. Auf der Grundlage von magnetischen Momenten, von Daten der sichtbaren Reflektions-und IR-Spektren wird eine pseudooctaedrische Struktur für Co(LH₂)Cl₂·2H₂O, eine pseudotetraedrische für Co(LH₂)(NCS)₂ und eine planar-quadratische für CoL·H₂O vorgeschlagen.

     

Redox behaviour of divalent metal saccharinates

Summary The electrochemical behaviour of a series of divalent metal saccharinates of stoichiometry [M ^II(sac)₂(H₂O)₄]·2H₂O was studied by cyclic voltammetry inDMF solutions using a glassy carbon electrode. The oxidation and the reduction of the metallic centers Fe(II) and Cu(II), respectively, is shown to occur in one electron-steps and to be quasireversible. The second electron transfer for the copper saccharinate is followed by decomposition of the complex associated with loss of the ligand and copper electrodeposition. Reduction of the ligand was observed for Ni(II), Fe(II), and Co(II) saccharinates at highly negative potential. On the contrary, oxidation or reduction peaks were not observed with sodium saccharinate. The uncoordinated ligand was inactive in the analyzed potential range.

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Elektrochemisches Verhalten zweiwertiger Metallsaccharinate

Zusammenfassung Das elektrochemische Verhalten einer Reihe zweiwertiger Metallsaccharinate der Stöchiometrie [M ^II(sac)₂(H₂O)₄]·2H₂O wurde inDMF mit Hilfe cyclischer Voltammetrie an Glaskohlenstoff-Elektroden untersucht. Die Oxidation bzw. Reduktion von Fe(II) und Cu(II) erfolgt durch einen Einelektronenprozeß und erwies sich als quasi-reversibel. Die zweite Elektronenübertragung wird im Falle des Kupfersaccharinats von einer Zersetzung des Komplexes begleitet, welche unter Ligandenverlust zur Abscheidung von Kupfer auf der Elektrode führt. Im Falle der Ni(II)-, Fe(II)- und Co(II)-Komplexe wurde eine Reduktion des Liganden bei sehr negativen Potentialen beobachtet. Dagegen wurden für Natriumsaccharinat keine Oxidations- oder Reduktionspeaks beobachtet; der unkomplexierte Ligand erwies sich im untersuchten Potentialbereich als inaktiv.

     

Rh(III), Pd(II), Pt(IV) and Au(III) complexes of 2-thiopyrimidine derivatives

Some news thiopyrimidine derivatives and complexes [4-amino-5-nitroso-6-oxo-1,2,3,6-tetrahydro-2-thio-pyrimidine (TANH), its 2-methylthio derivative (MTH), the ammonium salt ofTANH (sTANH) and six new complexes of formulas: Rh(MT)₂Cl · 2H₂O, Pd(MTH)₂Cl₂, Pt(MTH)₂Cl₄, Au(MTH)Cl₃ Pd(TANH)₂Cl₂ and Au(TAN ^–)Cl] have been synthesized and characterized by elemental analysis, IR and¹H-NMR spectroscopy techniques. The thermal behaviour of all compounds has also been studied.

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Rh(III), Pd(II), Pt(IV) und Au(III) Komplexe von 2-Thiopyrimidin Derivaten

Zusammenfassung Es wurden einige neue Thiopyrimidinderivate und deren Komplexe synthetisiert und mittels Elementaranalyse, IR und¹H-NMR charakterisiert: 4-Amino-5-nitroso-6-oxo-1,2,3,6-tetrahydro-2-thio-pyrimidin (TANH), dessen 2-Methylthio-Derivat (MTH), das Ammoniumsalz vonTANH (sTANH) und sechs neue Komplexe der Formeln Rh(MT)₂Cl · 2H₂O, Pd(MTH)₂Cl₂, Pt(MTH)₂Cl₄, Au(MTH)Cl₃, Pd(TANH)₂Cl₂ und Au(TAN ^–)Cl. Das thermische Verhalten der Verbindungen wurde ebenfalls untersucht.

     

Coordination compounds of heterocyclic azo derivatives. III. Co(II), Ni(II) and Cu(II) complexes of some arylazo-4,5-diphenylimidazole derivatives

The 3d transition metalion [Co(II), Ni(II) and Cu(II)] complexes of some 4,5-diphenylimidazole azo derivatives have been isolated and characterized by chemical analysis, conductance, electronic and IR spectra. These dyes are characterized by a high tendency towards complex formation with the neutral molecules coordinated to the metal ion as bidentate ligands. The molecular formula of the 1:1 and 1:2 complexes are suggested to be [MLX ₂(H₂O)₂] and [ML ₂ X ₂] or [ML ₂ X ₂]·2H₂O respectively, whereX=Cl^– or NO₃. the different bands observed in the visible spectra of methanolic solutions of the complexes have been assigned to the possible electronic transition type (L MCT and d-d). It is suggested that the complexes studied have a distorted octahedral geometry.

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Koordinatsverbindungen von heterocyclischen Azo-Derivaten, 3. Mitt.: Co(II)-, Ni(II)- und Cu(II)-Komplexe einiger Arylazo-4,5-diphenylimidazol-Derivate

Zusammenfassung Es wurden einige Komplexe von 4,5-Diphenylimidazol-azo-Derivaten mit den 3 d-Übergangsmetallen Co(II), Ni(II) und Cu(II) isoliert und mittels chemischer Analyse, Leitfähigkeitsmessungen und den Elektronen- bzw. IR-Spektren charakterisiert. Diese Farbstoffe zeigen eine sehr starke Tendenz zur Komplexbildung, wobei die neutralen Moleküle als zweizähnige Liganden an das Metallion koordinieren. Die Formeln für die 1:1- und 1:2-Komplexe werden mit [MLX ₂(H₂O)₂] und [ML ₂ X ₂] bzw. [ML ₂ X ₂]·2H₂O vorgeschlagen (X=Cl^– oder NO ₃ ^– ). Die verschiedenen Absorptionsbanden in den VIS-Spektren in methanolischer Lösung werden den möglichen e-Übergängen (L MCT und d-d) zugeordnet. Für die Komplexe werden verzerrte oktaedrische Geometrien vorgeschlagen.

     

Palladium(II), platinum(II) and platinum(IV) complexes of 2-mercapto-3-phenyl-4-quinazolinone: Reactions of palladium(II) chloride and platinum (IV) chloride with 2-mercapto-3-phenyl-4-quinazolinone in the presence and absence of variousN-heterocyclic bases

Summary Reactions of 2-mercapto-3-phenyl-4-quinazolinone (LH) with PdCl₂ · 2H₂O and PtCl₄ · 5H₂O lead to the formation of [ML₂ complexes (M = Pd^II or Pt^II). Reactions of PdCl₂ · 2H₂O with LH in the presence ofN-heterocyclic bases yield compounds of type [PdLClB], (B = py, 3-pic, (o-phen)_1/2, and (bipy)_1/2) or Pd(LH)Cl(imz). PtCl₄] · 5H₂O reacts with LH in the presence of variousN-heterocyclic bases to give [PtL₂B] compounds (B = py, 3-pic, (o-phen)_1/2 or (pyrm)_1/2) and [PtL₂BCl] (B = imz or pz). These complexes have been characterised on the basis of analytical, i.r. and electronic spectral and magnetic measurement studies, and tentative structures for them are proposed.     

Complex formation of hypoxanthine and 6-mercaptopurine with Cd(II) ion

Reaction of Cd(II) ion with hypoxanthine (H₂ Y) and with 6-mercaptopurine (H₂ MP) in dioxane-water (50%) leads to the formation of CdY·2H₂O and Cd(HMP)₂·2H₂O, respectively. In methanolic medium Cd(II) and H₂ MP give Cd(MP)·H₂O. These compounds have been characterized by chemical analysis, IR spectra and thermogravimetric analysis. The stability constant of CdY complex at 25±0.1 °C and 1M ionic strength with NaClO₄ in dioxane-water medium is log =10.25±0.05.

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Komplexbildung von Hypoxanthin und 6-Mercaptopurin mit Cd(II)

Zusammenfassung Die Umsetzung von Cd(II)-Ionen mit Hypoxanthin (H₂ Y) und 6-Mercaptopurin (H₂ MP) in Dioxan-Wasser (50%) ergibt die Verbindungen CdY·2H₂O und Cd(HMP)₂·2H₂O. In Methanol entsteht aus Cd(II) und H₂ MP CdMP·H₂O. Die Verbindungen wurden durch chemische Analysen, IR-Spektren und thermogravimetrische Analysen charakterisiert. Die Stabilitätskonstante der Verbindung CdY bei 25°C und bei einer Ionenstärke = 1 (NaClO₄) in Dioxan-Wasser wurde zu lg =10,25±0,05 bestimmt.

     

Synthesis and characterisation of nickel(II), cobalt(II), manganese(II), copper(II), zinc(II), dioxouranium(VI) and dioxomolybdenum(VI) complexes of tridentate dibasic ONO donor Schiff bases derived from 2-benzothiazolecarbohydrazide and salicylaldehyde/2-hydroxy-1-naphthaldehyde

Summary The syntheses of several new coordination complexes of nickel(II), cobalt(II), manganese(II), copper(II), zinc(II), dioxouranium(VI) and dioxomolybdenum(VI) with new Schiff bases derived from 2-benzothiazolecarbohydrazide and salicylaldehyde or 2-hydroxy-1-naphthaldehyde are described. These complexes have been characterised by elemental analyses, electrical conductance, magnetic susceptibility, molecular weight, i.r. and electronic spectra. The Schiff bases behave as dibasic and tridentate ligands coordinating through the ONO donor system and form complexes of the types NiL · 3H₂O, MnL · 2H₂O, CoL · 2H₂O, CuL, ZnL · H₂O, UO₂L · MeOH and MoO₂L · MeOH (where LH₂ = Schiff base). The copper(II) complexes exhibit subnormal magnetic moments indicating the presence of an antiferromagnetic exchange interaction, whereas the nickel(II), cobalt(II) and manganese(II) complexes behave normally at room temperature. Zinc(II), dioxouranium(VI) and dioxomolybdenum(VI) complexes are diamagnetic; the zinc (II) complexes are tetrahedral, the copper(II) complexes are square planar, all the other complexes are octahedral. Thev(C=N),v(C-O),v(N-N) andv(C-S) shifts have been measured in order to locate the Schiff base coordination sites.     

Über anomale Mischkristalle vom Typ Ammoniumchlorid-Kobalt(II)chlorid-Wasser

Zusammenfassung Untersucht wurde das System NH₄Cl–CoCl₂–H₂O bei 25,0°C mit und ohne Überschuß an HCl in der Lösung. Bestimmt wurden die Kristallisationsbereiche der anomalen Mischkristalle auf der Basis von Ammoniumchlorid, der anomalen Mischkristalle auf der Basis des Doppelsalzes 2 NH₄Cl·CoCl₂·2H₂O und der Kristallisationsbereich von CoCl₂·6H₂O. Die Gegenwart eines Säureüberschusses in der Lösung übt eine entsalzende Wirkung aus.Es wird gezeigt, daß die anomalen Mischkristalle Systeme darstellen, in denen mit der Zeit langsame Veränderungen eintreten. Die Einbaukomponente im Ammoniumchlorid ist das Doppelsalz 2 NH₄Cl·CoCl₂·2 H₂O. Dieses liegt metastabil im Kristallisationsbereich des Ammoniumchlorids vor und zerfällt langsam in seine Bestandteile. Das dabei gebildete Kobalt(II)chlorid verbleibt adsorbiert im Kristallverband des Ammoniumchlorids und wird zusätzlich hydratisiert.

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Anomalous mixed crystals of the ammonium chloride-cobalt(II) chloride-water type

The system NH₄Cl–CoCl₂–H₂O is investigated at 25.0°C, with and without excess of HCl. The crystallization ranges of the anomalous mixed-crystals on the basis of ammonium chloride, of the anomalous mixed-crystals on the basis of the double-salt 2NH₄Cl·CoCl₂·2H₂O and of CoCl₂·6H₂O were determined. The presence of HCl in the solution decreases the solubilities of the different phases occurring in the above system.It is shown that the anomalous mixed-crystals represent systems undergoing slow changes in time. The component which is built in ammonium chloride is the double-salt 2 NH₄Cl·CoCl₂·2 H₂O. It is unstable in the crystallization range of ammonium chloride. This is why it decomposes slowly, into its components. The cobalt(II) chloride set free remains adsorbed in the ammonium chloride crystals and is hydrated additionally.

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Mit 4 Abbildungen

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Am Versuchsteil hatte auch FrauMargarita Sheleva-Vogel Anteil, wofür ihr die Autoren ihren Dank aussprechen.     

Complexes of NS and NSO donor ligands. Nickel(II), copper(II) and cobalt(II) complexes of glyoxal bis(morpholineN-thiohydrazone) and diacetyl bis(morpholineN-thiohydrazone)

Summary Reactions of glyoxal bis(morpholineN-thiohydrazone), H₂gbmth, with NiCl₂·6H₂O, Ni(OAc)₂·4H₂O, Ni(acac)₂· H₂O, CuCl₂·2H₂O, Cu(OAc)₂·H₂O, Cu(acac)₂, CoCl₂· 6H₂O, Co(OAc)₂·4H₂O and Co(acac)₂·2H₂O yield complexes of the type [M(gbmth)], [M=Ni^II, Cu^II or Co^II]. Diacetyl reacts with morpholineN-thiohydrazide in the presence of nickel salts to yield [Ni^II(dbmth)], [Ni^II(dmth)(OAc)]H₂O and [Ni^II(Hdmth)(NH₃)Cl₂] involving N₂S₂ and NSO donor ligands. Copper and cobalt complexes of N₂S₂ and NSO donor ligands with compositions [Cu^II(dbmth)], [Co^II(dbmth)]·4H₂O and [Co^II(H₂dbmth)]Cl₂, have been isolated. The compounds have been characterised by elemental analyses, magnetic moments, molar conductance values and spectroscopic (electronic and infrared) data.     

Coordination compounds of Co(II), Ni(II) and Cu(II) with capric acid hydrazide

The reaction of aquo-ethanolic solutions of Co(II), Ni(II) and Cu(II) salts and ethanolic solution of capric acid hydrazide (L) yielded paramagnetic, high-spin bis- and tris(ligand) chelate complexes. The tris(ligand) complexes, [ML ₃]X ₂·nH₂O [M=Co(II), Ni(II);X=NO ₃ ^– , ClO ₄ ^– , 1/2SO ₄ ^2– ], have an octahedral structure formed on account of the bidentate (NO) coordination of three neutral hydrazide molecules. In the bis(ligand) complexes,ML ₂(NCS)₂ [M=Co(II), Ni(II)] and CuL ₂ X ₂·nH₂O (X=NO ₃ ^– , ClO ₄ ^– and 1/2SO ₄ ^2– ), the oxoanions and NCS^– take also part in coordination. The complexes have been characterized by elemental analysis, IR spectra, magnetic measurements, molar conductivity and TG analysis.

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Caprinsäurehydrazid-Komplexe von Co(II), Ni(II) und Cu(II)

Zusammenfassung Durch die Reaktion von wäßrig-ethanolischen Lösungen von Co(II)-, Ni(II)-und Cu(II)-Salzen mit einer ethanolischen Lösung von Caprinsäurehydrazid (L) wurden paramagnetische high-spin Bis- und Tris-Ligand-Chelatkomplexe erhalten. Tris-Ligand-Komplexe des Typs [ML ₃ X ₂·nH₂O [M=Co(II), Ni(II);X=NO ₃ ^– , ClO ₄ ^– , 1/2SO ₄ ^2– ], die eine oktaedrische Struktur besitzen, entstehen durch die Koordination von drei neutralen zweizähnigen (NO)-Hydrazidmolekülen. Bei den Bis-Ligand-KomplexenML ₂(NCS)₂ [M=Co(II), Ni(II)], sowie bei den Bis-Ligand-Komplexen CuL ₂ X ₂·nH₂O (X=NO ₃ ^– , ClO ₄ ^– , 1/2SO ₄ ^2– ) nehmen bei der Koordination außer Hydrazid auch die Säurereste teil. Die Komplexe wurden durch Elementaranalyse, IR-Spektren, magnetische Messungen, molare Leitfähigkeit und TG-Analysen charakterisiert.

     

Characterization of Copper(II), nickel(II), cobalt(II) and palladium(II) complexes of vicinal oxime-imine ligands; induced chelate isomerism in the same molecule of the nickel(II) complex

Summary Metal complexes of the title ligands were characterized in order to determine the factors influencing the stability of chelate isomerism in the same molecule. The ligands were prepared by 1:1 condensation of isonitrosoacetylacetone (Hiso) with eithero-aminophenol (H₂ isoaph),p-aminophenol (H₂ isopph), or aniline (Hisoanil). The following complexes have been synthesized: [(isoaph)Cu]₄, (Hisoaph)₂Co, (Hisopph)₂ M·nH₂O (M=Ni(II), n=2;M=Pd(II), n=0;M=Co(II), n=2), [(isopph) Cu·H₂O]₂, and (isoanil)₂ M (M=Ni(II), Cu(II), Co(II), or Pd(II)). Both chelate rings in these metal complexes are five-membered. Transimination of one –C=N–C₆H₅ group to –C=NH in (isoanil)₂Ni produced a six-membered chelate ring in (isoim)Ni(isoanil). The induced chelate isomerism is ascribed to intermolecular hydrogen bonding of the imino-hydrogen and the basic nitrogen of the same six-membered chelate ring of an adjacent square planar molecule. Other types of hydrogen bondings with the oximato oxygen (intra- or intermolecular) favour the formation of five-membered chelate rings. Analytical, spectroscopic, and magnetic moment data are in accordance with the suggested formulations.Part of the Ph.D. thesis of Sana M. Imam     

Voltammetric and titrimetric study of acid-base properties of some μ-oxo dimeric iron(III) complexes inDMF

Summary The acid-base properties of the -oxo bridged dimeric iron complexes [FeL]₂O with the ligands based on S-alkyl-1,4-bis(substituted salicylidene)isothiosemicarbazide and a tetramer with S-methyl-1,4-bis(salicylidene)isothiosemicarbazide, {[FeL]₂O}₂I₃·I₂, were investigated by cyclic voltammetry at glassy carbon electrode inDMF. Studies were carried out in the presence of either a weak (phenol) or a strong (HClO₄ aq.) acid. The stoichimoetry of the reaction, changes in the general voltammetric pattern and the electrode reaction mechanism were discussed. These studies served as the basis for three-electrode amperometric titrations to determine the content of several of these complexes.

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Voltammetrische und titrimetrische Untersuchung der Säure-Base-Eigenschaften einiger -oxo dimerer Eisen(III)-Komplexe inDMF-Lösungen

Zusammenfassung Die Säure-Base-Eigenschaften einiger dimerer -oxo-Eisen(III)-Komplexe [FeL]₂O mit Liganden auf Basis von 1,4-bis(substituierten Salicyliden)S-(alkyl)isothiosemicarbaziden sowie eines tetrameren Komplexes mit 1,4-Bis(salicyliden)S-methylisothiosemicarbazid, {[FeL]₂O}₂I₃·I₂, wurden mittels zyklischer Voltammetrie an der Glaskohlenstoffelektrode inDMF-Lösungen untersucht. Die Messungen wurden in Gegenwart entweder einer schwachen (Phenol) oder einer starken (HClO₄ aq.) Säure ausgeführt. Die Stöchiometrie der Reaktion, die Änderungen der voltammetrischen Kurven und der Elektroden-Reaktionsmechanismus wurden diskutiert. Diese Untersuchungen stellten eine Basis für Drei-Elektroden amperometrische Titrationen dar, die für die Bestimmung des Gehalts einiger dieser Komplexe angewendet wurden.

     

Die Möglichkeiten der Anwendung der Wechselstrompolarographie auf die Messung der Geschwindigkeitskonstanten

Zusammenfassung Die Wechselstrompolarographie ist für die Messung der Geschwindigkeitskonstanten der Elektrodenprozesse im Bereich von 5·10^–3–5·10^–2 cm sec^–1 anwendbar. Das bestätigen auch die Ergebnisse, die für ein Modellsystem erhalten wurden. Experimentell wurde die Anwendbarkeit der Methode am Redoxsystem [CrCl₂(H₂O)₄]⁺–[CrCl₂(H₂O)₄] in sauren 4–9n-LiCl-Lösungen nachgeprüft, und zwar durch den Vergleich der Resultate mit den Ergebnissen der Messungen derFaraday-impedanz und der Methode der überlagerten Spannung.

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Application of alternating current polarography for the measurement of rate constants

The method of alternating current polarography is known to be applicable to the measurement of rate constants of electrode reactions within the range of 5·10^–3 to 5·10^–2 cm sec^–1. This follows also from the results obtained with model systems. The applicability of the method has been studied in the redox-system [CrCl₂(H₂O)₄]⁺–[CrCl₂(H₂O)₄] in acid solutions of 4N to 9N LiCl. The results were compared with those obtained by measuring the faradaic impedance and with the results of the method of periodically changed rectangular voltage.

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Mit 7 Abbildungen     

Synthesis and characterization of nickel(II), cobalt(II), copper(II), manganese(II), zinc(II), zirconium(IV), dioxouranium(VI) and dioxomolybdenum(VI) complexes of a new Schiff base derived from salicylaldehyde and 5-methylpyrazole-3-carbohydrazide

Summary Synthesis of a new Schiff base derived from salicylaldehyde and 5-methylpyrazole-3-carbohydrazide, and its coordination compounds with nickel(II), cobalt(II), copper(II), manganese(II), zinc(II), zirconium(IV), dioxouranium(VI) and dioxomolybdenum(VI) are described. The ligand and the complexes have been characterized on the basis of analytical, conductance, molecular weight, i.r., electronic and n.m.r. spectra and magnetic susceptibility measurements. The stoichiometries of the complexes are represented as NiL · 3H₂O, CoL · 2H₂O, CuL, MnL · 2H₂O, ZnL · H₂O, Zr(OH)₂(LH)₂, Zr(OH)₂L · 2MeOH, UO₂L · MeOH and MoO₂L · MeOH (where LH₂ = Schiff base). The copper(II) complex shows a subnormal magnetic moment due to antiferromagnetic exchange interaction while the nickel(II), cobalt(II) and manganese (II) complexes show normal magnetic moments at room temperature. The i.r. and n.m.r. spectral studies show that the Schiff base behaves as a dibasic and tridentate ligand coordinating through the deprotonated phenolic.oxygen, enolic oxygen and azomethine nitrogen.     

Synthesis and spectral properties of new complexes between glycine and titanium(III), vanadium(III), chromium(III), iron(III), cobalt(II), nickel(II) and copper(II)

Summary Complexes of formula [MCl₃(glyH)₃] (M=Ti, V and Fe) [CrCl₃(glyH)₂H₂O], [MCl₂(glyH)₂(H₂O)₂] (M=Co and Cu) and [NiCl₂(glyH)₃H₂O] have been prepared and characterized by potentiometric curves, chemical analysis, magnetic properties, i.r. and electronic spectral data.     

The thermal decomposition of some Cr(III) complexes

The thermal decomposition reactions of the following chromium(III) complexes were investigated: Cr(CH₃COO)₃·2 H₂O, [C_r3O(CH₃COO)₆(H₂O)₃]Cl·2 H₂O and [Cr₃O(CH₂ClCOO)₆(H₂O)₃]Cl·6H₂O. Simultaneous TG/DTG/DTA were applied nonisothermal conditions. From the recorded curves, the activation energiesE _a were calculated for all the thermal decomposition steps. Appropriate chemical reactions were attributed to the thermal effects, with consideration to the X-ray diffraction and IR spectra results.

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Zusammenfassung Für die Untersuchung der thermischen Zersetzungsreaktion der Chrom(III)-Komplexe Cr(CH₃COO)₃·2H₂O [C_r3O(CH₃COO)₆·(H₂O)₃]Cl2H₂O und [C_r3O(CH₂ClCOO)₆·(H₂O)₃]C₁₆H₂O wurde simultane TG/DTG/DTA unter nichtisothermen Bedingungen eingesetzt. Ausgehend von den aufgezeichneten Kurven wurden für alle Schritte der Zersetzungsreaktion die E_a-Werte berechnet. In Übereinstimmung mit röntgenographischen und IR-spektroskopischen Ergebnissen wurden den thermischen Effekten passende chemische Reaktionen zugeordnet.

     

Cobalt(II), nickel(II), copper(II) and copper(I) complexes of 2-mercapto-5-methyl-1,3,4-thiadiazole and 2,5-bis(methylmercapto)-1,3,4-thiadiazole

Summary Some cobalt(II), nickel(II), copper(II) and copper(I) complexes of 2-mercapto-5-methyl-1,3,4-thiadiazole (mttz) and 2,5-bis(methylmercapto)-1,3,4-thiadiazole (bmttz) have been prepared and studied by conductometric and magnetochemical methods and by electronic and i. r. spectroscopy. The complexes CoX₂ · 2L (L=mttz, X=Cl, Br or I; L=bmttz, X=Br or I), CoCl₂ · bmttz are pseudotetrahedral, and the complexes NiX₂ · mttz (X=Cl or Br), NiCl₂ · 1.3 bmttz, NiBr₂ · 1.5 bmttz are pseudooctahedral. The complex Co₃(OAc)₂ · 4(mttz-H) · 2H₂O has an undefinite constitution. The polynuclear complexes CuCl₂ · 1.3 mttz and CuBr₂ · 1.2 mttz contain presumably pseudotetrahedral chromophores, the chloride having a subnormal magnetic moment. The CuX₂ · 2 bmttz (X=Cl, Br or NO₃) complexes have a six coordination with bridging ligand molecules. In the CuX · 2 mttz (X=Cl, Br or ClO₄) complexes the anions are coordinated, while in the CuClO₄ · 2 bmttz complex the perchlorate anion is ionically bonded.     

Synthesis and characterization of bis(diphenylphosphinomethyl)amino ligands and their Ni(II), Pd(II) complexes: Application to hydrogenation of styrene

Transition metal complexes of Ni(II) and Pd(II) with ditertiary bis(diphenylphosphinomethyl)amino ligands, (Ph₂PCH₂)₂NC(CH₃)₃ ( 1 ) and [(Ph₂PCH₂)Nm‐PhSO₃]Na ( 2 ) (Ph = phenyl), have been synthesized in good yields under nitrogen atmosphere by Schlenk technique. All complexes have been characterized using elemental analyses and spectroscopic techniques such as atomic absorption, FT‐IR, and NMR (¹H, ³¹P). Atomic absorption spectroscopic analysis showed that the reactions of ligands 1 and 2 with NiCl₂ ⋅ 6H₂O and [PdCl₂(COD)] occurred in 1:1 molar ratio. The metal complexes [NiCl₂(Ph₂PCH₂)₂Nm‐PhSO₃Na] ( 4 ) and [PdCl₂(Ph₂PCH₂)₂Nm‐PhSO₃Na] ( 6 ) were found to be soluble in ethanolic and aqueous solutions, as well as slightly soluble in water. Electrochemical behaviors of complexes were investigated by cyclic voltammetry. Catalytic effects of Pd(II) complexes were tested throughout the hydrogenation of styrene to ethylbenzene. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:113–118, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20384