Komplexbildung und Extraktion von Molybdän(VI) mit zweizähnigen Liganden

Coordination and Extraction of Molybdenum(VI) with Bidentate Ligands A series of bidentate ligands as well as their thio derivatives from the groups of 8-quinolinols, β-diketones, acylpyrazolones, and N-acyl-phenylhydroxylamines was studied for the ability to extract molybdenum(VI) from heptamolybdate. The extraction principally runs only in acidic medium, sulfur-containing extractants having no advantage. The composition of the complexes was determined by the isolation of compounds in the solid state and also by the interpretation of distribution data.     

Zum Verhalten von Cobalt(II) und Eisen(III) bei der Flüssig-Flüssig-Extraktion mit pyridylsubstituierten Benzensulfonamiden

On the Behaviour of Cobalt(II) and Iron(III) in Case of Liquid-liquid Extraction by Pyridyl Substituted Benzene Sulfonamides Pyridyl substituted benzene sulfonamides N 3 NHSO₂R and N 2 NHSO₂R which may be used as models of sulfonamide based metal extractants (LIX 34 et. al.) were studied as to their coordinative behaviour towards cobalt(II) and iron(III). The structure of Co(N 3 NSO₂R)₂ is distorted tetrahedral. Considering bond lengths and angles π-backdonation between cobalt and the nitrogen atoms is indicated which creates a higher effective charge on the central atom than in normal cobalt(II) complexes. Therefore, when observing normal conditions, Co(N 3 NSO₂R)₂ is not oxidized but reduced. Co(N 2 NSO₂R)₂ is a sulfonamide bridged tetramer with pentacoordinate cobalt(II). Iron(III) forms the low-spin complex salts [Fe(N 3 NHSO₂R)₂ (N 3 NSO₂R)](NO₃)₂ · xH₂O and [Fe(N 2 NHSO₂R)₂(N 2 NSO₂R)](NO₃)₂ · xH₂O which are insoluble in organic solvents. This is the reason why the copper(II)-iron(III) separation by sulfonamide based metal extractants proceeds without problems.     

Synthese,spektroskopische Eigenschaften und elektrochemisches Verhalten von Ruthenium(II)-Komplexen mit zweizähnigen Stickstoffliganden

Synthesis, Spectroscopic Data and Electrochemical Behavior of Ruthenium(II) Complexes with Bidentate Ligands The syntheses of coordination compounds of ruthenium (II) with bidentate nitrogen donors (aa) is described. The ligands (aa) used are related to dipyridyl, but differ from the latter in size of the π-electron systems. In some ligands, e.g. 10 , the two halves of the molecule are forced to be non planar by the aliphatic bridge between the two rings accomodating the nitrogen ligand atoms. The syntheses of the complexes Ru(dipy)₂(aa)²⁺, Ru(dipy)(aa)²⁺₂ and Ru(aa)²⁺₃ ((aa) 1–17 ) are described. Generally the crystalline salts with PF ^?₆ as counter-ion have been obtained. The complexes are characterized by elementary analysis, electronic spectra, infrared spectra, cyclic voltammograms, proton nuclear magnetic resonance spectra and, for those which have been obtained in optically active forms also by circular dichroism. In the discussion special emphasis is given to the change of properties compared to the well investigated Ru(dipy)²⁺₃ complex. In the visible range of the spectrum all complexes show one or several spin allowed charge transfer transitions at longer wave lengths then Ru(dipy)²⁺₃. The ground state oxidation potential to the 3+ state are little affected by substitution of one or more of the dipy ligands in Ru(dipy)²⁺₃ by the ligands (aa), whereas the reduction behavior is strongly influenced by such substitutions. The ¹H-NMR. spectra indicate rigid conformations of some of the nonplanar (aa)-ligands in the complexes.     

Alkyl- und Arylkomplexe des Iridiums und Rhodiums. XIX. Reaktion von Carbonsäuren mit ausgewählten Organoverbindungen von Ir(I) und Rh(I): Bildung von Arylhydrido-, Carboxylatohydrido- und Carboxylato-Derivaten

Alkyl and Aryl Complexes of Iridium and Rhodium. XIX. Reaction of Carboxylic Acids with Selected Organo Compounds of Ir(I) and Rh(I): Formation of Arylhydrido, Carboxylatohydrido, and Carboxylato Derivatives cis-Arylhydridoiridium(III) complexes IrH(Ar)(O₂CR)(CO)(PPh₃)₂ (R = Me: Ar = C₆H₅, 4-MeC₆H₄; R = Et: Ar = 4-MeC₆H₄, 2,4-Me₂C₆H₃) could be prepared by oxidative addition of carboxylic acids to aryliridium(I) compounds Ir(Ar)(CO)(PPh₃)₂. Reaction of aliphatic carboxylic acids with alkyliridium(I) derivatives Ir(Alk)(CO)(PPh₃)₂ and Ir(Alk)[PhP(CH₂CH₂CH₂PPh₂)₂] (Alk = CH₂CMe₃, CH₂SiMe₃) lead to dicarboxylatoiridium(III) hydrides IrH(O₂CR)₂(CO)(PPh₃)₂ (R = Me, Et, i-Pr) and IrH(O₂CR)₂[PhP(CH₂CH₂CH₂PPh₂)₂] (R = Me, Et). Ir(4-MeC₆H₄CO₂)(CO)(PPh₃)₂ was obtained from Ir(CH₂SiMe₃)(CO)(PPh₃)₂ and 4-MeC₆H₄CO₂H. Interaction of organorhodium complexes Rh(R′)(CO)(PPh₃)₂ (R′ = CH₂SiMe₃, 4-MeC₆H₄) and Rh(R′)[PhP(CH₂CH₂CH₂PPh₂)₂] (R′ = CH₂CMe₃, 4-MeC₆H₄) with aliphatic and aromatic carboxylic acids yielded carboxylatorhodium(I) compounds Rh(O₂CR)(CO)(PPh₃)₂ (R = Me, t-Bu, 4-MeC₆H₄) and Rh(O₂CR)[PhP(CH₂CH₂CH₂PPh₂)₂] (R = Me, 4-MeC₆H₄).     

Bestimmung des Enantiomerenüberschusses von chiralen Ammonium-Ionen mit Hilfe von Flüssigmembranelektroden

Determination of the Enantiomeric Excess of Chiral Ammonium long Using Liquid Membrane Electrodes A cell assembly with two membranes each containing one enantiomer of a chiral ionophore is described. It is suitable for the direct potentiometric determination of the enantiomeric excess of ions. The method is used to determine the enantiomeric excess of ephedronium ions in aqueous solutions.     

Über Metall-Stickoxid-Komplexe. XXVI. Nitrosyl-Komplexe von Kobalt und Eisen mit Chelatbildnern

Under replacement of NaBr five- and sixmembered nitrosyl chelat complexes are formed by the reaction of nitrosyl halides of iron and cobalt with sodium salts of acyloines like benzoin and 1,3-diketones such as actylacetone, benzoylacetone and dibenzoylmethane. In the same way react sodium salicylate and pyrocatechol yielding monomeric chelat complexes; by the reaction of disodium pyrocatechol with dinitrosylcobaltbromide a dimeric compound (ON)₂CoOC₆H₄OCo(NO)₂ was found containing oxobridges only. The IR-spectra are discussed.     

Elektromotorisches Verhalten von Flüssigmembranelektroden-Messketten mit enantiomerenselektiven chiralen Ionophoren

Electromotive Behaviour of Liquid-membrane Electrode Assemblies Based on Enantiomer-selective Chiral Ionophores A comprehensive theoretical treatment is given for the potentiometric behavior of enantiomer-selective membrane electrodes based on chiral ionophores and plasticizers. The membrane model allows for free and complexed enantiomeric or racemic ions (e.g. ephedronium and l-phenylethylammonium ions) as well as for achiral interfering ions. Experiments are derived for the determination of the stoichiometry and the relative stability of enantiomeric ion/enantiomeric ligand complexes, and for the analytical measurement of the enantiomeric excess of ions in solution.     

Über Metall-Stickoxid-Komplexe,XXVII. Nitrosyl-Komplexe von Metallen der Eisengruppe mit Aminosäuren und Aldoximen als Chelatbildnern

In addition to the previously described dinitrosyl complexes of iron and cobalt with anions of 1,3-diketones, salicylic acid etc. nitrosyl complexes which contain the anions of amino acids and aldoximes as chelate ligands have been prepared. Corresponding mononitrosyl chelate complexes of nickel are obtained from the dimeric [Ni(NO)P(C₆H₁₁)₃Br]₂. The infra red spectra and magnetic properties of these compounds are reported.     

Solvatochromie von Metall(0)-Komplexen der 6. Nebengruppe mit zweizähligen Azomethinen als Liganden

Solvatochromism of Subgroup VI Metal(0) Complexes with Bidentate Azomethine Ligands Some mononuclear and binuclear chelat compounds of azomethines, derived from the carbonyls of molybdenum and chromium are described. The spectrophotometrical behaviour of the compounds is compared with the behaviour of the diazabutadiene and dipyridyl metalcarbonyls. The complexes show strong negative solvatochromic effects in organic solutions and in polymers.