205Tl-NMR-spektroskopische Untersuchungen an Thallium(I)-und Organothallium(III)-Verbindungen

Inhaltsübersicht. Mittels ²⁰⁵Tl-Breitlinien- und hochauflösender ¹H-NMR wurden Tl(I)-sowie Organothallium(III)-Verbindungen untersueht und ²⁰⁵Tl- und ¹H-chemische Verschiebungen sowie ²⁰⁵Tl-¹H-Kopplungskonstanten ermittelt. Die NMR-Parameter dor Tl(I)-Verbindungen wurden mit Literaturwerten verglichen. Die paramagnetischen ²⁰⁵Tl-Verschiebungen von Verbindungen des Type R₂TlX (R = Me, Et. n-Pr, Ph; X = NO₃, F, Br, J) werden in Bezug auf Substituenten., Losungsmittel- und Konzentrationseinflüsse diskutiert. Auf der Basis eines 0.3 molaren wäßrigen TINO₃-Primärstandards werden die ²⁰⁵Tl-Verschiebungen in einer einheitlichen Verschiebungsskala geordnet und nach bindungstheoretischen Gesichtspunkten verglichen. ²⁰⁵Tl-N.M.R.-Spectroscopical Studies on Thallium(I) and Organothallium(III) Compounds Abstract. Tl(I) and organothallium(III) compounds are investigated by means of ²⁰⁵Tl wide line and high resolution ¹H-n.m.r. and ¹H chemical shifts as well as ²⁰⁵Tl-²H coupling constants are estimated. The n.m.r.-parameters of the Tl(I) compounds are compared with the values of the literature. The paramagnetic ²⁰⁵Tl shifts of compounds of the type R₂TlX (R = Me. Et, n-Pr. Ph; X = NO₃, F, Br. I) are discussed with reference to the influence of substituents, solvents, and concentrations. The ²⁰⁵Tl shifts are arranged on the basis of a 0.3 M aqueous TlNO₃ primary standard in a uniform shift scale and compared as to theoretical aspects of chemical bonds. Für die großzügige Unterstützung unserer Arbeit danken wir Herrn Prof. Dr. K.-D. Schleinitz.     

Einschiebungsreaktionen in die Organothallium(III)-Element-Bindung

Insertion Reactions to the Organothallium (III)-Element Bond Insertion reactions to the thallium-element bonds of Me₂Tl-NMe₂ and Me₂TI-OEt with RNCS, PhNCO, CS₂. COS, CO₂, SO₂ and SO₃ and the characterization of the reaction products with the chemical and spectroscopic methods are reported.     

Untersuchungen an Tetrachloroferraten(III)

Information on physical and chemical properties, especially on the structure and chemical bonding of M[FeCl₄]-complexes has been obtained by measurements of the optical absorption, the MÖSSBAUER effect and EPR. (M stands for a monovalent cation.) The iron(III) chlorocomplex compounds Ag[FeCl₄], Rb[FeCl₄] and Li[FeCl₄] have been proved to exist within the systems MCl? FeCl₃ by measurements of optical spectra and EPR.     

Arylvanadium(III)-Verbindungen. VII. Organovanadium(III)-Verbindungen vom Typ LiVMes3(ERn) und ihr Oxydationsverhalten

Arylvanadium(III) Compounds. VII. Organyl Vanadates of the Type LiVMes₃(ER_n) and their Oxidation Trimesityl vanadium yields with carbyl ligands lithium trimesityl organyl vanadates. It reacts also with LiER_n (E ? Si, Sn, N, P, O) forming complexes of the type LiVMes₃(ER_n). The oxidation behaviour of the amido compounds are investigated, and VMes₃(NPh₂) is synthesized. The compounds are characterized by their magnetical, spectral, and thermal properties.     

Thermogravimetrische Untersuchungen an zeolithischen Erdalkalithioferraten(III)

The degradation of the hydrates of the alkaline earth thioferratesM(FeS₂)₂·xH₂O,M=Ca, Sr, Ba, resulting from ion exchange on KFeS₂, is studied by TG and by X-ray diffraction analysis. The zeolitic character of the very loosely bound water in these compounds is proved. There exist several cristallographically distinct phases as a function of the water content.

Herrn Prof. Dr.O. Hoffmann-Ostenhof zum 65. Geburtstag gewidmet.     

Organothallium compounds : XVII. Halogenobis(polyfluorophenyl)thallium(III) complexes

The preparations, stabilities and structures of the complexes R₂TlX and R₂ LTlX (R = C₆F₅, p-HC₆F₄, or o-HC₆F₄; X = Br or Cl; L = Ph₃PO, 2,2′-bipyridyl (bpy) or Ph₃P) have been examined or (R = C₆ F₅) reinvestigated. The derivatives R₂TlX are monomeric in acetone, from which the complex (p-HC₆F₄)₂ Me₂COTIBr has been isolated. In this solvent, the complexes R₂LTlX (L = Ph₃PO, bpy, or Ph₃P) undergo partial dissociation by loss of L. When L = bpy, there is also slight ionization into R₂LTl⁺ and R₂TlX^?₂. The acceptor properties of R₂TlX compounds towards uncharged ligands decrease R = C₆F₅ ? p-HC₆F₄ > o-HC₆F₄ > Ph. Dimeric behaviour is observed for R₂TIX compounds in benzene, whilst R₂LTlX (L = Ph₃PO or bpy) derivatives show slight but significant association. In the solid state, R₂TlX compounds are considered to be polymeric with five coordinate thallium, and R₂LTlX derivatives to be dimeric with five (L = Ph₃PO) or six (L = bpy) coordinate thallium by contrast with four coordinate dimeric and four or five coordinate monomeric structures previously proposed for the respective pentafluorophenyl derivatives. Halogen bridging is unsymmetrical for R = C₆F₅ or p-HC₆F₄, but may be more symmetrical for R = o-HC₆F₄ when L = Ph₃PO or bpy. Reported structural data for the complexes (C₆F₅)LTlX (L = Ph₃AsO, Ph₃P, Ph₃As, or 1,10-phenanthroline; X = Br or Cl) and (C₆F₅)₂TlCl^?₂ are reinterpreted and the proposed structures revised.     

Elektrochemische Untersuchungen am Ninhydrin

Zusammenfassung Bei der potentiostatischen zweilektronigen Reduktion des Ninhydrins wird eine der beiden nicht hydratisierten Ketogruppen durchreduziert. Bei pH-Werten oberhalb 4,5 lagert sich dieses benzoide Reduktionsprodukt in eine tautomere chinoide Verbindung um, die im pH-Bereich 4,5–8 ein Proton und ein Molekül Wasser, bei pH-Werten oberhalb 11 zwei Protonen abspaltet. Im Gegensatz zum farblosen benzoiden 2e-Reduktionsprodukt hat die einfach ionisierte chinoide Verbindung eine rote, die zweifach ionisierte chinoide eine blaue Farbe. Die elektroneutrale chinoide Verbindung unterhalb pH 4,5 its farblos und dehydratisiert.Oberhalb pH 9 dissoziiert von der hydratisierten mittleren Ketogruppe des Ninhydrins ein Proton ab (pKs=8,6), was bei hohen pH-Werten zur raschen Umwandlung in o-Carboxymandelsäure führt. Ninhydrin läßt sich zweielektronig oxydieren zur o-Carboxy-phenylglyoxylsäure.Mit 8 Abbildungen     

UV-spektroskopische Untersuchungen an cis-und trans-Bis(phenyl)bis(phosphan)platin(II)-Verbindungen

A long-wavelength absorption band in the UV spectra of compounds of the typecis-and trans-bis(phenyl)bis(tri-n-butylphosphane) platinum(II) and cis-bis-(phenyl)bis(tris[4-(dimethylamino)phenyl]phosphane)platinum(II) is probably due to the influence of substituents in the phenyl rings in the form of a phenyl → platinum charge-transfer-transition.     

Organothallium compounds XII NMR spectra of some polyfluorophenylthallium (III) compounds

The PMR and ¹⁹F NMR spectra of the complexes R₂TlBr (R = C₆F₅, $\text{o}$-HC₆F₄, $\text{m}$-HC₆F₄, 3,5-H₂C₆F₃, or 3,6-H₂C₆F₃ and R₃Tl(diox) (R = C₆F₅, $\text{m}$-HC₆F₄, or 3,5-H₂C₆F₃; diox = 1,4-dioxan) have been recorded. Proton and fluorine chemical shifts, thallium-proton, thallium-fluorine, fluorine-fluorine, and fluorine-proton coupling constants, and thallium substituent chemical shifts are given and discussed     

Arylvanadin(III)-Verbindungen,III. Darstellung und Eigenschaften von Triarylvanadin-Verbindungen

Arylvanadium(III) Compounds. III. Preparation and Properties of Triaryl Vanadium Complexes The synthesis of triarylvanadium compounds, VR₃ (R = C₆H₅; 2,6-(CH₃)₂C₆H₃; 2,4,6-(CH₃)₃C₆H₂; (CH₃)₅C₆) is investigated. Only the compounds V[2,6-(CH₃)₂C₆H₃]₃ and V[2,4,6-(CH₃)₃C₆H₂]₃ (crystallized with tetrahydrofuran) are obtained. The complexes V(C₆H₅)(dipy)₂ · THF, V[2,4,6-(CH₃)₃C₆H₂]₃ · Do (Do = py, dipy) are described too.     

Arylvanadium(III)-Verbindungen. VI. Darstellung und Eigenschaften von Lithium-trimesityl-organyl-vanadaten(III)

Arylvanadium (III) Compounds. VI. Preparation and Properties of Lithium Trimesityl organyl Vanadates Trimesityl vanadium reacts with LiR (R = Ph, o-Tol, Dmop, CH₃, CPh₃) forming complexes Li(thf)₄ VMes₃R. With Li₂C₆H₄ and Li₂C₂ the compounds Li₂(thf) ₈ V(μ-C₆H₄)Mes₆ and Li₂(thf)₈V(μ-C₂)Mes₆ are obtained. All compounds are characterized by their thermal, magnetical, and spectral properties.     

31P-Kernresonanzspektrometrische Untersuchungen an Phosphato-Cobalt(III)- und Rhodium(III)-Komplexen

³¹P N.M.R. Spectroscopic Investigations of Phosphato Complexes of Cobalt(III) and Rhodium(III) ³¹P n.m.r. spectra of phosphato complexes of cobalt and rhodium(III) are recorded. The coordination shift of monodentate phosphate is 8–9 ppm, of bidentate phosphate 18 ppm, of phosphite 10–11 ppm, of fluorophosphate 6–7 ppm. Monophosphato and pentaamminaquacobalt complexes condense with the elimination of water to a m?-complex. The ability of the phosphato complexes of cobalt(III) to condense phosphate to diphosphate was investigated. After heating [CoPO₄en₂] · 2 H₂O with an excess of dihydrogenphosphate only small amounts of the expected diphosphate complex could be detected. The analogous reaction with fluorophosphate results in an appreciably higher yield of the diphosphate complex.     

Synthese und Eigenschaften von Intramolekular stabilisierten Gallium(III)- und Indium(III)-Verbindungen

Synthesis and Properties of Intramolecular Stabilized Gallium(III) and Indium(III) Compounds Novel organogallium and organoindium compounds containing stabilizing diphenylalkylphosphane, -stibane and -bismutane ligands are synthesized. The intramolecular coordination by formation of a metal(13)-metal(15) bond is proved by ¹H-NMR studies.     

Analyse unbest?ndiger organischer Phosphor (III)-, Arsen (III)- und Antimon(III)-Verbindungen

Ohne Zusammenfassung     

Elektrochemische Untersuchungen des Systems Ozon/Sauerstoff an verschiedenen Elektrodensubstraten

The cathodic reduction of O₃ and O₂ in O₃/O₂ gas mixtures was studied at Pt–Pt/Au-alloy-, Au–Ir and Rh-electrodes in 1N-H₂SO₄.The steady state polarization curves exhibitTafel-regions withb-values from 110–160 mV (260–280 mV at Rh). A single electron transfer reaction is found to be the rate determining step. In a region of high cathodic polarization limiting currents are observed which are controlled by diffusion. Platinum is the only electrode material at the O₃-electrode which is stable against corrosion.In the presence of O₃ a decrease of the cathodic polarization of +300 to +400 mV for the O₂ reduction is observed on Pt.This activation of the O₂-electrode is only quasi-stationary because the reduction of the Pt–O layer, which is electrocatalytically effective, proceeds at a low rate for the potentials concerned.The triangular voltage sweep curves show that formation and reduction of oxygen layers and the electrochemical reactions of O₃ and O₂ respectively occur independently of each other.

---

---

Mit 6 Abbildungen