Showing papers in "Inorganic Chemistry in 1976"

Synthesis of molybdenum(IV) and molybdenum(V) complexes using oxo abstraction by phosphines. Mechanistic implications

Abstract: Die Reaktionen der Mo(VI)-Verbindungen (I) mit tert. Phosphinen demonstrieren einen bequemen Weg zur Darstellung von Mo(V)-Spezies wie (IIa) und (IIb) und von Mo(IV)-Komplexen wie (IIIb) und (IIIc).

Electron-transfer reactions of excited states. Reductive quenching of the tris(2,2'-bipyridine)ruthenium(II) luminescence

Abstract: Spectrofluorimetry was used to measure the quenching of *Ru(pby)/sub 3//sup 2 +/ luminescence using the reducing agents Fe(CN)/sub 6//sup 4 -/, Co(phen)/sub 3//sup 2 +/, Ru(NH/sub 3/)/sub 6//sup 2 +/, Eu(II), S/sub 2/O/sub 4//sup 2 -/, Fe/sup 2 +/ and Mo(CN)/sub 8//sup 4 -/. Data, including the reduction potential, the electron self-exchange rate constant, the Stern-Volmer constant, quenching rate constant, and spectral data concerning the position(s) of the lowest energy excited states available to the reducing agent quenchers, was tabulated using experimental data and some literature data. The experimental results indicate the role of *Ru(bpy)/sub 3//sup 2 +/ as a strong oxidizing agent in the electron transfer process. (DDA)

Comprehensive study of satellite structure in the photoelectron spectra of transition metal compounds

Abstract: A wide variety of different transition metal compounds have been studied for their satellite structure found in photoelectron spectra, with specific emphasis on the 2p shell of the first-row transition metals. In particular, data on halides and cyanide complexes are presented. Results on second- and third-row transition metal compounds are also discussed. The relative roles of electron shake-up and multiplet splitting for producing the satellite structure are evaluated. The behavior of the satellite structure is generalized as a function of metal ion and ligand and the energy spacing of the metal and ligand orbitals. It is ascertained that the large, well-defined satellite peaks are due to electron shake-up involving excitation of electrons from a ligand to a metal orbital. (auth)

Synthetic analogues of the active sites of iron-sulfur proteins. XIII. Further electronic structural relationships between the analogues [Fe2S2(SR)4]2- and the active sites of oxidized 2Fe-2S* proteins

Abstract: One-electron reduction of the synthetic tetramers [FemSa(SR)~] 2(R CHgPh, Ph), by chemical and electrochemical methods affords the corres~ofiding-trianions. ~The collective results from optical, electron paramagnetic resonance, and M~ssbauer spectroscopy, when compared to available data for reduced 4-Fe and 8-Fe ferredoxi~ proteins and super-reduced Chromatium high-potential protein, reveal that [FeASa(SR)j are electronic analogs of the [Fe4S4(S-Cys) 4] active sites of these prot~ifis. \

Aqueous complexes of gallium(III)

Abstract: Die Komplexbildung von Ga(III) mit verschiedenen vielzahnigen Liganden wie Polyaminopolycarbonsauren, Hydroxyalkylaminocarbonsauren, Polycarbonsauren und phenolischen Aminocarbonsauren in wasriger Losung wird mittels spektroskopischer und potentiometrischer Methoden untersucht.

Identification of polyborate and fluoropolyborate ions in solution by Raman spectroscopy

Abstract: The polymeric ions B/sub 5/O/sub 6/(OH/sup -//sub 4/, B/sub 3/O/sub 3/(OH)/sup -//sub 4/, B/sub 4/O/sub 5/(OH)/sup 2 -//sub 4/, and B/sub 3/O/sub 3/F/sub 6//sup 3 -/ have been identified in solution and their regions of stability established. Comparisons of Raman spectra of the solutions with the spectra of solid reference materials containing the same structural entities, NaB/sub 5/O/sub 8/.5H/sub 2/O, orthorhombic metaboric acid (HBO/sub 2/)/sub 3/, Na/sub 2/B/sub 4/O/sub 7/.10H/sub 2/O, and Na/sub 3/B/sub 3/F/sub 6/O/sub 3/ were used to identify the ions. The charge on the polyborate ions was established on the basis of material and ionic balances. The hydrolytic behavior of Na/sub 3/B/sub 3/F/sub 6/O/sub 3/ was established. This compound is partially depolymerized into BF/sub 2/(OH)/sup -//sub 2/ ions which disproportionate into BF/sub 3/OH/sup -/, F/sup -/, and H/sub 3/BO/sub 3/. A new synthesis for Na/sub 3/B/sub 3/F/sub 6/O/sub 3/ was developed.

Oxidation of coordinated diamines in bis(2,2'-bipyridine) complexes of ruthenium

Abstract: A series of diaminebis(2,2'-bipyridine) complexes of ruthenium(II), e.g., [Ru(bipy)2(en)]2+, has been prepared and the spectral and redox properties were investigated. The ethylenediamine and trans-1,2-diaminocyclohexane complexes undergo net four-electron oxidations, either chemically or electrochemically, giving the corresponding a,d-diimine complexes. The chemical and spectral properties of the cup'-diimine complexes are similar to those of [Ru(bipy)3]z+. Complexes containing 2-(aminomethyl)pyridine and 1,2-diamino-2-methyIpropane undergo net two-electron oxidations, in which the single CH2-NH2 linkage has undergone oxidative dehydrogenation to the imine. Electrochemical and titrimetric data (using Ce(1V)) in acetonitrile show that the diamine oxidative dehydrogenation reactions are initiated by oxidation of ruthenium(I1) to ruthenium(III), and that the reactions probably occur in a stepwise manner via monoimine intermediates.

Synthesis and characterization of the organic derivatives of zirconium phosphate

Abstract: γ-Zirkoniumphosphat wird beim Tauchen in eine wasrige Losung von Athylenoxid in neue, bis 200°C stabile Phasen mit vergroserten Grundflachenabstanden umgewandelt, die in alkalischer Losung zu den Phosphorsaureestern von Athylenglykol und Zr-hydroxid hydrolysiert werden.

Crystal structure of zirconium monochloride. A novel phase containing metal-metal bonded sheets

Abstract: Monocrystals of ZrCl were obtained by the reaction of ZrCl/sub 4/(g) with a large excess of electropolished Zr in a sealed tantalum tube under a 600-800/sup 0/C gradient for 24 days. Integrated diffraction data were secured on an automated diffractometer using Mo K..cap alpha.. radiation. Systematic absences among 203 observed reflections together with tuned diffraction data established a C-centered monoclinic cell with a = 5.943 (6), b = 3.419 (3), c = 9.087 (18) A, ..beta.. = 102.5 (1)/sup 0/, Z = 4. The structure was solved by standard Patterson and Fourier techniques to a conventional residual of 0.080 and R/sub w/ = 0.087. The structure contains homoatomic layers sequenced Cl-Zr-Zr-Cl so as to generate four-layer sheets, the layers and sheets being geometrically close to cubic close packed along (001). The result is found to be within experimental error of a higher symmetry trigonal cell (Z = 6) with the rhombohedral space group R3m. The diffraction data were therefore converted, averaged, and refined utilizing 85 independent reflections, half as many positional parameters, and a = 3.424 (2), c = 26.57 (4) A to give R = 0.071 and R/sub w/ = 0.087. Distances are not statistically distinguishable in the twomore » refinements; although the rhombohedral description is formally preferred, the real symmetry probably depends appreciably on the crystalline perfection in the (001) direction. Each zirconium atom has three neighbors in the adjacent sheet at 3.09 A (Pauling bond order of 0.5), six more in the same sheet at 3.42 A, and three chlorine atoms on the other side at 2.63 A. Weak chlorine-chlorine interactions between sheets at 3.61 A contrast with the strong metal-metal binding within the sheets; the former are presumably responsible for the graphitic properties and anisotropic conduction of the compound.« less