87 research outputs found
Iron(II) High-Spin and Low-Spin Complexes from Pentaisopropylcyclopentadienyliron(II) Bis(trimethylsilyl)amide
No full textParamagnetic 18-Valence-Electron Alkylcyclopentadienylnickel(II) Bromide Dimers
No full textThe paramagnetic behavior of 18-electron cyclopentadienylnickel(II) complexes of the [CpNi(mu-Br)](2) type with two unpaired electrons per metal ion has been investigated by H-1 and C-13 NMR spectroscopy of [Cp''Ni(mu-Br)](2) (1; Cp'' = 1,3,4-(Bu3C5H2)-Bu-t), [(CpNi)-Cp-3(mu-Br)](2) (2; Cp-3 = 1,3,4-iPr(3)C(5)H(2)), and [(CpNi)-Cp-4(mu-Br)](2) (3; Cp-4 = 2,3,4,5-iPr(4)C(5)H). The tri-tert-butylcyclopentadienyl derivative 1 crystallizes in the triclinic space group P (1) over bar and has been investigated by X-ray crystallography. Solid-state magnetic susceptibility measurements of 3 revealed an effective magnetic moment at room temperature of 4.04 mu(B),confirming the presence of two d(8) nickel(II) ions. While antiferromagnetic coupling via the bromo bridges is weak (J = 2.4 cm(-1)), zero-field splitting is substantial (D = +48.2 cm(-1)). NMR spectra of complexes 1-3 show signals with half-widths up to 3600 Hz within a spectral window exceeding 500 ppm (H-1) or 2200 ppm (C-13). An analysis of the spectra gave insight into the spin delocalization, the equilibrium orientation of the iPr substituents, and the presence of different conformers of compound 3. Paramagnetic behavior has also been observed for the Cp derivative [Cp Ni(mu-Br)](2) (Cp = C5Me5) by H-1 NMR spectroscopy. The presence of two unpaired electrons is discussed in terms of the weak ligand field originating from the combined interaction of poorly pi accepting allcylcyclopentadienyl and pi donating bromo ligands with the nickel(II) center
The Decaphosphatitanocene Dianion — A New Chapter in the Chemistry of Naked Polyphosphorus Ligands.
No full text
Anfängerpraktikum mit Recycling:<i> Praktikum in Allgemeiner Chemie Teil I. Hrsg. v. H. Fischer. VCH Verlagsgesellschaft, Weinheim, 1992. 322 S., Spiralbindung, DM 48,-. ISBN 3-527-29034-6.</i>
No full text‐butyl)cyclopentadienyl}mercury by Transfer of Alkylated Cyclopentadienyl Rings from Bismuth to Mercury (Transmetallation)
No full textAbout the first industrial scale PEF – Plants and Heinz Doevenspeck's role – A historical review
No full textInspired by the work of Sven Carlson, Heinz Helmut Doevenspeck, a German engineer, was starting in 1958 to develop his so-called "Elektroimpulsverfahren", which used for the first time defined discharges of capacitors to generate homogeneous, pulsed electric fields. He applied these fields on dispersed systems of inorganic or organic origin to influence the membranes of plant or animal cells or the surface charges of particles. Cracking of cells, growing and/or killing of microorganisms, acceleration of fermentation processes and treatment of wastewater had been identified, described and patented by Doevenspeck as suitable applications already in the early 1960s. Until mid of the 1980s, working as an independent consultant, he did many trials at technical scale plants without reaching a breakthrough of his technology. From 1985 until 1993 he was cooperating with Krupp Company, Hamburg. In 1988 the first industrial scale plants were built and during this period several applications and process mechanisms were identified, mathematically modeled and presented to the scientific public for the first time
Ansätze zur Vorbereitung auf das Alter Dokumentation zur Expertentagung der Weltenburger Akademie vom 15. - 19. November 1976
No full text- …
