In all metallofullerenes known before this work, metal atoms form single highly polar bonds with non-metal atoms in endohedral cluster. This is rather surprising for titanium taking into account the diversity of organotitanium compounds. Here we show that the arc-discharge synthesis of mixed titanium-lutetium metallofullerenes in the presence of ammonia, melamine or methane unexpectedly results in the formation of TiLu 2 C@ I h -C 80 with an icosahedral I h (7) carbon cage. Single-crystal X-ray diffraction and spectroscopic studies of the compound reveal an unprecedented endohedral cluster with a μ 3 -carbido ligand and Ti-C double bond. The Ti(IV) in TiLu 2 C@ I h -C 80 can be reversibly reduced to the Ti(III) state. The Ti=C bonding and Ti-localized lowest unoccupied molecular orbital in TiLu 2 C@ I h -C 80 bear a certain resemblance to titanium alkylidenes. TiLu 2 C@ I h -C 80 is the first metallofullerene with a multiple bond between a metal and the central, non-metal atom of the endohedral cluster.

The magnetic properties of nitride clusterfullerenes GdxSc3-xN@C80 (x = 1-3) are studied as a function of the number of Gd atoms in the cluster. The intracluster interaction of the Gd ions in Gd2ScN@C80 and Gd3N@C80 is ferromagnetic with exchange constants of -1.2 K ± 0.1 K and -0.6 K ± 0.1 K, respectively. At 2 K, the magnetization curves exhibit noticeable deviations from the Heisenberg model pointing to a non-negligible anisotropy.

Equilibrium and kinetics are compared for conjugated polymers, supposing the charged states are either polarons (Ps) and bipolarons (BPs) or polarons and polaron pairs (PPs). For low concentrations equilibrium and kinetics are virtually indistinguishable. Both are essentially different for high concentrations due to the fact that the extension of the bipolaron is almost the same as that of one polaron whereas the polaron pair has the extension of two polarons. As a result, the polaron concentration, i.e. the spin concentration, shows for a system with bipolarons a maximum and decreases for continuing increase of the potential. This dependence corresponds to results of ESR spectroelectrochemistry. In contrast, for the system with PPs both P and PP concentrations saturate at high potentials. Thus, the PP model is only reasonable if an additional subsequent second oxidation step is possible. The kinetics of the formation and dissociation of PPs or BPs, is essentially the same for concentrations that can be achieved in accumulation layers in organic MOS devices. The estimated relaxation times point to the formation and dissociation of either BPs or PPs as processes that can either cause or influence hysteresis effects in polymeric MOS capacitors, which can be described by an interface charge, depending on the sweep direction in the capacitance-voltage measurements.

. Triphenylamine was electrochemically polymerized in a mixture of toluene and acetonitrile with different electrolyte salts. The poly(triphenylamine) (PTPA) films are insoluble in polar solvents and show high stability and no degradation or loss in electrochemical properties when stored in a laboratory atmosphere. The PTPA films were characterized in situ by FTIR external reflection spectroscopy and by Raman spectroscopy.

In this work PPV films were prepared by electrochemical reduction of alpha,alpha,alpha,alpha -tetrabromo-p-xylene in dimethylformamide and tetraethylammonium tetrafluoroborate. To get more information about the mechanism behind electrochemical polymerization of PPV and its doping reaction, in situ ESR- UV-VIS measurements were made on the electrochemically synthesized conducting polymer PPV.

Chemie Ingenieur TechnikVolume 73, Issue 6 p. 716-716 Article Azacage Compounds as Efficient Tools for Enhancing Metal Ion and Anion Extraction K. Wichmann, K. WichmannSearch for more papers by this authorM. Grotjahn, M. GrotjahnSearch for more papers by this authorK. Gloe, K. Gloe Institute of Inorganic Chemistry, TU Dresden, 01062 Dresden, GermanySearch for more papers by this authorM. Möder, M. Möder Centre for Environmental Research Leipzig-Halle, 04318 Leipzig, GermanySearch for more papers by this authorL. Dunsch, L. Dunsch Institute for Solid State and Materials Research Dresden, 01171 Dresden, GermanySearch for more papers by this authorH. Stephan, H. Stephan Institute of Bioinorganic and Radiopharmaceutical Chemistry, Research Center Rossendorf, 01314 Dresden, GermanySearch for more papers by this authorF. Vögtle, F. Vögtle Kekulé-Institute of Organic Chemistry und Biochemistry, University of Bonn, 53121 Bonn, GermanySearch for more papers by this author K. Wichmann, K. WichmannSearch for more papers by this authorM. Grotjahn, M. GrotjahnSearch for more papers by this authorK. Gloe, K. Gloe Institute of Inorganic Chemistry, TU Dresden, 01062 Dresden, GermanySearch for more papers by this authorM. Möder, M. Möder Centre for Environmental Research Leipzig-Halle, 04318 Leipzig, GermanySearch for more papers by this authorL. Dunsch, L. Dunsch Institute for Solid State and Materials Research Dresden, 01171 Dresden, GermanySearch for more papers by this authorH. Stephan, H. Stephan Institute of Bioinorganic and Radiopharmaceutical Chemistry, Research Center Rossendorf, 01314 Dresden, GermanySearch for more papers by this authorF. Vögtle, F. Vögtle Kekulé-Institute of Organic Chemistry und Biochemistry, University of Bonn, 53121 Bonn, GermanySearch for more papers by this author First published: 12 July 2001 https://doi.org/10.1002/1522-2640(200106)73:6<716::AID-CITE7161111>3.0.CO;2-SAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume73, Issue6Juni 2001Pages 716-716 RelatedInformation

Polystyryl-lithium of low polydispersity has been reacted with C-60, C-70, C-84 and C-96 in a non-polar solvent. Star-shaped polymers were always obtained and in all cases the maximum number of grafts attached to the fullerene was found to be 6. This upper limit is a consequence of the fact that the number of pentagons stays constant whatever is the size of the fullerene. In order to get the needed reactive double bond, the pentagones have to form a pyracyclene unit (2 pentagons and 2 hexagons). The number of pentagons being always 12, no more than 6 chains can be grafted on a fullerene by this kind of chemistry.

The advantages of lithographic-galvanic (LIGA) fabricated microstructured honeycomb electrodes are demonstrated for spectroelectrochemical cells with respect to the response time (the time necessary to generate the product in a sufficient layer thickness close to the electrode to be detectable by UV-Vis-NIR spectroscopy) and to the conversion of the redox system in solution under thin-layer conditions. Transmission UV-Vis-NIR spectroscopy for several electrochemical applications can be performed in a special spectroelectrochemical cell based on the LIGA electrode and the two quartz rods, forming the walls of the cell and conducting the light beam through the cell. They are limiting the diffusion layer at the structured part of the working LIGA electrode. These microstructured LIGA-electrodes can be used as well defined models of porous electrodes at which redox processes occur under finite diffusion conditions. Such electrodes have been successfully used in the voltammetric and spectroelectrochemical study of various redox systems in both aqueous and non-aqueous solvents. The possibility to fabricate the well defined microstructures from various organic conducting polymers is demonstrated by the electrochemical deposition of polypyrrole in moulded LIGA-forms at high current densities in aqueous solutions.

We have measured the thermoelectric power and conductivity as a function of temperature of a wide range of polypyrrole samples, including a film of soluble polypyrrole synthesized chemically, and wrinkled films synthesized using indium-tin oxide electrodes; other samples investigated include high-conductivity polypyrrole films synthesized at different temperatures and current densities, films grown on nonconducting substrates, and polypyrrole gas sensors. The thermoelectric powers are remarkably similar and metal-like for the medium and high conductivity samples but show nonzero extrapolations to zero temperature for wrinkled samples. The temperature dependence of conductivity tends to be greater for samples of lower conductivity. In contrast to polyaniline and polyacetylene, a crossover to metallic sign for the temperature dependence of conductivity at higher temperatures is not observed in any of our samples; the fluctuation-induced tunnelling and variable-range hopping expressions account for nearly all our conductivity data except for low-temperature anomalies. (C) 1999 John Wiley & Sons, Inc.

Impedance spectra of free standing polyaniline membranes were recorded in the symmetric and the asymmetric cell configuration. The polyaniline membranes were made by solution-casting of chemically polymerised polyaniline. The impedance spectra are discussed according to a model of parallel ionic and electronic conduction paths with capacitive and resistive coupling. Furthermore the ion exchange behaviour of the membranes was studied. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The generation of grafting radicals by electron irradiation is measured ESR spectroscopically in different celluloses. It is shown that the formation of radicals depends strongly on the moisture and that the radical decay led to the conclusions of two different radical structures. The mobility of the radicals in the amorphous region is strongly influenced by the moisture content of cellulose. This is used to explain the grafting reactions of ionic monomers onto cellulose. Grafting of a useful extent of ionic monomers was done at low energy doses without a remarkable degradation of the cellulose.

The interaction of chloride ions with glassy carbon electrodes is studied by means of 36Cl as radiotracer. Chloride ions are bonded on the electrode in case of anodization depending on electrode potential and duration of the polarization. Strong interaction is observed at electrode potentials more positive than +1.3 V. A significant part of the chloride ions bonded at the glassy carbon can not be displaced neither by cathodic polarization nor by rinsing with water or non-labelled solutions. It is concluded that chloride ions are chemically bonded at the surface and the surface region of glassy carbon. Keywords: anodic treatmentcarbonchloride ionschlorine 36electrochemistryelectrodesvitreous carbonsurfacestracer techniques

We first report on electropolymerization of flavins: riboflavin, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) – by their oxidation at high anodic potentials. Electropolymerization of flavins noticed as an appearance of a new (polymer-type) redox activity, has never been claimed before. Electroactivity of the electropolymerized flavins is highly recognizable in acidic, neutral and basic solutions; formal potentials of both monomer- and polymer-type redox activities are pH dependent. Cyclic voltammetric and impedance investigations of polyflavins pointed to their high electronic conductivity. Electropolymerized flavins with polymer-type electroactivity are promising materials for electrocatalysis and analytical applications.

Various methods for characterization the initiators and products of grafting reactions (ESR spectroscopy, tracer technique, voltammetry, and polarography) are described. Recent developments and analytical techniques are considered.

AbstractEs wurde die Elektrolyse von Anilin an Reinstgraphitelektroden — insbesondere die pH‐ Änderungen im Elektrolyten und die Beschaffenheit der Anodenoberfläche — sowie die physika‐ lisch‐chemischen Eigenschaften von Anilinschwarz untersucht. Das elektrochemisch dargestellte Anilinschwarz besitzt eine hohe Spinkonzentration sowie eine gute elektrische Leitfähigkeit und ist röntgenkristallin. Außerdem wurden Hinweise auf die Struktur von Anilinschwarz erhalten. Aufgrund der elektrochemischen Eigenschaften von Anilinschwarz ergeben sich Schwierigkeiten bei dessen Verwendung als Elektrodenmaterial.