ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 25 (1991), S. viii 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Voltammetrisches Verhalten des Nickels in Gegenwart von Cobalt, Zink und TensidenAn Quecksilberelektroden wurde die Reduktion des Nickel-Dimethylglyoxim-Komplexes in Gegenwart von elektrochemisch störenden Ionen (Co2+, Zn2+) untersucht. Außerdem wurde der Einfluß verschiedener Tenside auf den Reduktionsprozeß mittels adsorptiver Differenzpuls-Stripping-Voltammetrie charakterisiert. Ausgehend von diesen Ergebnissen konnte die Selektivität für die Spurenbestimmung des Nickels in Gegenwart von Cobalt durch die in-situ Modifizierung der Quecksilberelektrode mit adsorbierten Tetrabutylammoniumionen verbessert werden, ohne die Empfindlichkeit herabzusetzen. Die Untersuchungen zeigten auch, daß sich Nickel in einem Leitelektrolyten mit ausreichender NH3-Konzentration trotz eines 106fachen Zn2+-Überschusses bestimmen läßt.
    Notes: The reduction of the nickel dimethyldioxime complex at mercury electrodes is investigated in the presence of electrochemically interfering ions (Co2+, Zn2+). In addition the influence of various surfactants on the reduction process was studied by differential pulse adsorptive stripping voltammetry. An improvement of the selectivity without a loss of sensitivity was achieved for the trace determination of nickel in the presence of cobalt by the use of an in-situ modification of the mercury electrode with adsorbed tetrabutylammonium. It is shown that a 106-fold excess of zinc does not distrub the nickel signal in the presence of a sufficient amount of ammonia in the supporting electrolyte.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 608 (1992), S. 56-59 
    ISSN: 0044-2313
    Keywords: Tripotassiumorthonitrate ; preparation ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal Growth and X-ray Structure Determination of the TripotassiumorthonitrateThe title compound has been characterized by single crystal x-ray diffraction: 1126 diffractometer data, space group Pnma, a=10.921(1), b=7.952(1), c=5.667(1) Å, Z=4, Rw =0.024. The distance N—O in the tetrahedron oxoanion (1.398 Å) is only little, but significantly larger than in Na3NO4. More significant are the shifts of the absorption frequencies in the vibrational spectra to lower wave numbers (e.g. 24 cm-1 for the symmetric stretching mode). The anions are arranged similar to a cubic closest packing with potassium placed on all tetrahedral and octahedral sites.
    Notes: Die Kristallstruktur der Titelverbindung wurde auf der Basis von Vierkreisdiffraktometerdaten (1126 unabhängige Strukturfaktoren) gelöst und verfeinert: Raumgruppe Pnma; a = 10,921(1); b = 7,952(1); c= 5,667(1) Å Z = 4; Rw = 0,024. Der Bindungsabstand N—O im tetraedrischen Oxanion ist mit d=1,398 Å geringfügig, jedoch signifikant vergrößert gegenüber dem in Na3NO4. Deutlicher fällt eine wohl damit in Zusammenhang stehende Verschiebung der symmetrischen Streckschwingung um 24 cm-1 zu kleineren Wellenzahlen aus. Die Anionen sind im sind im Sinne einer kubisch dichtesten Anordnung gepackt, Kalium besetzt alle Tetraeder- und Oktaederlücken.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 610 (1992), S. 64-66 
    ISSN: 0044-2313
    Keywords: Dipotassium peroxide ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Refinement of the Crystal Structure of K2O2The crystal structure of K2O2 has been refined using 241 diffractometer data (Cmca; a = 6.733(1), b = 6.996(1), c = 6.474(1) Å; Z = 4; Rw = 0.050). The distance O—O (1.541(6) Å) is significantly larger than that one assumed for alkali metal peroxides, so far.
    Notes: Die Kristallstruktur von K2O2 wurde auf der Basis von Vierkreisdiffraktometerdaten (241 unabhängige Strukturfaktoren) verfeinert (Cmca; a = 6,733(1), b = 6,996(1), c = 6,474(1) Å; Z = 4; Rw = 0.050). Der gefundene O—O-Abstand weist mit 1,541(6) Å einen deutlich größeren Wert auf als bisher für die Alkalimetallperoxide angenommen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 0044-2313
    Keywords: Dinuclear cobalt complexes ; oxidative addition and substitution reactions ; formation of dinuclear and chiral complex salts ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Bis(cyclopentadienyl)methane-bridged Dinuclear Complexes. VIII. Dinuclear Cobalt Complexes with the Dianion of Bis(cyclopentadienyl)methane and Bis(tetramethylcyclopentadienyl)dimethylsilane as Bridging LigandsThe dinuclear cobalt complex [CH2(C5H4)2][Co(CO)2]2 (4) which is obtained from [Co(CO)4I] (2) and Li2[CH2(C5H4)2] (3) in 75% yield reacts with PMe3, PiPr3, P2Me4, Me2PCH2CH2PMe2 and (EtO)2POP(OEt)2, to the compounds 5-9 substituting one CO ligand per cobalt atom. Oxidative addition of CH3I to [CH2(C5H4)2][Co(CO)(PMe3)]2 (5) leads to the formation of the dinuclear cobalt(III) complex [CH2(C5H4)2][Co(COCH3)(PMe3)I]2 (11). The reaction of 4 with iodide generates [CH2(C5H4)2][Co(CO)I2]2 (12) which with PMe3, P(OMe)3, P(OiPr)3, and CNMe reacts under CO substitution to [CH2(C5H4)2][Co(L)I2]2 (13-16) and with PMe2H to {[CH2(C5H4)2][Co(PMe2H)3]2}I4 (17). The electrophilic addition reactions of NH4PF6 and CH3I to [CH2(C5H4)2][Co(PMe3)2]2 (20) produce the complex salts {[CH2(C5H4)2][CoR(PMe3)2]2}X2 (21: R = H; 22: R = CH3). From 22a (X = I) and LiCH3 the dinuclear tetramethyldicobalt compound [CH2(C5H4)2] · [Co(CH3)2(PMe3)]2 (23) is obtained which further reacts, via the intermediate 24, to the chiral complex {[CH2(C5H4)2] · [CoCH3(PMe3)P(OMe)3]2}(PF6)2 (25). The reaction of 20 with C2(CN)4 and E- or Z-C2H2(CO2Me)2 gives the olefin(trimethylphosphine) cobalt(I) derivatives 26 und 27. The synthesis of the dinuclear compounds 31-38 with [Me2Si(C5Me4)2]2- as the bridging unit is also described.
    Notes: Der Cobalt-Zweikernkomplex [CH2(C5H4)2] · [Co(CO)2]2 (4), der aus [Co(CO)4I] (2) und Li2[CH2(C5H4)2] (3) mit 75%iger Ausbeute entsteht, reagiert mit PMe3, PiPr3, P2Me4, Me2PCH2CH2PMe2 und (EtO)2POP(OEt)2 unter Substitution je eines CO-Liganden pro Cobaltatom zu den Verbindungen 5-9. Aus [CH2(C5H4)2][Co(CO)(PMe3)]2 (5) und CH3I erhält man durch oxidative Addition den zweikernigen Cobalt(III)-Komplex [CH2(C5H4)2][Co(COCH3)(PMe3)I]2 (11). Die Umsetzung von 4 mit Iod liefert die Verbindung [CH2(C5H4)2][Co(CO)I2]2 (12), die mit PMe3, P(OMe)3, P(OiPr)3 und CNMe unter CO-Verdrängung zu [CH2(C5H4)2] · [Co(L)I2]2 (13-16) und mit PMe2H zu {[CH2(C5H4)2] · [Co(PMe2H)3]2}I4 (17) reagiert. Die Umsetzungen von [CH2(C5H4)2][Co(PMe3)2]2 (20) mit NH4PF6 und CH3I führen unter elektrophiler Addition zu den Komplexsalzen {[CH2(C5H4)2][CoR(PMe3)2]2}X2 (21: R = H; 22: R = CH3). Aus 22a (X = I) und LiCH3 ist die zweikernige Tetramethyldicobalt-Verbindung [CH2(C5H4)2][Co(CH3)2(PMe3)]2 (23) und daraus über die Zwischenstufe 24 der chirale Komplex {[CH2(C5H4)2][CoCH3(PMe3)P(OMe)3]2}(PF6)2 (25) zugänglich. Aus 20 und C2(CN)4 und E- oder Z-C2H2(CO2Me)2 erhält man die Olefin(trimethylphosphan)cobalt(I)-Derivate 26 und 27. Die Synthese der Zweikernkomplexe 31-38 mit [Me2Si(C5Me4)2]2- als verbrückender Einheit wird ebenfalls beschrieben.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Non Steroidal Antiinflammatory Agents. V. Basic Esters of IndometacinThe reaction of diisopropylcarbodiimid 1a with ethanolamines 2a, b affords isoureas 3a, b which in turn react with indometacin 4 to yield the title compounds 6a, b. The noncatalyzed reaction of 1a, b with 4 (also in the presence of 2) leads to the ureido-indometacines 8a, b.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 13C-13C-Spin-Spin Coupling Constants Through One Bond in Pentamethin-merocyanine.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The tissue/biomaterial interface reactions of four elastomers - selected as candidates for scaffolding for tympanic membrane tissue in a total alloplastic middle ear prosthesis - were studied at the electron microscopical level after implantation in the rat middle ear. Time-dependent changes in the phagocyte/polymer interface suggested degradation of porous implants made of Estane polyether urethane, polypropylene oxide, and a poly(ethylene oxide hydantoin) and poly(tetramethylene terephthalate) segmented polyether polyester copolymer (HPOE/PBT copolymer), but not of dense Silastic silicone rubber implants. Silastic was always encapsulated in fibrous tissue. Contact between fibrous tissue and HPOE/PBT copolymer or Estane was established in the third month, but fibrous tissue was never seen close to polypropylene oxide. Bone made contact only with Estane and HPOE/PBT copolymer implants. The bone/copolymer interface showed an electron-dense layer morphologically similar to that seen between bone and hydroxyapatite ceramic, suggesting that with respect to bone HPOE/PBT copolymer behaves like a bioactive implant material. The electron-dense layer was absent at the bone/Estane interface. Estane and especially HPOE/PBT copolymer seem to be suitable as alloplastic tympanic membrane because of their interface behavior with respect to fibrous tissue and bone.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The biocompatibility of dense Silastic implants and porous implants made of Estane 5714 F1 polyether urethane, polypropylene oxide, and an HPOE/PBT segmented polyether polyester copolymer was evaluated during an induced Staphylococcus aureus middle ear infection.The middle ear response to infection seemed not to be affected by the presence of implants made of either of the polymers. Light microscopical morphometry and transmission electron microscopy showed degradation of the porous implants under study, but not of Silastic implants, which were invariably surrounded by a fibrous capsule. This finding, combined with the degree of porous implant degradation, the composition of the tissues surrounding the implants, and the tissue/biomaterial interface reactions are consistent with the results obtained in the noninfected middle ear. Round-cell infiltrates however, were predominantly associated with implants made of polypropylene oxide and HPOE/PBT copolymer; while the presence of (phagocytosed) microbial debris was associated with copolymer.The present findings indicate that with respect to implant behavior in infected surroundings Estane is the best porous material, whereas the behavior of Silastic implants did not deviate from that in noninfected ears.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...