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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 207 (1991), S. 185-190 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An immunocytological study of four different parts of the gut of Helix aspersa clearly demonstrates the presence of many cells and fibers immunoreactive toward antibodies directed to vertebrate (α, β-endorphin, α, β-MSH, ACTH 1-24 and ACTH 17-39, met-enkephalin, somatostatin, insulin, glucagon, P.P., serotonin) or invertebrate (FMRF-amide) peptides.These results are evidence of the presence of different substances related to known peptides or amines in the epithelial and connective tissue cells and nerve fibers of the snail gut. Immunocytochemistry may help to elucidate the morpho-functional characteristics of the enteroendocrine cells of H. aspersa.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    ISSN: 0044-2313
    Keywords: Copper(I) complex ; homoleptical copper(I) chalcogenolates ; synthesis ; crystal structures ; NMR spectra ; cryoscopic measurements ; electrochemistry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Structure of Copper(I)Chalcogenolate-2,2′-Bipyridine Complexes [CuS(2,4,6-iPr3C6H2)]4(Bipy)2 and [CuSe(2,4,6-iPr3C6H2)]2(Bipy)2The oligomeric homoleptical copper(I) chalcogenolate compounds [CuS(2,4,6-iPr3C6H2)]x=4,8 and [CuSe(2,4,6-iPr3C6H2)]6 react with 2,2′-bipyridine (Bipy) to yield the tetranuclear complex [CuS(2,4,6-iPr3C6H2)]4(Bipy)2 (4) and the dinuclear complex [CuSe(2,4,6-iPr3C6H2)]2(Bipy)2 (5). The structures of 4 and 5 were determined by X-ray analysis. In the eight-membered Cu4S4 core of 4 with chair conformation the copper atoms are linked by μ2-bridging selenolate ligands. Only two copper atoms are coordinated by 2,2′bipyridine. The corresponding copper(I) selenolate complex (5) forms a folded four-membered Cu2Se2 ring with μ2-bridging selenolate ligands. The Cu—Cu distance of 2.52 Å is relatively short. In contrast to the reaction performed with 2,2′-bipyridine, addition of phenantroline to 1 respectively 2 yields a dinuclear complex [CuS(2,4,6-iPr3C6H2)]2(Phen)2 (10). NMR spectroskopic and cryoscopic measurement of 4 show that this complex dissociates into smaller fragments in solution which undergo rapid exchange reactions. However, corresponding investigations performed on 5 indicate that the solid state structure is maintained in solution. The electrochemical behaviour of 4, 5 and 10 was studied in CH2Cl2 and in any case no reversible redox processes could be observed.
    Notes: Die oligomeren homoleptischen Kupfer(I)-chalkogenolat-Verbindungen [CuS(2,4,6-iPr3C6H2)]x=4,8 (1, 2) und [CuSe(2,4,6-iPr3C6H2)]6 (3) wurden mit 2,2′-Bipyridin (Bipy) zu dem tetranuklearen Kupferkomplex [CuS(2,4,6-iPr3C6H2)]4(Bipy)2 (4) und dem dinuklearen Komplex [CuSe(2,4,6-iPr3C6H2)]2(Bipy)2 (5) umgesetzt, deren Strukturen durch Einkristall-Röntgenstrukturanalysen bestimmt wurden. In dem achtgliedrigen Cu4S4-Ring von 4 mit Sesselkonformation sind die Kupferatome über μ2-verbrückende Thiolat-Liganden verknüpft, wobei nur 2 Kupferatome von 2,2′-Bipyridin koordiniert werden. Der entsprechende Kupfer(I)-selenolat-Komplex (5) bildet einen gefalteten viergliedrigen Cu2Se2-Ring mit μ2-verbrückenden Selenolat-Liganden. Der Cu—Cu-Abstand ist mit 2.52 Å relativ kurz. Im Gegensatz zu der Umsetzung mit 2,2′-Bipyridin entsteht aus 1 bzw. 2 und Phenantrolin (Phen) ein dinuklearer Komplex [CuS(2,4,6-iPr3C6H2)] 2(Phen)2 (10). Während 5 sich offensichtlich ohne Zerfall löst, wie NMR-spektroskopische und kryoskopische Untersuchungen zeigen, dissoziiert 4 in Lösung in kleinere Aggregate, die miteinander im Gleichgewicht stehen. Das elektrochemische Verhalten von 4, 5 und 10 wurde in CH2Cl2 studiert. In allen Fällen wurden keine reversiblen Redoxprozesse beobachtet.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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