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    Mixtures obtained by reacting trans-(�)-1,2diaminocyclohexane with acetylacetone in the presence of simple cobalt(II) salts.


    McCann, Malachy and Townsend, Sean and Devereux, Michael and McKee, Vickie and Walker, Brian (2001) Mixtures obtained by reacting trans-(�)-1,2diaminocyclohexane with acetylacetone in the presence of simple cobalt(II) salts. Polyhedron, 20. pp. 2799-2806.

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    Abstract

    In the absence of a metal ion, racemic trans-1,2-diaminocyclohexane (trans-(�)DCH) reacts with acetylacetone (acacH) (1:2.5 mole ratio) to form the bisoxoenamine condensation product, boe (1). CoCl2·6H2O and Co(ClO4)2·6H2O each react with trans-(�)DCH in air to give complexes containing the oxidised Co(III) ion, [Co((�)DCH)3]3+, which does not subsequently react with added acacH to give a Schiff base complex. Mixtures of complexes are obtained from one-pot reactions involving trans-(�)DCH, a simple Co(II) salt and acacH (1:1:2.5 mole ratio). When CoCl2·6H2O is used, the mixed-ligand Co(II) complex [Co((�)DCH)Cl2] (4) precipitates first and, after a period of weeks, the Co(II) complex (diazH)2[CoCl4] (5) (diazH+ is a diazepinium cation), the Co(II) complex [Co(boe)Cl2]n (6) and the Co(III) complex [Co(acac)3] (7), co-crystallise from the mother liquor. Using Co(ClO4)2·6H2O in the reaction with trans-(�)DCH and acacH also gives a mixture of products. Complexes 7, the Co(II) complex [Co2(acac)4(H2O)2][Co(acac)(H2O)4]ClO4·EtOH (8) and the Co(III) complex [Co(acac)2(�)DCH]ClO4 (9) co-crystallise. Complexes 1, 5, 7, 8 and 9 were characterised using X-ray crystallography. The major difference between using CoCl2·6H2O and Co(ClO4)2·6H2O in reactions involving (�)DCH and acacH is that no DCH/acacH condensation products are identified in the product mixtures when the perchlorate salt is employed.

    Item Type: Article
    Keywords: trans-(�)-1,2-Diaminocyclohexane; Acetylacetone; Cobalt(II) salts; Schiff base complexes;
    Academic Unit: Faculty of Science and Engineering > Chemistry
    Item ID: 9719
    Depositing User: Dr. Malachy McCann
    Date Deposited: 26 Jul 2018 14:32
    Journal or Publication Title: Polyhedron
    Publisher: Elsevier
    Refereed: Yes
    URI:

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