Synthesis and reactivity of the macrobicyclic complexes (1,5,8,12-tetraaza-17-oxabicyclo[10.5.2]-nonadecane)cobalt(III) perchlorate ([Co(L1)(CIO4)]-(CIO4)2), [(chloro(1,4,8,11-tetraaza-17-oxabicyclo-[9.5.3]nonadecane)cobalt(III) perchlorate ([Co(L2)-(CI)](CIO4)2)

Theo Rodopoulos, Koji Ishihara, Mary Rodopoulos, M. J. Zaworotko, M. Maeder, A. McAuley

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    2 Citations (Scopus)

    Abstract

    The potentially penta-coordinating ligands L2 and L3 have been synthesized by reaction of the 10-membered macrocycle 1,5-diaza-8-oxacyclodecane with either 1,9-dichloro-3,7-diazanonane-2,8-dione, and subsequent reduction of the diamide (3), or with 1,9-dichloro-3,7-(dimethyl) diazanonane-2,8-dione and reduction (L3)-. A similar procedure is outlined for the dimethylated macrobicycle (L4), based on the corresponding nine-membered 1,4-diaza-7-oxacyclononane. The Co(III) complexes of these ligands and of 1,5,8,12-tetraaza-17-oxabicyclo[10.5.2]nonadecane (L 1) have been prepared. Spectrophotometric determinations on the L1 complex ion confirm the presence of two hydrogen ion related equilibria, one of which (pK = 2.2 ± 0.2) is associated with the proposed replacement of the apical ether oxygen by a water molecule that is bound to the metal centre and hydrogen bonded to the ether. The species derived from L 1 and L2 exhibit remarkable kinetic stability. Studies on the anation of the [Co(L1)(H2O)](CIO4) 3 with chloride ions in acidic media are consistent with the reaction of both the proton-related complex and the [Co(L1)(H 2O)]3+ ion. Whilst complex ions containing two secondary NH groups maintain the metal-ion coordination in strongly acidic media, corresponding species with ligands containing all four tertiary amine sites are subject to attack by protons leading to a relatively facile demetallation of the complexes. The latter finding is supported by kinetic studies and mass spectrometric fragmentation patterns of the ions.

    Original languageEnglish
    Pages (from-to)894-902
    Number of pages9
    JournalCanadian Journal of Chemistry
    Volume83
    Issue number6-7
    DOIs
    Publication statusPublished - 2005 Jun

    Fingerprint

    Cobalt
    Ions
    Protons
    Ligands
    Ether
    Hydrogen
    Ethers
    Diamide
    Kinetics
    Amines
    Metal ions
    Chlorides
    Metals
    N-(3-N-(benzyloxycarbonyl)amino-1-carboxypropyl)leucyl-O-methyltyrosine N-methylamide
    perchlorate
    nonadecane
    Oxygen
    Molecules
    Water

    Keywords

    • Anation
    • Cobalt(III)
    • Hydrolysis
    • Macrobicycle
    • Spectroscopic analysis

    ASJC Scopus subject areas

    • Chemistry(all)

    Cite this

    @article{377c2f3da5924b459b3127e796e1eef2,
    title = "Synthesis and reactivity of the macrobicyclic complexes (1,5,8,12-tetraaza-17-oxabicyclo[10.5.2]-nonadecane)cobalt(III) perchlorate ([Co(L1)(CIO4)]-(CIO4)2), [(chloro(1,4,8,11-tetraaza-17-oxabicyclo-[9.5.3]nonadecane)cobalt(III) perchlorate ([Co(L2)-(CI)](CIO4)2)",
    abstract = "The potentially penta-coordinating ligands L2 and L3 have been synthesized by reaction of the 10-membered macrocycle 1,5-diaza-8-oxacyclodecane with either 1,9-dichloro-3,7-diazanonane-2,8-dione, and subsequent reduction of the diamide (3), or with 1,9-dichloro-3,7-(dimethyl) diazanonane-2,8-dione and reduction (L3)-. A similar procedure is outlined for the dimethylated macrobicycle (L4), based on the corresponding nine-membered 1,4-diaza-7-oxacyclononane. The Co(III) complexes of these ligands and of 1,5,8,12-tetraaza-17-oxabicyclo[10.5.2]nonadecane (L 1) have been prepared. Spectrophotometric determinations on the L1 complex ion confirm the presence of two hydrogen ion related equilibria, one of which (pK = 2.2 ± 0.2) is associated with the proposed replacement of the apical ether oxygen by a water molecule that is bound to the metal centre and hydrogen bonded to the ether. The species derived from L 1 and L2 exhibit remarkable kinetic stability. Studies on the anation of the [Co(L1)(H2O)](CIO4) 3 with chloride ions in acidic media are consistent with the reaction of both the proton-related complex and the [Co(L1)(H 2O)]3+ ion. Whilst complex ions containing two secondary NH groups maintain the metal-ion coordination in strongly acidic media, corresponding species with ligands containing all four tertiary amine sites are subject to attack by protons leading to a relatively facile demetallation of the complexes. The latter finding is supported by kinetic studies and mass spectrometric fragmentation patterns of the ions.",
    keywords = "Anation, Cobalt(III), Hydrolysis, Macrobicycle, Spectroscopic analysis",
    author = "Theo Rodopoulos and Koji Ishihara and Mary Rodopoulos and Zaworotko, {M. J.} and M. Maeder and A. McAuley",
    year = "2005",
    month = "6",
    doi = "10.1139/v05-089",
    language = "English",
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    journal = "Canadian Journal of Chemistry",
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    publisher = "National Research Council of Canada",
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    }

    TY - JOUR

    T1 - Synthesis and reactivity of the macrobicyclic complexes (1,5,8,12-tetraaza-17-oxabicyclo[10.5.2]-nonadecane)cobalt(III) perchlorate ([Co(L1)(CIO4)]-(CIO4)2), [(chloro(1,4,8,11-tetraaza-17-oxabicyclo-[9.5.3]nonadecane)cobalt(III) perchlorate ([Co(L2)-(CI)](CIO4)2)

    AU - Rodopoulos, Theo

    AU - Ishihara, Koji

    AU - Rodopoulos, Mary

    AU - Zaworotko, M. J.

    AU - Maeder, M.

    AU - McAuley, A.

    PY - 2005/6

    Y1 - 2005/6

    N2 - The potentially penta-coordinating ligands L2 and L3 have been synthesized by reaction of the 10-membered macrocycle 1,5-diaza-8-oxacyclodecane with either 1,9-dichloro-3,7-diazanonane-2,8-dione, and subsequent reduction of the diamide (3), or with 1,9-dichloro-3,7-(dimethyl) diazanonane-2,8-dione and reduction (L3)-. A similar procedure is outlined for the dimethylated macrobicycle (L4), based on the corresponding nine-membered 1,4-diaza-7-oxacyclononane. The Co(III) complexes of these ligands and of 1,5,8,12-tetraaza-17-oxabicyclo[10.5.2]nonadecane (L 1) have been prepared. Spectrophotometric determinations on the L1 complex ion confirm the presence of two hydrogen ion related equilibria, one of which (pK = 2.2 ± 0.2) is associated with the proposed replacement of the apical ether oxygen by a water molecule that is bound to the metal centre and hydrogen bonded to the ether. The species derived from L 1 and L2 exhibit remarkable kinetic stability. Studies on the anation of the [Co(L1)(H2O)](CIO4) 3 with chloride ions in acidic media are consistent with the reaction of both the proton-related complex and the [Co(L1)(H 2O)]3+ ion. Whilst complex ions containing two secondary NH groups maintain the metal-ion coordination in strongly acidic media, corresponding species with ligands containing all four tertiary amine sites are subject to attack by protons leading to a relatively facile demetallation of the complexes. The latter finding is supported by kinetic studies and mass spectrometric fragmentation patterns of the ions.

    AB - The potentially penta-coordinating ligands L2 and L3 have been synthesized by reaction of the 10-membered macrocycle 1,5-diaza-8-oxacyclodecane with either 1,9-dichloro-3,7-diazanonane-2,8-dione, and subsequent reduction of the diamide (3), or with 1,9-dichloro-3,7-(dimethyl) diazanonane-2,8-dione and reduction (L3)-. A similar procedure is outlined for the dimethylated macrobicycle (L4), based on the corresponding nine-membered 1,4-diaza-7-oxacyclononane. The Co(III) complexes of these ligands and of 1,5,8,12-tetraaza-17-oxabicyclo[10.5.2]nonadecane (L 1) have been prepared. Spectrophotometric determinations on the L1 complex ion confirm the presence of two hydrogen ion related equilibria, one of which (pK = 2.2 ± 0.2) is associated with the proposed replacement of the apical ether oxygen by a water molecule that is bound to the metal centre and hydrogen bonded to the ether. The species derived from L 1 and L2 exhibit remarkable kinetic stability. Studies on the anation of the [Co(L1)(H2O)](CIO4) 3 with chloride ions in acidic media are consistent with the reaction of both the proton-related complex and the [Co(L1)(H 2O)]3+ ion. Whilst complex ions containing two secondary NH groups maintain the metal-ion coordination in strongly acidic media, corresponding species with ligands containing all four tertiary amine sites are subject to attack by protons leading to a relatively facile demetallation of the complexes. The latter finding is supported by kinetic studies and mass spectrometric fragmentation patterns of the ions.

    KW - Anation

    KW - Cobalt(III)

    KW - Hydrolysis

    KW - Macrobicycle

    KW - Spectroscopic analysis

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    U2 - 10.1139/v05-089

    DO - 10.1139/v05-089

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    AN - SCOPUS:29244490670

    VL - 83

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    EP - 902

    JO - Canadian Journal of Chemistry

    JF - Canadian Journal of Chemistry

    SN - 0008-4042

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