Copper-2.2'-bipyridines: catalytic performance and structures in aqueous alkaline solutions

Heikki Korpi, Väinö Sippola, Ilari Filpponen, Jussi Sipilä, Outi Krause, Markku Leskelä, Timo Repo

    Research output: Contribution to journalArticleScientificpeer-review

    Abstract

    "2,2'-Bipyridine and ten modified 2,2'-bipyridines were complexed in situ with copper(II) sulphate in aqueous alkaline solution. In oxidation studies with these complexes, the substituents of the bipyridine ring were found to have a significant effect on the catalytic activity. Parallel screening revealed that Cu-complexes with the bipyridine ligands substituted in 4,4'- and 5,5'-positions were highly active in the oxidation of veratryl alcohol with molecular oxygen. More detailed studies with 4,4'-disubstituted bipyridines showed that the electron donating methyl and methoxy substituents, enhance the oxidation activity of Cu-bipyridine. The most effective Cu-complexes in the oxidation of veratryl alcohol also catalysed the oxidation of 2,2'-biphenol and the oxidative depolymerisation of the carbohydrate model compound dextran. The performance of Cu-2,2'-bipyridines in oxygen delignification of softwood pulp were in accordance with the model compound studies; the catalysts lowered the lignin content of the pulp, but they also tended to damage the cellulose fibres. According to the oxidation results, the complex distribution calculations and the UV-vis studies the structures of the active species were [Cu(2,2'-bipyridine)(2)OH](+) and [Cu(4,4'-dimethoxy-2,2'-bipyridine)(2)OH](+). (c) 2006 Elsevier B.V. All rights reserved."
    Original languageEnglish
    JournalApplied Catalysis A: General
    Volume302
    Issue number2
    Pages (from-to)250-256
    Number of pages7
    ISSN0926-860X
    DOIs
    Publication statusPublished - 2006
    MoE publication typeA1 Journal article-refereed

    Fields of Science

    • catalytic oxidation
    • copper
    • 2,2'-bipyridine
    • complex structure
    • UV-vis spectroscopy
    • CRYSTAL-STRUCTURES
    • MOLECULAR-OXYGEN
    • OXIDATION
    • COMPLEXES
    • COPPER(II)
    • ALCOHOLS
    • CATION
    • 116 Chemical sciences

    Cite this