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Synthesis, X-ray characterization and catalytic homogenous alcohol oxidation activity of Co(II)–carboxamide complex with green oxidant (H2O2) under mild conditions

  • Hakan Ünver ORCID logo EMAIL logo


In this study, a new air and moisture stable mononuclear cobalt(II)–carboxamide complex, [Co(TCrbx)2(CH3OH)2](ClO4)2, was synthesized and characterized (TCrbx = N-(4-methylpyridin-2-yl)thiophene-2-carboxamide). Complex characterization mainly was done with single crystal X-ray analysis. Ligand characterization was done with several spectroscopic techniques (Elemental Analysis, FT-IR, 1H NMR, 13C NMR). Cobalt(II) complex possesses distorted octahedral geometry coordinated with two carboxamide ligands at equatorial and two methanol ligands at axial positions and two perchlorate anions as counter ions. Synthesized complex was successfully tested as homogenous catalyst for the oxidation of benzyl alcohol with environmental friendly oxidant hydrogen peroxide (H2O2) under mild conditions. Benzaldehyde was selectively obtained with the conversion value of 99.5% in dimethyl formamide after 3-h reaction time at 50 °C with 133 TON value. Solvent and temperature effects were also investigated.

Corresponding author: Hakan Ünver, Department of Chemistry, Faculty of Science, Eskişehir Technical University, Eskişehir, 26210, Turkey, E-mail:


The author thankfully acknowledges the Medicinal Plants and Medicine Research Centre of Anadolu University, Eskişehir, Turkey for the use of X-ray Diffractometer and Eskişehir Technical University, Department of Chemistry, Eskişehir, Turkey for the other spectroscopic measurements.

  1. Author contribution: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.

  2. Research funding: None declared.

  3. Conflict of interest statement: The authors declare no conflict of interest, financial or otherwise.


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Supplementary Material

CCDC 1869717 contains the supplementary crystallographic data for complex.

The online version of this article offers supplementary material (

Received: 2020-04-03
Accepted: 2020-06-13
Published Online: 2020-07-01
Published in Print: 2020-07-28

© 2020 Walter de Gruyter GmbH, Berlin/Boston

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