What question did this study set out to answer?

The aim is to synthesize and characterize mixed-valent cobalt-oxido complexes and evaluate their electrochemical and magnetic properties.

March 26, 2026

Multinuclear Mixed-Valent Co-Oxido Complexes: Synthesis, Structure, Magnetic, and Electrochemical Properties

Key Points

The aim is to synthesize and characterize mixed-valent cobalt-oxido complexes and evaluate their electrochemical and magnetic properties.
Synthesis of mixed-valent cobalt-oxido clusters using N-methyldiethanolamine as a ligand.
Structural characterization through single-crystal X-ray diffraction and spectroscopy techniques including FT-IR and UV-vis.
Electrochemical analysis performed using cyclic voltammetry to assess water oxidation activity.
Magnetic susceptibility measurements conducted at varying temperatures.
Synthesis of eight distinct cobalt-oxido clusters with varying Co compositions and structures.
Characterization confirms the presence of various Co-O scaffolds, including Co3O4 and Co13O24.
Cyclic voltammetry reveals significant electrochemical activity related to water oxidation.
Magnetic susceptibility studies indicate the presence of complex magnetic interactions within the clusters.

Abstract

A series of mixed-valent, multinuclear cobalt-oxido clusters CoIIICoII2(mdea)3(H2mdea)ClO4 (1), CoIII2CoII2(mdea)4(DAA)2(BPh4)2 (2), CoIII3CoII4(mdea)6(NO3)3(NO3)2 (3), CoIII3CoII4(mdea)6(fa)3(ClO4)2 (4), Na2CoIII4CoII4(mdea)6(CO3)4(OH)2(H2O)2 (5), CoIII3CoII7(mdea)6(fa)5(OH)4(ClO4)3 (6), and CoIII4CoII9(mdea)8(NO3)4(OH)8(NO3)2 (7) containing up to 13 Co atoms were synthesized and structurally characterized using single-crystal X-ray diffraction as well as FT-IR and UV-vis spectroscopy. The cobalt-oxido clusters contain N-methyldiethanolamine (H2mdea) as a stabilizing ligand and feature Co3O4 (1), Co4O6 (2), Co7O12 (3, 4), Na2Co8O18 (M10O18) (5), Co10O16 (6), and Co13O24 (7) scaffolds. The increasing number of Co cations in the cobalt-oxido cores of compounds 1-7 results from the systematic addition of pseudocubane Co3O4 units and the progressive incorporation of hydroxide ligands. The water oxidation activity and electrochemical properties of the CoII/CoIII centers in the complexes were studied by cyclic voltammetry (CV), while their magnetic properties were investigated via temperature-dependent magnetic susceptibility.

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Multinuclear Mixed-Valent Co-Oxido Complexes: Synthesis, Structure, Magnetic, and Electrochemical Properties

Key Points

Abstract

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