Mixed-Valent Trinuclear CoIII-CoII-CoIII Complex with 1,3-Bis(5-chlorosalicylideneamino)-2-propanol

A mixed-valent trinuclear complex with 1,3-bis(5-chlorosalicylideneamino)-2-propanol (H(3)clsalpr) was synthesized, and the crystal structure was determined by the single-crystal X-ray diffraction method at 90 K. The molecule is a trinuclear Co-III-Co-II-Co-III complex with octahedral geometries, having a tetradentate chelate of the Schiff-base ligand, bridging acetate, monodentate acetate coordination to each terminal Co3+ ion and four bridging phenoxido-oxygen of two Schiff-base ligands, and two bridging acetate-oxygen atoms for the central Co2+ ion. The electronic spectral feature is consistent with the mixed valent Co-III-Co-II-Co-III. Variable-temperature magnetic susceptibility data could be analyzed by consideration of the axial distortion of the central Co2+ ion with the parameters Delta = -254 cm(-1), lambda = -58 cm(-1), kappa = 0.93, tip = 0.00436 cm(3) mol(-1), theta = -0.469 K, g(z) = 6.90, and g(x) = 2.64, in accordance with a large anisotropy. The cyclic voltammogram showed an irreversible reduction wave at approximately -1.2 V center dot vs. Fc/Fc(+), assignable to the reduction of the terminal Co3+ ions.

Automated summary

A mixed-valent trinuclear complex with a complex structure has been synthesized and characterized. The electronic spectral features and cyclic voltammogram of the complex have been analyzed to understand its properties.