Mixed-Valent Trinuclear Co III -Co II -Co III 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 Co 3+ ion and four bridging phenoxido-oxygen of two Schiff-base ligands, and two bridging acetate-oxygen atoms for the central Co 2+ 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 Co 2+ ion with the parameters Δ = -254 cm -1 , λ = -58 cm -1 , κ = 0.93, tip = 0.00436 cm 3 mol -1 , θ = -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·vs. Fc/Fc + , assignable to the reduction of the terminal Co 3+ ions.