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

A mixed-valent trinuclear complex with 1,3-bis(5-chlorosalicylideneamino)-2-propanol (Hclsalpr) 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-Co-Co complex with octahedral geometries, having a tetradentate chelate of the Schiff-base ligand, bridging acetate, monodentate acetate coordination to each terminal Co ion and four bridging phenoxido-oxygen of two Schiff-base ligands, and two bridging acetate-oxygen atoms for the central Co ion. The electronic spectral feature is consistent with the mixed valent Co-Co-Co. Variable-temperature magnetic susceptibility data could be analyzed by consideration of the axial distortion of the central Co ion with the parameters Δ = -254 cm, = -58 cm, = 0.93, = 0.00436 cm mol, = -0.469 K, = 6.90, and = 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 ions.