Syntheses and X-ray Structures of Mixed-Ligand Salicylaldehyde Complexes of Mn(III), Fe(III), and Cu(II) Ions: Reactivity of the Mn(III) Complex toward Primary Monoamines and Catalytic Epoxidation of Olefins by the Cu(II) Complex

The Schiff base (L), synthesized from 2-(dimethylamino)ethylamine and salicylaldehyde acts as a tridentate ligand. This ligand, when stirred with 1 equiv of KOH in methanol, undergoes partial hydrolysis of the imine bond. This solution readily takes up Mn(II)/Mn(III) acetate or Fe(III) chloride/perchlorate to form mixed-ligand Mn(III) or Fe(III) complexes, respectively. The neutral dark brown complex, [Mn(L-H)(NCS){o-(CHO)C6H4O-}] (1), crystallizes in the presence of thiocyanate in the orthorhombic space group Pbca with a = 15.271(8), b = 19.522(7), c = 13.213(7) A; Z = 8; R = 0.060; and Rw = 0.062. The coordination geometry around Mn(III) ion is distorted octahedral with donation from one L-H, one salicylaldehyde and, one thiocyanate ligand. With Fe(III), the dark red complex isolated in the solid state is found to be a neutral μ-oxo Fe(III) dimer with the formula [{o-(CHO)C6H4O-}(L-H)Fe]2O (3). The structure of 3 has been solved and successfully refined in the monoclinic space group C2/c with a = 18.558...