Cobalt Complexation with Unsymmetrical Tripodal Ligands

Abstract

The reaction of the aliphatic unsymmetrical tripod [N(CH2CH2NH2)2(CH2CH2OH)], H5-1, with cobalt(II) chloride in THF yields after aerial oxidation the dinuclear complex [(H4-1)CoIII(μ-OH)CoIII(H4-1)](CoIICl4)Cl, [5](CoCl4)Cl. The trianion 53− contains two cobalt atoms triply bridged by two alkoxo groups of the singly deprotonated ligand (H4-1)− and a hydroxo group. The new ligand [N(CH2CH2CH2NH2)(CH2CH2OH)2], H4-3, providing an N2O2 donor set reacts with cobalt(II) chloride to give after aerial oxidation the hexanuclear complex [CoIII4(H2-3)4CoII2(HOMe)2Cl2(μ-OH)4], [6]Cl2, containing an unprecedented mixed-valent CoIII4CoII2 core.