Syntheses and Characterizations of Metal Complexes Derived from <i>cis,cis</i>-1,3,5-Triaminocyclohexane-<i>N</i>,<i>N</i>‘,<i>N</i>‘ ‘-triacetic Acid

A convenient six-step procedure is developed to routinely prepare the hexadentate ligand cis,cis-1,3,5-triaminocyclohexane-N,N‘,N‘ ‘-triacetic acid (H3tachta) as an HCl salt. Complexes of gallium(III) and indium(III), [Ga(tachta)] and [In(tachta)], are synthesized from the reactions of the ligand and the corresponding metal precursors. Copper(II), palladium(II), and cobalt(II) complexes, [Cu(Htachta)], [Pd(Htachta)], and [Co(Htachta)], are obtained from the reactions of H3tachta with the corresponding metal chlorides. The structures of H3tachta·3HCl·2H2O (C12H28Cl3N3O8) and [Ga(tachta)] (C12H18GaN3O6) are characterized. The crystal of H3tachta·3HCl·2H2O is monoclinic, of the space group P21/c, with a = 15.1688(4) Å, b = 8.4708(2) Å, c = 15.9408(2) Å, β = 108.058(1)°, and Z = 4; that of [Ga(tachta)] is cubic, of space group Pa3, with a = 14.0762(1) Å and Z = 8. The gallium atom of [Ga(tachta)] is six-coordinated in the solid state, and the complex assumes a pseudooctahedronal geometry with the completely deprotonated hexadentate ligand encapsulating the metal ion.