A new ferromagnetically coupled μ-alkoxo-μ-acetato copper(II) trinuclear complex:: [Cu3(H2tea)(Htea)(CH3COO)2](ClO4) (H3tea = triethanolamine)

A mu-alkoxo-mu-acetato trinuclear copper(H) complex, [Cu-3(H(2)tea)(Htea)(CH3COO)(2)](CIO4) 1, has been synthesized by reacting copper(H) perchlorate, triethanolamine and sodium acetate. The unit cell contains two centrosymmetric, crystallographically independent trinuclear Cu(II) complexes and two CIO4- ions. The crystallographically independent trinuclear Cu(II) complexes differ mainly in some of their geometry parameters. The coordination environment of the central copper atom is square-planar, in one trinuclear entity, and elongated octahedral in the other one (in this last case, the coordination number of the central copper atom increases through the semicoordination of an oxygen atom arising from the aminoalcohol). The acetato groups exhibit the classical syn-syn bridging mode. The distances between the copper(II) ions in the two entities are, respectively: 3.043(3) and 3.034(4) angstrom. The cryomagnetic investigation of 1 reveals a ferromagnetic interaction between the copper(II) ions (J = + 84 cm(-1)), which is due to a countercomplementary effect of the acetato and alkoxo bridges. (c) 2005 Elsevier B.V. All rights reserved.