Three cobalt (II) complexes with triethylenetetraaminehexaacetic acid: From binuclear complex to 3d-4f coordination polymers

The cobalt(II)-lanthanide(III) heteronuclear complexes [Ln(H2O)(4)Co-2(TTHA)(SCN)(2)]center dot H3O+ (H(6)TTHA = triethylenetetraaminehexaacetic acid, Ln = La(2), Ce(3)) have been synthesized based on a binuclear building block of [Co-2(H(2)TTHA)(H2O)(2)] in [Co-2(H(2)TTHA)(H2O)(2)]center dot 4H(2)O (1). Single-crystal structures show that complex 1 is a binuclear complex, containing the [Co-2(H(2)TTHA)(H2O)(2)] unit as a useful building block. Adding the La3+ and Ce3+ ions to this synthesis system, two new 3d-4f mixed complexes 2 and 3 were obtained. Complexes 2 and 3 show 3D framework, comprising an infinite 1D (one-dimensional) chain based on heterometallic Ln(2)Co(2) (Ln = La(2), Ce(3)). Further investigations such as IR spectra, UV-vis spectra, TGA, XRD and magnetic properties were studied. (C) 2012 Elsevier B.V. All rights reserved.