Structures and magnetic properties of two heterometallic Cu(ii)–Cd(ii) polymers exhibiting antiferromagnetic ordering

Abstract

Two novel heterometallic Cu(II)–Cd(II) coordination polymers, two-dimensional (2D) [Cu₂Cd(MMA)₂(NTA)₂(H₂O)₂]_n (1) and one-dimensional (1D) {[CuCd(MMA)₂(H₂O)₆]·4H₂O}_n (2), were synthesized with methylmalonic acid (H₂MMA) and nicotinic acid (HNTA) as mixed reactants under the conditions of 100 °C and room temperature, respectively. Complex 1 has a 2D layer structure consisting of the tetranuclear [Cu₂Cd₂] cluster-based 1D chain unit and NTA⁻ linker. 2 exhibits a 1D chain structure with the Cu²⁺ and Cd²⁺ ions alternately bridged by the MMA²⁻ ligand. Magnetic studies show that the magnetic interactions for the neighboring Cu²⁺ ions are both antiferromagnetic within and between the [Cu₂Cd₂] cluster of the 1D chain in 1 (J_d = −1.39(1) cm⁻¹ and J_c = −1.77(1) cm⁻¹) and there is predominantly ferromagnetic coupling in the 1D chain of 2 (J = 4.96(1) cm⁻¹). Furthermore, 1 displayed antiferromagnetic ordering at lower temperature with T_N = 4.0 K.