Two carbonato-bridged Cu(II) complexes, [Cu 3 (dmMePEA) 3 (m 3 -CO 3 )(ClO 4 ) 3 ]ClO 4 (1) and [Cu 2 (iptren) 2 (m 2 -CO 3 )]-(ClO 4 ) 2 ÁH 2 O (2), (dmMePEA = N-methyl(2-(2-pyridyl)ethyl)-(4-methoxy-3,5-dimethyl-2-pyridylmethyl)amine, iptren = tris[2-(isopropylamino)ethyl]amine) were synthesized through the atmospheric fixation of CO 2 . The complexes were structurally and magnetically characterized. Tris(bidentate) and bis (monodentate) carbonato-bridge bonding modes were found in the two complexes. Variable temperature magnetic susceptibility (2-300 K) revealed weak bulk ferromagnetic coupling in complex 1 (J = 1.1 cm À1 ) and very strong antiferromagnetic coupling in 2 (J = À167.7 cm À1 ). The magnetic properties of the two complexes are discussed as a function of their structure parameters and in relation to those of other related complexes of similar carbonato-bridging bonding modes.Chart 1 Coordination modes of m 3 -and m 2 -carbonato-bridged M(II) complexes.
Chart 2The structural formulas of ligands used in this study together with related tri-and tripodal tetra-dentate amines.