Syntheses, structures and magnetic properties of two novel 3D helical dicyanamide complexes containing polyamine ligand

Two isomorphous novel 3D helical dicyanamide complexes, Co(tmeda)(dca)2 (1) and Ni(tmeda)(dca)2 (2) (tmeda=tetramethylethylenediamine) have been synthesized and their crystal structures, IR spectra, magnetic properties were determined. Complex 1 displays antiferromagnetic coupling (T>70 K, θ=−27 K, C=3.78 cm3 mol−1 K) between the adjacent cobalt(II) ions, while weak ferromagnetic interaction (θ=3.8 K, C=1.12 cm3 mol−1 K) is observed in complex 2.