Syntheses, crystal structures and magnetic properties of heteronuclear bimetallic compounds of [Cu(pdc)2][M(H2O)5]2•H2O [M=Ni(II), Co(II), Mn(II); pdc=2,6-pyridinedicarboxylato]

The complexes [M(H2O)(5)][Cu(pdc)(2)]center dot 2H(2)O [M=Ni(II) 1, Co(II) 2, Mn(II) 3; pcd=2,6-pyridinedicarboxylato] are prepared and their crystal structures, magnetic susceptibilities and UV-Visible properties reported. In all cases, the Cu(II) ion occupies the chelating site in the pdc ligand, while the M(II) occurs as a pentaaqua ion bridged to the [Cu(pdc)(2)] moiety through a carboxylate as demonstrated by both UV-Visible spectroscopy and X-ray diffraction. Single crystal X-ray diffraction shows the three complexes to be isostructural. Weak antiferromagnetic interactions between the metal ions are observed in 1 and 3, while the magnetic behavior of 2 is dominated by single ion anisotropy.