One-dimensional coordination polymers constructed from binuclear 3d–4f nodes and isonicotinato spacer

Abstract

Three new 1-D coordination polymers, [Co(valpn)Gd(hfac)₂(IN)]_n (1), [Ni(valpn)Gd(hfac)₂(IN)]_n (2), and [Ni(valpn)Dy(hfac)₂(IN)]_n (3), were constructed by connecting {M^II(valpn)Ln^III(hfac)₂} nodes through isonicotinato spacers (IN⁻), with hexafluoroacetylacetonato being hfac and 1,3-propanediylbis(2-iminomethylene-6-methoxy-phenol) (H₂valpn) being the Schiff base obtained from the condensation reaction between o-vanillin and 1,3-diaminopropane. The synthetic approach relied on the substitution of the acetate ligands from the binuclear precursors [M^II(CH₃OH)(valpn)Ln^III(hfac)₂(CH₃COO)] with the isonicotinato ligand. The investigation of the magnetic properties of all compounds showed a ferromagnetic interaction attributed to the intranode exchange interaction between the 3d and 4f metal ions. For compound 3, the AC magnetic measurements indicated a field-induced slow relaxation of the magnetization of the [Ni^IIDy^III] nodes.