New coordination polymers based on a novel polynitrile ligand: Synthesis, structure and magnetic properties of the series [M(tcnoetOH)2(4,4′-bpy)(H2O)2] (tcnoetOH− = [(NC)2CC(OCH2CH2OH)C(CN)2]−; M = Fe, Co and Ni)

A novel polynitrile anionic ligand, tcnoetOH−(=[(NC)2CC(OCH2CH2OH)C(CN)2]−), has been synthesized by a one-pot reaction from a cyclic acetal and malononitrile. This ligand has been successfully used to prepare, with 4,4′-bpy as co-ligand, a novel series of coordination polymers formulated as [M(tcnoetOH)2(4,4′-bpy)(H2O)2] with M(II) = Fe (1), Co (2) and Ni (3). These isostructural compounds present a linear chain structure consisting of octahedrally coordinated metal ions bridged by trans 4,4′-bpy ligands. The coordination sphere of the metal ions is completed with two terminal tcnoetOH− ligand and two water molecules. The magnetic properties indicate that the three compounds are paramagnetic, as expected from the long 4,4′-bpy bridge connecting the metal atoms. Their magnetic properties have been fitted with a model of isolated ions including a zero field splitting for the Fe(II) and Ni(II) derivatives.

Graphical abstractA new polynitrile anionic ligand, tcnoetOH− was prepared and used to synthesize a series of coordination polymers with different magnetic ions and 4,4′-bpy. These compounds, formulated as [M(tcnoetOH)2(4,4′-bpy)(H2O)2] (M(II) = Fe, Co, Ni), present a chain structure demonstrating the feasibility of this novel ligand to construct novel coordination magnetic polymers.Figure optionsDownload full-size imageDownload as PowerPoint slide