1D Manganese(II) Derivatives of an Imidazole-Substituted Nitronyl Nitroxide. An Approach toward Molecular Magnetic Materials of High Dimensionality.

Extended linear complexes of manganese(II) with a bis-chelating nitronyl nitroxide ligand, 2-(2-imidazolato)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-3-oxide-1-oxy (NITIm), have been prepared where metallic and organic spin carriers alternate. Depending on the deprotonating agent, the solvent, and the counteranion, the species [Mn(NITIm)(H(2)O)(2)]CH(3)COO, 1, [Mn(NITIm)(DMSO)(2)]BPh(4), 2, [Mn(NITIm)(H(2)O)(ImH)]NO(3), 3, and [Mn(NITIm)(NITImH)]ClO(4), 4, have been obtained, which differ by the additional ligands completing the metal coordination sphere. Complexes 1-3 are cis isomers and 4 is found as the mer modification; in all compounds, one observes a regular alternation of Lambda and Delta metal environments.

Two-Dimensional Nitroxide-Based Molecular Magnetic Materials.

Manganese(II) complexes of imidazolyl-substituted chelating nitronylnitroxides are characterized by a stereoselective arrangement of the metal centers and the ligands to give a honeycomblike layer structure (shown on the right). The magnetic properties at high temperature indicate the presence of a ferrimagnetic structure within the layers. At low temperatures, ferromagnetic ordering is observed.