Binuclear CuLn complexes (LnIII = Gd, Tb, Dy) of alcohol-functionalized bicompartmental Schiff-base ligand. Hydrogen bonding and magnetic behaviors

Preparation, crystal structures and magnetic properties of a series of four binuclear Cu–Ln complexes are reported (Ln = GdIII, TbIII, and DyIII). These are based on a bicompartmental Schiff-base ligand formed by condensation of 1,3-diaminopropan-2-ol with ortho-vanillin. This Schiff-base is known to usually involve its deprotonated alcohol group in metal coordination, which is not the case here. Instead the OH unit is engaged in H-bonding interactions. Intra- and inter-molecular H-bonds are formed when the alcohol group is located in axial position of the six-member ring formed by the diamino moiety and the Cu atom. In equatorial position, this group is only involved in intermolecular bonding. The corresponding Cu–Tb derivative is shown to behave as a Single Molecule Magnet with ΔkB = 24.6 K and τ0 = 2.1 × 10−8 s (HDC = 1.5 kOe).

Binuclear 3d–4f Schiff-base complexes formed with a bicompartmental ligand substituted by an alcohol function are reported. Slow relaxation of the magnetization has been found for Cu–Tb derivative.Figure optionsDownload as PowerPoint slide