Crystal structures of binuclear complexes of gadolinium(III) and dysprosium(III) with oxalate bridges and chelating ,'-bis-(2-oxido-benz-yl)-,'-bis-(pyridin-2-ylmeth-yl)ethyl-enedi-amine (bbpen).

The reaction between mononuclear [(bbpen)Cl] [ = Gd or Dy; Hbbpen = ,'-bis-(2-hy-droxy-benz-yl)-,'-bis-(pyridin-2-ylmeth-yl)ethyl-enedi-amine, CHNO] and potassium oxalate monohydrate in water/methanol produced the solvated centrosymmetric isostructural binuclear (μ-oxalato)bis-{[,'-bis-(2-oxidobenzyl-κ)-,'-bis-(pyridin-2-ylmethyl-κ)ethyl-enedi-amine-κ ,']dilanthanide(III)}-methanol-water (1/4/4) complexes, [ (CHNO)(CO)]·4CHOH·4HO, with lanthanide(III) = gadolinium(III) ( = Gd) and dysprosium(III) ( = Dy), in high yields ( 70%) directly from the reaction mixtures. In both complexes, the lanthanide ion is eight-coordinate and adopts a distorted square-anti-prismatic coordination environment. The triclinic ( ) unit cell contains one dimeric unit together with four water and four methanol mol-ecules; in the final structural model, two of each type of solvating mol-ecule refine well. In each lanthanide(III) dimeric mol-ecule, the medium-strength O⋯H-O hydrogen-bonding pattern involves four oxygen atoms, two of them from the phenolate groups that are 'bridged' by one water and one methanol mol-ecule. These inter-actions seem to contribute to the stabilization of the relatively compact shape of the dimer. Electron densities associated with an additional water and methanol mol-ecule were removed with the SQUEEZE procedure in [Spek (2015 ▸). C, 9-18]. These two new compounds are of inter-est with respect to magnetic properties.