Syntheses, crystal structures, thermal and magnetic properties of new heterotrinuclear CuII–LnIII–CuII complexes incorporating N2O4-donor Schiff base ligands

Structural, Luminescent and Thermal Properties of Heteronuclear PdII–LnIII–PdII Complexes of Hexadentate N2O4 Schiff Base Ligand

“…The conformation of the organic ligand has been flattened slightly in comparison to previously reported complexes with Cu II –Ln III –Cu II (Figure 3) [15]. The valence angles in 1 – 4 between two planes of benzene rings around the palladium(II) ions are in the range of 9–39° ( ψ , Table 1), whereas the corresponding values for Cu II –Ln III –Cu II compounds are in the range of 40–47°.…”

“…The deviation of the Pd II ion from the N 2 O 2 mean plane is nearly zero (Δ, Table 1). The dihedral angle between the PdO (phenoxo)2 and LnO (phenoxo)2 planes is also small (in the range of 0–10°, σ , Table 1), similar to complexes of H 4 L with Cu II and Ln III metal ions [15] and unlike other 3d-4f complexes. For example, in complexes of Zn II –Ln III –Zn II with a ligand based on a 2-hydroxypropanyl bridge, the σ value was approximately 35° [16].…”

“…The crystal structure was reported previously [15]. 2,2-Dimethyl-1,3-propanediamine (0.51 g, 5 mmol, 5 mL methanol) was added dropwise to 2,3-dihydroxybenzaldehyde (1.38 g, 10 mmol) dissolved in hot methanol (50 mL).…”

“…Overlay of selected molecular fragments of coordination units in complexes of 1 (red), 2 (black), 3 (grey) and a previously reported complex of H 4 L with Cu II –Nd III –Cu II (green) [15]. The superposition was made for the benzene rings.…”

“…Previously, we reported complexes of the H 4 L ligand with Cu II –Ln III –Cu II metal ions [15]. The geometry of the coordination sphere around the pentacoordinated copper(II) showed a high degree of planarity of the N 2 O 2 chelating cavity with low deviation of the Cu II ion from the base plane.…”