Crystal and molecular structures of bis[2-hydroxy-N-3-hydroxypropyl-5-nitrobenzylideneaminato-(µ-O)-copper(II)] and bis[2-hydroxy-N-3-hydroxypropyl-α-methylbenzylideneaminato-(µ-O)-copper(II)] and relation of structural and magnetic properties

Abstract

The crystal structures of the title complexes (Ia) Cu₂O₈N₄C₂₀H₂₀ and (Ib) Cu₂O₄N₂C₂₂H₂₆ have been studied by single crystal X-ray diffraction, from counter data. Crystal data: (Ia), space group P2₁/c, Z= 2, a= 10.988(5), b= 5.444(5), c= 17.455(7)Å, β= 96.49°, R 0.098, 506 reflections; (Ib), space group C2/c, Z= 8, a= 20.700(9), b= 9.555(6), c= 21.64(1)Å, β= 92.49(4)°, R 0.034, 1 649 reflections. The structures were solved by the heavy-atom method.

Complex (Ia) has the closest intermolecular Cu ⋯ Cu distance for any complex of this type [3.6 Åvs. Cu ⋯ Cu (intramolecular) 3.0 Å], a property probably responsible for the high degree of cohesion in the lattice; it is also the closest to being completely coplanar. Complex (Ib) differs from others of this type in space group, and in the inequivalence of the two copper atoms in the binuclear molecule. The structures and magnetic properties of both complexes support a general correlation between decreasing strength of antiferromagnetic interaction and increasing distortion towards tetrahedral metal environment in binuclear copper(II) complexes.