Crystal Structure and Magnetism of (μ-Maleato)Bis[(N-(2-(Diethylamino)Ethyl)-Salicylidenaminato)Copper(II)]- Methanol

The crystal and molecular structure of ( w -maleato)bis[(N-(2-(diethylamino)ethyl)salicylidenaminato)-copper(II)]-methanol, [Cu₂(salNet₂)₂( w -mal)]·CH₃OH, where salNet₂ = N-(2-(diethylamino)ethyl)salicylidenaminate, has been determined by single-crystal X-ray analysis. The compound crystallizes in the monoclinic space group P2₁/c, with a =11.994(1), b =14.723(1), c =20.0384(1) Å, and g =96.145(2)°. In the structure two copper(II) ions are bridged by the maleato ligand, which coordinates as a monodentate through its first carboxylato group and as a bis-monodentate ligand through its second carboxylato group. The local geometry around the first copper(II) ion is square planar, whereas that around the second is square pyramidal. Fitting of variable-temperature magnetic susceptibility data to the HDVV Ĥ = -2JŜ₁Ŝ₂, S ₁ = S ₂ = 1/2 spin exchange model, yields of 2J value of -4.56 cm^-1. The mechanism of the observed antiferromagnetic interactions is discussed in the light of extended Hückel calculations. Analysis shows an almost linear dependence of the magnitude of the exchange coupling constant, |2J|, upon the calculated energy difference between the two SOMOs for a series of w -dicarboxylato-bridged bis-Cu(salNet₂) complexes.

Keywords:

• Copper
• Schiff Base
• X-ray Structure
• Magnetism