The square-planar structure of bis[N-(<i>i</i>-propyl)-3-oxy-2-naphthaldiminato]copper(II)

The stepped square-planar Schiff base copper(II) complex bis[N-(<i>i</i>-propyl)-3-oxy-2-naphthaldiminato]copper(II) (<b>1</b>) is presented. This compound was synthesized and characterized by chemical analysis, mass spectrometry, UV–visible, IR, far-IR, and X-ray crystallography. In addition, EPR studies were carried out for <b>1</b>. In this complex, the geometry around the copper ion is stepped square planar. EPR spectra in toluene, chloroform, and DMF solutions at 77 K suggest that the geometry of <b>1</b> is similar to that observed in the solid state by X-ray crystallography. Kohn–Sham geometry optimizations on this complex are in good agreement with the experimental data. Additionally, we show that a square planar structure for the bis-(N-i-Pr-3-oxy-2-naphthaldiminato)copper(II) complex can also be found in gas phase and not only in the solid state, result that challenges the hypothesis that packing effects are crucial for obtaining this structure.