A new copper(II)-iron(II) complex [Cu(acac)(bpy)(py)]2[Fe(CN)5(NO)] based on nitroprusside:: Synthesis, structure and spectroscopic studies

A new complex [Cu(acac)( bpy)(py)](2)[Fe(CN)(5)(NO)] (acac(-) = acetylacetonate, py = pyridine, bpy = 2,2'-bipyridine) has been prepared and investigated by single-crystal X-ray analysis, IR (infrared), EPR (electron paramagnetic resonance) and Mossbauer spectroscopy, and variable-temperature magnetic susceptibility. The structure consists of two [Cu(acac)(bpy)(py)](+) cations and one [Fe(CN)(5)(NO)](2-) anion. It crystallizes in space group P1 with cell parameters a=9.963(3), b = 10.485(2), c=11.749(2)Angstrom, alpha=111.35(2), beta=96.18(2), gamma = 95.43(2)degrees. The structure refined to a final X-value of 0.045 for 2103 observed reflections [I greater than or equal to 3 sigma(I)]. The copper(II) atoms are in a distorted square-based pyramidal geometry with two oxygen atoms of the acac- ligand and two nitrogen atoms of the bpy ligand lying in the basal plane and one nitrogen atom of py occupied in the apical position. Mossbauer and magnetic susceptibility studies evidence the low-spin state of the iron(II) metal center. EPR spectroscopy and magnetism show the operation of weak magnetic interactions in the solid state, which may be transmitted through the pi-stacking interactions between the bpy ligands of adjacent [Cu(acac)(bpy)(py)](2)[Fe(CN)(5)(NO)] constitutive units.