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(-) = acetylaceto nate, py = pyridine, bpy = 2,2'-bipyridine) has been prepared and investiga ted by single-crystal X-ray analysis, IR (infrared), EPR (electron paramagn etic resonance) and Mossbauer spectroscopy, and variable-temperature magnet ic susceptibility. The structure consists of two [Cu(acac)(bpy)(py)](+) cat ions and one [Fe(CN)(5)(NO)](2-) anion. It crystallizes in space group P1 w ith cell parameters a=9.963(3), b = 10.485(2), c=11.749(2)Angstrom, alpha=1 11.35(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 e qual to 3 sigma(I)]. The copper(II) atoms are in a distorted square-based p yramidal geometry with two oxygen atoms of the acac- ligand and two nitroge n 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 spect roscopy and magnetism show the operation of weak magnetic interactions in t he solid state, which may be transmitted through the pi-stacking interactio ns between the bpy ligands of adjacent [Cu(acac)(bpy)(py)](2)[Fe(CN)(5)(NO) ] constitutive units.