Synthesis, Crystal Structure and Spectroscopic Properties of Bis(1-(E)-2-formylpyridine semicarbazone)nickel(II) Diperchlorate Monohydrate

Pale-green crystals of the title complex were prepared by reaction of 2-formylpyridine semicarbazone (HCSpy) and nickel(11) perchlorate in boiling ethanol. The crystals are triclinic with the nickel ion in an octahedral arrangement, coordinated by two nitrogen atoms and one oxygen donor atom from each ligand molecule. The effect of coordination on bond lengths and angles was explored by comparison with the single-crystal structure data of the free ligand HSCpy, which was collected as well. The assumed coordination mode was supported by H-1 and C-13 NMR spectroscopic data. A detailed analysis of the electronic properties, including semi-empirical quantummechanical calculations is presented. Furthermore, the data obtained from magnetic susceptibility and EPR measurements are in accordance with a low-spin d(8) nickel(II) complex.