Solid state M�ssbauer, e.p.r., magnetic properties and thermally induced stereochemical studies on double complex salts of cyclic diamine containing cationic copper(II) complexes and a hexacyanoferrate(III) anion

Abstract

Double complex salts containing cationic CuII having cyclic ligand piperazine (pipz), N-methylpiperazine (mpipz) and N,N′-dimethylpiperazine (dmpipz) and hexacyanoferrate(III) ion have been synthesized and characterized by elemental analyses, i.r. and electronic spectra, and magnetic moment measurements. Mossbauer spectra at room temperature and at 80 K, were recorded in order to evaluate the metal-metal charge transfer and the impact of the cyclic ligand present in cationic moiety of the double complex salt upon the Mossbauer spectra of the hexacyanoferrate(III) ion. Evidence for metal-metal charge transfer is supported by electronic spectra and magnetic susceptibilities. Variable temperature e.p.r. spectra were recorded in order to determine the distortion of crystal system. Thermally induced stereochemical studies have been carried out with the help of i.r. spectral data. Kinetics of thermochemical reactions have also been studied. Activation energies (Einfasup*) and inception temperatures for the thermochemical reactions show the order of stability of the double complex salts follows the trend: dmpipz > mpipz > pipz, which indicates that the + I effect is more pronounced than steric effect.