Synthesis, spectral investigation and thermal aspects of coordination polymeric chain assemblies of some transition metal ions with bis-pyrazolones

Abstract

A few coordination chain polymeric assemblies of the type [M(SB)(H 2O) 2] n · xH 2O or [VO(SB)(H 2O)] n ·H 2O [where M = Mn(II), Cu(II) and Zn(II), x = 1; Co(II) and Ni(II) x = 2, H 2SB = (4 Z,4′ Z)-4,4′-(2,2′-(4,4′-methylenebis(4,1-phenylene)bis(azanediyl))bis(1-hydroxy ethan-2-yl-1-ylidene))bis(3-methyl-1-phenyl-1 H-pyrazol-5(4H)-one)] have been investigated. Structural and spectroscopic properties have been studied on the basis of elemental analyses, infrared spectra, 1H and 13C NMR spectra, electronic spectra, magnetic measurements and thermo gravimetric analyses. FT-IR, 1H and 13C NMR studies reveal that the ligand (H 2SB) exists in the tautomeric enol form in both the states with intramolecular hydrogen bonding. Magnetic moment and reflectance spectral studies reveal that an octahedral geometry has been assigned to all the prepared coordination polymers. The kinetic parameters such as order of reaction ( n) and the energy of activation ( E a) have been reported using Freeman–Carroll method. The pre-exponential factor ( A), the activation entropy (Δ S #), the activation enthalpy (Δ H # ) and the free energy of activation (Δ G # ) have been calculated.