Study Self-association, Optical Transition Properties and Thermodynamic Properties of Neomycin Sulfate Using UV-Visible Spectroscopy

摘要

In this paper UV-Vis spectroscopy was used to study the self-association, optical transition probabilities (molar decadeic absorption coefficient, integrated absorption cross-section, transition dipole moment and oscillator strength of the spectra) and thermodynamic properties of Neomycin sulfate in aqueous solution at room temperature (295K). The optical transition probabilities were calculated by integrated absorption coefficient techniques in the wave number range 27173.9 - 37650.6 cm~(-1). The dimerization constant of Neomycin Sulfate (1.062 10~(5) M ~(-1)) was analyzed using dimer model by nonlinear curve fitting to the experimental values. In addition the thermodynamic parameters (Gibbs free energy, enthalpy and entropy) of dimerization reactions for the self -association of the compound were investigated using Vant’s Hoff equation at the temperature range (295 –312)K. Thus, the change of enthalpy calculated for Neomycin Sulfate is (3.765 ± 0.666) ΔH /k J .mole ~(-1 ). The values of change in enthalpy and entropy indicate that the hydrophobic interaction play the major role in the interaction between the molecules of Neomycin sulfate.