Low-temperature Structural Dynamics of Isatin in Dimethyl Sulfoxide (DMSO) Using Dielectric Spectroscopy

Abstract

Structural and dynamical properties of heterocyclic organic compound isatin in the solution state with DMSO has been studied in the frequency region of 10 MHz to 50 GHz over the temperature range of 273.15–298.15 K using time domain reflectometry. High- and low-frequency relaxation has been observed for Isatin + DMSO. The high-frequency relaxation peak is due to free DMSO molecules while low-frequency relaxation peak is attributed to isatin. Dielectric permittivity, static dielectric constant, relaxation time, dipole moment, correlation factor along with thermodynamical parameters have been calculated. Molecular interaction has been discussed broadly under solute–solute, solute–solvent, and solvent–solvent category.

Keywords:

• Isatin
• DMSO
• dielectric and thermodynamic parameter
• structural dynamic

Acknowledgments

Komal B. Kabara is thankful to the School of Physical Sciences, S. R. T. M. University Nanded for providing instrumentation facility for time domain reflectometry. Also, she gratefully acknowledges D.S.T. New Delhi for providing TDR facility through project sanctioned to Dr Ashok V. Sarode (SERB/F/4632/2013-2015) and Dr Arvind C. Kumbharkhane (SB/S2/LOP-032/2015).

Disclosure statement

No potential conflict of interest was reported by the author(s).