**Acknowledgements**

The author is thankful to the Head, PGTD of Chemistry, R.T.M. Nagpur University, Nagpur, for laboratory facilities, and to the Vice Chancellor, Nagpur University, Nagpur, for the sanction of research project work under the University Research Project Scheme, awarded vide No. Dev/RTMNURP/AH/1672 (9) dated 24 September 2016.
