**Acknowledgements**

Dr Fahmina Zafar is thankful to UGC (New Delhi, India) for Dr DS Kothari Postdoctoral Fellowship, Ref. # F.4/2006(BSR)/13‐986/2013(BSR). The author is also thankful to Prof. Nahid Nishat (Mentor), Inorganic Materials Research Lab, Department of Chemistry, Jamia Millia Islamia (a Central University) New Delhi, India, for her kind support.
