1. Department of Chemistry, Guru Nanak Dev University, Amritsar, India
2. Department of Pharmacology, Penn State Cancer Institute, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
3. Department of Chemistry, Khalsa College, Amritsar, India
4. Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181, Unité de Catalyse et Chimie du Solide (UCCS), F-59000 Lille, France