[1] Keene State Coll, Dept Chem, Keene, NH 03435 USA
[2] Howard Univ, Dept Chem, Washington, DC 20059 USA
[3] Univ Mysore, Dept Studies Chem, Mysore 570006, Karnataka, India
[4] Mangalore Univ, Dept Studies Chem, Mangalagangothri 574199, Karnataka, India