1. a Department of Chemistry, Sri Krishnadevaraya University Post-Graduate Centre, Kurnool-518 002, India
2. b Department of Chemistry, Sri Krishnadevaraya University Post-Graduate Centre, Kurnool-518 002, India
3. c Department of Chemistry, Sri Krishnadevaraya University Post-Graduate Centre, Kurnool-518 002, India
4. d Department of Chemistry, Sri Krishnadevaraya University Post-Graduate Centre, Kurnool-518 002, India