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  • TITLE
  • CERTIFICATE
  • DECLARATION
  • ACKNOWLEDGEMENT
  • DEDICATION
  • CONTENTS
  • 1. Introduction and Objectives
  • ABSTRACT
  • 1.1. General
  • 1.2. Interaction of Ionizing Radiation with Matter
  • 1.2.1 The Photoelectric Effect
  • 1.2.2 Compton Scattering
  • 1.2.3 Pair Production
  • 1.3. Radiation Chemical Techniques
  • 1.3.1 Pulse radiolysis
  • a) Detection by Optical Absorption
  • b) Detection by Conductometry
  • c) Detection by Electron Spin Resonance
  • d) Detection by Resonance Raman Spectroscopy
  • e) Detection by Rayleigh Light Scattering
  • 1.3.2 Kinetic sepectrophotometry
  • 1.3.3 Dosimetry
  • 1.3.4 Steady-state Radiolysis
  • 1.4. Radiation chemistry of aqueous solutions
  • 1.4.1 Properties of primary radicals and molecular products
  • 1.4.2 Yields of primary radicals
  • 1.4.3 Primary and Secondary Radicals and Their Properties
  • a) Hydroxyl radical (OH)
  • b) Aqueous electron (e.aq.-)
  • c) Hydrogen radical (H)
  • d) Per hydroxyl radical (HO2)
  • 1.4.4 Other Secondary Radicals
  • 1.5. Radiation chemistry of nucleic acids and their model compounds
  • 1.6. Nucleobases, Nucleosides and Nucleotides: Model Systems for Radiation Damage of DNA
  • 1.6.1 Redox Titration Technique
  • 1.6.2 Reactions of Hydroxyl radicals (OH)
  • 1.6.3 Reactions of Hydrated Electron (e aq-) and Hydrogen atom
  • 1.6.4 Reactions of Sulfate Radical Anion (SO4+)
  • 1.7. Objectives
  • References
  • 2. Experimental
  • ABSTRACT
  • 2.1. Materials
  • 2.2. Preparation of Solutions
  • 2.3. Generation of Radicals
  • 2.3.1 Hydroxyl radicals (OH) and Oxide radical anion (O)
  • 2.3.2 Sulfate radical anion (SO4+)
  • 2.3.3 Hydrated electrons (e-aq) and Hydrogen atom (H+)
  • 2.4. Pulse Radiolysis
  • Fig. 2.1: Schematic representation of a Linear Accelerator
  • Fig.2.2: Schematic representation of the Pulse-Radiolysis setup at BARC, Mumbai
  • 2.4.1 Optical Absorption Measurements
  • 2.4.2 Radiation Dosimetry
  • Thiocyanate Dosimeter
  • 2.5. Instrumental Analyses
  • 2.5.1 UV-VIS Spectroscopy
  • 2.5.2 pH Meter
  • 2.5.3 Theoretical calculations Method
  • References
  • 3. Redox Chemistry of 8-Azaadenine: A Pulse Radiolysis Study
  • ABSTRACT
  • 3.1. Introduction
  • 3.2. Theoretical calculations
  • Fig.3.1: NBO Charge population (in au) of 8 Azaadenine (This demonstrates the C (4) I0.35 au) is the most probablesite of electrophillic attack]
  • 3.3. Reactions of Hydroxyl Radicals OH
  • 3.4. Reaction of oxide radical anion (O+)
  • 3.5. Reaction of sulfate radical anion (SO4)
  • 3.6. Reactions of hydrated electrons (e aq-) and hydrogen atom (H)
  • 3.7. Conclusion
  • References
  • 4. Redox Chemistry of 5-Azacytocine and 5-Azacytidine: A Pulse Radiolysis and Theoretical Study
  • ABSTRACT
  • 4.1. Reactions of Oxidizing Radicals
  • 4.1.1 Reactions with +OH
  • a) Pulse Radiolysis Study
  • b) Theoretical Study
  • Fig. 4.5: 5-azacytosine optimized picture, atomic charges onC4, N5 and C6 are shown in parenthesis.
  • Fig. 4.7: Optimised structures of possible hydroxyl radicaladducts
  • c) Reaction Mechanism
  • 4.1.2 Reaction of oxide radical anion (O+)
  • a) Pulse Radiolysis
  • b) Theoretical Study
  • Fig.4.13: Optical structure of possible oxide radical adducts
  • c) Reaction Mechanism
  • 4.1.3 Reaction of sulfate radical anion (SO4+)
  • 4.2. Reactions of Reducing Radical
  • 4.2.1 Reaction of hydrated electrons
  • 4.3.Conclusion
  • References
  • Publications
  • Curriculum Vitae