Abstract
This thesis investigates the ability of polymeric and oligomeric organic hosts in controlling photochemical reaction pathways. Spatially organized and confined domains provided by Nafion, polystyrene based water soluble polymer and cyclodextrins were explored as reaction media in achieving selectivity in photochemical reactions.Chapter 1 provides a brief introduction to various potential hosts that can be employed as reaction media for photochemical reactions. This chapter also highlights photochemical and photophysical studies that were previously examined by various research groups on these supramolecular systems.Chapter 2 discusses the product selectivity obtained in various photochemical reactions within alkali ion exchanged Nafion beads. The role of cations that reside within Nafion on the photodimerization of aromatic hydrocarbons were examined. Also, the utility of Nafion as a reaction medium for asymmetric induction in photochemical reactions and for singlet oxygen mediated oxidation of olefin were investigated.Chapter 3 presents the ability of hydrophobic reaction cavities provided by a styrene based water soluble polymer (polymer-A) in controlling photochemical reactions in aqueous media. Polymer-A provides better selectivities than conventional micelles and micelles obtained from block copolymer with similar hydrophobic core. The aggregation behavior and the micropolarity within polymer-A aggregates were probed by a fluorescent probe, pyrene. Photodimerization of acenaphthylene and anthracene-9-derivative within polymer-A also serve as probes for better understanding of the nature of hydrophobic reaction cavities provided by polymer-A.Chapter 4 presents the effect of cyclodextrin cavities on the product distribution of alpha-alkyl dibenzyl ketones. The stability constant measurements with UV-Vis spectrometric analysis provide better understanding of the photochemical behaviors of alpha-alkyl dibenzyl ketones inclusion complexes with beta3-CD and gamma-CD in aqueous solutions.