Photochemical reactions in zeolites: Effect of acidity, confinement and non-bonding interactions

This report investigates photochemical reactions carried out in zeolites from the point of view of understanding the effect of the confined spaces and the exchanged canons on the product selectivity observed in these reactions. The first chapter provides an introduction to this theme with topics on the properties of zeolite.; The second chapter investigates the effect of zeolite acidity on olefins using 1,1-diarylolefins as the probe molecules. It also deals with the effect of the activation conditions on this acidic character. The results from the product studies with 1,1-diarylolefins are discussed along with the NMR studies on this acidic property. With this a model according to which the acidity depends on the activation conditions and the exchanged cation is proposed.; In the third chapter, wavelength dependency of the oxygen mediated photochemical electron transfer reactions of l,l-diarylolefins is discussed. The dependency of the product distribution on the excitation wavelength is highlighted and is explained based on difference in the nature of the species being excited. This also highlights the role of the zeolite as a confining medium.; In the fourth chapter, selective isomerization of 1,2-diaryl substrates like stilbene and 1,2-diphenylcyclopropane is discussed with the goal of highlighting the role played by non-bonding interactions like cation-p resulting higher stabilization of the cis isomers in all the above cases. The product studies are aptly supported by theoretical studies carried out on these interactions at abinitio level. It has been clearly shown that there is a good agreement between the theoretical studies and the experimental results.; In the fifth chapter, an attempt has been made to explain the photochemical results obtained in the case of enone photochemistry in zeolites using photophysical and theoretical studies of some model enones. The theoretical studies clearly highlight the role played by cation-carbonyl interactions in this selectivity. These results are supported by photophysical studies of acetophenones carried out inside zeolites.