Photochemistry Of Aromatic Thiones And Of Compartmentalized Ketones

This thesis is concerned with three main topics. The first of them refers to some mechanistic aspects of the photocyclization of phenyl 1-naphthyl thione (PNT) and related thiones. It was found that for PNT the disappearance quantum yield increases mildly with electron-withdrawal substituents in the para position of the phenyl ring. The transients generated by laser flash photolysis of the thiones are assigned to their triplet states. The triplet of PNT is quenched by oxygen with a rate constant of 2.8 x 10(\u279) M(\u27-1) s(\u27-1).;By monitoring the triplet tetracene generated by energy transfer from PNT excited by a 337 nm-laser, the intersystem crossing quantum yield of the thione could be estimated. The values thus obtained were 0.71 for PNT and 0.65 for phenyl 6-chrysenyl thione. It is concluded that the main reason for the disappearance quantum yield being low is not the reversion of an intermediate, but its inefficient formation owing to competing photophysical processes.;Absorption spectroscopy of nitrite esters and carbonyl functions, and (\u2713)C chemical shifts of the oxo-carbon, in substituted dodecanoate micelles appear to indicate the presence of a polar environment in the neighbourhood of the substituent.;Photolysis of 5-nonanone in an urea inclusion compound leads to the formation of Norrish Type II products. The product distribution is different from that formed by irradiation in solution. The cyclization to fragmentation ratio was higher for irradiations in the urea inclusion compound than in solution. One cyclobutanol was formed in the urea inclusion compound; the other was almost entirely absent