| The application of lasers to photochemical studies has resulted in the ability to produce high-intensity, multiple-photon, photochemical reactions. The absorption of two or more photons by a molecule, or transient intermediate, can result in the production of a higher excited state in an intratransient reaction. The production of higher concentrations of transient intermediates, such as radicals, biradicals, carbene, or nitrenes, can also be achieved using this technique. The higher concentrations increase the likelihood for an intertransient reaction to occur between two such intermediates. Both of the aforementioned cases can lead to the formation of photochemical products that previously had not been observed under conventional, low-intensity, conditions.; High-intensity reactions have been investigated in this laboratory using the argon-ion, laser-jet apparatus. A number of compounds were chosen for this research to possibly provide answers to questions resulting from previous observations under high-intensity conditions. The types of reactions studied were symmetry-governed reactions: 3,4-benzocoumarin (11) and bifluorenylidene (22); and intertransient reactions: 1,8-naphthalic anhydride (26), 2,3-naphthalic anhydride (31), N-phenyl-1,8-naphthalimide (37), N-phenyl-2,3 naphthalimide (38), and N-phenyl-phthalmide (39). The application of the laser-jet technique to photo-induced electron transfer reactions was also investigated. Two classes of compounds were investigated as possible targets for this type of reaction: diphenylalkanediones; 1,6-diphenyl-1,6-hexanedione (41), 1,8-diphenyl-1,8-octanedione (42), 1,10-diphenyl-1,10-decanedione (43), and 1,12-diphenyl-1,12-dodecanedione (44); and N-(phenylalkyl)phthalimides; N-(3-phenylpropyl)phthalimide (68) and N-(4,4,4-triphenylbutyl)phthalimide (71). The incorporation of an excimer laser in the laser jet technique, along with the required modifications of the laser-jet apparatus, also is reported. |
