Study of Organic Reaction Processes by the Use of Low-Temperature Matrix-Isolation Technique

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The object of this research is to establish the low-temperature matrix-isolation method as a general technique for the study of an organic reaction mechanism by the expansion of the application range of this technique. In order to make possible to apply this technique to less volatile substrates and to reactive intermediates generated by a large apparatus such as laser and flash vacuum pyrolysis, an inner-rotation mechanism was employed in the low-temperature matrix-isolation apparatus which was designed and set up with the aid of this grant. The ability of this new apparatus to make a low-temperature matrix satisfactory for spectroscopic observations was confirmed by the isolation of p-nitorophenyl azide in an argon matrix and comparison of its IR spectrum with that recorded previously using the other apparatus. The direct observation of the processes of the reaction of p-nitrophenylcarbene (1) with acetonitrile was examined next. Irradiation of (p-nitrophenyl)diazomethane matrix-isolated in argon doped with acetonitrile at 10K gave the carbene 1, which reacted with acetonitrile photochemically or thermally. The reactions were nicely monitored by IR and UV-Vis spectroscopy to find that the product formed by the further photolysis of 1 in an acetonitrile-doped matrix was different from that obtained thermally in the matrix. The structure of these products was estimated on the basis of the isotope experiment and DFT calculations. These preliminary results were suggested that the low-temperature matrix-isolation technique would be a powerful method for studying the reaction mechanism of organic reactive intermediates.