摘要:
Flash vacuum pyrolysis (FVP) or matrix photolysis of 2-(diazomethyl)phenylamine, 1-azido-2-methylbenzene (2-tolyl azide), o-aminobenzyl alcohol, or 2-indolinone provide entries into the C7H7N hypersurface. The matrix-isolated (argon, 10 K products have been characterized by IR and UV-vis spectroscopy in combination with high level (MP2/6-31G(d) and HF/6-31G(d,p)) ab-initio calculations. FVP (500-800 degrees C) of the first three of these precursors produces high yields of E/Z-mixture s of 6-methylene-2,4-cyclohexadien-1-imine (o-iminoquinone methide), while the bicyclic isomer benzoazetine is not formed under these conditions. FVP of 2-tolyl azide at very high temperatures (> 900 degrees C) leads to the formation of benzaldimine and benzonitrile, Photolysis of the matrix-isolated precursors allows one to selectively generate the E- and Z-isomer of the iminoquinone methide as well as benzoazetine. In addition, 2-tolylnitrene and 1-aza-3-methyl-1,2,4,6-cycloheptatetraene are produced as intermediates in the photolysis of 2-tolyl azide. The nitrene is thermally stable up to 80 K (in xenon matrix), although the hydrogen migration to give (E)-o-iminoquinone methide is calculated to be exothermic by 42 kcal/mol. Irradiation of 2-(diazomethyl)phenylamine directly yields the quinone methide while io-aminophenyl)carbene, which is the most reasonable intermediate, is not observed.