The Lifetime and Reactivity of Singlet Tetrachloropyridyl-4-nitrene

The principal direction in the photolytic decomposition of 4-azidotetrachloropyridine in methylene chloride solution involves the intermediate formation of singlet tetrachloropyridyl-4-nitrene, the lifetime of which amounts to 50 nsec. The nitrene reacts readily with the pyridine (k _pyr = 2.67·10⁷ mole^-1·sec^-1) with the formation of the corresponding pyridinium ylide, which has a characteristic absorption band in the UV spectrum with a maximum at 406 nm.