The E.P.R. of Ground State Triplet Nitrenes

Study of photochemical transformations of organic azides by matrix isolation techniques and quantum chemistry

“…58,69,70 More recently, a series of alkylnitrenes have been generated by intramolecular sensitisation, 71 ± 73 including that in an argon matrix. 73 For example, the irradiation of a-azidoacetophenone (9) and its derivatives gives benzoyl radical (10) (through the a-C7C bond cleavage) and triplet nitrene 11.…”

“…69 Shortly thereafter, the low-temperature electronic absorption spectrum of nitrene 3 (29) was recorded in a glassy matrix. 138 More recent studies 139 showed that this nitrene readily undergoes isomerisation to ketene imine 28 upon irradiation.…”

Semi-empirical calculations of the zero-field-splitting parameters of the lowest triplet states of aromatic ketones

“…Hirota and his collaborators [3] and also Chan and Schmidt [4] obtained the zero-field-splitting (ZFS) parameters D and E, the total decay rates k i (i= x, y, and z), the radiative decay rates k~ r, and the populating rates Pi, for the lowest triplet states of acetophenone and the related aromatic ketonesJ'. The observed ]D[ values are larger than those of the usual 7r, ~r * triplet states [5], but are smaller than those of the usual n, rr * ones [6][7][8][9]2. Moreover, the sign of D was determined to be negative for some aromatic ketones [1,3,11], while it is positive for the usual rr, 7r * triplet states [12].…”

The rhodium(II)-catalyzed aziridination of olefins with {[(4-nitrophenyl)sulfonyl]imino}phenyl-lambda3-iodane

“…Photolytic decomposition of NsN 3 (20 mmol) in the presence of [Rh 2 (R)-(-)-bnp) 4 ] (1.0 mmol) afforded the aziridine 5c in 9% yield and 17% ee. Since photolysis of sulfonylazides is known to produce sulfonylnitrenes (39), the observation of enantioselectivity implies that at least part of the reaction must proceed via a metal-complexed nitrene 26. The trapping efficiency is, however, much lower than that of 100% observed by Jacobsen (8) in the Cu-catalyzed aziridination.…”