Adamantylidene revisited: flash photolysis of ...
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| Title | Adamantylidene revisited: flash photolysis of adamantanediazirine |
| Author(s) | R. Bonneau, B. Hellrung, M. Liu, J. Wirz |
| Journal | Journal of Photochemistry and Photobiology A-Chemistry |
| Date | 1998 |
| Volume | 116 |
| Issue | 1 |
| Start page | 9 |
| End page | 19 |
| Abstract | Irradiation of 2-adamantane-2,3'-[3H]-diazirine (1) in isooctane at room temperature gives two primary photoproducts, 2-diazoadamantane and 2-adamantylidene (Ad:), with quantum yields of about 0.5 each. The fluorescence quantum yield of 1 is small, phi(f) approximate to 10(-4). The reactivity of Ad: was studied by nanosecond laser flash photolysis; it is best described as that of a carbene equilibrating between the singlet ground state and a low-lying triplet state. Ad: reacts with the precursor diazirine 1, pyridine, acetonitrile, tetramethylethylene, amines, water, and acetic acid with rate constants approaching the diffusion-controlled limit, as well as with molecular oxygen (k(O2) = 2.3 x 10(9) M-1 s(-t)). Reaction of Ad: with 1 (k(X) = 3.6 x 10(9) M-1 s(-1)) gives an ylide, lambda(max) = 290 nm, which forms adamantanone azine as a stable product by a reaction having activation parameters E-a = 15.5 kcal mol(-1) and A = 2 x 10(12) s(-t). At low concentrations of 1 in thoroughly dry, degassed solvents, the lifetime of Ad: reaches ca. 225 ns in isooctane, 500 ns in perfluorodecalin, and 700 ns in benzene. Diazoadamantane forms azine by a second-order reaction with a half-life of several hours at 10(-4) concentration. (C) 1998 Elsevier Science S.A. All rights reserved. |
| ISSN | 1010-6030 |
Using APA 6th Edition citation style.
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