Spectroscopic and chemical evidence for methylene singlet-triplet intersystem crossing in solution
✍ Scribed by Nicholas J Turro; Yuan Cha
- Publisher
- Elsevier Science
- Year
- 1986
- Tongue
- French
- Weight
- 268 KB
- Volume
- 27
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
Singlet-triplet intersystem crossing of methylene in perfluorohexane solution has been investigated by CIDNP. Evidence of this process is shown by the polarized absorption 1 H-NMR signal of ClxC-CHZD, a triplet product, which is obtained upon direct irradiation of diazirine in perfluorohexane solution containing saturated deuteriochloreform. These results are confirmed by product analysis as a function of dilution by perfluorohexane. The rate constant for intersystem crossing for singlet methylene to triplet methylene is evaluated as ca. 8 x lo8 S -1 from the data. -Methylene (CH2), the parent carbene, has been studied extensively by chemists, 1,2 spectroscopists, 3 and chemical physicists. 4,5 Its unique chemistry is primarily due to the substantially different chemical behavior of two low-lying electronic states,