New perthiophosphonic acid anhydrides (R-PSJ, with R = 2,4,6-tri-isopropyIphenyI and 2,4-di-tert-butyl-6-methylphenyl haw been prepared. For the latter case, the isolation of the monomer (n = I ) , the 2,4-di-tertbutyl-6-methyIphe~zyI-dithioxophosphorane, and both dimers (n = 2), cis-and trans-2,4-b
Study of the monomer-dimer equilibrium of nitrosobenzene using multinuclear one- and two-dimensional NMR techniques
✍ Scribed by Keith G. Orrell; Vladimir Šik; David Stephenson
- Publisher
- John Wiley and Sons
- Year
- 1987
- Tongue
- English
- Weight
- 467 KB
- Volume
- 25
- Category
- Article
- ISSN
- 0749-1581
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✦ Synopsis
The monomer-dimer equilibrium of nitrosobenzene in CDCl, solution was studied in the temperature range -50 to 30 "C using "C, 15N and "0 NMR spectroscopy. Decreasing temperature favours the dimeric azodioxy species, and below ca 10 "C both cis and trans dimers were detected in addition to the monomer. The relative abundance of the trans dimer is low (<6%) at all temperatures and this is the first report of its existence in solution. The monomer and dimer species were characterized by their I3C and I5N shifts, and exchange between them was measured quantitatively by I3C 2D-EXSY spectra. Exchange occurred exclusively between the cis-dirner and monomer and between the trans-dimer and monomer, activation energies, AG'(298.15 K) being 65.8k 0.1 and 70.0k0.3 kJ mol-', respectively.
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