Nuclear magnetic resonance study of sulphur diimides bearing the Di-tert-butylphosphinyl substituent—application of Hahn-echo extended pulse sequences
✍ Scribed by Bernd Wrackmeyer; Silke Gerstmann; Max Herberhold
- Publisher
- John Wiley and Sons
- Year
- 1993
- Tongue
- English
- Weight
- 495 KB
- Volume
- 31
- Category
- Article
- ISSN
- 0749-1581
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✦ Synopsis
Abstract
Sulphur diimides of the type BuP(NSN)R′ [R′ = PBu (1), Bu^t^ (2), SiMe~3~ (3), SiPh~2~Me (4), SiMe~2~Bu^t^ (5), SiPh~2~Bu^t^ (6), SiBuH (7), Si~2~Me~5~ (8), GeMe~3~ (9), SnMe~3~ (10), SnBu~3~ (11), SnPh~3~ (12)] and Bu(E)P(NSN)R′ [R′ = Bu^t^, E = S, Se [2(S), 2(Se)]; R′ = SiPh~2~Bu^t^, E = S, Se [6(S), 6(Se)]] were studied by solution‐state ^15^N and ^31^P NMR in order to obtain information on their preferred configuration in solution. Hahn‐echo extended (HEED) pulse sequences served for measuring coupling constants ^1^J(^31^P ^15^N) from ^31^P NMR spectra, giving at the same time isotope‐induced chemical shifts ^1^Δ ^15/14^N(^31^P) with ^15^N at natural abundance. Chemical shifts δ ^15^N are sensitive towards substituents in E‐ (deshielding) and Z‐positions (shielding). All NMR data indicate that most compounds are fluxional, at least at room temperature, with respect to interconversion of configurational isomers (E/E, E/Z, Z/E). The consistent NMR data suggest that the BuP group prefers the E‐position. Solid‐state ^31^P and ^15^N cross‐polarization magic angle spinning NMR spectra of 1 and 7 support the assumption of different structures in solution and in the solid state, in accord with the assumed fluxional behaviour in solution.