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Nuclear magnetic resonance study of sulphur diimides bearing the Di‐ tert ‐butylphosphinyl substituent—application of Hahn‐echo extended pulse sequences
Author(s) -
Wrackmeyer Bernd,
Gerstmann Silke,
Herberhold Max
Publication year - 1993
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260310515
Subject(s) - chemistry , chemical shift , substituent , nmr spectra database , stereochemistry , crystallography , nuclear magnetic resonance spectroscopy , spectral line , resonance (particle physics) , magic angle spinning , proton nmr , nuclear magnetic resonance , atomic physics , physics , astronomy
Sulphur diimides of the type Bu 2 t P(NSN)R′ [R′ = PBu 2 t(1), Bu t (2), SiMe 3 (3), SiPh 2 Me (4), SiMe 2 Bu t (5), SiPh 2 Bu t (6), SiBu 2 r H (7), Si 2 Me 5 (8), GeMe 3 (9), SnMe 3 (10), SnBu 3 (11), SnPh 3 (12)] and Bu 2 t (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 Bu 2 t P 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.