Unsymmetrisch substituierte Phosphinoschwefeldiimide – NMR-Untersuchungen über die Konfiguration in Lösung/ Unsymmetrically Substituted Phosphino Sulfur Diimides – NMR Studies on the Configuration in Solution

Abstract

Abstract The phosphino-substituted sulfur diimides S(N-PtBu2)2 (1), tBu;P(NSN)PRR′ (R = R′ - phenyl (2a), cyclohexyl (2b), isopropyl (2c), ethyl (2d); R = phenyl, R′ = tert-butyl (2e)) and tBu2P(NSN)tBu (3) were studied in solution by 1H, 13C and 31P NMR spectroscopy**. The coupling constants 4J(31P31P) of the compounds containing different phosphino groups, 2a-e, depend both on the nature of the solvent and the temperature. The NMR results are interpreted in accord with a rapid Z/E⇄ E/Z interconversion at room temperature and the predominance of a single configurational isomer at low temperatures. There is no indication for the presence of the “symmetrical” configurations, Z/Z or E/E respectively, in solution in appreciable amounts. 15N NMR data are also reported for a series of sulfur diimides.