The 2-imino-1,3-selenazolidine group bonded to phosphorus and silicon: a multinuclear magnetic resonance study

A tris(imino)phosphane (3), its sulfide [3(S)], an iminodiphenylphosphane ( 4), and an iminotrimethylsilane (5), in all of which the imino group belong s to a pseudo-ephedrine-derived 2-imino-1,3-selenazolidine ring, were prepa red and studied by multinuclear magnetic resonance (H-1, C-13, N-15, Si-29, P-31, Se-77 NMR). By application of various 1D and 2D NMR techniques, NMR parameters such as the isotope induced chemical shifts (1)Delta N-14/15 (P- 31) for 4, (1)Delta N-14/15(Si-29) for 5, numerous coupling constants and c hemical shifts could be obtained. The absolute sign of (1)J(Si-29,N-15) (>0 ) was determined for 5. The largest values so far for (3)J(Se-77,P-31) (198 .0 Hz in 3 and 194.0 Hz in 4) were observed, and the absolute sign of these coupling constants (3)J(Se-77 P-31) > 0 was determined, together with the signs of various other coupling constants involving Se-77 or P-31. Copyrigh t (C) 2001 John Wiley & Sons, Ltd.