Einige Aussagen über die Bindungseigenschaften von Silyl-, Germyl- und Stannylphosphinen auf der Grundlage ihrer 31P-NMR-Verschiebungen und zu deren Interpretation mit Hilfe der Theorie von Letcher und van Wazer

The ³¹P-NMR chemical shifts of silyl-, germyl- and stannylphosphines (R₃M)_n · PX_3–n (M = Si, Ge, Sn; R = H, CH₃, C₆H₅, C₄H₉; X = CH₃, C₆H₅ H) are discussed using the theory of LETCHER and VAN WAZER and the chemical shift increments of the R₃M-groups. It is shown that in both the GeP and the SnP bond (P(3p) → M(nd))π-interactions play an important role, which is not found for the SiP bond. The general applicability of the theory of LETCHER and VAN WAZER is critically considered.