Indirekte Kernspinkopplung zwischen Protonen und Elementen der IV. Gruppe

Abstract

The indirect spin-spin coupling between protons and Ge73, spin 9/2, in the tetraedric molecule GeH4 has been measured. JGe-H = 97,6 Hz. Introducing the normalized coupling constant J′ which is obtained by dividing the measured coupling constant by the product of the magnetogyric ratios of the coupling nuclei, a strong correlation is found between this quantity for XH4 (X = C, Si, Ge, Sn, Pb) and the electron density of the valence electron at the nucleus obtained from HARTREE-FOCK calculations or experimental atomic data. This demonstrates that at least in these cases the FERMI contact contribution is dominant. For the analogeous tetramethyl compounds the same relation holds only to the extend that the C - H coupling in the methyl group is constant.