HETERONUCLEAR SPIN-SPIN COUPLING IN (CH2CH)(N)X VINYL COMPOUNDS

The proton magnetic resonance spectra of (CH2CH)4Si, (CH2CH)4Sn and (CH2CH)4Pb are analysed to give the indirect spin-spin coupling constants between protons and 13C, 29Si, 119Sn and 207Pb. Using the known absolute signs of the heteronuclear spin coupling constants in methyl- and ethyl-compounds and all available data on JXH in vinyl compounds (CH2CH)nX the absolutesigns of the normalized constants 2JXH '(gem), 3JXH' (cis) 3JXH' (trans)are deduced to be positive from a correlation of the values of heteronuclear coupling constants with the number of valence electrons of the nucleus X. © 1969.