C13–H and X—H Coupling Constants for Compounds of the Type X(CH3)4

Publisher Website
Google Scholar
Abstract
From high‐resolution proton magnetic resonance experiments, absolute magnitudes of JC13–H and JX–C–H have been determined for compounds of the type X(CH3)4, where X=Si, Ge, Sn, and Pb. The JC13–H values yield the s characters of the carbon orbitals in the C–H and C—X bonds as well as the Juan—Gutowsky s character affinity ΔX. Rough calculations of JX–C–H based on the Fermi contact term give widely varying results depending on the value of the effective charge used. A straight line correlation of JX–C–H with n3 can be explained crudely on the basis of the Fermi contact term.