Interpretation of isomer shift-quadrupole splitting correlations for pentacoordinate trimethyltin complexes

Linear correlations between ¹¹⁹Sn isomer shifts δ and quadrupole coupling constants e²qQ are noted for several series of pentacoordinate trimethyltin derivatives. The sign of the gradient of a δ versus e²qQ plot is interpreted as indicating whether the predominant effect on δ in a given series arises from rehybridization of the tin bonding orbitals or from a p-electron deshielding mechanism. Differences in magnitudes of the slopes are related to differences in the fractional s-character of the bonds between tin and the axial substituents.