Magnetic double resonance studies of 119Sn chemical shifts in organotin compounds

Tin-119 chemical shifts in 59 organo-tin compounds have been obtained by 1H–{119Sn} double-resonance experiments. This technique offers considerable advantages in precision and sensitivity over the conventional method. Correlations with electronegativity of the groups attached to tin are noted, and it is concluded that the pπ–dπ overlap may be important in halogen compounds. Dispersion forces also appear to affect the shifts when bulky polarizable groups are present. High-resolution INDOR spectra are presented, and are used to confirm certain structures, and to estimate otherwise inaccessible couping constants.