Isotope 13/12C effects on 119Sn nucleus shielding in ethynylstannanes

Abstract Isotope shifts in 119 Sn NMR spectra caused by the replacement of 12 C by 13 C in the acetylenylstannanes (CH 3 ) 3− n (t-C 4 H 9 ) n SnC α C β X were shown to be interrelated as indicated by a set of correlations between individual isotope shifts. Linear correlations were found between isotope shifts and the coupling constants n J ( 119 Sn- 13 C). The different best-fitting lines observed for compounds with n = 0-3 as well as for (R′CH 2 ) 3 Sn derivatives are explained by hyperconjugation.