The Molecular Structure of Allenes and Ketenes, XI Semiempirical Calculations of 1H-Chemical Shifts of Allenes

A comparison between calculated and observed values demonstrates that “ansätze” derived from an algebraic model in connection with appropriate boundary conditions are able to account for a quantitative description of the proton chemical shifts of allenes. Correlations of the proton chemical shifts with other NMR data, such as 13C-chemical shifts and one-bond carbon-proton coupling constants, reveal some insigths into the nature of the 1H substituent chemical shifts of alienes.