Theoretical 1H(Se—H) NMR shifts in meta-substituted Ph—XH (X = O, S, Se)

A systematic comparative theoretical study has been performed on a series of fourteen metasubstituted selenophenols. The optimal geometries were calculated using the density functional theory (DFT) and the Nuclear Magnetic Resonance parameters were computed by applying the Gauge Including Atomic Orbital (GIAO) method. The calculated NMR shifts were correlated with the Hammett constants. The obtained results were also compared with the theoretical data obtained for thiophenols and phenols. Our results indicate the linear dependence between the gas-phase NMR shifts and Hammett constants. However, the presence of large selenium atoms is able to suppress significantly the substituent effect in meta position. Therefore six substituents (Me, OH, MeCO, COOMe, COOEt and CF3 groups) were excluded from the data evaluation. Correlations with the fundamental stretching vibration frequencies of the mode with the dominant Se-H vibration have not been found.