Dual substituent parameter (DSP) analysis is applied to model substituent effects on 13C substituent chemical shifts (SCS) and νCO stretching frequencies in two series of α-enones with rigid cisoïd and transoïd conformations. The regression coefficients of DSP analysis for the 13C SCS of the conjugated systems are discussed in terms of the relative importance of the various mechanisms of transmission of electronic effects. The differences between the regression coefficients relative to the field and resonance effects for the cisoïd and transoïd systems reflect very well the variations of geometries between both series. Concerning the i.r. data, the DSP analysis leads to an apparently unprecedented observation since it appears that the stretching frequencies of the carbonyl group are more sensitive towards substituent effect in the aplanar cisoïd system than in the more planar transoïd system. This surprising result is discussed.
|Number of pages||14|
|Journal||Spectrochimica Acta Part A: Molecular Spectroscopy|
|Publication status||Published - Jun 1992|
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