The correlation analysis of Substituents effect on 13C NMR chemical shifts of E-2-(-4’-X-sbenzylidene)‎-1-indanones, -tetralones, -benzosuberones and Chalcones

Abstract EN

The P13PC Substituent Chemical Shifts (SCS) effect on (CRαR) CR2R, CR9aR, (CRβR) CR10R and CR1’R atoms for E-2-(-4’-X-benzylidene)-1-indanones, -tetralones,–benzosuberones and Chalcones (X = H, NMeR2R, OMe, Me, F, Cl, Br, CN, NOR2R) in CDClR3R solvent.

The effect was studied using two different types of substituent parameter: namely mono substituent parameter MSP (σP13P model, Hammett’s and the Brown-Okamoto models), and dual substituent parameters DSP (modified Swain-Lupton, Reynolds, Taft and modified Godfrey models).

Both MSP and DSP models reflected that the resonance effect contributes more on the chemical shift of (CRαR) CR2R, while inductive effects primarily affect the chemical shift of (CRβR) CR10R of the enone moiety of all the four series.

The latter effect, however, is far not as pronounced as that of the former one.

It is found that DSP model (ρRFR and ρRRR values) of P13PC SCS effect on CR2R can serve as a measure to study the conformation (or the planarity) of the investigated enones in the four series.

Finally, MSP and DSP models performance are performed.