Evaluation of New Substituent Parameters to Explain 13C Chemical Shift for para-Substituents in Benzene Ring

Department of Chemistry, Sambalpur University, Jyoti Vihar, Burla-768 017

The ¹³C chemical shift data of 1,4-disubstituted benzenes have been used to evaluate para-substituent constants (\(\alpha^4_X\)and\(\beta^4_X\)) and their applicability has been examined in 39 different sets of data. These parameters have been found highly suitable to correlate the ¹³C chemical shifts of aromatic, aliphatic and Heterocyclic systems.