All correlations were done using KaleidaGraph software, Reading, PA, USA. All the chemical structures were drawn using chemdraw. The pKaH+ data is from different sources . All reaction constants (Hammett  and Taft *) are to be understood as positive values. All the loci of the plots in this article are with negative slope because the pKaH+ data is plotted against the substituent constants (Hammett  and Taft *).