Hammett spectral LFER of some antioxidant substituted benzylidene hydrazines

About nine (E)-(2,5-dinitrophenyl)-2-(substituted benzylidene)hydrazines have been synthesized by hydroxy apatite catalyzed condensation of 2,4-dinitrophenyl hydrazine and substituted benzaldehydes under microwave irradiation conditions. The obtained yields of these hydrazines are more than 85%. The purities of synthesized hydrazines are examined by the analytical and spectroscopic data reported earlier. The infrared spectral C=N, NH frequencies (v, cm-1) and the NMR spectral chemical shifts of CH, NH protons and carbons are assigned and are correlated with Hammett substituent constants, F and R parameter using single and multi-regression analysis. From the results of statistical analysis the effects of substituent on the group frequencies have been discussed. The antioxidant activities of these synthesized hydrazines were measured using DPPH radical scavenging method. The hydroxy- and methoxy- substituted hydrazines shows significant antioxidant activity.