Synthesis and antioxidant activity screening of new poly (imide-sulfonate) S have Schiff base linkage

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“…The infrared spectra of the compound (5) illustrated the clear distinguishing absorption bands at 1764, 1716, and 1685 cm -1 which are belong to (C=O) ester, ʋ(C=O) imide, and ʋ(C=O) ketone, respectively. Likewise, the main absorption bands at 2943-2910 cm -1 due to C-H aliphatic groups, and band of (C≡N) group at 2241 cm -1 , further absorptions bands seemed at 1602-1630 cm -1 , 1452-1510 cm -1 , 1267 cm -1 , and 1078 cm -1 that are belong to ʋ (C=C) chalcone, ʋ (C=C) aromatic, asymmetric and symmetric ʋ (C-O-C) cm -1 , respectively [20,21]. 1 H-NMR spectrum of polymer (5) displayed a signal at δ = 1.36-2.34, δ = 3.35, and δ = 3.86 ppm which are due to (CH2) protons, (O=CCH3) protons, and (OCH3) protons, while signals fit to (C=C) aromatic protons seemed at δ = 6.88-8.1 ppm.…”

“…The spectrum also displayed the strong absorption bands at 1647-1672 cm -1 , 1589-1637 cm -1 , 1494-1545 cm -1 , and 1265-1280 cm -1 which recognized to carbonyl ketone, ʋ(C=C) chalcone, ʋ(C=C) ring, and ʋ(C-O), respectively, while the absorption bands owing to ʋ(C-O-C) seemed at 1232 cm -1 . 1 H-NMR spectrum of chalcone (1) showed a clear signal at δ=3.76 ppm belong to protons of O-CH3 group and signals at δ=7.95-8.56 ppm belong to (CH=CH-C=O) chalcon protons as well as the signals at 6.63-7.67 ppm fit to aromatic protons, while signals belong to O-H proton and NH amine proton seemed at δ=9.25 ppm and δ=6.02 ppm, respectively [20]. Infrared spectrum of amic acid (2) presented the presence of clear absorption bands at 3479 cm -1 , 3412-3429 cm -1 , and 3369-3400 cm -1 owing to ʋ(O-H) carboxyl, (O-H) phenolic, and (N-H) proving the success of compound (2) formation.…”