Evaluation of Corrosion Inhibition Efficiency of Aluminum Alloy 2024 by Diaminostilbene and Azobenzene Schiff Bases in 1 M Hydrochloric Acid

Table 2

((FT-IR), ¹H NMR), molecular formula, and melting point data of SDS and SDA.

No.	Diamines	IR and ^1H NMR data
(1)	N,N-bis(Salicylidine)-4,4-diaminostilbene (SDS); Molecular formula: C28 H22 N2 O2; Molecular mass: 418.28 g/Mol; Melting point: 240-244°C	IR/ν (KBr) cm^-1: 3320-3500, 2940-2990, 1605, 1150, 1130; ^1H NMR (DMSO-d6, 500 MHz) δ (ppm): 13 (s, 2H), 8.5 (s, 2H), 7-7.9 (m, 16H), and 6.8 (d, 2H). MS (EI, m/z): 418 (M+, 7) and 392 (11)
(2)	N,N-bis(Salicylidine)-4,4-diaminoazobenzene (SDA); Molecular formula: C26 H20N4 O2; Molecular mass: 420.26 g/Mol; Melting point: >300°C	IR/ν (KBr) cm^-1: 3310-3450, 3030, 1609, 1170, and 1150; ^1H NMR (DMSO-d6, 500 MHz), δ (ppm): 13.31 (s, 2H), 8.73 (s, 2H), 8.07 (d, 4H), 7.42(m, 4H), 7.36 (m, 2H), 7.27 (q, 4H), and 6.22 (t, 2H). MS (EI, m/z): 420 (M+, 40) and 392 (18).