Synthesis of novel Schiff Bases containing acryloyl moiety and the investigation of spectroscopic and electrochemical properties

Article abstract of DOI:10.1016/j.molstruc.2016.03.028

A novel Schiff bases and their acryloyl derivatives were synthesized through the reaction of p-hydroxybenzaldehyde in order of with aniline, p-chloroaniline, p-nitroaniline, p-methylaniline and p-aminobenzoic acid. The structures of these compounds were characterised spectroscopic techniques such of IR, ¹H NMR, ¹³C NMR and Mass spectroscopy. π→π?and n→π?transitions were determined via UV-vis spectroscopy studies performed in EtOH, CHCl_3, and DMF. Furthermore, the inhibition efficiencies of these new compounds were investigated on the surface of steel within the solution of 0.1 M NaCl, 0.1 M NaOH and 0.10 M H₂SO₄ solution via cyclic voltammetry and Tafel extrapolation methods.

Full text of DOI:10.1016/j.molstruc.2016.03.028

Accepted Manuscript
Synthesis of Novel Schiff Bases Containing Acryloyl Moiety and the Investigation of
Spectroscopic and Electrochemical Properties
Pakize Sılku, Sevil Özkınalı, Zeynel Öztürk, Abdurrahman Asan, D. Ali Köse
PII:
S0022-2860(16)30223-X
10.1016/j.molstruc.2016.03.028
MOLSTR 22339
DOI:
Reference:
To appear in: Journal of Molecular Structure
Received Date: 15 November 2015
Revised Date: 8 March 2016
Accepted Date: 9 March 2016
Please cite this article as: P. Sılku, S. Özkınalı, Z. Öztürk, A. Asan, D.A. Köse, Synthesis of Novel
Schiff Bases Containing Acryloyl Moiety and the Investigation of Spectroscopic and Electrochemical
Properties, Journal of Molecular Structure (2016), doi: 10.1016/j.molstruc.2016.03.028.
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ACCEPTED MANUSCRIPT

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Synthesis of Novel Schiff Bases Containing Acryloyl Moiety and the Investigation of
Spectroscopic and Electrochemical Properties
Pakize Sılku1, Sevil Özkınalı*1, Zeynel Öztürk2, Abdurrahman Asan2, D. Ali Köse1
1 Department of Chemistry, Faculty of Science and Literature, Hitit University, Çorum,
2 Department of Chemical Engineering, Faculty of Engineering, Hitit University, Çorum,
TURKEY
*Corresponding Author.
Tel.: +903642267000-1636;
Fax: +903642277005
e-mail: sevilozkinali@hitit.edu.tr
ABSTRACT
A novel Schiff bases and their acryloyl derivatives were synthesized through the reaction of
p-hydroxybenzaldehyde in order of with aniline, p-chloroaniline, p-nitroaniline, p-metilaniline
and p-aminobenzoic acid. The structures of these compounds were characterised
1
spectroscopic techniques such of IR, H-NMR, 13C-NMR and Mass spectroscopy. π→π* and
n→π* transitions were determined via UV-Vis spectroscopy studies performed in EtOH,
CHCl3, and DMF. Furthermore, the inhibition efficiencies of these new compounds were
investigated on the surface of steel within the solution of 0.1M NaCl, 0.1 M NaOH and 0,10
M H2SO4 solution via cyclic voltammetry and Tafel extrapolation methods.
Keywords: Schiff bases; acryloyl chloride; Tafel polarisation analysis; corrosion inhibition
Highlights
Novel Schiff bases containing acryloyl moiety were synthesised.
Structural characterizations were performed via IR, UV-Vis, and NMR spectroscopy.

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The inhibition efficiencies of these novel Schiff bases were investigated by cyclic
voltammetry and Tafel extrapolation methods.
These compounds may have a pioneer significance role in synthesizing novel organic
materials.
1. Introduction
Schiff bases are versatile molecules and have received much attention in many types
of research [1-2]. They are widely used in various fields, particularly as corrosion inhibitors,
dyes and pigments, and catalysts for activation of small molecules and also they have a fairly
large biological activities [2-6]. Structurally, a Schiff base (also known as imine or
azomethine) is a nitrogen analogue of an aldehyde or ketone in which the carbonyl group
(C=O) has been replaced by an imine or azomethine group [3]. Due to the presence of the –
C=N- group, an electron cloud on the aromatic ring, the electronegative nitrogen, and the
oxygen and sulphur atoms in the molecule, Schiff bases are considered as good corrosion
inhibitors [7]. Inhibitors are used to prevent metal dissolution and thus minimise the acid
consumption. Schiff bases are shown to have excellent corrosion inhibition efficiencies as
compared to those of the individual constituents [8-9]. Also, they are easily obtained from
cost-effective starting materials and harmless to the environment [10]. Despite a large number
of organic compounds, there is always a need for the development of new organic corrosion
inhibitors [7]. Generally, Schiff bases come into effect on a metal surface with adsorption [11-
12]. The corrosion inhibition efficiency depends on the electron density and polarizability of
the functional groups [13]. Both protonated and non-protonated functional groups form
intermediate bridges with the metal surface blocking the interactions between the metal
surface and corrosive ingredients [14]. The mechanism of corrosion inhibition on metals can
be clarified primarily using theoretical modelling and simulations. The highest occupied

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molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) calculations
indicate the mechanism of corrosion inhibition as well as the interactions with the metal
surface [15].
In this study, we have reported the synthesis of novel Schiff bases with imine (>C=N)
and acryloyl groups. The compounds have been synthesised in two stages. In the first stage,
Schiff bases were obtained by the reaction between various aniline derivatives with p-hydroxy
benzaldehyde at pH 5. In the second stage, the acryloyl derivatives of Schiff bases have been
obtained by the reaction of metallic sodium and acryloyl chloride under inert atmosphere
according to the Schotten-Baumann method.
The structural characterizations were performed by spectroscopic methods (IR, UV-
1
Vıs, H-NMR, 13C-NMR, and Mass). UV-VIS spectroscopy analyses were performed in a
variety of solvents with different polarity and pH values. Moreover, their inhibition
efficiencies were determined in basic and acidic media by cyclic voltammetry and Tafel
extrapolation methods. Synthesis of novel Schiff bases containing acryloyl moiety has never
been reported so far to the best of our knowledge.
2. Experimental
The melting points were determined using a digital melting point apparatus. The
spectrum was recorded on a Thermo Scientific Class 1 Laser Product FTIR spectrophotometer
via ATR. Absorption spectra in ethanol, chloroform, and DMF were determined using a
1
Thermo Scientific Genesys 10S UV-VIS spectrophotometer. Elemental, H-NMR, and 13C-
NMR analyses were performed in the Instrumental Analysis Laboratory of METU Central
Laboratory. All electrochemical measurements were performed in an Ivium Compactstat
Potentiostat/Galvanostat device through two scans. The syntheses were carried out in the
Organic Chemistry Laboratory, Science and Literature Faculty, Hitit University, and the

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inhibition activities were determined in the Research Laboratory, Engineering Faculty, Hitit
University.
2.1. The synthesis of acryloyl derivatives of Schiff bases.
In the first step, Schiff bases were prepared by the reaction between p-
hydroxybenzaldehyde and aniline, p-chloroaniline, p-nitroaniline, p-methylaniline, and p-
aminobenzoic acid separately in dry Toluene at 1:1 molar ratio as described in the literature
[2, 16-17]. In the second step, acryloyl derivatives of Schiff bases were synthesised by the
reaction of these compounds with metallic sodium, and then acryloyl chloride under N2
atmosphere at 1:1 molar ratio. The general reaction scheme and the structure of the related
compounds were shown in Figure 1.
2.1.1. Synthesis of (E)-4-((Phenylimino)methyl)phenol), 1
p-hydroxybenzaldehyde (1.22 g; 0,01 mol) and aniline (0.93 g; 0.91 mL) were dissolved in
dry Toluene of 35 mL. Glacial acetic acid was added dropwise to the solution obtained until
pH: 4-5 and then refluxed for 24 hours. The by-product (water) was removed by distillation in
order to increase the Schiff bases yield. The remaining solution was refluxed again for three
hours. The product precipitated by cooling solution to the room temperature. The reaction
medium was filtered and dried. The product was purified from ethanol/water to give the
present compound of m.p. 124-125 °C. Yield: 84 %. IR (cm-1): 3391-3121 (OH), 1573, 1514
(-C=C-), 1601 (HC=N-), 1283, 1241 (C-O). 1H-NMR (500 MHz, d6-DMSO, ppm): δ 10.19
(1H, s, ArOH), 8.44 (1H, s, N=CH, (H3), 7.79 (2H, d, Arbenz.(H2)), 7.37 (2H, t, ArAniline
13
(H5)), 7.21 (3H, d, ArAniline (H4, H6)), 6.94 (2H, d, Arbenz.(H1)). C NMR (500 MHz, d6-
DMSO, ppm): δ 161.2 (C1), 160.4 (C5, -CH=N), 152.5 (C6), 131.2 (C3), 129.9 (C8), 128.0
(C4), 125.8 (C9), 121.3 (C7), 116.2(C2).
2.1.2. Synthesis of (E)-4-((Phenylimino)methyl)phenyl) acrylate, 2

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4-((Phenylimino)methyl)phenol (1) (0.6405 g; 3.25 mmol) and fresh metallic sodium (74.77
mg; 3.25 mmol) in dry THF (30 mL) were mixed amd stirred under N2 atmosphere for 24 h.
Then acryloyl chloride (0.271 mL; 3.25 mmol) was directly added dropwise to the THF
solution of sodium salt of Schiff bases under dry nitrogen atmosphere. After 4 hours stirring,
the mixture was filtered and the desired product was precipitated out by evaporating the THF.
Afterwards, a pale yellow solid was recrystallized from THF-water. Yield: 64%, m.p.: 140-
142 ºC, IR (cm-1): 1773 (-C=O), 1629, 1584 (-C=C-), 1600 (-HC=N-), 1292, 1196, 1165 (C-
1
O). H-NMR (500 MHz, d6-DMSO, ppm): δ 8.44 (1H, s, N=CH, (H3)), 7.78 (2H, d,
Arbenz.(H2)) , 7.38 (2H, d, ArAniline (H5)), 7.20 (2H, d, ArAniline (H4)), 7.19 (1H, t, ArAniline
13
(H6)), 6.91 (2H, d, Arbenz.(H1)), 6.30 (1H, d, (H7)), 5.60 (2H, d, (H8, H9)) (CH2=CH-). C
NMR (500 MHz, d6-DMSO, ppm): δ 165.2 (C11 ) (>C=O); 160.5 (C5, -CH=N), 152.5 (C1),
149.9 (C6), 132.6 (C13), (CH2=CH-), 131.1 (C4), 129.7 (C8), 129.6 (C3), 127.8 (C12), 125.8
(C9), 121.3 (C7), 116.2 (C2) Anal. Calcd for C16H13O2N: C, 76.49; H, 5.17; N, 5.57 %.
Found: C, 75.87; H, 5,14; N, 5.12 %.
2.1.3. Synthesis of (E)-4-((4-Chlorophenylimino)methyl)phenol), 3
The procedure used for the synthesis of compound 1 was also used for the synthesis of
compound 3. Therefore, compound 3 was synthesised by using p-hydroxybenzaldehyde (1.22
g; 0.01 mol) and 4-chloroaniline (1.27 g; 0.01 mol) in dry Toluene (35 mL) at pH 4-5 and
purified using ethanol/water. m.p.: 184-185 °C. Yield: 82%. IR (cm-1): 3236-3180 (OH),
1586, 1514 (-C=C-), 1598 (HC=N-), 1288, 1250 (C-O), 1109 (C-Cl). 1H-NMR (500 MHz, d6-
DMSO, ppm): δ 10.18 (1H, s, ArOH), 8.45 (1H, s, N=CH, (H3)), 7.76 (2H, d, Arbenz.(H2)),
13
7.43 (2H, d, ArAniline (H5)), 7.23 (2H, d, ArAniline (H4)), 6.94 (2H, d, Arbenz.(H1)). C NMR
(500 MHz, d-DMSO, ppm): δ 161.3 (C1), 161.2 (C5, -CH=N), 151.2 (C6), 131.3 (C9), 129.9
(C3), 129.5 (C8), 127.7 (C4), 123.2 (C7), 116.4 (C2),
2.1.4. Synthesis of (E)-4-((4-Chlorophenylimino)methyl)phenyl) acrylate, 4

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The procedure used in the synthesis of compound 2 was also used in the synthesis of
compound 4. Therefore, compound 4 was synthesised using (E)-4-((4-Chlorophenylimino)
methyl) phenol), (3) (1.779 g; 8.26 mmol) and fresh metallic sodium (189.9 mg; 8.26 mmol)
in dry THF (40 mL) and acryloyl chloride (0.688 mL; 8.26 mmol) and the yellow product was
purified using THF-water. Yield: 79%, m.p: 144-145 ºC, IR (cm-1): 1749 (-C=O), 1662, 1627
1
(-C=C-), 1597 (-HC=N-) 1337, 1202, 1164 (C-O), 1089 (C-Cl). H-NMR (500 MHz, d6-
DMSO, ppm): δ 8.66 (1H, s, N=CH, (H3)), 8.01 (2H, d, Arbenz.(H2)), 7.48 (2H, d, ArAniline
(H5)), 7.35 (2H, d, Arbenz.(H1)), 7.30 (2H, d, ArAniline (H4)), 6.59 (1H, d, (H8)), 6.45 (1H, dd,
13
(H7)), 6.21 (1H, d, (H9)) (CH2=CH-). C NMR (500 MHz, d6-DMSO, ppm): δ 164.3 (C11)
(>C=O), 160.9 (C5, -CH=N); 153.2 (C1), 150.5 (C6), 134.5 (C4), 134.1 (C13), 130.8 (C9),
130.6 (C8), 129.6 (C3), 127.1 (C12), 123.3 (C7), 122.8 (C2) Anal. Calcd for C16H12O2NCl: C,
67.25; H, 4.20; N, 4.90 %. Found: C, 67.87; H, 4.01; N, 4.38 %.
2.1.5. Synthesis of (E)-4-((4-Nitrophenylimino)methyl)phenol), 5
The procedure used in the synthesis of compound 1 was also used in the synthesis of
compound 5. Therefore, compound 5 was synthesised using p-hydroxybenzaldehyde (1.22 g;
0.01 mol) and 4-nitroaniline (1.38 g; 0.01 mol) in dry Toluene (35 mL) at pH 4-5 and was
purified using ethanol/water. m.p.: 182-183 °C. Yield: 83%. . IR (cm-1): 3356 (OH), 1628
1
(HC=N-), 1600, 1585 (-C=C-), 1468 (-NO2), 1282, 1181 (C-O). H-NMR (500 MHz, d6-
DMSO, ppm): δ 10.60 (1H, s, ArOH), 9.77 (1H, s, N=CH, (H3)), 7.93 (2H, d, ArAniline (H5)),
7.73 (2H, d, Arbenz.(H2)), 6.94 (2H, d, Arbenz.(H1)), 6.69 (2H, d, ArAniline (H4)), 13C NMR (500
MHz, d-DMSO, ppm): δ 163.8 (C1), 163.2 (C3, -CH=N), 156.1 (C6), 136.2 (C9), 132.5 (C5),
128.9 (C4), 126.8 (C8), 116.3 (C7), 112.8 (C2).
2.1.6. Synthesis of (E)-4-((4-Nitrophenylimino)methyl)phenyl) acrylate, 6
The procedure used in the synthesis of compound 2 was also used in the synthesis of
compound 6. Therefore, compound 6 was synthesised using (E)-4-((4-nitrophenylimino)

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methyl) phenol), (5) (2.023 g; 8.27 mmol) and fresh metallic sodium (190.3 mg; 8.27 mmol)
in dry THF (40 mL) and acryloyl chloride (0.699 mL; 8.27 mmol) and the yellow product
purified using THF-water. Yield: 72%, m.p.: 114-115 ºC, IR (cm-1): 1744 (-C=O), 1693,1596
1
(-C=C-), 1627 (-HC=N-), 1468 (-NO2), 1295, 1281 (C-O), H-NMR (500 MHz, d-DMSO,
ppm): δ 8.66 (1H, s, N=CH, (H3)), 8.03 (2H, d, Arbenz.(H2)), 7.93 (2H, d, Arbenz.(H1)), 7.41
(2H, d d, ArAniline (H4)), 7.28 (2H, d, ArAniline (H5)), 6.59 (1H, d, (H8)), 6.44 (1H, m, (H7)),
6.20 (1H, d, (H9)) (CH2=CH-). 13C NMR (500 MHz, d6-DMSO, ppm): δ 164.3 (C11)
(>C=O), 163.3 (C5, -CH=N), 156.2 (C6), 153.7 (C1), 145.4 (C9), 134.7 (C13), 133.6 (C4),
131.6 (C3), 127.9 (C12), 126.9 (C8), 125.4 (C7), 122.4 (C2) Anal. Calcd for C16H12O4N2: C,
64.86; H, 4.05; N, 9.45 %. Found: C, 63.97; H, 3.93; N, 9.21 %.
2.1.7. Synthesis of (E)-4-((4-tolylimino)methyl)phenol), 7
The procedure used in the synthesis of compound 1 was also used in the synthesis of
compound 7. Therefore, compound 7 was synthesised using p-hydroxybenzaldehyde (1.22 g;
0.01 mol) and 4-methylaniline (1.07 g; 0.01 mol) in dry Toluene (35 mL) at pH 4-5 and
purified using ethanol/water. m.p.: 220-221 °C. Yield %81. IR (cm-1): 3291 (OH), 2919,
1
2861(-CH3), 1605, 1574 (-C=C-), 1605 (HC=N-), 1284, 1241,1162 (C-O). H-NMR (500
MHz, d6-DMSO, ppm): δ 10.18 (1H, s, ArOH), )), 8.46 (1H, s, N=CH, (H3), 7.74 (2H, d,
Arbenz.(H2) , 7.17 (2H, d, ArAniline (H4)), 7.12 (2H, d, ArAniline (H5)), 6.92 (2H, d, Arbenz.(H1)),
13
2.37 (3H, s, -CH3 (H6)). C NMR (500 MHz, d6-DMSO, ppm): δ 160.9 (C1), 159.6 (C5, -
CH=N), 149.8 (C6), 135.0 (C9), 130.9 (C3), 130.1 (C8), 128.1 (C4), 121.3 (C7), 116.1 (C2),
21.0 (C10), (-CH3)
2.1.8. Synthesis of (E)-4-((4-Tolylimino)methyl)phenyl) acrylate, 8
The procedure used in the synthesis of compound 2 was also used in the synthesis of
compound 8. Therefore, compound
8
was synthesised using (E)-4-((4-

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Tolylimino)methyl)phenol), (7) (1.7282 g; 8.19 mmol), fresh metallic sodium (188.0 mg; 8.19
mmol) in dry THF (40 mL) and acryloyl chloride (0.683 mL; 8.19 mmol) and the dark yellow
product was purified using THF-water. Yield: 86%, m.p.: 170-171 ºC, IR (cm-1): 2919, 2850
(-CH3), 1749 (-C=O), 1652, 1506 (-C=C-), 1599 (-HC=N-) 1202, 1164, 1138 (C-O). 1H-NMR
(500 MHz, d6-DMSO, ppm): δ 8.64 (1H, s, N=CH, (H3)), 7.98 (2H, d, Arbenz.(H2)), 7.34 (2H,
d, Arbenz.(H1)), 7.21 (2H, d, ArAniline (H5)), 7.19 (2H, d, ArAniline (H4)), 6.55 (1H, d, (H8)),
6.43 (1H, m, (H7)), 6.19 (1H, d, (H9)) (CH2=CH-), 2.37 (3H, s, -CH3 (H6)). 13C NMR (500
MHz, d-DMSO, ppm): δ 164.4 (C11), 159.1 (C5, -CH=N), 155.2 (C1), 152.8 (C6), 149.1
(C9), 135.9 (C13), 134.4 (C4), 130.3 (C8), 130.2 (C3), 127.9 (C12), 122.7 (C7), 121.5 (C2),
21.1 (C10), (-CH3) Anal. Calcd for C17H15O2N: C, 76.98; H, 5.66; N, 5.28 %. Found: C,
76.25; H, 5.38; N, 5.13 %.
2.1.9. Synthesis of (E)-4-(4-hydroxybenzylideneimino) benzoic acid, 9
The procedure used in the synthesis of compound 1 was also used in the synthesis of
compound 9. Therefore, compound 9 was synthesised using p-hydroxybenzaldehyde (1.22 g;
0.01 mol) and 4-methylaniline (1.37 g; 0.01 mol) in dry Toluene (35 mL) at pH 4-5 and
purified using ethanol/water. m.p.: 254-255 °C. Yield: 94%. IR (cm-1): 3411-2352 (OH), 1679
(-COOH), 1611 (HC=N-), 1587, 1561, 1518 (-C=C-), 1277, 1232, 1160 (C-O). 1H-NMR (500
MHz, d6-DMSO, ppm): δ 12.69 (1H, s, -COOH (H6)), 10.30 (1H, bs, ArOH), 8.43 (1H, s,
N=CH, (H3)), 7.96 (2H, d, ArAniline (H5)), 7.78 (2H, d, Arbenz.(H2)), 7.25 (2H, d, ArAniline
(H4)), 6.93 (2H, d, Arbenz.(H1)). 13C NMR (500 MHz, d6-DMSO, ppm): δ 167.6 (C10), (-
COOH), 161.9 (C1), 161.6 (C5, -CH=N), 156.4 (C6), 131.6 (C8), 131.1 (C3), 127.8 (C4),
127.7 (C9), 121.4 (C7), 116.2 (C2).
2.1.10. Synthesis of (E)-4-(4-hydroxybenzylideneimino) benzoic acid acrylate, 10
The procedure used in the synthesis of compound 2 was also used in the synthesis of
compound 10. Therefore, compound 10 was synthesised using (E)-4-(4-hydroxybenzylidene

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imino) benzoic acid, (9) (2.2273 g; 9.23 mmol), fresh metallic sodium (212.2 mg; 9.23 mmol)
in dry THF (40 mL) and acryloyl chloride (0.763 mL; 9.23 mmol) and the dark yellow
product was purified using THF-water. Yield: 64%, mp: 227-228 ºC, IR (cm-1): 3339-2547 (-
COOH), 1739 (-C=O), 1673, 1600 (-HC=N-), 1543, 1512 (-C=C-), 1266, 1205, 1163 (C-O),
1673 (-COOH). 1H-NMR (500 MHz, d6-DMSO, ppm): δ 12.74 (1H, s, -COOH (H6)), 8.64
(1H, s, N=CH, (H3)), 7.79 (2H, d, Arbenz.(H2)), 7.21 (2H, d, ArAniline (H5)), 7.19 (2H, d,
ArAniline (H4)), 6.94 (2H, d, Arbenz.(H1)), 6.55 (1H, d, (H8)), 6.43 (1H, m, (H7)), 6.19 (1H, d,
(H9)) (CH2=CH-). 13C NMR (500 MHz, d6-DMSO, ppm): δ 168.5 (C10), (-COOH), 166.9
(C11) (>C=O), 163.5 (C5, -CH=N), 143.0 (C6), 142.9 (C1), 132.0 (C13), 131.5 (C4), 130.4
(C3), 130.1 (C8), 128.4 (C9), 127.6 (C12), 118.6 (C7), 118.3 (C2) Anal. Calcd for
C17H13O4N: C, 69.15; H, 4.40; N, 4.74 %. Found: C, 68.92; H, 4.33; N, 3.92 %.
2.2. Electrochemical Measurements
The electrochemical measurements were carried out in a three-compartment Pyrex cell
with a separate compartment for the reference electrode connected to the main compartment
via a Luggin capillary. A saturated calomel electrode (SCE) was used as the reference
electrode and a platinum sheet as the counter electrode. The working electrode employed was
prepared using ST 304 steel (X5CrNi18-10). The working electrode was in the form of a rod
prepared in a cylindrical form and embedded in epoxy resin leaving an open surface area of
0.6 cm2.
The working electrode was mechanically polished using 1200 grit emery paper,
washed with double distilled water, and then placed in the test solution. The electrochemical
measurements were conducted after 30 minutes immersion time in an experimental solution
that ensure a dependable corrosion potential and a system in equilibrium.

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The potentiodynamic experiments were carried out at a scan rate of 2 mV s−1 and the
cyclic voltammograms were recorded at a scan rate 50 mV s−1 in between -1.7 V and -0.5 V
potential.
First, the solutions of Schiff bases synthesised in NaOH of 0.10 M with the
concentrations of 10, 25, 50 and 100 ppm were prepared. Then all electrochemical
measurements were performed at room temperature by using Ivium Compactstat (Eindhoven,
Netherlands) potentiostat/galvanostat. The measurements were run in each solution using ST
304 steel (X5CrNi18-10) as a working electrode, a platinum plate as a counter electrode, and
a calomel electrode as a reference. Cyclic voltammetry measurements were performed at a 50
mV/s scan rate and 10 mV data capture frequency in the range of -1.7 V /-0.5 V potential
values. The linear sweep measurements were performed in the same conditions and Tafel
polarisation transformations were calculated. At last, cycles of cyclic voltammograms and
Tafel polarisation curves were collected in the same graph for each Schiff base for different
concentrations of solutions for better comparison.
3. Results and Discussion
3.1. Spectral Analyses of Compounds
In the FT-IR spectra of the Schiff bases obtained by the reaction of p-
hydroxybenzaldehyde with aniline derivatives, the carbonyl stretching peak of p-
hydroxybenzaldehyde at 1663 cm-1 have disappeared and new peaks at 1628-1598 cm-1 and
1627-1597 cm-1 have appeared which are attributed to imine group of Schiff bases and their
acryloyl derivatives respectively. The stretching frequencies of the -OH groups of Schiff
bases with the compound numbers of 1, 3, and 7 were observed at ca. 3391-3121 cm-1 due to
the strong intramolecular hydrogen bonding [18-20]. The stretching frequencies of the -OH
groups of compound 5 were observed as a narrow peak at 3356 cm-1 for those with non-
intramolecular hydrogen bonding. For compound 9, the stretching frequencies of the -OH

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groups were observed at 3414-2352 cm-1 as very broad peaks, due to the carboxyl groups
which were observed in the same region. The middle and sharp absorptions at about 3180 cm-
1
in the IR spectra of Schiff bases are attributed to the vibration of the –NH groups [21-22].
The -OH group peak in the acryloyl derivative of Schiff bases (compound 2, 4, 6, and 8) was
not observed as expected, due to the esterification of the hydroxyl group with the acryloyl
chloride. For compound 10, the stretching frequencies of the -OH groups were observed at
3339-2547 cm-1 as very broad peaks due to the carboxyl groups. The acryloyl derivatives of
Schiff bases, characteristic stretching peak of the carbonyl groups of the acryloyl moiety was
observed as a very strong singlet absorption at 1773-1739 cm-1 [23-24]. For the Schiff bases
and their acryloyl derivatives, the strong band was determined in the 1628-1597 cm-1 and was
assigned to the stretching of imine groups. This peak was shifted slightly towards the lower
frequencies in the acryloyl derivatives [5, 25]. The other stretching bands appeared at 1693-
1506 cm-1 and 1337-1202 cm-1; 1241-1157 cm-1 in the spectrum of the compounds are
attributed to ethenyl (CH2=CH-) and aromatic –C=C-; -C(O)-O- and Ar-O, respectively, as
given in Section 2. In the IR spectra of Schiff bases, Ar-O stretching peaks were determined
in the same region by means of the –C(O)-O- stretching peak of acryloyl derivatives of Schiff
bases. The IR spectrum of the Schiff base 8 containing an acryloyl group was shown in Figure
2 as a typical example.
3.2. UV-Vis Spectral Analysis of the Compounds
The characteristic UV-Vis absorption bands of the compounds 1-10 were analysed and
investigated in different solvents like absolute ethanol, chloroform, and DMF, depending on
their solubility. Moreover, same analyses were also performed in DMF at pH=12 and pH=2.
The UV-Vis absorption bands related to the compounds 1-10 are given in Table 1. The bands
observed in the range of 250 to 300 nm were assigned to the B-bands of benzene which were

12
ACCEPTED MANUSCRIPT
common in all Schiff bases. The band at 380 nm was assigned to n→π* transitions related to
azomethine chromophore (-CH=N) [2, 19]. In UV-Vis spectra of the Schiff bases and their
derivatives in EtOH, the absorption maxima at 288-320 nm with a high extinction coefficient
is attributed to the π→π*. Furthermore UV-Vis spectra of the Schiff bases and their
derivatives in EtOH, the absorption maxima at 332-373 nm with a low extinction coefficient
are attributed to the n→π*. In addition, in EtOH all acryloyl derivatives (2, 4, 6, 8) except 9,
the bands of π→π* transitions were determined in hypochromic shifts at about 3-32 nm as
compared to the related Schiff bases (1, 3, 5 and 7) due to electron-withdrawing effect of
acryloyl groups. In DMF, it was observed that π→π* and n→π* transitions of the Schiff
bases and their acryloyl derivatives (1-10) show bathochromic shifts as compared to their
peaks in chloroform. These bathochromic shifts may be a consequence of the higher polarity
of DMF than that of chloroform as reported in the literature [2]. While in DMF at pH=2 the
Schiff bases and their acryloyl derivatives appear as having an absorption maxima similar
with that of DMF as seen in Table 2. Absorption maxima of all the compounds at pH=12
show bathochromic shifts about 19-189 nm as compared to that in DMF. However, at pH=12,
the absorption bands indicates that aqueous sodium hydroxide does not hydrolyse the Schiff
bases containing acryloyl groups.
The absorption maxima (λmax.,) for the compounds 1-10 were observed in ethanol at
288-320 nm and 332-373 nm, in chloroform at 292-304 nm and 308-349 nm, in DMF at 289-
321 nm and 321-383 nm, at pH=2 287-292 nm and at 384 nm, and at pH=12 288-317 nm and
336-503 nm. In these results, Schiff bases and their acryloyl derivatives appearing as
absorption maxima with a high extinction coefficient are attributed to the π→π* and n→π*.
The UV-Vis spectrum of the compound 6 can be seen in Figure 3.
3.3. NMR Spectral Analyses of the Compounds

13
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1
The H-NMR chemical shift values of the Schiff bases and their acryloyl derivatives
1
recorded in d6-DMSO are given in Table 2. The H-NMR spectrum of the Schiff base 8
containing an acryloyl group is shown in Figure 4 as a typical example. It was observed in the
1H-NMR Spectra of Schiff bases (1, 3, 5, 7, 9) that the hydroxyl protons resonated at 10.18-
10.60 ppm due to strong intramolecular hydrogen bonds. After esterification reaction, the
hydroxyl peak was not detected due to the lack of hydroxyl groups as expected (see Table 2
and Figure 4). A sharp singlet is observed within the 9.77–8.44 ppm region of the spectrum,
which corresponds to the azomethine (CH=N) proton. It is remarkable that the downfield
chemical shift (compound 5 H3= 9.77 ppm) corresponds to the azomethine proton of the p-
NO2 derivative (5), having has the highest electron affinity. After esterification of the Schiff
bases (2, 4, 8, 10) except p-NO2 derivative, protons of imine group shifted downfield due to
the electronic attractive effect of the acryloyl group. Thus, it can be concluded that the
position of the azomethine proton is strongly affected by the electronegative character of the
substituents on the phenyl ring as reported in the literature [26-27]. The peaks at 6.69- 8.28
ppm are attributed to aniline protons, and the peaks at 6.91-8.03 ppm are attributed
benzaldehyde protons. For acryloyl derivatives, phenyl groups’ protons were shifted to
downfield as compared to those of Schiff bases analogues. The resonance peaks of ethenyl
hydrogen atoms in acryloyl groups of the compounds 2-10 were identified as three different
groups (H7, H8, H9) at 5.60-6.59 ppm in good agreement with the literature [28-30]. The
peaks of the H7 in Z configuration with respect to the carbonyl group in an acryloyl moiety
were observed at 6.30-6.45 ppm as doublets and multiplets. On the other hand, the peaks of
the H9 in E configuration with respect to the carbonyl group were seen at 5.60-6.21 ppm as
doublets. For the H8, the related peaks were resonated at 6.47-6.59 ppm. In addition, the
binding of acryloyl groups was confirmed by the displacement and disappearance of the
hydroxyl signals.

14
ACCEPTED MANUSCRIPT
13
The C-NMR chemical shift values of the compounds 1-10 are summarised in Table
3. The spectrum of compound 8 is given in Figure 5. In the 13C-NMR spectrum of the
compound 8, it is clearly seen that the acryloyl group was successfully attached to the oxygen
of the hydroxyl group, the presence of >C=O group signal at 164.40 ppm prove this
phenomenon, which is in good agreement with the literature value [23-24]. The peaks
appearing at 127.93 ppm and 134.47 ppm in the spectra of the compound 8 are attributed to
=CH- and =CH2 fragments of the CH2=CH- group, respectively, as expected. These values are
in accordance with the literature [23-24]. The imine group peak (-CH=N), represented by C5
in Figure 5, was observed at 159.11 ppm. In the aromatic region, the peaks at 155.24, 134.43,
130.17, and 121.46 ppm are attributed to benzaldehyde carbon atoms C1, C4, C3 and C2,
respectively. The up field peaks at 152.83, 149.11, 130.30, and 122.71 ppm correspond to the
aniline group of the carbon atoms C6, C9, C8, C7, respectively. The peak appearing at 21.05
13
ppm in the spectrum of the compound 8 is attributed to the Ar-CH3 group. In the C-NMR
spectra of all acryloyl derivatives, C1 atoms bonded to the acryloyl groups were shifted
upfield and C4 atoms were shifted downfield compared to their Schiff bases analogues due to
the lack of hydroxyl group. There is no significant difference between aniline carbon atoms
peak shifts of Schiff bases and their acryloyl derivatives.
3.4 Mass Spectral Studies
The fragmentation pattern of the acryloyl derivative (6) is taken as a general scheme
showing the main fragmentation paths involved (Figure 6). The mass spectral pattern of
compound 6 shows a molecular ion peak (m/z 296.11) which is in good agreement with the
molecular weight of the compound 296.24 g/mol. [NO2-C6H4-N=CH-C6H4(OH2)+] ion gives
the characteristic peak of m/z 242.09 through the loss of CH2CHCO- fragment. The loss of
the [-O-C6H4-CH]+ fragment gives the strong peak at m/z 151.03 (25%). The peak observed at
m/z 105 results from the elimination of the nitro group from the phenyl group.

15
ACCEPTED MANUSCRIPT
The EI-MS of the acryloyl derivative (8) shows all the expected prominent peaks in
good agreement with previously proposed fragmentation paths for compound 6. In Figure 7,
the molecular ion peak appeared at m/z 265.04 (27%) is the molecular weight of the
compound 8, as 266.16 g/mol. The loss of an acryloyl group (CH2CHCO+) gives a strong
peak at m/z 211.12 (100%). The loss of CH=N and –CH3 fragments from the Schiff bases is
confirmed by the fragment at M-42 (m/z 120.06, 47%). The peak at m/z 91.05 (C6H5-CH2)+ is
attributed to a tropylium cation.
3.5 Polarisation measurements
Figure 8 represents potentiodynamic polarisation curves for a steel rod in a 0.1 M NaOH
solution in the absence and presence of various concentrations of compounds. As can be seen,
anodic reactions of steel are not inhibited in the presence of the inhibitor molecules. Thus, the
addition of these inhibitor molecules does not reduce the mild steel dissolution reaction. Table
4 shows the electrochemical corrosion parameters as the corrosion potential (Ecorr) and
corrosion rate obtained by extrapolation of the Tafel lines. Values of current corrosion density
icorr value were increased by the addition of the compound in 0.1 M NaOH. Corrosion
potential (Ecorr) shifted to negative potentials.
3.6. Corrosion Protection Analysis of Acrylates
Acrylates of compounds synthesised were tested for the protection corrosion in 0.10 M
NaOH for different concentrations of inhibitors. Selected concentrations were 10, 25, 50 and
100 ppm as compared to inhibitor-free solutions, 0 ppm. Corrosion protection, in the other
word, working electrode surface passivation was monitored with the cycle voltammograms
(CV) for the inhibitor, and in the same concentration. The first cycles of CV diagrams for
each inhibitor, in each concentration, are given in Figure 8. Frequently, reduction curves
(bottom left of CV) are not used for the comparison of corrosion protection, because reduction
peaks can be the result of the decomposition of an inhibitor. This is why the anodic side of

16
ACCEPTED MANUSCRIPT
curves was zoomed out for better comparison. It was found that increased concentration of all
inhibitors causes current resistance at the same potential. Moreover, at the negative current,
much more reduction was observed than that in oxidation reactions; this means that solved
inhibitor molecules were started to decompose. Compound 4 shows the difference in terms of
peak point’s order in the increased concentration of inhibitors at the same potential.
Linear sweep measurements and related Tafel polarisation transformation diagrams are
given in Figure 9. According to the diagrams, anodic lines have different slopes representing
different corrosion rates. The anodic and cathodic lines were used to calculate corrosion rate
in mm/year according to Tafel transformations from Tafel diagrams.
Model diagram fit model process was also used to calculate the corrosion rate and also
for the comparison with Tafel data. Different corrosion rate calculation methods are
represented in Figure 10, and other corrosion rates are given in Table 4. Tafel anodic and
cathodic lines selected manually while the intersection point in the corrosion potential line for
more accurate corrosion rate calculations. On the other hand, a fit model calculates corrosion
rate automatically for the model polarisation curve.
It is found that the Tafel and model data corrosion rates and potential calculation
results are all in a good correlation with each other. This is why only Tafel data is given in
Table 4. It is clear in Table 4 that these compounds do not work as an inhibitor in basic media
for compound 10. The corrosion rates of working electrodes in basic media for 25, 50 and 100
ppm for compound 10 are smaller than the rates in inhibitor-free NaOH solution. The
convenient compound is the compound 10 and the concentration was 25 ppm in NaOH
solution of 0.1 M for corrosion protection of the working electrode, X5CrNi18-10 steel.
Compound 6 was added at the concentrations of 10, 25, 50 and 100 ppm to the
solution of H2SO4 (0.10 M) to investigate corrosion inhibition ability of compounds in acidic
media. Interestingly, acrylate compounds have the ability to inhibit the corrosion of working

17
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electrodes in acidic solutions. According to Figure 9.f, slopes of anodic lines in acidic media
increases with the increasing concentration of compound 6. In other words, compound 6 is
able to protect ST 304 steel against corrosion in acidic media but not in basic media. The
order of protection, in other words, the corrosion rate is not linear with increasing amount of
inhibitor. The deviation could be explained with the interactions between inhibitor molecules
and the working electrode. The electrode surface could be blocked against current density
only at the optimum concentration of inhibitors. Additionally, a situation in which optimum
concentration is low or high could be explored using molecular simulation calculations. In
future works, we will investigate the inhibition ability of acrylates in NaCl and H2SO4 in
solutions with different concentrations. Moreover, the inhibition mechanism of acrylate
compounds will be explored.
4. Conclusion
In this study Schiff bases containing the acryloyl moiety have been synthesised
through a reaction between Schiff bases and acryloyl chloride at 1:1 molar ratio. The
1
13
structures of these compounds have been characterised via IR, UV-vis, H-NMR, C-NMR,
and mass spectroscopy techniques. In the IR spectra of the acryloyl derivatives, characteristic
stretching peaks of the carbonyl groups of the acryloyl moiety were observed as a very strong
singlet absorption band at 1773-1739 cm-1. The stretching frequencies of the -OH groups of
Schiff base compounds observed at ca. 3391-3121 cm-1 were attributed to hydroxyl groups
with hydrogen bonding. After esterification, the hydroxyl peaks were not observed as
expected. In UV-vis spectra, absorption maxima with a high extinction coefficient of Schiff
bases and their acryloyl derivatives were attributed to the π→π* and n→π*, respectively. 1H-
NMR spectra of the compounds in DMSO has showed a sharp singlet peak within the 9.77–
8.44 ppm region, corresponding to the azomethine (CH=N) proton. The mass spectra of the

18
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compound 6 and 8 show a molecular ion peak m/z 296.11 and m/z 265.04, respectively,
which are in good agreement with the molecular weight of the compounds. In inhibitory
studies, it was found that synthesised Schiff bases containing acryloyl moiety as inhibitors in
0.10 M NaOH do not work for the protection of steel against corrosion, but they have great
potential in acidic media. The addition of compound 6 into the solution of H2SO4 (10 M) gave
resistance ability to a working electrode against corrosion between 10 and 50% as compared
to inhibitor-free media.
To best of our knowledge, this report is the first example the use of Schotten-Baumann
reaction for the modification of Schiff Bases containing acryloyl moiety. This new Schiff
bases containing acryloyl moiety have potential applications in electrochemical technologies
especially, electrocatalytic, electrochromic, electro-sensing, and data storage applications.
Likewise, the investigation of corrosion efficiencies of these new Schiff bases in acidic media
is currently underway.
Acknowledgement
This study was supported by Hitit University’s Scientific Research Council with BAP
(Project No: FEF 04.11.005).
References
[1] E. İspir, The Synthesis, Characterization, electrochemical character, catalytic and
antimicrobial activity of novel azo-containing Schiff bases and their metal complexes,
Dyes and Pigments 82 (2009) 13-19.
[2] K.K. Upadhyay, A. Kumar, S. Upadhyay, P.C. Mishra, Synthesis, characterizaiton,
structural optimization using density functional theory and superoxide ion scavenging
activity of some Schiff Bases, Journal of Molecular Structure 873 (2008) 5-16.
[3] C.M. Silva, D.N. Silva, L.V. Modolo, R.B.Alves, M.A. Resende, C.V.B. Martins, A.
Fatima, Schiff Bases: A short review of their antimicrobial activities, Cario University

19
ACCEPTED MANUSCRIPT
Journal of Advanced Research, 2 (2011), 1-8.
[4] G. Ceylan, M. Köse, M. Tümer, İ. Demirtaş, A.Ş. Yağlioğlu, V. McKee, Structural
characterization of some Schiff bases compounds: Investigation of their
electrochemical, photoluminescence, thermal and anticancer activity properties, Journal
of Luminescence, 143 (2013) 623-634.
[5] H.M. Marwani, A.M. Asiri, S.A. Khan, Spectrophotometric and spectrofluorimetric
studies of novel heterocyclic Sciff base dyes, King Saud University Arabian Journal of
Chemistry, 7 (2014) 609-614.
[6] A.M. Asiri, S. A. Khan, H.M. Marwani, K. Sharma, Synthesis, spectroscopic and
physicochemical investigations of environmentally bening heterocyclic Schiff bases
derivatives as antibacterial agents on the bases of in vitro and density functional theory,
Journal of Photochemistry and Photobiology B: Biology, 120 (2013) 82-89.
[7] A.S. Patel, V.A. Panchal, G.V. Mudaliar, N.K. Shah, Impedance spectroscopic study of
corrosion inhibition of Al-Pure by organic Schiff base in Hydrochloric acid, King Saud
University Journal of Saudi Chemical Society, 17 (2013), 53-59.
[8] K. Mallaiya, R. Subramaniam, S.S. Srikandan, S. Gowri, N. Rajasekaran, A. Selvaraj,
Electrochemical characterization of the protective film formed by the unsymmetrical
Schiff’s base on the mild steel surface in acid media, Electrochimica Acta, 56, (2011)
3857-3863.
[9] Y.K. Agrawal, J.D. Talati, M.D. Shah, M.N. Desai, N.K. Shah, Schiff bases of
ethylenediamine as corrosion inhibitors of zinc in sulphuric acid, Corrosion Science, 46
(2004) 633-651.
[10] M. Lashgari, M.R. Arshadi, S. Miandari, The enhancing power of iodide on corrosion
prevention of mild steel in the presence of a synthetic-soluble Schiff-Base:
Electrochemical and surface analyses, Electrochimica Acta, 55 (2010) 6058-6063.

20
ACCEPTED MANUSCRIPT
[11] N.A. Negm, M.F. Zaki, Corrosion inhibition efficiency of non-ionic Schiff base
amphiphiles of p-aminobenzoic acid for aluminum in 4N HCl, Colloids and Surface A:
Physicochemical and Engineering Aspects, 322 (2008) 97-102.
[12] S. Issaadi, T. Douadi, A. Zouaoui, S. Chafaa, M.A. Khan, G. Bouet, Novel thiophene
symmetrical Schiff base compounds as corrosion inhibitor for mild steel in acidic
media, Corrosion Science, 53 (2011) 1484-1488.
[13] M.I. Mejeha, M.C. Nwandu, K.B. Okeoma, L.A. Nnanna, M.A. Chidiebere, F.C. Eze,
E.E. Oguzie, Corrosion inhibition and adsorption behaviour of leaf extracts of Aspilia
Africana on aluminium alloy AA 3003 in hydrochloric acid, Journal of Materials
Science, 47 (2012) 2559-2572.
[14] E.E. Oguzie, Influence of halide ions on the inhibitive effect of congo red dye on the
corrosion of mild steel in sulphuric acid solution, Materials Chemistry and Physics, 87
(2004) 212-217.
[15] E.E. Oguzie, C.E. Ogukwe, J.N. Ogbulie, F.C. Nwanebu, C.B. Adindu, I.O. Udeze,
K.L. Oguzie, F.C. Eze, Broad spectrum corrosion inhibition: Corrosion and microbial
(SRB) growth inhibiting effects of Piper guineense extract, Journal of Materials
Science 47 (2012)3592-3601.
[16] T.Tao, F. Xu, X. C. Chen, Q. Q. Liu, W. Huang, X.Z. You, Comparisons between azo
dyes and Schiff bases having the same benzothiazole/phenol skeleton: Syntheses,
crystal structures and spectroscopic properties, Dyes and Pigments, 92 (2012) 916-922.
[17] K. Nejati, Z. Rezvani, B. Massoumi, Syntheses and investigation of thermal properties
of copper complexes with azo-containing Schiff base dyes, Dyes and Pigments, 75
(2007) 653-657.
[18] H. Dinçalp, F. Toker, İ. Durucasu, N. Avcıbaşı, S. İçli, New thiophene-based azo
ligands containing azo methine group in the main chain for the determination of

21
ACCEPTED MANUSCRIPT
copper(II) ions, Dyes and Pigments, 75 (2007) 11-24.
[19] M. Usharani, E. Akila, R. Rajavel, Mixed Ligand Schiff Base Complexes: Synthesis,
Spectral Characterizaiton and Antimicrobial Activity, Journal of Chemical and
Pharmaceutical Research, 4(1) (2012) 726-731.
[20] A. H. Kianfar, M. Paliz, M. Roushani, M. Shamsipur, Synthesis, spectroscopy,
electrochemistry and thermal study of vanadyl tridentate Schiff bases complexes,
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 82 (2011), 44-
48.
[21] L.M. Kostochka, V.P. Lezina, Imine-enamine tautomerism of tropanone Schiff’s bases,
Chemistry of Heterocyclic Compounds, 30 (3) (1994) 335-359.
[22] N. Zhang, C.Y. Huang, D.H. Shi, Z.L. You, Unprecedented preparation of bis-Schiff
bases and their manganese (III) complexes with urease inhibitory activity, Inorganic
Chemistry Communications, 14 (2011) 1636-1639.
[23] S. Özkınalı, Spectroscopic and thermal properties of newly mixed azocalix[4]arene
ester derivatives, Dyes and Pigments, 107 (2014) 81-89.
[24] M.Gür, H. Kocaokutgen, Synthesis, spectral and thermal characterisation of some azo-
ester derivatives containing a 4-acryloyloxy group, Dyes and Pigments, 72 (2007) 101-
108
[25] A. Golcu, M. Tumer, H. Demirelli, R.A. Wheatley, Cd(II) and Cu(II) complexes of
polydentate Schiff Base ligands: Synthesis, characterization, properties and Biological
activity, Inorganica Chimica Acta, 358 (2005) 1785-1797.
1
13
[26] Y.M.Issa, H.B. Hassib, H.E. Abdelaal, H NMR, C NMR and mass studies of some
Schiff bases derived from 3-amino-1,2,4-triazole, Spectrochimica Acta Part A:
Molecular and Biomolecular Spectroscopy, 74 (2009) 902-910.
[27] R. Suresh, D. Kamalakkannan, K. Ranganathan, R. Arulkumaran, R. Sundararajan, S.P.

22
ACCEPTED MANUSCRIPT
Sakthinathan, S. Vijayakumar, K. Sathiyamoorthi, V. Mala, G. Vanagamudi, K.
Thirumurthy, P. Mayavel, G. Thirunarayanan, Solvent-free synthesis, spectrsl
correlations and antimicrobial activities of some aryl amines, Spectrochimica Acta Part
A: Molecular and Biomolecular Spectroscopy, 101 (2013) 239-248.
[28] H. Kocaokutgen, M. Gür, M.S. Soylu, P. Lönnecke, Spectroscopic, thermal and crystal
structure properties of novel (E)-2,6-dimethyl-4-(4-tert-butylphenyldiazenyl)phenyl
acrylate dye, Dyes and Pigments 67 (2005) 99-103.
[29] S. Özkınalı, H. Kocaokutgen, Synthesis, spectral characterisation and thermal
behaviours of some new p-tert-butylcalix[4]arene and calix[4]arene-esters containing
acryloyl groups, Journal of Molecular Structure, 1031 (2013) 70-78.
[30] R.M. Silverstein, F.X. Webster, Spectroscopic Identficationof Organic Compounds,
John Wiley&Sons, USA, 1997.

23
ACCEPTED MANUSCRIPT
CAPTIONS
Table 1.
Table 2.
Table 3.
Table 4.
The UV-VIS data of related compounds
1H-NMR data of the related compounds
13C-NMR data of the related compounds
Corrosion potentials and rates of working electrode in 0.10 M NaOH with
each concentration of compounds
Figure 1.
Figure 2.
Figure 3.
Synthesis of Schiff bases and their acryloyl derivatives
The IR spectrum for (E)-4-((4-Tolylimino)methyl)phenyl) acrylate (8)
The UV-Vis spectrum for Synthesis of (E)-4-((4-Nitrophenylimino)-
methyl)phenyl) acrylate (6), in CHCl3, EtOH, DMF, DMF (pH=1), DMF
(pH=12) 1.0x10-5 M
Figure 4.
Figure 5.
Figure 6
1H-NMR spectrum of the (E)-4-((4-Tolylimino)methyl)phenyl) acrylate, 8
13C-NMR spectrum of the (E)-4-((4-Tolylimino)methyl)phenyl) acrylate, 8
The mass spectrum and fragmentation pattern of (E)-4-((4-
Nitrophenylimino)-methyl)phenyl) acrylate (6)
Figure 7
Figure 8
Figure 9.
The mass spectrum and fragmentation pattern of (E)-4-((4-
Tolylimino)methyl)phenyl) acrylate (8)
CV diagrams at 0, 10, 50 and 100 ppm concentration of (a); compound 2,
(b); compound 4, (c); compound 6, (d); compound 8 and (e); compound 10.
Tafel polarisation curves on 0, 10, 25, 50 and 100 ppm concentrations of (a);
compound 2, (b); compound 4, (c); compound 6, (d); compound 8, (e); compound
10 and (f); compound 6 at H2SO4 solution.
Figure 10
Corrosion rate calculation diagrams of 100 ppm compound 2, (a); Tafel

24
ACCEPTED MANUSCRIPT
polarisation technique and (b); fit model technique

1
ACCEPTED MANUSCRIPT
TABLES
Table 1. The UV-VIS data of related compounds 1-10
Wavelength [λmax (nm)][logε (L/mol.cm)]
Compounds
CHCl3
EtOH
DMF
pH 1-2
(DMF)
292 (4.32)
pH 12
(DMF)
293 (4.38)
311o (4.34)
307 (4.30)
293 (4.25)
328 (3.26)
377 (2.96)
302 (3.94)
347 (4.47)
1
297 (4.16)
308o (4.14)
289 (3.46)
294 (4.20)
326° (3.68)
291 (4.29)
290 (4.40)
311 (4.00)
378 (4.31)
2
3
297 (4.38)
295o (4.29)
319 (4.34)
301o (4.48)
321 (4.52)
306o (4.11)
348 (4.56)
385o (4.11)
304 (3.27)
331o (3.16)
290 (4.13)
332o (3.58)
314 (3.08)
289 (3.56)
299 (4.11)
336 (3.96)
408o (3.47)
503 (3.56)
4
293 (4.15)
349 (4.44)
291 (4.16)
370 (4.07)
293 (4.41)
383 (4.30)
291 (4.55)
384 (4.26)
309o (4.18)
348 (4.86)
383o (4.27)
5
6
7
8
345 (4.47)
288 (3.95)
373 (4.31)
383 (4.52)
287 (4.25)
384 (4.47)
351 (4.55)
460 (4.05)
489o (3.85)
293 (4.45)
322 (4.45)
312 (4.14)
320 (4.40)
293 (4.19)
339 (3.55)
291 (4.28)
288 (4.00)
303 (3.88)
351 (4.36)
377 (4.22)
292 (3.89)
322 (3.87)
288 (3.46)
289 (3.36)
288 (4.13)
317o (4.03)
375 (4.14)
452o (3.41)
297° (3.63)
326 (3.72)
290 (4.52)
296 (4.57)
293 (4.51)
291 (4.50)
292 (4.57)
291 (4.62)
335o(4.13)
9
294 (3.42)
292 (4.38)
297 (4.33)
290 (4.47)
346 (4.69)
10

ACCEPTED MANUSCRIPT
2
1H-NMR data of the related compounds
Table 2
7
H
O
O
1
1
2
2
1
2
8
4
4
5
3
H
4
5
3
6
R
H
O
6
R
N
H
9
N
1
2
5
4
5
R=H (1), CI (3), NO2 (5), CH3 (7), COOH (9)
R=H ( ), CI (4), NO ( ), CH ( ), COOH ( )
6
2
8
3
10
2
-OH
R Group
Benzaldeyhe
Aniline Phenyl
Group
N=CH
Acryloyl Group
Phenyl Group
Compound
H6
H2
H1
H5
H4
H3
H7
H8
H9
10.19 (s)
-
8.44 (s)
8.44 (s)
8.45 (s)
7.79 (d)
7.78 (d)
7.76 (d)
6.94 (d) 7.37 (t)
6.91 (d) 7.38 (d)
6.94 (d) 7.43 (d)
7.21 (d)
7.20 (d)
7.23 (d)
7.21 (d)
-
-
-
1
2
3
7.19 (t)
-
6.30 (d)
-
6.53 (d)
-
5.60 (d)
-
10.18 (s)
-
8.66 (s)
8.01 (d)
7.35 (d) 7.48 (d)
7.30 (d)
-
6.45 (d,d)
6.59 (d)
6.21 (d)
4
10.60 (s)
-
9.77 (s)
8.66 (s)
8.46 (s)
7.73 (d)
8.03 (d)
7.74 (d)
6.94 (d) 7.93 (d)
7.93 (d) 8.28 (d)
6.92 (d) 7.12 (d)
6.69 (d)
7.41(d,d)
7.17 (d)
-
-
-
-
-
5
6
7
6.44 (m)
-
6.59 (d)
-
6.20 (d)
-
10.18(s)
2.37(s)
-
8.64 (s)
8.43 (s)
8.44 (s)
7.98 (d)
7.34 (d) 7.21 (d)
7.19 (d)
2.31 (s)
6.43 (m)
6.55 (d)
6.19 (d)
8
10.30(bs)
-
7.78 (d)
7.79 (d)
6.93 (d) 7.96 (d)
6.94 (d) 7.90 (d)
7.25 (d)
7.75 (d)
12.69(bs)
12.74 (s)
-
-
-
9
6.32 (d)
6.47 (m)
5.82 (d)
10

ACCEPTED MANUSCRIPT
3
Table 3. 13C-NMR data of the related compounds
O
O
12
2
2
3
3
1
2
11
4
4
5
5
8
8
1
7
7
4
3
13
6
R
H
O
10
6
9
N
N
R
1
2
5
R=H (2), CI (4), NO2 (6), CH3 (8), COOH (10)
R=H (1), CI (3), NO2 (5), CH3 (7), COOH (9)
Acryloyl Group
C13 C12
R
>C=0
C11
-CH=
C5
Benzaldehyde Phenyl Group
Aniline Phenyl Group
C9 C8 C7
Compound
1
C10
C1
161.15
C4
C3
C2
C6
-
160.42
128.00
131.14
127.74
134.48
128.87
133.64
128.08
134.43
127.81
131.51
131.18 116.15
129.60 116.18
129.98 116.14
129.60 122.78
132.53 112.83
131.64 122.38
130.99 116.07
130.17 121.46
131.09 116.21
130.38 118.32
152.47 125.78 129.96 121.34
149.90 125.77 129.69 121.33
151.22 131.32 129.50 123.16
150.54 130.77 130.55 123.34
156.11 136.16 126.83 116.28
156.15 145.42 126.85 125.44
149.79 135.03 130.09 121.26
152.83 135.94 130.30 122.71
156.42 127.65 131.55 121.36
143.00 128.36 130.09 118.61
-
-
-
165.2
160.52
161.21
160.91
163.22
163.26
152.46
161.31
153.15
163.78
153.65
132.60
127.77
-
2
3
-
-
-
-
164.34
134.10
127.12
-
4
-
-
-
-
5
164.34
-
134.56
-
127.87
-
6
159.57 160.93
-
21.02
21.05
167.61
168.48
7
164.40
-
159.11
161.56
163.48
155.24
161.86
142.90
135.91
-
127.93
-
8
9
166.90
132.03
127.60
10

4
ACCEPTED MANUSCRIPT
Table 4. Corrosion potentials and rates of working electrode in 0.10 M NaOH with
each concentration of compounds
Compound
Concentration
Ecorr. (V)
2
2
2
2
4
4
4
4
10
25
50
100
10
25
50
100
-1,14
-1,17
-1,075
-1,143
-1,205
-1,152
-1,13
-1,099
Corr. R (mm/y)
Compound
Concentration
Ecorr. (V)
0,425
6
0,165
6
0,186
6
0,26
6
0,538
8
0,159
8
0,104
8
0,148
8
10
25
50
100
10
25
50
100
-1,17
-1,12
-1,122
-1,056
-1,184
-1,049
-1,09
-1,082
Corr. R (mm/y)
Compound
0,194
10
0,195
10
0,129
10
0,194
10
0,146
0,167
0,097
0,143
-
0
10
25
50
100
Concentration
Ecorr. (V)
-1,19
-1,182
-1,138
-1,223
-11,25
Corr. R (mm/y)
0,187
0,012
0,028
0,019
0,123