A. Tazouti et al. / Journal of Molecular Liquids 221 (2016) 815–832
817
Table 1
The characteristics of the synthesized compounds.
Compounds
SQ
MOSQ
260
MOSMQ
253
Melting point
239
(
°C)
1
1
H RMN (300
7.29–7.50 (m, 6H, HAr), 7.63 (d, 1H, CH, CH
ethylenic, 3J = 16.5 Hz), 7.73–7.80 (m, 3H,
7.45 (s, 1H), 7.50 (d, 2H,3J = 8.4 Hz), 7.60 (d, 1H, CH 7.30–7.35 (m, 2H, HAr), 7.42 (m, 2H, HAr), 7.49–7.57
ethylenic, 3J = 16.2 Hz), 7.78 (d, 2H, 3J = 8.4 Hz), (m, 2H, HAr), 7.64 (d, 1H, CH ethylenic, 3J = 16.2 Hz),
MHz,
DMSO-d6) δ HAr), 8.08 (d, 1H, CH ethylenic, 3J = 16.5 Hz), 8.00 (s, 1H), 8.06 (d, 1H, CH ethylenic, 3J = 16.2 Hz), 7.81 (m, 1H, HAr), 7.98 (m, 1H, HAr), 8.45 (d, 1H, CH
ppm)
12.48 (s, 1H, NH) 12.64(s, 1H, NH). ethylenic, 3J = 16.2 Hz), 12.56 (s, 1H, NH)
C RMN (75.5 115.7, 122.4, 124.0, 128.1, 128.8, 129.0, 129.5, 112.55(2 × C), 115.56, 116.63,123.82, 124.05,128.29, 115.8, 124.1, 125.6, 127.9, 128.3, 129.1, 130.5, 130.7,
(
3
MHz,
DMSO-d6) δ 153.5, 155.3
ppm)
129.7, 129.9, 130.3, 132.1, 132.8, 136.4, 137.5, 129.27, 129.69 (2 × C), 131.73, 133.09, 138.25,
131.2, 132.3, 132.6, 132.7, 133.9, 134.2, 153.1, 155.2
151.59, 153.96, 155.36.
(
The calculate
elementary
analysis (%)
the percentage C 77.37, H 4.88, N 11.26
founded
values
C 77.40, H 4.87, N 11.28
C 73.37, H 5.07, N 10.07
C 67.97, H 3.92, N 9.91
C 67.78, H 3.80, N 9.74
m/z (M + H)+ = 293
C 73.17, H 5.08, N 10.09
Mass
spectroscopy
m/z (M + H)+ = 249
m/z (M + H)+ = 279
(
(
FAB
MNBA))
HCl solution with and without different inhibitor concentrations. All the
aggressive acid solutions were open to air. After 6 h of immersion, the
specimens were taken out, washed, dried, and weighed accurately.
The inhibition efficiency (ηWL%) and surface coverage (θ) were calculat-
ed as follows:
chemical hardness (η). According to them, mentioned these parameters
are given as [26,27]:
ꢀ
ꢁ
∂
E
χ ¼ −μ ¼ −
ð8Þ
ð9Þ
∂N υðrÞ
!
W −Wa
ꢀ
ꢁ
2
b
CR ¼
ð5Þ
ð6Þ
ð7Þ
1
2
∂μ
∂N
1
2
∂ E
At
η ¼
¼
2
υðrÞ
∂N
υðrÞ
ꢀ
ꢁ
wi
w0
ηWLð%Þ ¼ 1−
ꢀ 100
To calculate the chemical reactivity descriptors such as chemical
hardness, chemical potential and electronegativity, Pearson and Parr
derived the following equation by applying to Eqs. (8) and (9) [28].
θ ¼ 1− w
i
w0
I þ A
where W
in the tested solution, w
losses of mild steel in uninhibited and inhibited solutions, respectively,
A the total area of the mild steel specimen (cm ) and t is the exposure
b
and W
a
are the specimen weight before and after immersion
and w are the values of corrosion weight
χ ¼ −μ ¼
ð10Þ
ð11Þ
2
0
i
I−A
2
η ¼
2
time (h).
here, I and A are first vertical ionization energy and electron affinity
values of any chemical system, respectively.
2
.4. Computational details and equations
Koopman's theorem [29] provides an alternative method the
prediction of ionization energy and electron affinities of chemical spe-
cies. According to this theorem, the negative of the highest occupied
molecular orbital energy and the negative of the lowest unoccupied
molecular orbital energy corresponds to ionization energy and electron
affinity, respectively (−EHOMO = I and −ELUMO = A). As a result of this
theorem, chemical hardness, electronegativity and chemical potential
can be defined as:
In recent times, DFT methods are widely used the prediction of
chemical reactivity of molecules, clusters and solids. All computations
have been carried out with the Gaussian package program. For
calculations, B3LYP method, a version of the DFT methods, was used
and polarized basis sets such as 6-311G (d,p), 6-311++G (d,p), 6-
3
11G++ (2d,2p) were preferred. A full optimization was performed
up to a higher basis set denoted by 6-31G++ (d, p) because this
basis set gives more accurate results in terms of the determination of
geometries and electronic properties for a wide range of organic com-
pounds. The mentioned calculations were performed not only in the
gas phase but also in the hydrochloric acid medium. In addition to calcu-
lations made for neutral forms of studied compounds, required quan-
tum chemical parameters have been also calculated for the protonated
forms of them.
The aim of quantum physicists and chemists is obtain new
formulations for calculating of chemical reactivity indices and the
understanding of the nature of chemical interactions. Based on the
idea that the electron density is the fundamental quantity for describing
atomic and molecular properties, Parr and coworkers defined as
derivatives of the electronic energy (E) with respect to number of elec-
trons (N) at a constant external potential, υ(r) the chemical reactivity
indices such as chemical potential (μ), electronegativity (χ) and
ELUMO þ EHOMO
μ ¼ −χ ¼
ð12Þ
ð13Þ
2
ELUMO−EHOMO
η ¼
2
Global softness [30,31] is one of the most important reactivity
descriptors. This quantity is defined as the inverse of global hardness
and is given as:
ꢀ
ꢁ
1
∂N
∂μ
S ¼ η ¼ 2
ð14Þ
υðrÞ
Electrophilicity [32] that indicates the tendency of the inhibitor
molecule to accept electrons is an important parameter in terms of the