Synthesis and XRD of neutral NiL complex using unsymmetrical ONNO tetradentate schiff base: Hirschfeld, spectral, DFT and thermal analysis

Article abstract of DOI:10.1080/00958972.2020.1762870

The unsymmetrical tetradentate ONNO Schiff base 6,6’-((1E,1’E)-((2-methylpropane-1,2-diyl)bis(azanylylidene))bis(methanylylidene))bis(2,4-di-tert-butylphenol) (H₂L) was prepared following a slightly modified known condensation reaction. The neu

Full text of DOI:10.1080/00958972.2020.1762870

Journal of Coordination Chemistry
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Synthesis and XRD of neutral NiL complex using
unsymmetrical ONNO tetradentate schiff base:
Hirschfeld, spectral, DFT and thermal analysis
Musa A. Said, Hamza A. Qasem, Seraj O. Alzahrani, Abdelkader Zarrouk &
Ismail Warad
To cite this article: Musa A. Said, Hamza A. Qasem, Seraj O. Alzahrani, Abdelkader Zarrouk
& Ismail Warad (2020): Synthesis and XRD of neutral NiL complex using unsymmetrical ONNO
tetradentate schiff base: Hirschfeld, spectral, DFT and thermal analysis, Journal of Coordination
Chemistry, DOI: 10.1080/00958972.2020.1762870
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JOURNAL OF COORDINATION CHEMISTRY
https://doi.org/10.1080/00958972.2020.1762870
Synthesis and XRD of neutral NiL complex using
unsymmetrical ONNO tetradentate schiff base:
Hirschfeld, spectral, DFT and thermal analysis
Musa A. Saida, Hamza A. Qasema, Seraj O. Alzahrania, Abdelkader Zarroukb and
Ismail Waradc
aDepartment of Chemistry, Faculty of Science, Taibah University, Al-Madinah Al-Munawarah, Saudi
b
Arabia; Laboratory of Materials, Nanotechnology and Environment, Faculty of Sciences, Mohammed
c
V University, Agdal-Rabat, Morocco; Department of Chemistry and Earth Sciences, Qatar University,
Doha, Qatar
ABSTRACT
ARTICLE HISTORY
Received 28 December 2019
Accepted 5 April 2020
The unsymmetrical tetradentate ONNO Schiff base 6,6’-((1E,1’E)-
((2-methylpropane-1,2-diyl)bis(azanylylidene))bis(methanylylide-
ne))bis(2,4-di-tert-butylphenol) (H2L) was prepared following a
slightly modified known condensation reaction. The neutral NiL
complex has been synthesized in high yield via [1H2L:1Ni(II)] dir-
ect addition. The XRD-measurement reflects a NiII center with
slightly distorted square planar geometry. Moreover, the lattice is
stabilized by a number of H-bond and H … p stacking interac-
tions. The structure connections have been illustrated by electro-
static potential surface (Molecular Electrostatic Potential, MEP)
and Hirschfeld surface (HSA) and Fingerprint (FP) analysis to sup-
port such interactions. IR and UV-visible spectra were measured
to compare free H2L with NiL behaviors. The DFT-optimized structure
was compared to the XRD-structure parameters. NiL reflects high ther-
mal stability and decomposed mainly via one-step to form NiO as the
final product.
KEYWORDS
Ni-Complex; XRD; ONNO
ligand; HSA; MEP; DFT;
thermal analysis
CONTACT Ismail Warad
ismail.warad@qu.edu.qa
Department of Chemistry and Earth Sciences, Qatar
University, PO Box 2713, Doha, Qatar
Supplemental data for this article is available online at https://doi.org/10.1080/00958972.2020.1762870.
ß 2020 Informa UK Limited, trading as Taylor & Francis Group

2
M. A. SAID ET AL.
1. Introduction
There is a huge number of reports on Schiff bases (S.Bs) and their transition metal
complexes including tetradentate S.Bs with ONNO type of ligands [1–5]. This is
because S.B metal complexes are becoming increasingly important as antimicrobial
agents and involved in the biochemical basis for the role of extensive effects of met-
als, e.g. zinc in cell division [6–12]. A motivating fact about S.Bs is that they can be
easily obtained under mild reaction conditions and in high percentage yield [12–20].
Also, they are successful models of biological systems and they have unique proper-
ties, e.g. the azomethine linkage which is responsible for medical actions: e.g. the
delivery of doxorubicin from biodegradable PEG hydrogels can form Schiff base
linkages [14–22]. Noticeably, more symmetrical ONNO types, when compared to

JOURNAL OF COORDINATION CHEMISTRY
3
unsymmetrically substituted S.Bs, are known, although unsymmetrically substituted
S.Bs as polymerization catalysts are found to be more effective than symmetrically
substituted S.B metal complexes [23, 24]. Related examples of nickel complexes have
been reported recently [25–27]. Given these facts, we have been stimulated to study
the unsymmetrical (H2L: N,N’-bis(3,5-di-t-butylsalicylidene)-1,2-diamino-2-methylpro-
pane) ligand and its nickel complex NiL. Interestingly, H2L possesses four tertiary butyl
groups at two different positions on each ring; hence, it enhances solubility in many
organic solvents [13]. In addition, H2L favors monomeric complexes due to the steric
hindrance on the ligand. In this study, the steric effect from bulky groups of this Salen
complex has suppressed the formation of oxo dimeric or polymeric metal com-
plexes [28–30].
2. Experimental and methodology
2.1. Chemicals, instruments and computation
Chemicals which were used in this study were received from Sigma-Aldrich. HSA was
carried out using Crystal Explorer Version 3.1 software [31]. MS were measured on a
Varian MAT 711. CHN: Perkin-Elmer Series I1 Analyzer 2400. IR (m/cmꢀ1) were recorded
1
on a Nicolet Nexus spectrometer. 13C and H NMR were carried out on a JEOL ECS 400
spectrometer. The UV-vis spectrophotometer was measured on a ThermoScientific
Genesys 10 s. The salicylaldimine H2L used in this study was obtained through con-
densation of two equivalents of commercially available 3,5-di-tert-butyl-2-hydroxyben-
zaldehyde with 2-methylpropane-1,2-diamine according to a standard literature
procedure with a slight modification [29]. The DFT-computations were carried out in
gaseous phase using Gaussian09 software at the B3LYP/DFT level with the 6-311 G(d,p)
basis set for all the light atoms; for Cd and I their potential effective core LANL2DZ
was also performed using Gaussian09 software [32].
2.2. Synthesis
[2,20-f(2-methylpropane-1,2-diyl)bis[(azanylylidene)methanylylidene]gbis(4,6-di-
t-butylphenolato)]-(oxido)-nickel, NiL. H2L (0.50 g, 0.96 mmol) and Ni(OAc)2ꢁ2H2O
(0.24 g, 0.96 mmol) were added to a two-necked flask charged with a stir bar under
argon gas in the presence of Et3N (0.26 mL, 0.19 g, 1.92 mmol). A mixture of degassed
(degassed with argon for 10 min) methanol and chloroform (30 mL) in 5:1 ratio was
added and stirred under reflux overnight. The solvents were reduced to one-third,
using a vacuum pump, and placed in an ice bath for 35 min. The mixture was filtered
in air and the product then washed well with cold ethanol (20 ml) and ice water
(10 mL) kept in the fridge beforehand. The yield was (0.43 g, 78%). HRMS (ESI) m/z
calc. (C34H50N2NiO2) 576.32, found 576.32 (M-H).
2.3. Xrd data collection
The X-ray data for the NiL complex were recorded at 100(2) K on a Bruker APEX-II
CCD diffractometer, with 0.71073 Å Mo-Ka radiation. The procedure and data reduction

4
M. A. SAID ET AL.
Table 1. Crystal data for NiL.
Chemical formula
C34H50N2NiO2
CCDC
1992035
Mr
577.47
Monoclinic, P21/c
Crystal system, space group
Temperature (K)
a, b, c (Å)
b (ꢂ)
100
10.0272(7), 27.2922(15), 11.6233(7)
90.622(4)
3180.7(3)
V (Å3)
Z
4
Radiation type
Cu Ka
1.11
m (mm–1
)
Crystal size (mm)
Diffractometer
0.07 ꢃ 0.02 ꢃ 0.003
Bruker APEX-II CCD
18737, 4282, 3763
No. of measured, independent and
observed [I > 2r(I)] reflections
Rint
0.052
58.8
0.555
hmax (ꢂ)
(sin h/k)max (Å–1
)
R[F2 > 2r(F2)], wR(F2), S
0.085, 0.217, 1.08
4282, 367
0.87, ꢀ0.49
No. of reflections, parameters
Dqmax, Dqmin (e Å–3
)
Scheme 1. Synthesis of unsymmetrical ligand (H2L) and its NiL complex.
were obtained using SAINT PLUS [33]. The structure was solved using the SHELXS
structure solution program by direct methods and refined with the SHELXL [34, 35]
refinement package using least squares minimization. The geometrical calculations
were carried out using PLATON [36] and the diagrams were generated using
MERCURY [37]. The crystal data are illustrated in Table 1.
3. Results and discussion
3.1. Synthesis and CHN analysis
The desired S.B, H2L of type ONNO tetradentate ligand, was synthesized following a
slightly modified known condensation reaction [29] (see Supporting Information). The
reaction of H2L with Ni(OAc)2ꢁ2H2O, in 1:1 molar ratio, progressed in a mixture of sol-
vents (degassed methanol and chloroform, 1:5 ratio) in the presence of triethylamine
to afford the NiL complex in high yield as illustrated in scheme 1. Elemental analysis
indicated the theoretical values, for the formation of 1:1 nickel complex, were in
agreement with the actual results (Table 2).
The NiL complex is stable in air, colored, a non-hygroscopic solid and melts at a higher
temperature. The nickel complex is not soluble in water; however, it is soluble in many
common organic solvents. The H2L ligand coordinated to the Ni center in a tetradentate
mode, using ONNO donor sites of the azomethine-N and phenolic-O (scheme 1).

JOURNAL OF COORDINATION CHEMISTRY
5
Table 2. Physical data for compounds H2L and NiL.
Cpd.
Color
T (ꢂC)
C% (found)
C% (Calc.)
H (found)
H (Calc.)
N (found)
N (Calc.)
H2L
NiL
Yellow
Green
165-167
>360
78.43
70.91
78.41
70.72
10.07
8.97
10.6
8.73
5.42
4.88
5.35
4.85
Figure 1. NiL complex structural belongings (a) ORTEP, (b) optimized B3LYP structure, (c) H-bonds
and (d) 2H … .C ¼ C interactions.
3.2. Nil solid-state XRD and DFT structures
The solid-state ORTEP structure of the desired NiL complex is illustrated together with
the DFT-optimized structure (Figures 1(a,b)); XRD/DFT selected bond lengths and
angles are illustrated in Table 3. The neutral NiL complex crystallized in a monoclinic
lattice, space group P21/c, without any solvent molecules in the crystal lattice. The
Ni(II) ion was found to be surrounded by 2 N-imine and 2 O-phenolic atoms, where
each N atom is trans to an O atom to form three new five-membered rings via metal
center coordination, which have also been observed by DFT structural optimization. A
slightly distorted square–planar geometry around Ni(II) with t ꢄ ꢀ15.55(ꢂ) was
observed by both DFT and XRD. The bond lengths of Ni–N were found to be ꢄ1.84
and Ni–O ꢄ 1.83 Å; the main angles around the center are N(1)–Ni–N(2) 86.8(3),
O(2)–Ni–O(2) 86.2(2), O(1)–Ni–N(2) 94.6(2) and O(1)–Ni–N(1) 169.9(2). These results are
consistent with similar Ni(II) complexes [17, 30]. In the crystal packing system, two
types of short interactions were detected: 2H-bonds C-H … .O of 2.433 Å and
2H … .C ¼ C bonds of 2.665 Å.

6
M. A. SAID ET AL.
Table 3. Selected exp. XRD and DFT-B3LYP bond lengths and angles.
Bond no.
Bonds (Å)
Exp. XRD
DFT/B3LYP
Angle no.
Angles (ꢂ)
Exp. XRD
DFT/B3LYP
1
2
3
4
5
6
7
8
Ni1
O1
O2
N7
N8
C3
C4
C5
C6
C13
C16
C14
C25
C11
C24
C9
C22
C24
C32
C13
C16
1.834(5)
1.838(5)
1.849(6)
1.836(6)
1.318(7)
1.312(7)
1.442(9)
1.39(1)
1.8051
1.8068
1.7762
1.7866
1.3252
1.3272
1.438
1.4253
1.4292
1.434
1.3842
1.5391
1.4182
1.4212
1.3115
1.4867
1.312
1.5162
1.4209
1.3886
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
O1
O1
O1
O2
O2
N7
Ni1
Ni1
O1
O1
C5
O2
O2
C13
C3
C3
C14
C3
Ni1
Ni1
Ni1
Ni1
Ni1
Ni1
O1
O2
C3
C3
C3
C4
C4
C4
C5
C5
C5
C6
C6
C6
O2
N7
FN8
N7
N8
N8
C3
C4
C5
86.2(2)
169.9(2)
94.6(2)
94.0(2)
171.4(2)
86.8(3)
129.4(4)
128.5(4)
119.9(6)
121.5(6)
118.5(6)
122.5(6)
119.0(6)
118.6(6)
117.8(6)
120.3(5)
121.9(6)
119.8(6)
122.3(6)
117.9(6)
88.8
163.58
94.03
93.37
163.27
88.57
131.01
131.2
121.28
121.19
117.54
121.22
121.41
117.37
118.39
120.23
121.38
121.46
120.01
118.52
Ni1
Ni1
Ni1
O1
O2
C3
C3
C4
C4
C5
C5
C6
C6
N7
N7
N8
N8
C9
9
1.42(1)
10
11
12
13
14
15
16
17
18
19
20
1.438(9)
1.389(8)
1.52(1)
1.43(1)
1.43(1)
1.29(1)
1.486(9)
1.30(1)
1.493(9)
1.40(1)
C6
C6
C13
C16
C16
C14
C25
C25
C11
C24
C24
C3
C11
C10
1.392(8)
Figure 2. (a) XRD/DFT bonds distances relation, (b) bonds distances graphical correlation, (c) DFT/
XRD angles relation and (d) angles graphical correlation.
Very good agreement between DFT/XRD bond distances and angles were observed
as shown in Figure 2(a,c), respectively. The bond lengths graphical correlation (R2) was
found to be 0.982 (Figure 2(b)), whereas the angles graphical correlation (R2) was
found to be 0.9907 (Figure 2(d)). In general, significant matching between XRD/DFT
structural parameters was observed.

JOURNAL OF COORDINATION CHEMISTRY
7
3.3. HSA, FP and MPE computation
Figure 3 elucidates the molecular interactions in the NiL complex with the aid of HSA
and FP calculations using the CIF. The result was compared with the XRD-packing
result [38–43]. HSA reflects the presence of 2 red points around O atoms (Figure 3(a)),
indicating the H-O … .H and H … .C ¼ C bonds connected the NiL complex lattice in
layer-by-layer diminutions. This finding supported the XRD-packing result. The percen-
tages ratio of atom … atom FP contacts are ordered as H—H(82.0%)>H—C > H—
O > H—N and H—Ni (<0.4%), as shown in Figure 3(d).
The MEP created in space around the NiL complex by the charge allocation is use-
ful in showing the interacting sites for an electrophilic and nucleophilic hit in the bio-
logical system. The MEP result of the NiL complex strongly supports the HSA and XRD
results. The different electrostatics potential values are presented by various colors;
blue represents the positive region of electrostatic potential that is due to CH2 in the
diamine ligand part. The red color reflected the high electrostatic potential that is
around e-rich O atoms only. The green color represents less positive potential regions
in the complex. MEP suggests the HCH … O hydrogen bond and HCH … pC ¼ C bonds
can be formed via the interaction between the e-rich (2 O) with e-poor (CH3, CH2
and ¼ CH) functional groups [40–44]. This observation is matched with the XRD and
HSA results (Figure 4).
3.4. Infra-red studies of H2L ligand and NiL complex
Several functional groups such as Csp3-H, Csp2-H C ¼ N, C ¼ C, C-O, C-C, Ni-O and Ni-N
were detected by FT-IR, theoretically and experimentally as shown in Figure 5.
Noticeably, the B3LYP-IR frequencies of the main functional groups in the gaseous
sate are higher than those experimentally observed for the equivalent groups, in solid
state. The Exp./DFT IR are in high agreement as seen by the 0.998 correlation coeffi-
cient shown in Figure 5. The solid state infrared spectrum of the free H2L exhibits no
broad band for the pronounced OH vibration in the region of 3410–3450 cmꢀ1, prob-
ably due to the strong (O-H … N ¼ C) intra-molecular hydrogen bonding [44].
Therefore, the undistinguished broad band of the OH in the free H2L is not helpful in
confirming Ni coordination. However, coordination of the free ligand with the Ni cen-
ter can be confirmed by two other options. The chemical shift of the azomethine
C ¼ N group in the complex shifted to lower energy by 17 units (1612 cmꢀ1) when
compared to the same azomethine group in the free ligand (1629 cmꢀ1), as can be
seen in Figure 5(a). The Ni-O and Ni-N exhibit a broad peak at 540 cmꢀ1 in the spec-
trum of the complex, indicating a coordination mode through these two atoms as
shown in Figure 5(b) [28]. The DFT-IR for NiL was performed for comparison. The
study shows several functional groups consistent with the complex structure
(Figure 5).
3.5. UV-Vis
UV-Vis behaviors of both free H2L ligand and its NiL complex were compared in etha-
ꢅ
nol (Figure 6). The p!p electron transfer H2L ligand bands were observed at 277 nm

8
M. A. SAID ET AL.
Figure 3. Hirshfeld surfaces views for the NiL complex (a) dnorm, (b) shape index, (c) curvedness
structures and (d) inside/outside 2 D-FP plot.
and 335 nm, whereas in the NiL complex these bands were shifted slightly to lower
energy 280 nm and 342 nm, respectively. These shifts confirm formation of the new
Ni-N and Ni–O bonds. The new MLCT broadband appeared only in the NiL complex
(at 425 nm), supporting the formation of square planar geometry around the Ni center
(Figure 6(b)).
3.6. Thermal gravimetric analysis
TG/DSC analysis of the NiL complex showed one stage of decomposition pattern with
heating rate of 10 ꢂC minꢀ1 in the 25 to 800 ꢂC temperature range and air atmosphere
(Figure 7). Below 260 ꢂC, the NiL complex displayed significant thermal stability; no

JOURNAL OF COORDINATION CHEMISTRY
9
Figure 4. MEP map of NiL complex.
Figure 5. Exp. IR spectra of (a) free H2L ligand, (b) NiL complex, (c) DFT/B3LYP/6-311G(d) of NiL
and (d) DFT/Exp. correlation coefficient.

10
M. A. SAID ET AL.
Figure 6. UV–vis spectra of free H2L (a) and NiL complex (b) dissolved in ethanol.
Figure 7. TG/DSC curves.
loss of water or other solvent molecules in the complex lattice were observed. This obser-
vation is in agreement with the IR and XRD results. The ligand ONNO was thermally de-
structured from the NiL through a broad one step in ꢄ280–450 ꢂC with two TDSC ¼ 305
and 318 ꢂC. The organic content completely decomposed parallel to NiO formation with
12.5% as a final product; the NiO final product was confirmed by IR [45].
4. Conclusion
In this study, the X-ray crystallography study confirms the structure of a newly synthe-
sized Ni complex. The Schiff base acts as a single tetradentate ONNO chelating agent
through the azomethine nitrogen atoms and the phenolic oxygen atoms. It shows a
NiII center with slightly distorted square planar geometry. Moreover, a sufficient num-
ber of H-bonds and H … p stacks stabilized the lattice. Electrostatic potential surface
(MEP) and Hirschfeld surface analysis (HSA) were found to be in good agreement with
the corresponding experimental data. The DFT-optimized NiL reflected significant ther-
mal stability and it decomposed in open atmosphere in a one-step thermal decompos-
ition process.

JOURNAL OF COORDINATION CHEMISTRY
11
Acknowledgement
M. A. Said is thankful to Alexander von Humboldt Stiftung, Germany for the opportuni-
ties provided.
Disclosure statement
No potential conflict of interest was reported by the authors.
References
[1] S. Chatterjee, D. Sukul, P. Banerjee, J. Adhikary. Inorg. Chim. Acta, 474, 105 (2018).
€
[2] D. C¸akmak, S. C¸akran, S. Yalc¸inkaya, C. Demetgul. J. Electroanal. Chem, 808, 65 (2018).
[3] L.H. Abdel-Rahman, N.M. Ismail, M. Ismael, A.M. Abu-Dief, E.A.-H. Ahmed. J. Mol. Struct.,
1134, 851 (2017).
[4] N. Kavitha, P.V. Anantha Lakshmi. J. Saudi Chem. Soc., 21, S457 (2017).
[5] Y. Jia, J. Li. Chem. Rev., 115, 1597 (2015).
[6] C.J. Reda, F.M. Elshaarawy, Z.H. Kheiralla, A.A. Rushdy, C. Janiak. Inorg. Chim. Acta, 421,
110 (2014).
[7] M.S.S. Adam, L.H. Abdel-Rahman, A.M. Abu-Dief, N.A. Hashem. Inorg. Nano-Met. Chem., 50,
132 (2020).
[8] K. Jana, S. Das, H. Puschmann, S.C. Debnath, A. Shukla, A.K. Mahanta, M. Hossain,
T. Maity, B.C. Samanta. Inorg. Chim. Acta, 487, 128 (2019).
[9] M.M. Mostafa, K.M. Ibrahim, M.N.H. Moussa. Trans. Met. Chem., 9, 243 (1984).
[10] M. Salehi, M. Hasanzadeh. Inorg. Chim. Acta, 426, 6 (2015).
[11] M. Gupta, V. Kumar Vaidya. Int. Res. J. Pharm. Med. Sci., 2, 36 (2019).
[12] M.S. Altowyan, A. Barakat, A.M. Al-Majid, H.A. Ghabbour, A. Zarrouk, I. Warad. BMC Chem,
13, 1 (2019).
[13] P.G. Cozzi. Chem. Soc. Rev., 33, 410 (2004).
[14] G.P. Wu, W.M. Ren, Y. Luo, B. Li, W.Z. Zhang, X.B. Lu. J. Am. Chem. Soc., 134, 5682 (2012).
€
[15] F. Kratz, U. Beyer, M.T. Schutte. Crit. Rev. Ther. Drug Carrier Syst., 16, 245 (1999).
[16] H. Saito, A.S. Hoffman, H.I. Ogawa. J. Bioact. Compat. Polym., 22, 589 (2007).
[17] N. Charef, F. Sebti, L. Arrar, M. Djarmouni, N. Boussoualim, A. Baghiani, S. Khennouf, A.
Ourari, M.A. AlDamen, M.S. Mubarak, D.G. Peters. Polyhedron, 85, 450 (2015).
[18] P.K. Sasmal, A.K. Patra, A.R. Chakravarty. J. Inorg. Biochem., 102, 1463 (2008).
[19] K. Dhahagani, S. Mathan Kumar, G. Chakkaravarthi, K. Anitha, J. Rajesh, A. Ramu, G.
Rajagopal. Spectrochim. Acta, Part A, 117, 87 (2014).
[20] L. Peng, C. Chen, C.R. Gonzalez, V. Balogh-Nair. Int. J. Mol. Sci., 3, 1145 (2002).
[21] H. Keypour, M. Ahmadi, M. Rezaeivala, A. Chehregani, R. Golbedaghi, A.G. Blackman.
Polyhedron, 30, 1865 (2011).
[22] A. Choudhary, R. Sharma, M. Nagar. Int. Res. J. Pharm. Pharmacol., 1, 2251 (2011).
[23] S. Matsunaga, M. Shibasaki. Chem. Commun., 50, 1044 (2014).
[24] Z. Liu, F.C. Anson. Inorg. Chem., 40, 1329 (2001).
[25] S.N. Shukla, P. Gaur, M.L. Raidas, B. Chaurasia. J. Mol. Struct., 1202, 127362 (2020).
[26] Z.M. Bikbaeva, D.M. Ivanov, A.S. Novikov, I.V. Ananyev, N.A. Bokach, V. Yu. Kukushkin.
Inorg. Chem., 56, 13562 (2017).
[27] D.S. Bolotin, Z.M. Bikbaeva, A.S. Novikov, V.V. Suslonov, N.A. Bokach. Chem. Select., 15,
9669 (2017).
[28] A.D. Garnovskii, A.L. Nivorozhkin, V.I. Minkin. Coord. Chem. Rev., 126, 1 (1993).
[29] C.T. Cohen, C.M. Thomas, K.L. Peretti, E.B. Lobkovsky, G.W. Coates. Dalton Trans., 60, 237
(2006).
[30] W.K. Dong, Y.X. Sun, G.H. Liu, L. Li, X.Y. Dong, X.H. Gao. Z. Anorg. Allg. Chem., 638, 1370
(2012).

12
M. A. SAID ET AL.
[31] M.A. Turner, J.J. McKinnon, S.K. Wolff, D.J. Grimwood, P.R. Spackman, D. Jayatilaka,
M.A. Spackman. CrystalExplorer, Version 17, University of Western Australia, Perth (2017).
[32] D.J. Frisch, J. Trucks, G.W. Schlegel, H.B. Scuseria, G.E. Robb, M.A. Cheeseman,
J.R. Scalmani, G. Barone, V. Mennucci, B. Petersson, G.A. Nakatsuji, H. Caricato, M. Li,
X. Hratchian, H.P. Izmaylov, A.F. Bloino, J. Zheng, G. Sonnenberg. J. Revis. A.1.
M. Gaussian, Inc., Wallingford, CT (2009).
[33] A.P.E.X. Bruker. SAINT-plus and SADABS, Bruker AXS Inc., Madison, WI (2004).
[34] G.M. Sheldrick. Acta Crystallogr. A Found. Crystallogr., 64, 112 (2008).
[35] G.M. Sheldrick. Acta Crystallogr. A Found. Adv., 71, 3 (2015).
[36] A.L. Spek. Acta Crystallogr. D Biol. Crystallogr., 65, 148 (2009).
[37] C.F. Macrae, I.J. Bruno, J.A. Chisholm, P.R. Edington, P. McCabe, E. Pidcock, L. Rodriguez-
Monge, R. Taylor, J. van de Streek, P.A. Wood. J. Appl. Crystallogr., 41, 466 (2008).
[38] A. Titi, T. Shiga, H. Oshio, R. Touzani, B. Hammouti, M. Mouslim, I. Warad. J. Mol. Struct.,
1199, 1 (2020).
[39] M.R. Aouad, M. Messali, N. Rezki, N. Al-Zaqri, I. Warad. J. Mol. Liq., 264, 621 (2018).
[40] A. Barakat, M.S. Islam, A.M. Al-Majid, H.A. Ghabbour, S. Atef, A. Zarrouk, I. Warad. J. Theor.
Comput. Chem., 17, 1850005 (2018).
[41] F.A. Saleemh, S. Musameh, A. Sawafta, P. Brandao, C.J. Tavares, S. Ferdov, A. Barakat,
A.A. Ali, M. Al-Noaimi, I. Warad. Arab. J. Chem., 10, 845 (2017).
[42] I. Warad, F.F. Awwadi, B. Abd Al-Ghani, A. Sawafta, N. Shivalingegowda, N.K. Lokanath,
M.S. Mubarak, T. Ben Hadda, A. Zarrouk, F. Al-Rimawi, A.B. Odeh, S.A. Barghouthi.
Ultrason. Sonochem., 48, 1 (2018).
[43] M.R. Aouad, M. Messali, N. Rezki, M.A. Said, D. Lentz, L. Zubaydi, I. Warad. J. Mol. Struct.,
1180, 455 (2019).
[44] R. Mathammal, K. Sangeetha, M. Sangeetha, R. Mekala, S. Gadheeja. J. Mol. Struct., 1120,
1 (2016).
[45] A. Barakat, M. Al-Noaimi, M. Suleiman, A.S. Aldwayyan, B. Hammouti, T.B. Hadda,
S.F. Haddad, A. Boshaala, I. Warad. Int. J. Mol. Sci., 14, 23941 (2013).