Synthesis, Spectral Characterization, and Thermal and Cytotoxicity Studies of Cr(III), Ru(III), Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) Complexes of Schiff Base Derived from 5-Hydroxymethylfuran-2-carbaldehyde

Article abstract of DOI:10.1155/2018/5816906

Coordination compounds of Cr(III), Ru(III), Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) ions were synthesized from the furan ligand [5-hydroxymethylfuran-2-yl-methyleneaminoquinolin-2-one] (H-MFMAQ) derived from the condensation of 5-hydroxymethylfuran-2-c

Full text of DOI:10.1155/2018/5816906

Hindawi
Journal of Chemistry
Volume 2018, Article ID 5816906, 17 pages
https://doi.org/10.1155/2018/5816906
Research Article
Synthesis, Spectral Characterization, and Thermal and
Cytotoxicity Studies of Cr(III), Ru(III), Mn(II), Co(II), Ni(II),
Cu(II), and Zn(II) Complexes of Schiff Base Derived from
5
-Hydroxymethylfuran-2-carbaldehyde
1
2,3
Amani S. Alturiqi, Abdel-Nasser M. A. Alaghaz ,
4
,5
6
Reda A. Ammar, and Mohamed E. Zayed
1
Department of Chemistry, College of Science, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia
Department of Chemistry, Faculty of Science, Jazan University, Jazan, Saudi Arabia
2
3
4
5
6
Department of Chemistry, Faculty of Science (Boys), Al-Azhar University, Cairo, Egypt
Department of Chemistry, College of Sciences Al Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 11623, Saudi Arabia
Department of Chemistry, Faculty of Science (Girls), Al-Azhar University, Cairo, Egypt
Department of Botany and Microbiology, Faculty of Science, King Saud University, Riyadh 11541, Saudi Arabia
Correspondence should be addressed to Abdel-Nasser M. A. Alaghaz; aalajhaz@hotmail.com
Received 24 December 2017; Revised 18 February 2018; Accepted 8 March 2018; Published 9 May 2018
Academic Editor: Josefna Pons
Copyright © 2018 Amani S. Alturiqi et al. Tis is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly
cited.
Coordination compounds oꢀ Cr(III), Ru(III), Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) ions were synthesized ꢀrom the
ꢀ
uran ligand [5-hydroxymethylꢀuran-2-yl-methyleneaminoquinolin-2-one] (H-MFMAQ) derived ꢀrom the condensation oꢀ 5-
1
13
15
hydroxymethylꢀuran-2-carbaldehyde and 1-aminoquinolin-2(1H)-one. Elemental analytical data, IR, NMR ( H, C, and N),
EPR, XRD, SEM, ꢁEM, EDX, ꢁGA, mass, molar conductance, magnetic moment, and UV-Visible spectra techniques were used
to confrm the structure oꢀ the synthesized chelates. According to the data obtained, the composition oꢀ the 1 : 1 metal ions : ꢀuran
Schiꢂ base ligand was ꢀound to be [M(MFMAQ)Cl ] (M = Cr(III) and Ru(III)) and [M(MFMAQ)Cl(H O)]⋅nH O in which (M =
2
2
2
Mn(II); ꢀ = 1, Co(II); ꢀ = 0, Ni(II); ꢀ = 2, Cu(II); ꢀ = 0 and Zn(II); ꢀ = 2.5). Te measurements oꢀ magnetic susceptibility, ligand
feld parameter, and reꢃectance spectra suggested an octahedral geometry ꢀor the complexes. Central metals ions and ꢀuran Schiꢂ
base coordinated via O3 and N donor sites which was observed ꢀrom IR spectra. Te cytotoxic activities oꢀ all inspected compounds
were evaluated towards human breast (MCF-7) and lung cancer (A549) cell lines.
1
. Introduction
in bioinorganic chemistry and may give the models basis ꢀor
active sites oꢀ biological systems [2–4]. For a long time, it had
ꢁ
ransition metal complexes derived ꢀrom the Schiꢂ base
been identifed as a serious coꢀactor in biological compounds,
either as a compositional template in protein ꢀolding or as a
Lewis acid catalyst which can readily adopt the coordination
numbers 4, 5, or 6 [5, 6]. Coordination chemistry oꢀ cobalt
complexes was a substantial importance as a result oꢀ the
toxic environmental eꢂect oꢀ cobalt. Te cobalt mobiliza-
tion and immobilization in the climate, organisms, and
approximately technical systems (such as in ligand exchange
chromatography) have been presented maniꢀestly to depend
ligands with biological potency have been broadly studied.
Schiꢂ bases appear to be an important intermediate in a
number oꢀ enzymatic reactions including interaction oꢀ an
enzyme with an amino or a carbonyl group oꢀ the substrate.
Te biochemical process which involves the condensation
oꢀ a primary amine in an enzyme may be one oꢀ the most
important catalytic mechanisms kinds [1]. ꢁransition metal
complexes with diꢂerent oxidation states have a strong role

2
Journal oꢀ Chemistry
OH
OH
．
（2
O
O
O
N
O
+
−
（ ／
2
N
N
O
Sꢄꢅꢆꢇꢆ 1: Synthetic route oꢀ ligand H-MFMAQ.
1
5
1
on the complexation oꢀ the metal center by chelating nitrogen
donor ligands [7]. Te size and shape oꢀ the nanomaterials
are considered the key ꢀactors ꢀor shaping their charac-
teristics such as electrical, optical, magnetic, antimicrobial,
and catalytic potency. Metal and metal oxide nanoparticles
have ꢀound a wide range oꢀ uses, including heterogeneous
catalysts, environmental remediation, electronics, chemical
sensing devices, medicinal felds, separations, thin flms, inks,
disinꢀection, and antimicrobial activity [8]. Tese diꢂerent
applications altered with morphology and size oꢀ those metal
and metal oxide nanoparticles [9]. Detection oꢀ metal ions
oꢀ biological importance has attracted much attention. Like
spectrometer. Te { N, H} NMR correlation spectrum oꢀ
samples was recorded in a Bruker Avance III 400 MHz
(9.4 ꢁ) spectrometer. Te samples were analyzed in a d6-
DMSO solution and the chemical shiꢈs were given relative
13
15
to tetramethylsilane (ꢁMS). Te C and N solid state
NMR (SSNMR) spectra were recorded in a Bruker 300 MHz
spectrometer, using the combination oꢀ cross-polarization,
proton decoupling, and magic angle spinning (CP/MAS) at
10 kHz. Electrospray ionization mass spectrometry (ESI-MS)
measurements were carried out using a Waters Quattro Micro
API. Samples were evaluated in the positive mode. Ligand was
analyzed in a 1 : 1 methanol : water solution with addition oꢀ
0.10% (v/v) ꢀormic acid; Cu(II) complex was analyzed in a 1 : 1
acetonitrile : water with 0.10% (v/v) ꢀormic acid; Co(II) and
Ru(III) complexes were dissolved in a minimum amount oꢀ
DMF and ꢀurther dissolved in a 1 : 1 methanol : water solution
with addition oꢀ 0.10% (v/v) ꢀormic acid immediately beꢀore
2+
Zn ion ꢃuorescent probes or sensors have achieved special
2
+
interest. Zn is an essential trace element and the second
2+
(
aꢈer Cu ) most abundant metal ion in humans [10, 11].
In our present work, novel [M(MFMAQ)Cl ] (M = Cr(III)
2
and Ru(III)) and [M(MFMAQ)Cl(H O)]⋅ꢀH O (M = Mn(II);
2
2
ꢀ
ꢀ
= 1, Co(II); ꢀ = 0, Ni(II); ꢀ = 2, Cu(II); ꢀ = 0 and Zn(II);
= 2.5) complexes were discussed using diꢂerent studding
the experiments. Each solution was directly inꢀused into
the instrument’s ESI source and analyzed in the positive
mode, with capillary potential oꢀ 3.00 kV, trap potential
techniques such as elemental analyses, molar conductance,
∘
1
13
15
oꢀ 2 kV, source temperature oꢀ 150 C, and nitrogen gas
magnetic moment, and UV–Vis., IR, NMR ( H, C and N),
mass, EPR, XRD, SEM, ꢁEM, EDX, and ꢁGA behavior. Also,
the ligand (H-MFMAQ) and its complexes show remarkable
cytotoxicity against human breast (MCF-7) and lung cancer
ꢀ
or desolvation. Room temperature magnetic susceptibility
measurements were carried out on a modifed Gouy-type
magnetic balance, Hertz SG8-5HJ. Te room temperature
molar conductivity oꢀ the complexes in MeOH, EtOH,
(
A549) cell lines.
−1
and DMSO solutions (0,001 mol⋅L ) was measured using a
deep vision 601 model digital conductometer. Te X-band
EPR spectrum was perꢀormed at LNꢁ (77 K) using ꢁCNE
as the g-marker. Powder X-ray diꢂraction patterns were
2
. Experimental
2
.1. Materials and Methods. All the metal salts were gained
ꢀ
rom E-Merck and used without ꢀurther purifcation. Solvents
recorded with a X’Pert PRO Diꢂractometer using CuKꢁ
1
MeOH, EtOH, DMF, DMSO, and agar were procured ꢀrom
Hi-media chemicals. However, the solvents were purifed by
the standard procedures. Elemental analyses were perꢀormed
on a Perkin Elmer 2400 CH/N Analyzer. Metal contents
were determined complexometrically by standard EDꢁA
radiation (ꢂ = 1.54060 A˚ ) with operating voltage 40 kV and
a current oꢀ 30 mA. Termal studies were carried out using
Q 600SDꢁ and Q 20 DSC thermal analyzer. SEM images
were recorded in a Hitachi SEM analyzer and transmission
electron microscopy (ꢁEM) images were taken by Zeiss-
EM10C-100 KV. Energy Dispersive X-Ray Analysis (EDX)
(EDAX Falcon System) was conducted to analyze the pres-
ence oꢀ elements in the specimens that have been sputtered
with carbon black. Te cytotoxic activity oꢀ the inspected
ꢀree ligand and complexes (1–7) was studied towards human
breast (MCF-7) and lung cancer (A549) cell lines at the
Regional Center ꢀor Microbiology and Biotechnology, Al-
Azhar University as well as the other biological activities.
titration and the Cl was tested gravimetrically using AgNO .
3
Electronic spectra oꢀ the complexes were recorded on a Shi-
madzu Model 1601 UV-Visible Spectrophotometer. Inꢀrared
spectroscopy measurements were perꢀormed on an Agilent
Cary 630 FꢁIR spectrometer, using the Attenuated ꢁotal
Reꢃectance (AꢁR) method, with a diamond cell. Spectra
–
1
were recorded ꢀrom 4000 to 400 cm , with 64 scans and
–
1
1
15
1
resolution oꢀ 4 cm . Te H and { N, H} correlation NMR
spectra oꢀ samples were recorded in a Bruker Avance III
1
5
00 MHz (11.7 ꢁ) spectrometer. Te H NMR spectrum oꢀ
2.2. Synthesis of Schiꢀ Base Ligand (H-MFMAQ). New Schiꢂ
base ligand (H-MFMAQ) (Scheme 1) was prepared when
samples was recorded in a Bruker Avance III 600 MHz (14 ꢁ)

Journal oꢀ Chemistry
3
ꢁꢉꢊꢋꢆ 1: Analytical and physical data oꢀ the ligand H-MFMAQ and complexes 1–7.
Compound
Number
∘
Elemental analysis calc. (ꢀound)
Color
M.P. C Yield%
(
ꢀormula wt.) [M.Wt.]
C%
67.16
(67.13)
46.18
(46.12)
41.02
(40.97)
45.76
(45.73)
47.45
(47.42)
43.37
(43.34)
46.88
(46.83)
H%
N%
Cl%
M%
--
H-MFMAQ
4.51
(4.49)
10.44
(10.42)
Pale yellow
146
211
91
78
83
82
84
77
86
73
--
(
C H N O ) [268.3]
1
5
12
2
3
[
Cr(MFMAQ)Cl ]
Dark
brown
2.84
(2.82)
7. 18
(7.14)
18.17
(18.11)
13.33
(13.32)
23.01
2
1
(
C H11Cl CrN O ) [390.2]
1
5
2
2
3
[
(
[
(
[
(
[
(
Ru(MFMAQ)Cl ]
2.52
(2.50)
6.38
(6.34)
16.14
(16.10) (23.00)
2
2
3
4
5
6
7
Black
Wine red
Olive
219
224
218
226
233
208
C H Cl N O Ru) [439.2]
15
12
2
2
3
Mn(MFMAQ)Cl(H O)]⋅H O
3.84
(3.83)
7. 12
(7.11)
9.00
(8.98)
13.95
(13.91)
15.52
(15.50)
14.13
(14.10)
16.54
(16.51)
2
2
C H ClMnN O ) [393.7]
1
5
15
2
5
Co(MFMAQ)Cl(H O)]
3.45
(3.43)
7. 3 8
(7.33)
9.34
(9.32)
2
C H ClCoN O ) [379.7]
1
5
13
2
4
Ni(MFMAQ)Cl(H O)]2H O
4.12
(4.10)
6.74
(6.72)
8.53
(8.51)
2
2
Brown
C H ClN NiO ) [415.5]
1
5
17
2
6
[Cu(MFMAQ)Cl(H O)]
(
Grass
green
3.41
(3.38)
7. 29
(7.23)
9.23
(9.20)
2
C H ClCuN O ) [384.3]
1
5
13
2
4
[
Zn(MFMAQ)Cl(H O)]⋅2.5H O
41.79
(41.72)
4.21
(4.18)
6.50
(6.48)
8.22
(8.19)
15.16
(15.12)
2
2
Yellow
(
C H ClN O Zn) [431.1]
15
18
2
6.5
5
-hydroxymethylꢀuran-2-carbaldehyde (1.24 g, 11.23 mmol)
in ethanol exhibited fve absorption bands (Figure 2(a))
∗
was added to 1-aminoquinolin-2(1H)-one (1.79 g, 11.23 mmol),
both dissolved in absolute ethanol (50 ml). Mixture was
heated under reꢃux ꢀor 3 h to be a pale-yellow precipitate and
was ꢀormed upon cooling the solution to room temperature.
Te product was fltered oꢂ and washed with ꢀew amounts oꢀ
ethanol then diethyl ether, air-dried, and recrystallized ꢀrom
ethanol. Te yield was 2.77 g (91%). Te physical properties
and analytical data oꢀ the ꢀuran Schiꢂ base ligand and its
metal complexes are scheduled in ꢁable 1.
at 233–338 nm regions which is due to ꢃ
→
ꢃ
and
∗
ꢀ
→
ꢃ
transitions utilizing molecular orbital oꢀ the
quinoline and ꢀuran rings, C=N and C=O groups. Never-
theless, the IR spectrum oꢀ ꢀuran Schiꢂ base ligand (H-
–
1
MFMAQ) (Figure 3(a)) does not show any band at 1700 cm ,
–
1
–1
3380 cm , and 3250 cm corresponding to the carbonyl
groups and ꢀree primary amino groups; this confrms the
complete condensation between keto and amino groups. Te
–
1
band at 1637 cm is corresponding to ] (CH=N) stretching
vibration. Te IR spectrum oꢀ ꢀuran Schiꢂ base ligand (H-
–
1
2
.3. Synthesis of Schiꢀ Base Metal(II/III) Complexes. A mix-
ture oꢀ ꢀuran Schiꢂ base ligand H-MFMAQ (6.76 mmol;
.81 g) dissolved in an ethanol (20 ml) and chloride salt
oꢀ Cr (III), Ru(III), Mn(II), Co(II), Ni(II), Cu(II), or Zn
II) (6.76 mmol) dissolved in the same solvent (20 ml) was
heated ꢀor two hours under reꢃux on a water bath. Te
MFMAQ) displays a broad band at 3483 cm , which can
1
be assigned to ](OH) group. Te H-NMR spectra oꢀ the
1
ꢀ
uran Schiꢂ base ligand (H-MFMAQ) (Figure 4(a)) exhibit
signals due to aromatic protons as multiplet at ꢄ 6.80–7.23
(8H) and a broad signal at ꢄ (11.35) ppm is assigned ꢀor
O–H proton, which disappeared with addition oꢀ D O due
(
2
13
ꢀ
ormed precipitate was fltered oꢂ, washed with ethanol and
to the proton exchange. In C NMR oꢀ ligand (H-MFMAQ)
(Figure 5(a)) (–C=O) carbonyl carbon showed signal at
166.47 ppm, (–C=N–) azomethine carbon at 162.12 ppm,
(–C–O) phenolic group carbon at 158.27 ppm, and (C–O)
diethylether, and fnally dried to give [Cr(MFMAQ)Cl ] (1),
2
[
Ru(MFMAQ)Cl ] (2), [Mn(MFMAQ)Cl(H O)]⋅H O (3),
2
2
2
[
Co(MFMAQ)Cl(H O)] (4), [Ni(MFMAQ)Cl(H O)]⋅2H O
2
2
2
1
(
5), [Cu(MFMAQ)Cl(H O)] (6), and [Zn(MFMAQ)Cl(H O)]⋅
ꢀuran ring at 170.12. Te spectrum 5N-NMR oꢀ the ligand
2
2
2
.5H O (7) complexes.
(H-MFMAQ) (Figure 6(a)) shows two signals centered 244.3
and 163.3 ppm, which were assigned to N12 (azomethine) and
N1 (quinoline), respectively.
2
3
. Results and Discussions
3
.1. Ligand (H-MFMAQ). H-MFMAQ percentage oꢀ purity
3.2. Complexes. Te empirical ꢀormulae oꢀ complexes show-
ing number oꢀ water molecules are presented in ꢁable 1. All
synthesized solid complexes are stable in air. Tey are prac-
tically insoluble in water, but on the contrary quite soluble
in polar organic solvents (e.g., EtOH, MeOH, DMF, and
DMSO). Te structures oꢀ the complexes could not be deter-
mined because single crystals were not obtained. Te molar
conductivity data (ꢁable 2) clearly indicate that all complexes
in MeOH and DMSO as well as Cr(III), Ru(III), Mn(II),
Co(II), Ni(II), Cu(II), and Zn(II) complexes in MeOH,
was 99.97%; it has been measured by HPLC. Mass spectrum
oꢀ the ꢀuran Schiꢂ base ligand (H-MFMAQ) (Figure 1(a))
has fnal peak at 268 amu corresponding to the ꢀuran Schiꢂ
base ligand moiety [C H N O ] (atomic mass 268 amu)
15
12
2
3
(
Scheme 2). Other peaks like 52, 82, 148, 152, 208, and
2
27 amu were suggested according to diverse ꢀragments.
From this study, it was ꢀound that the intensity oꢀ the
peaks gave inꢀormation on the stability oꢀ ꢀragmentation. Te
electronic spectrum oꢀ ꢀuran Schiꢂ base ligand (H-MFMAQ)

4
Journal oꢀ Chemistry
+
1
18
(CoC H N O ) . Tis schematic mass spectral ꢀragmenta-
15
11
2
3
1
00
tion pattern oꢀ ligand is consistent with its structure which is
depicted in Scheme 3.
9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
O
N
N
52
HO
2
08
8
2
Te ESI mass spectrum oꢀ the Cu(II) complex
O
[Cu(MFMAQ)Cl(H O)] (Figure 1(c)) shows the parental ion
1
48
2
2
27
Ligand
(M.Wt. = 268)
+
peak at ꢅ/ꢆ = 384 corresponding to (CoC H ClN O ) .
152
15 13
2
4
268
Te diꢂerent ꢀragments oꢀ the complex with diꢂerent
+
+
ꢅ/ꢆ values are present at 97 (C H NO) , 120 (C H N ) ,
5
7
7
8
2
+
50
100
150
200
Mass/Charge
a)
250
300
350
400
202 (CuC6H7N2O2) , and 326 (CuC13H11ClN2O2). Tis
schematic mass spectral ꢀragmentation pattern oꢀ ligand is
consistent with its structure which is depicted in Scheme 4.
Te ESI mass spectrum oꢀ the Ru(III) complex
(
144
[Ru(MFMAQ)Cl ] (Figure 1(d)) shows the molecular ion
2
1
00
Co(II) complex
Cl
peak at ꢅ/ꢆ = 439 corresponding to (RuC H Cl N O )+.
9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
N
15 11
2
2
3
(
M.Wt. = 379)
N
O
Co
118
Te other ꢀragments oꢀ the complex show the peaks at
77
O
O
+
+
diꢂerent ꢅ/ꢆ values like at 56 (C H ) , 210 (RuC H NO) ,
／（2
4
8
6
7
+
+
1
58 (C H N ) , 263 (RuC H N O ) , and 326
1
0
10
2
8
6
2
2
+
(RuC H N OCl) . Tis schematic mass spectral ꢀragmen-
3
79
11 14
2
379
tation pattern oꢀ ligand is consistent with its structure
which is depicted in Scheme 5. Tese ꢀacts were matched
to the suggested molecular ꢀormula ꢀor these complexes,
that is, [Co(MFMAQ)Cl(H2O)], [Cu(MFMAQ)Cl(H2O)],
5
0
100 150 200 250 300 350 400 450 500
Mass/Charge
(b)
and [Ru(MFMAQ)Cl ], where MFMAQ is the ligand. Tis
2
1
20
1
00
Cl
Cu
confrms the Schiꢂ base ꢀrame ꢀormation. Elemental analysis
values were appropriate with those values calculated ꢀrom
the molecular ꢀormulae assigned to these complexes which
are ꢀurther supported by mass studies.
9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
N
N
O
Cu(II) complex
M.Wt. = 384)
(
O
O
（
2
／
97
202
156
326
384
3.2.2. Electronic Absorption, Magnetic Measurements, and
Ligand Field Parameter. Te electronic absorption spectra oꢀ
the ꢀree Schiꢂ base ligand and its complexes (Cr(III), Ru(III),
Mn(II), Co(II), Ni(II), Cu(II), and Zn(II)) were studied in
Nujol mull.
50
100 150 200 250 300 350 400 450 500
Mass/Charge
(
c)
−
1
−1
1
58
ꢁ
wo bands were showed at 18,995 (ꢇ = 46 Lmol cm )
1
00
–1
−1
−1
and 16,238 cm (ꢇ = 34 Lmol cm ); ꢀor Cr(III) complex
9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
Ru(III) complex
M.Wt. = 439)
Cl
N
(
[Cr(MFMAQ)Cl ] electronic spectrum, those may be con-
O
2
N
Ru
4
4
4
4
signed to A g(F)→ ꢁ g(F) and A g(F)→ ꢁ g(F) transi-
2
1
2
2
56
263
O
O
tions, respectively, in an octahedral geometry [13], whereas
Cl
439
4
4
the third band, which is due to A g (F)→ ꢁ g (P) tran-
2
1
326
sition, lies in the range oꢀ the ligand transitions that were
–
1
−1
−1
5
0
100 150 200 250 300 350 400 450 500
Mass/Charge
predicted at 34,264 cm (ꢇ = 132 Lmol cm ). Te ligand
feld parameters oꢀ the current Cr(III) complex have been
–
1
calculated using ꢁanabe-Sugano diagramsꢈ (583 cm ), 10ꢉꢊ
(
d)
–
1
(
1742 cm ), and ꢋ (0.53). Te eꢂective magnetic moment oꢀ
Fꢌꢍꢎꢏꢆ 1: Mass spectrum oꢀ (a) ligand, (b) Co(II) complex, (c) Cu(II)
complex, and (d) Ru(III) complex.
the complex is 3.92 BM, which is consistent with the spin-only
value ꢀor three unpaired electrons (3.87 BM) [14].
Electronic
spectrum
oꢀ
Mn(II)
complex
[
Mn(MFMAQ)Cl(H O)]⋅H O exhibits ꢀour weak intensity
2
2
−
1
−1
–
1
2
–1
absorption bands at 17,943 (ꢇ = 30 Lmol cm ), 22,806 (ꢇ =
DMF, and DMSO are in the range 7.58–15.24 Ω cm mol
−
1
−1
−1
−1
−1
3
(
6 Lmol cm ), 27,216 (ꢇ = 64 mol cm ), and 37,489 cm
indicating the nonelectrolytic nature oꢀ all complexes [12].
Tis fnding is consistent with the inꢀrared spectral data that
showed the coordinated nature oꢀ chloride anions.
−
1
−1
ꢇ = 138 Lmol cm ). Tese bands may be assigned to the
6
4
6
4
4
transitions: A1g→ ꢁ1g (4G), A1g→ Eg, A1g (4G) (10ꢈ
6
4
6
4
+
5ꢌ), A g→ Eg (4D) (17ꢈ + 5ꢌ), and A g→ ꢁ g (4P)
1
1
1
3
.2.1. Mass Spectra of Complexes. Te ESI mass spectrum
(7ꢈ + 7ꢌ), respectively. Te ligand parameters ꢈ and ꢌ were
calculated ꢀrom the second and third electronic transitions
because these electronic transitions are ꢀree ꢀrom the crystal
feld splitting and depend on ꢈ and ꢌ parameters [13, 14]. Te
calculated values oꢀ the ligand feld parameters are given in
ꢁable 3. Room temperature magnetic moment oꢀ the Mn(II)
oꢀ the Co(II) complex [Co(MFMAQ)Cl(H O)] (Figure 1(b))
2
shows the parental ion peak at ꢅ/ꢆ = 379 corresponding to
+
(
CoC H ClN O ) . Te other ꢀragments oꢀ the complex
1
5
13
2
4
give the peak with various intensities at diꢂerent ꢅ/ꢆ values
+
+
+
like at 74 (CoO) , 77 (C H ) , 144 (CoC H NO) , and 326
6
5
4
7

Journal oꢀ Chemistry
5
+
O
N
+
O
N
+
N
O
N
OH
OH
m/z = 208 (65.27%)
m/z = 227 (46.07%)
+
+
O
N
+
HO
N
N
O
N
O
N
NH
OH
m/z = 148 (49.86%)
m/z = 152 (30.29%)
m/z = 263 (36.43%)
+
O
+
O
m/z = 82 (63.74%)
+
∙
．
+
m/z = 118 (100%)
m/z = 52 (67.39%)
Sꢄꢅꢆꢇꢆ 2: Mass ꢀragmentation pattern oꢀ ꢀuran Schiꢂ base ligand (H-MFMAQ).
2
1
1
0
0
.0
.5
.0
.5
.0
1.50
- ∗ furanyl group
Ru(III) complex

1.25
2４
2g
4４1g
Cl
N
N N
O
1.00
0.75
0.50
N
O
Ru
HO
- ∗ phenyl group
O
O
O

2４
2g
4４2g
Cl
2４2g
4
- ∗ azomethꢀne group
！1g

∗
n-  -C=N & -C=O groups
0.25
0.00
250
300
350
400
450
300 400 500 600 700 800 900 1000 1100
Wavelength (nm)
Wavelength (nm)
(a)
(b)
Fꢌꢍꢎꢏꢆ 2: Electronic spectrum oꢀ (a) ligand and (b) Ru(III) complex.

6
Journal oꢀ Chemistry
100
105
Cl
N
9
7
6
4
0
5
0
5
O
N
O
N
O
N
Cr
7
5
2
5
0
5
HO
O
O
Cl
4000
3500 3000 2500 2000 1500 1000
500
4000 3500 3000 2500 2000 1500 1000
500
Wavenumber (＝Ｇ−1)
Wavenumber (＝Ｇ−1)
(
a) H-MFMAQ
(b) [Cr(MFMAQ)Cl ]
2
100
8
6
4
2
0
0
0
0
Cl
N
N
O
Co
O
O
（
2
／
4
000 3500 3000 2500 2000 1500 1000
500
Wavenumber (＝Ｇ−1)
(
c) [Co(MFMAQ)Cl(H O)]
2
Fꢌꢍꢎꢏꢆ 3: (a) IR spectrum oꢀ ligand, (b) IR spectrum oꢀ Cr(III) complex, and (c) IR spectrum oꢀ Zn(II) complex.
Cl
N
2.5（2O
N
O
Zn
O
O
／
（2
(
b) [Zn(MFMAQ)Cl(（ O)]2.5（ O
2 2
13
12
11
10
9
8
7
6
5
4
3
2
1
N
O
(a) lꢀgand (H-MFMAQ)
N
OH
O
13
12
11
10
9
8
7
6
5
4
3
2
1
1
Fꢌꢍꢎꢏꢆ 4: H NMR spectra oꢀ (a) Schiꢂ base ligand and (b) Zn(II) complex.

Journal oꢀ Chemistry
7
Cl
N
2.5（2O
N
O
Zn
O
O
／
（2
(
b) [Zn(MFMAQ)Cl(（ O)]2.5（ O
2
2
180
160
140
120
100
80
O
60
40
20
(
ppm)
N
N
OH
O
(a) lꢀgand (H-MFMAQ)
180
160
140
120
100 80
60
40
20
(ppm)
13
Fꢌꢍꢎꢏꢆ 5: C NMR spectra oꢀ (a) Schiꢂ base ligand and (b) Zn(II) complex.
Cl
N12
N1
O
Zn
O
O
N1, N12
／
（2
(
b)
250
200
150
100
50
(ppm)
N1
N1 N12
O
O
N12
HO
(
a)
250
200
150
100
50
(ppm)
15
Fꢌꢍꢎꢏꢆ 6: N NMR spectra oꢀ (a) Schiꢂ base ligand and (b) Zn (II) complex.
−
1
2
−1
∘
ꢁ
ꢉꢊꢋꢆ 2: Molar conductivity oꢀ complexes Λ M/Ω cm mol ꢀor 0,001 mol⋅L−1 solutions in MeOH, DMF, and DMSO at 25 C.
2
−1
Λ
[Ω−1 cm mol ]
M
Complex
MeOH
14.36
12.87
12.42
11.57
DMF
15.24
DMSO
7.58
[
[
[
[
[
[
[
Cr(MFMAQ)Cl ]
2
Ru(MFMAQ)Cl ]
14.25
14.85
13.93
9.77
8.56
8.45
9.27
7.89
2
Mn(MFMAQ)Cl(H O)]⋅H O
2
2
Co(MFMAQ)Cl(H O)]
2
Ni(MFMAQ)Cl(H O)]⋅2H O
12.84
10.75
11.59
14.47
13.74
14.66
2
2
Cu(MFMAQ)Cl(H O)]
2
Zn(MFMAQ)Cl(H O)]⋅2.5H O
8.98
2
2

8
Journal oꢀ Chemistry
+
+
+
Cl
N
N
O
O
N
N
Co
Co
O
O
O
O
／
（2
m/z = 77 (63.43%)
m/z = 326 (2.97%)
m/z = 379 (7.38%)
+
+
NH
+
Co
CoO
OH
O
m/z = 74 (11.14%)
m/z = 144 (100%)
m/z = 118 (71.26%)
Sꢄꢅꢆꢇꢆ 3: Mass ꢀragmentation pattern oꢀ Co(II) complex [Co(MFMAQ)(H O)Cl].
2
+
+
+
Cl
H
N
N
Cl
O
N
N
N
O
Cu
N
Cu
Cu
O
O
O
／
（2
m/z = 326 (2.18%)
m/z = 156 (31.23%)
m/z = 384 (5.07%)
+
+
．
（2
N
+
（2
N
O
N
m/z = 120 (100%)
O
HN
Cu
m/z = 97 (43.26%)
O
m/z = 202 (38.72%)
Sꢄꢅꢆꢇꢆ 4: Mass ꢀragmentation pattern oꢀ Cu(II) complex [Cu(MFMAQ)(H O)Cl].
2
4
4
4
4
complex lies at 5.94 BM; this value is in tune with a high-spin
octahedral confguration.
(F)(] ), ꢁ g→ A g (F)(] ), and ꢁ g→ ꢁ g (P)(] ) tran-
1
1
2
2
1
1
3
sitions, respectively, suggesting an octahedral geometry
around Co(II) ion [13, 14]. Octahedral cobalt(II) complex,
Te electronic spectrum oꢀ cobalt (II) complex
[
Co(MFMAQ)Cl(H O)] recorded in Nujol mulls exhibits
however, preserves a large orbital contribution to magnetic
2
−1
−1
4
three absorption peaks at 13,897 (ꢇ = 24 Lmol cm ), 15,368
moment on account oꢀ ꢁ g (F) ground term and exhibits ꢍeꢂ
1
−1
−1
−1
−1
–1
(
ꢇ = 27 Lmol cm ), and 25,157 (ꢇ = 53 Lmol cm ) cm ,
in the range 4.8–5.6 B.M [15]. Te magnetic measurements
reported here lie at 5.18 BM and demonstrate that the Co(II)
4
4
respectively. Tese bands can be assigned to ꢁ g→ ꢁ g
1
2

Journal oꢀ Chemistry
9
+
+
+
Cl
N
N
N
Cl
O
N
N
O
Ru
N
Ru
O
O
Cl
m/z = 158 (100%)
m/z = 326 (3.27%)
m/z = 439 (3.78%)
+
+
+
N
N
O
N
Ru
O
O
Ru
m/z = 56 (45.32%)
m/z = 210 (22.91%)
m/z = 263 (49.88%)
Sꢄꢅꢆꢇꢆ 5: Mass ꢀragmentation pattern oꢀ Ru(II) complex [Cu(MFMAQ)Cl ].
2
ꢁꢉꢊꢋꢆ 3: Ligand feld parameters oꢀ the complexes.
−
1
−1
−1
Complex
Dq (cm )
ꢈ (cm )
ꢋ
0.88
–
LFSE (kJmol )
[
[
[
[
[
[
[
Cr(MFMAQ)Cl ]
1674
–
1168
792
–
792
–
208.68
2
Ru(MFMAQ)Cl ]
–
100.47
114.23
–
–
–
2
Mn(MFMAQ)(H O)Cl]⋅H O
808
–
0.73
0.95
–
2
2
Co(MFMAQ)(H O)Cl]
2
Ni(MFMQ)(H O)Cl]⋅2H O
–
2
2
Cu(MFMAQ)Cl(H O)]
492
–
0.81
–
2
Zn(MFMAQ)Cl(H O)]2.5H O
–
2
2
complex was paramagnetic and has a high-spin octahedral
results show that the interelectronic repulsion oꢀ d-electrons
4
confguration with ꢁ g(F) ground state.
in a complex is less than in the ꢀree ion. Te value oꢀ ꢈ in a
1
Te ligand feld parameters (ꢁable 3) ꢈ (interelectronic
complex is 78% oꢀ the ꢀree ion value. Te ꢋ value is related
repulsion oꢀ the d-electrons in complex), ꢋ (Te Nephelaux-
etic eꢂect), and 10ꢉꢊ are calculated according to the equation
reported ꢀor the octahedral Co(II) complex.
directly to covalence.
Te reduction oꢀ ꢈ is caused by complex ꢀormation by the
delocalization oꢀ the d-electron cloud on the ligand, which in
turn causes the covalent bond ꢀormation. Te data shows the
Co(II) complex has covalent character in the metal ligand “ꢔ”
bond [15].
ꢍ
= 4.98 (1 − 4ꢂ) = 10ꢉꢊ,
ef
−
1
ꢂ = −178 cm
Electronic spectrum oꢀ [Ni(MFMAQ)Cl(H O)]⋅2H O
2
2
−1
−1
2
2
complex shows bands at 15,053 (ꢇ = 23 Lmol cm ), 17,892
ꢎ4 ꢏ] − 15ꢉꢊꢐ − 10ꢉꢊ ꢑ
3
−1
−1
–1
−1
−1
(
ꢇ = 28 Lmol cm ), and 22,111 cm (ꢇ = 43 Lmol cm ).
ꢈ =
(1)
3
3
ꢒ60 ꢏ] − 15ꢉꢊꢐ − 180ꢉꢊꢓ
3
Tese bands may be specifed to A g(F)→ ꢁ g(F)(] ),
2
2
1
3
3
3
3
A g(F)→ ꢁ g(F)(] ), and A g(F)→ ꢁ g(P)(] ) transi-
2
1
2
2
1
3
]
= 10ꢉꢊ
1
tions, respectively. It proposes octahedral geometry oꢀ
[
Ni(MFMAQ)Cl(H O)]⋅2H O complex [13, 14]. Te mag-
ꢈ ꢏcomplexꢐ
ꢈ (ꢀree ion)
2
2
ꢋ =
,
netic moment was evaluated which gave 3.08 ꢍB, ꢀor
[
Ni(MFMAQ)Cl(H O)]⋅2H O complex which lies in the
2
2
−1
where ꢈ (ꢀree ion) ꢀor Co(II) is 996 cm . Te 10ꢉꢊ, ꢈ, and ꢋ
extent (2.9–3.3 ꢍB) oꢀ the Ni(II) octahedral complexes
[15]. Te Nephelauxetic parameter ꢋ (ꢁable 3) was readily
−
1
−1
values are 7032 cm , 698 cm , and 0.68, respectively. Tese

10
Journal oꢀ Chemistry
−
1
ꢁ
ꢉꢊꢋꢆ 4: IR spectral data (cm ) oꢀ the H-MFMAQ ligand and its metal complexes.
Number
H-MFMAQ
1
2
3
4
5
6
7
]OH
3483br
]
]
]
]
]M–O
–
]M–N
–
]M–Cl
–
(OH)water
C=O
C=N
(C−O–C)ꢀuran
–
–
–
1712m
1693w
1698m
1695s
1693m
1697m
1696m
1698m
1637m
1621m
1622m
1622m
1625sh
1624m
1625m
1623m
1618m
–
–
–
–
–
–
–
1600m
1600w
1605w
1602m
1605m
1604m
1603m
543m
548s
552m
547m
552m
549m
547m
433w
434w
438m
434m
437m
435m
438m
416m
412w
414m
41 m
413m
414m
415m
3320br
3300r
3320br
3300r
3318br
sh: sharp, m: medium, br: broad, s: small, and w: weak.
obtained by utilizing the correlation ꢋ = ꢈ (complex)/ꢈ (ꢀree
vibration which was shiꢈed to lower ꢀrequency by 14–19
–
1
–1
ion), where ꢈ (ꢀree ion) ꢀor Ni(II) is 1041 cm [15]. Te value
and 12–16 cm , suggesting oxygen carbonyl and nitrogen
–
1
oꢀ ꢋ lies at 0.27. Tese values indicated the covalent character
in metal ligand “ꢔ” bond [13].
azomethine involvements in complexity. At 1618 cm , the
band was assigned to the ꢀuran ring ](C–O–C) vibrations
–
1
Te Cu(II) complex [Cu(MFMAQ)Cl(H O)] spectrum
2
which is also shiꢈed to lower ꢀrequency by 13–18 cm ,
which is suggestive to involvement oꢀ the ꢀuran ring in
−1
−1
−1
displayed a band at 22,137 cm (ꢇ = 41 Lmol cm ) assigned
2
2
–
1
to Eg→ ꢁ g transition assuming octahedral geometry
2
chelation. Also, at 3483 cm , the band was attributed to ]OH
in the ligand (H-MFMAQ) which disappeared in its metal
complexes indicating deprotonation oꢀ the OH moiety during
coordination [17]. Te new bands at 543–552, 433–438,
around the central Cu(II) ion [15]. Te emulated magnetic
moment oꢀ the Cu(II) complex is 1.98 BM, which assures the
octahedral structure oꢀ this complex [15].
−1
Te electronic spectrum oꢀ ruthenium(III) complex
and 412–416 cm were assigned to M–O (carbonyl), M–O
(phenol), M–N (azomethine) and (M–Cl) in the metal com-
plexes spectra were observed [15, 17]. Te IR results showed
that the metal was harmonized through one nitrogen atom
(azomethine group) and three oxygen atoms (deprotonated
hydroxyl group, carbonyl group, and ꢀuran ring) besides
chlorine atoms.
[
Ru(MFMAQ)Cl ] records three bands at 15,167 (] ) (ꢇ
2
1
−
1
−1
−1
−1
=
22 Lmol cm ), 17,353 (] ) (ꢇ = 27 Lmol cm ), and
2
−
1
−1
−1
2
5,158 cm (] ) (ꢇ = 61 Lmol cm ) (Figure 2(b)). Tese
3
2
4
2
4
bands may be assigned to ꢁ g→ ꢁ g, ꢁ g→ ꢁ g, and
2
1
2
2
2
4
ꢁ
g→ A g transitions in order oꢀ increasing energy. Te
2
1
position oꢀ bands is in tune with the prediction ꢀor octahedral
complexes oꢀ the metal ions [13]. Te ligand feld parameters
Δ, B, and ꢋ have been calculated by using the relation
3.2.4. NMR Spectra Investigation. Te proton NMR spec-
troscopy oꢀ H-MFMAQ ligand (Figure 4(a)) and its
2
8
6 (ꢈ)
[
Zn(MFMAQ)Cl(H O)]2.5H O complex (Figure 4(b)) was
]
= Δ − 4ꢈ +
2
2
1
Δ
evident in DMSO-d solution employing tetramethylsilane
6
(
2)
2
(ꢁMS) as internal standard. OH signal was ꢀound at
11.35 ppm in the spectrum oꢀ the ligand H-MFMAQ
which completely disappeared in the spectrum oꢀ the
2
(ꢈ)
]
= Δ + 12ꢈ +
.
2
Δꢔ
−
1
Te value oꢀ ꢈ in ꢀree ion is 638 cm . Te value oꢀ ꢋ
indicates that there is low covalency in the metal ligand ꢔ-
band [16]. Te Ru(III) complex shows magnetic moments at
room temperature 1.76 BM, which is lower than the predicted
[Zn(MFMAQ)Cl(H2O)]2.5H2O complex. Tis suggests
the sharing oꢀ the OH group in chelation with Zn(II)
through isolation oꢀ the OH proton. Te azomethine
proton signal was shiꢈed to high feld in the spectrum oꢀ
[Zn(MFMAQ)Cl(H O)]2.5H O complex. It was looked
value oꢀ 2.17 BM. Te lowering in ꢍ values may be due
ef
2
2
to lower symmetry ligand felds, metal-metal interaction, or
at 8.13 ppm as compared to 8.67 ppm in the Schiꢂ’s base
H-MFMAQ. Tis reꢀers to the complexity oꢀ the zinc atom
through nitrogen atom azomethine. However, multiple bands
assigned to the aromatic protons were ꢀound at 6.92–7.97 and
6.98–7.96 ppm in the ꢀree Schiꢂ 22 base ligand and Zn(II)
complex, respectively. Te signal observed at 3.2 ppm with
an integration corresponding to seven protons in the case oꢀ
Zn(II) complex was assigned one coordinate water molecule
and halꢀ past two hydrate water molecules.
extensive electron delocalization [14].
Te Zn(II) complex [Zn(MFMAQ)Cl(H O)]⋅2.5H O is
2
2
diamagnetic as predictable and its geometry is most likely
octahedral likewise Mn(II), Cu(II), Ni(II), and Co(II) com-
plexes oꢀ H-MFMAQ ligand [15].
3
.2.3. Infrared Spectra of Complexes. Te study oꢀ inꢀrared
spectra oꢀ the ꢀuran Schiꢂ base H-MFMAQ comparing to
their metal complexes (1–7) (ꢁable 4; Figure 3) ꢀoremost
revealed that the ligand is tetradentately coordinated to
13
In C NMR oꢀ ligand (Figure 5(a)) (–C=O) carbonyl
carbon showed signal at 166.47 ppm, (–C=N–) azomethine
carbon at 162.12 ppm, (–C–O) phenolic group carbon at
158.27 ppm, and (C–O) ꢀuran ring at 170.12. Te signals due
the metal ions. Te bands were symbolized at 1712 and
637 cm– due to the carbonyl and azomethine stretching
1
1

Journal oꢀ Chemistry
ꢉꢊꢋꢆ 5: Te spin-Hamiltonian parameters oꢀ Cr(III) and Cu(II) Schiꢂ base complexes in DMSO at 300 and 77 K.
11
ꢁ
−
4
−1
Hyperfne constant × 10 cm
Complex
ꢕ
ꢕ
ꢕ
ꢖ
ꢖ
ꢖ
‖
⊥
iso
‖
⊥
iso
[
Cr(MFMAQ)Cl ]
–
163
–
47
84
106
–
–
2.04
1.97
2.11
2
[
Cu(MFMAQ)Cl(H O)]
2.34
2
3
.0
.5
.0
.5
.0
.5
to (–C=N–) azomethine, (–C–O) phenolic, and (C–O) ꢀuran
carbons were slightly shiꢈed downfeld in comparison to the
corresponding signals oꢀ these groups in the ligand thereby
confrming the complexation (Figure 5(b)) with zinc metal
ion.
2
2
1
1
0
1
5
Te N NMR spectra oꢀ the ꢀree ligand (Figure 6(a))
and the Zn(II) complex (Figure 6(b)) were also obtained. Te
spectrum oꢀ the ligand shows two signals centered at 244.3
and 163.3 ppm, which were assigned to N (azomethine)
0.0
−0.5
−
−
−
−
−
−
1.5
2.0
2.5
3.0
3.5
4.0
12
and N (quinoline), respectively. In the spectrum oꢀ Zn(II)
1
complex only one broad signal is observed ꢀor the nitrogen
atoms at 162.7 ppm. Tis behavior led us to assign the broad
signal in the spectra oꢀ the complexes as both N and N
−4.5
12
1
atoms. With this assignment, N shiꢈed 81.6 ppm downfeld
12
3
000 3100 3200 3300 3400 3500 3600 3700 3800 3900
upon coordination to Zn(II). On the other hand, the nitrogen
H [G]
N shiꢈs only 0.6 ppm upon coordination with Zn(II). Tis
1
minor shiꢈ indicates that this atom is not involved in
(a)
coordination as already evidenced by other techniques.
3
2
.0
.5
3
.2.5. ESR Spectra. ꢁhe ESR spectrum oꢀ the [Cr(MFMAQ)Cl ]
2.0
1.5
2
complex (ꢁable 5) has been recorded as polycrystalline sam-
ple at room temperature. No hyperfne interaction was
1
0
0
0.5
1.5
.0
.5
.0
observed in the ESR spectra oꢀ the [Cr(MFMAQ)Cl ] com-
2
plex at room temperature. Te ꢖ-values are calculated by
using the expression, ꢖ = 2.0023(1−4ꢂ/10ꢉꢊ), where ꢂ is the
spin–orbit coupling constant ꢀor the metal ion in the complex.
Owen [18] gives the reduction oꢀ the spin–orbit coupling
−
−
−2.0
−2.5
−1
−
−
−
−
3.0
3.5
4.0
4.5
constant ꢀrom the ꢀree ion value; 90 cm ꢀor chromium(III)
can be employed as a measure oꢀ metal ligand covalency
(
Figure 7(a)). It is possible to defne a covalency parameter
analogues to the Nephelauxetic parameter which is the ratio
oꢀ the spin–orbit coupling constant ꢀor the complex and the
3000 3100 3200 3300 3400 3500 3600 3700 3800 3900
ꢀ
ree Cr(III) ions.
H [G]
Te solid state ESR spectrum oꢀ [Cu(MFMAQ)Cl] com-
(
b)
plex (Figure 7(b)) is displayed at room temperature. Te
shape oꢀ the spectrum is consistent with octahedral envi-
ronment around Cu(II) ion and the higher ꢖ value ꢀor
the investigated [Cu(MFMAQ)Cl] complex (ꢁable 5), when
compared to that oꢀ ꢀree electron (ꢖ = 2.24) revealing an
Fꢌꢍꢎꢏꢆ 7: EPR spectra oꢀ (a) Cr(III) complex and (b) Cu(II) complex
as polycrystalline sample.
2
2
appreciable covalency oꢀ metal ligand bonding withꢗꢘ -ꢙ as
the ground-state characteristic oꢀ octahedral stereochemistry
[Co(MFMAQ)Cl(H2O)], and [Cu(MFMAQ)Cl(H2O)] com-
plexes are depicted. Te indexing procedures were perꢀormed
using (CCP4, UK) CRYSFIRE program [20, 21] giving tri-
clinic crystal system ꢀor [Cr(MFMAQ)Cl2] (Figure 8(a)) hav-
ing M(9) = 7, F(6) = 8, [Co(MFMAQ)Cl(H2O)] orthorhom-
bic crystal system (Figure 8(b)) having M(9) = 8, F(6) = 8,
and tetragonal crystal system ꢀor [Cu(MFMAQ)Cl(H2O)]
(Figure 8(c)) having M(6) = 14, F(6) = 6, as the superior
solutions. Teir cell parameters are interpreted in ꢁable 6.
[
19]. Also, the ꢖ‖/ꢕ‖ value 143 ꢀor the [Cu(MFMAQ)Cl]
complex lies just within the range expected ꢀor octahedral
complex [19]. Te decrease oꢀ the ꢖ-value by 9 compared
to that oꢀ the ꢀree-electron value (2.07) is an approximate
measure oꢀ the ligand feld strength; the stronger the ꢀuran
Schiꢂ’s base ligand feld, the smaller the decrease in the ꢖ
value and vice versa.
3
.2.6. XRD, EDX, SEM, and TEM Morphological Stud-
ꢁhe
images
SEM
oꢀ
[Cr(MFMAQ)Cl ],
2
ies. In Figure 8, XRD patterns oꢀ the [Cr(MFMAQ)Cl ],
[Ni(MFMAQ)Cl(H O)]⋅2H O, and [Cu(MFMAQ)Cl(H O)]
2
2
2
2

1
2
Journal oꢀ Chemistry
ꢁ
ꢉꢊꢋꢆ 6: Crystallographic data ꢀor the Schiꢂ base complexes [Cr(MFMAQ)Cl ], [Co(MFMAQ)Cl(H O)], and [Cu(MFMAQ)Cl(H O)].
2
2
2
Data
[Cr(MFMAQ)Cl ]
[Co(MFMAQ)Cl(H O)]
[Cu(MFMAQ)Cl(H O)]
2
2
2
Empirical ꢀormula
Formula weight
g/mol)
C H Cl N O Cr
C H Cl N O Co
C H Cl N O Cu
15
11
2
10
3
15 13
2
2
4
15 13
2
2
4
390.2
379.7
384.3
(
Radiation
Cu-Kꢁ1
Cu-Kꢁ1
Cu-Kꢁ1
2
ꢚ range
5–60
5–60
1.49997
Orthorhombic
P4/m
5–60
Wavelength ( A˚ )
1.501189
ꢁriclinic
P4/m
1.52153
ꢁetragonal
P4/m
Crystal system
Space group
Unit cell dimensions
∘
(
A˚ , )
ꢛ ( A˚ )
7.986878
8. 00053 4
17.23584
90
90
90
1010.47
17.2354
17. 23 62
16.2358
90
90
90
7.315829
7. 315829
7. 315829
90
90
90
698.74
ꢜ ( A˚ )
∘
ꢝ ( )
∘
ꢁ
( )
∘
ꢋ ( )
∘
ꢞ ( )
3
Volume ( A˚ )
5234.35
(
(
Calc.) density
−
3
1.89785
1.34
1.89
g/cm )
0
≤ ℎ ≤ 3, 0 ≤ ꢟ ≤ 1, 1
3 ≤ ℎ ≤ 10, 1 ≤ ꢟ ≤ 6, 3 ≤
2 ≤ ℎ ≤ 8, 1 ≤ ꢟ ≤ 8, 0 ≤ l
Limiting indices
≤
l ≤ 7
l ≤ 10
≤ 2
ꢠ
2
6
6
ꢡꢢ
0.0000901
298
0.000027
298
0.0000783
298
ꢁ
emperature (K)
1
1
500
200
1050
840
630
420
210
0
Cl
Cr
O
Cl
N
N
O
N
Cl
9
6
3
00
00
00
0
N
O
Co
O
O
／（
2
O
0
10
20
30
40
50
60
70
80
0
10
20
30
(b)
40
2
50
60
70
80
2
(a)
1050
8
6
4
2
40
30
20
10
0
Cl
N
O
N
Cu
O
O
／（
2
0
10
20
30
40
50
60
70
80
2
(
c)
Fꢌꢍꢎꢏꢆ 8: Powder XRD spectra oꢀ (a) Cr(III), (b) Co(II), and (c) Cu(II) complexes.

Journal oꢀ Chemistry
13
ꢁꢉꢊꢋꢆ 7: Termal decomposition steps oꢀ the Cr(III), Ni(II), and Cu(II) complexes in ꢁG plots.
ꢁ
emperature
Weight loss (%)
DꢁG peaks
Residue ꢀound%
Complex
∘
∘
Assignments
range ( C)
( C)
(calc.%)
Obs.
45.59
34.88
Cal.
45.62
34.90
372–423
418
544
−C H NOCl
1/2Cr O
6
5
2
2
3
[
[
Cr(MFMAQ)Cl ]
2
1
9.71 (19.73)
473–798
−C H NO
9
6
0.5
−
2H O (hydrated) +
2
92–194
12.87
12.99
122, 163
H O (coordinated)
NiO
2
Ni(MFMAQ)Cl(H O)]⋅2H O
2
2
1
7.92 (17.97)
313–444
43.18
25.72
4.62
43.22
25.77
4.68
398
722
249
326
565
−C H NOCl
9
6
4
62–799
92–273
293–484
06–798
−C H NO
6
5
1
−H O (coordinated)
2
CuO
20.63 (20.68)
[
Cu(MFMAQ)Cl(H O)]
2
46.95
27.58
46.99
27.61
−C H NOCl
9
7
5
−C H NO
6
4
complexes were showed in Figures 9(a)–9(c), respectively.
Te micrograph oꢀ [Cr(MFMAQ)Cl ] complex shows
which is 39.64% (calc. 38.46%). Te fnal pyrolysis prod-
uct, projected as chromium(III) oxide, and some unreacted
residue had an observed mass oꢀ 33.52% (calc. 33.34%).
Te ꢁG curve oꢀ the [Ni(MFMAQ)Cl(H O)]⋅2H O com-
2
peel shaped particles. Te [Ni(MFMAQ)Cl(H O)]⋅
2
2
[
H O complex mentions ice rock structure. Te
2
2
2
Cu(DPPMHQ)Cl(H O)] complex grain-structure oꢀ ice
plex shows the three-step decomposition process; in the frst
step 4.52% (calc. 4.23%) weight loss has been observed in the
2
was existent. Te chemical composition oꢀ Schiꢂ base
complexes was determined using energy dispersive X-
ray diꢂraction (EDX). In EDX profle oꢀ Cr(III), Ni(II),
and Cu(II) complexes (Figures 9(a)–9(c)) the peaks oꢀ
essential elements like C, N, O and respective Cr(III),
Ni(II), and Cu(II) elements which constitute the molecules
oꢀ [Cr(MFMAQ)Cl ], [Ni(MFMAQ)Cl(H O)]⋅2H O, and
∘
range oꢀ 92–124 C, which indicates the presence oꢀ one lattice
water molecule in the complex. Another 4.86% (calc. 4.23%)
weight loss corresponds to one coordinated water molecule
∘
which has been observed in the range oꢀ 124–173
C. In the
∘
∘
second step oꢀ decomposition starting ꢀrom 313 C to 442 C,
nonchelated part oꢀ the ligand is eliminated which has been
ꢀound to be 24.82% (calc. 26.04%). In the last step starting
2
2
2
[
Cu(MFMAQ)Cl(H O)] complexes are clearly identifed
2
∘
supporting the proposed structures. All positions contain
predictable elements, and diꢂerent elements such as impurity
were not detected.
ꢀrom 462 C to the fnal temperature, 46.84% (calc. 46.28%)
weight loss corresponds to the remaining part oꢀ the ligand
which has been noticed and the ultimate pyrolysis product is
obtained as nickel(II) oxide oꢀ mass 18.96% (calc. 18.03%).
Quite similar results have been recorded ꢀor
Figures 10(a)–10(c) show the ꢁEM images oꢀ
[
[
Cr(MFMAQ)Cl ], [Ni(MFMAQ)Cl(H O)]⋅2H O, and
2
2
2
Cu(MFMAQ)Cl(H O)] complexes, respectively. Te con-
2
[Cu(MFMAQ)Cl(H2O)] where decomposition takes place
∘
∘
sistency and resemblance in between the particle ꢀorms oꢀ
synthesized dimeric complexes suggest that structural phases
have a similar template. Te particles diameter is ꢀound in
nano range as ꢀollows: Cr(II), 62–224 nm; Ni(II), 18–23 nm;
Cu(II), 12–32 nm. Nanoparticle-size complexes may act
strong in diꢂerent application areas in a biological one.
in three steps in the range oꢀ 192–273 C, 293–484 C,
∘
and 506–798 C, respectively, and copper (II) oxide; mass
oꢀ 21.19% (calc. 19.78%) seems to be the fnal product.
Te only diꢂerence is that no lattice water molecule is
presented in [Cu(MFMAQ)Cl(H O)] complex. On the
2
basis oꢀ ꢁG analysis the increasing order oꢀ the stability oꢀ
complexes is as ꢀollows: [Ni(MFMAQ)Cl(H O)]⋅2H O <
2
2
[
Cu(MFMAQ)Cl(H O)] < [Cr(MFMAQ)Cl ]. Tus, the
2
2
3
.2.7. ꢁermal Decomposition. ꢁo evaluate the thermal
Co(II) complex shows excellent thermal stability in all the
complexes when subjected to higher temperature; hence it is
used in such types oꢀ applications.
behavior oꢀ metal complexes, the thermogravimetric (ꢁG/
DꢁG) curves ꢀor the complexes are represented in Figure 11
and weight loss at diꢂerent decomposition stages, tem-
peratures ranges with DꢁG peaks, assignments, and the
fnal pyrolysis product observed in the present studies are
summarized in ꢁable 7.
3.2.8. Structure of the Complexes. Based on the above studies,
the ꢀollowing structure (Scheme 6) may suggest these com-
plexes.
In ꢁGA curve oꢀ the [Cr(MFMAQ)Cl ] complex does
2
∘
not show any weight loss up to 385 C; this indicates the
absence oꢀ lattice and coordinated water molecules in it.
Te [Cr(MFMAQ)Cl ] complex shows two-step decompo-
3.2.9. Cytotoxicity Studies. Te anticancer activities oꢀ the H-
MFMAQ Schiꢂ base ligand and its metal(II/III) complexes
against the human breast (MCF-7) and lung cancer (A549)
cell lines were screened using Mꢁꢁ assay. Te results were
analyzed by cell viability curves and expressed as IC
2
∘
∘
sition process in the range oꢀ 372–423 C and 473–798 C,
respectively; the frst step is relatively ꢀast and a total oꢀ
50
2
6.84% weight loss has been observed which corresponds
values. Te maximal inhibition concentrations (IC ) given
50
to the nonchelated part oꢀ the ligand moiety. Te remaining
chelated part oꢀ the ligand is decomposed in the second step
in ꢁable 8 showed that the cytotoxicity eꢐciencies oꢀ the
compounds under investigation ꢀollow the order: Cr(III)

14
Journal oꢀ Chemistry
10000
(a)
(a)
8
6
4
2
000
000
000
000
0
C
Cl
N
O
N
Cr
N
O
O
O
Cl
Co
Co
0
5
10
KeV)
15
20
a)
(
(
10000
(
b)
(b)
8
6
4
2
000
000
000
000
0
C
Cl
Ni
N
O
N
2
（ ／
2
N
O
O
O
／（
2
Ni
Ni
0
5
10
KeV)
15
20
b)
(
(
10000
(
c)
(c)
C
8
6
4
2
000
000
000
000
0
O
Cl
N
O
N
Cu
N
O
O
Cu
／（2
Cu
0
5
10
KeV)
15
20
(
(
c)
Fꢌꢍꢎꢏꢆ 9: Te SEM/EDX images oꢀ (a): Cr(III), (b): Ni(II), and (c): Cu(II) complexes.

Journal oꢀ Chemistry
15
(a)
(b)
(a)
(b)
(c)
(
c)
Fꢌꢍꢎꢏꢆ 10: ꢁEM images oꢀ (a): Cr(III), (b): Ni(II), and (c): Cu(II) complexes.
1
7
5
2
0
00
5
2
0
−
−
−
2
4
6
0
5
C
B
F
C
I
D
TG
DTG
1
00 200 300 400 500 600 700
Temp.
∘
Fꢌꢍꢎꢏꢆ 11: ꢁG and DꢁG 3D-plots oꢀ Cr(III), Ni(II), and Cu(II) complexes up to 800 C.
complex > Ru(III) complex > H-MFMAQ > Mn(II) complex
and damage its structure resulting in the impairment oꢀ its
ꢀunction, which is ꢀollowed by replication and transcription
processes inhibition and eventually cell death that is what we
can suppose [22–26]. Tus, the relatively higher cytotoxicity
exhibited by the Cr(III) and Ru(III) complexes may be due to
the relatively stronger binding ability oꢀ the complexes with
DNA as shown in the DNA binding studies.
>
Co(II) complex > Ni(II) complex > Cu(II) complex >
Zn(II) complex. From the results, it is evident that the Cr(III)
and Ru(III) complexes exhibited higher in vitro cytotoxicity
against both the selected cell lines when compared to the
Schiꢂ base ligand. Also, the cytotoxicity eꢐciency oꢀ the
Cr(III) and Ru(III) complexes is comparable with that oꢀ the
standard drug, cis-platin, while the Mn(II), Co(II), Ni(II),
Cu(II), and Zn(II) complexes showed lower anticancer activ-
ities when compared to that oꢀ the ligand. Te cytotoxicity oꢀ
metal complexes is depending on their ability to bind DNA
4. Conclusion
Te structures oꢀ the complexes oꢀ H-MFMAQ with Cr(III),
Ru(III), Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) ions are

1
6
Journal oꢀ Chemistry
A-549
a
ꢁ
ꢉꢊꢋꢆ 8: Cytotoxicities (IC , ꢍM) oꢀ the Schiꢂ base ligand and its complexes .
50
Compound
Ligand
Cr(III) complex
Ru(III) complex
Mn(II) complex
Co(II) complex
Ni(II) complex
Cu(II) complex
MCF-7
25 ± 1.2
28 ± 1.4
17 ± 1.6
20 ± 1.7
18 ± 1.5
21 ± 1.7
21 ± 1.6
24 ± 1.6
19 ± 1.7
22 ± 1.9
21 ± 1.7
28 ± 1.4
26 ± 1.5
37 ± 0.8
Zn(II) complex
29 ± 1.7
38 ± 1.2
Cisplatin
13 ± 0.5
12 ± 0.9
a
IC : concentration oꢀ the drug required to inhibit growth oꢀ 50% oꢀ the cancer cells (ꢀM). Te data are mean ± SD oꢀ three replicates each.
50
Cl
M
Cl
M
N
N
O
O
N
N
n（ ／
2
O
O
O
O
Cl
／（2
M = Mn(II), n = 1 (3);
M = Cr(III) (1) & Ru(III) (2).
Co(II), n = 0 (4);
Ni(II), n = 2 (5);
Cu(II), n = 0 (6) and
Zn(II), n = 2.5 (7)
Sꢄꢅꢆꢇꢆ 6: Te proposed structures oꢀ H-MFMAQ complexes.
1
13
confrmed by the elemental analyses, IR, NMR ( H, C, and
N) NMR, molar conductance, magnetic moment, UV–Vis.,
mass, ESR, SEM, EDX, ꢁEM, and thermal analyses data.
Tereꢀore, ꢀrom the IR spectra, it is concluded that H-
MFMAQ behaves as a Schiꢂ’s base tetradentate ligand with
Acknowledgments
15
Tis work was ꢀunded by the Deanship oꢀ Scientifc Research
at Princess Nourah Bint Abdulrahman University, through
the Research Groups Program (Grant no. RGP-1438-00. . ..).
O N sites coordinating to the metal ions via the azomethine
N group, ꢀuran O ring, carbonyl O group, and deprotonated
hydroxyl-O group. From the molar conductance data oꢀ the
3
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