Synthesis, structural characterization and biological evaluation of mononuclear transition metal complexes of zwitterionic dehydroacetic acid N-aroylhydrazone ligand

Article abstract of DOI:10.1002/aoc.4278

Synthesis and characterization of mononuclear transition metal complexes viz., Co(II), Ni(II), Cu(II) and Zn(II) with a newly designed ligand, (E)-2-benzamido-N'-(1-(2-hydroxy-6-methyl-4-oxo-4H-pyran-3-yl) ethylidene) benzohydrazide (H₂L) are r

Full text of DOI:10.1002/aoc.4278

Received: 30 October 2017
DOI: 10.1002/aoc.4278
Revised: 21 December 2017
Accepted: 23 December 2017
F U L L P A P E R
Synthesis, structural characterization and biological
evaluation of mononuclear transition metal complexes of
zwitterionic dehydroacetic acid N‐aroylhydrazone ligand
1
1
1
1
Umashri Kendur | Geeta H. Chimmalagi | Sunil M. Patil | Kalagouda B. Gudasi
|
2
Christopher S. Frampton
1
Department of Studies in Chemistry,
Synthesis and characterization of mononuclear transition metal complexes viz.,
Co(II), Ni(II), Cu(II) and Zn(II) with a newly designed ligand, (E)‐2‐benzamido‐
N'‐(1‐(2‐hydroxy‐6‐methyl‐4‐oxo‐4H‐pyran‐3‐yl) ethylidene) benzohydrazide
Karnatak University, Dharwad 580003
Karnataka, India
2
Institute of Materials & Manufacturing,
Wolfson Centre for Materials Processing,
Brunel University, London, Uxbridge, UK
(
H L) are reported. Molecular structures of H L, Ni(II) and Cu(II) complexes
2 2
were determined by single‐crystal X‐ray diffraction studies. The structures were
stabilized by various intra/inter‐molecular H‐bonding, C‐H···π and π···π stack-
Correspondence
Kalagouda B. Gudasi, Department of
Studies in Chemistry, Karnatak
University, Dharwad‐580003, Karnataka,
India.
ing interactions. H L exists in zwitterionic form and acts in a monoanionic man-
2
ner. Ligand/metal ratio was 2:1 for cobalt, nickel and zinc, whereas 1:1 for the
copper complex. Co(II), Ni(II) and Zn(II) complexes display distorted octahedral
geometry, while the Cu(II) complex shows distorted square pyramidal geometry
around the metal ion. Hirshfeld surface analysis and 2D fingerprint plots
Email: kbgudasi@gmail.com
Funding information
DST‐PURSE Phase II programme; UPE‐
FAR‐I programme
revealed that H L and its complexes were supported mainly by H⋯H, O⋯H
2
and C⋯H intermolecular interactions. The synthesized compounds were
screened for in vitro anti‐inflammatory activity by gelatin zymography and the
activity was comparable with tetracycline. Their cleavage behavior towards calf
thymus DNA has been studied using agarose gel electrophoresis method. H2L
and Cu(II) complex were selected by National Cancer Institute (NCI) for
in vitro single dose testing in the full NCI 60 cell lines panel assay. Finally, molec-
ular docking simulation effectively proves the binding of all the synthesized com-
pounds at cyclooxygenase‐2 (COX‐2) active sites.
KEYWORDS
(E)‐2‐amino‐N'‐(1‐(2‐hydroxy‐6‐methyl‐4‐oxo‐4H‐pyran‐3‐yl)ethylidene) benzohydrazide, anti‐
inflammatory and anticancer activity, molecular docking, single crystal X‐ray diffraction study,
transition metal complexes
1
| INTRODUCTION
numerous diseases. Most biological molecules (proteins
and DNA) are electron‐rich, while on the contrary; metal
The profuseness of metal housed compounds in medicine
dates from the 16 century, since then metals or metal‐
bearing compounds were used in the treatment of
ions are electron‐poor, accordingly, there is a general pro-
pensity for metal ions to bind to and interact with many
essential biological molecules. Metal ions also have a
th
[1]
Appl Organometal Chem. 2018;e4278.
wileyonlinelibrary.com/journal/aoc
Copyright © 2018 John Wiley & Sons, Ltd.
1 of 21
https://doi.org/10.1002/aoc.4278

2
of 21
KENDUR ET AL.
[
8]
great affinity for small molecules, like O , being essential
Rosenberg et al. . Compared to platinum‐based drugs,
copper‐based coordination compounds may act as more
potent anticancer agents, with reduced toxicity towards
normal cells and may potentially evade the chemo‐
2
for life. These considerations have incited much of the
past and present interest in devising novel means to use
metals or metal‐bearing compounds to modulate
[2a,b]
[9]
biological systems.
resistance related to platinum‐based drugs.
Curiosity in metal‐based therapy has been revolution-
ized, as on coordination, not only bioactive ligands may
improve their bioactivity profiles, but also inactive ligands
In line with the above discussion, here we report the
synthesis, characterization and crystal structures of
transition metal complexes of newly designed tridentate
ONO‐chelator (H L). Structural descriptions of H L,
[3a–e]
might acquire pharmacological properties.
Metal
2
2
coordination is one of the most efficient approaches to
Ni(II) and Cu(II) complexes have been corroborated with
calculations of Hirshfeld surfaces which reveal an effect of
noncovalent interactions on the properties of the surfaces.
The in vitro anti‐inflammatory potency of all the synthe-
sized compounds by gelatin zymography is comparable
[4]
design long‐acting or slow‐release drugs. In this regard,
hydrazones constitute an important class of biologically
active ligand molecules which have fascinated
bioinorganic and medicinal chemists due to their versatile
coordination behavior, chelating capacity, structural trac-
tability (that can furnish rigidness to the skeletal frame-
work of the prepared metal complexes) and are endowed
with various pharmacological properties. Hydrazones in
concert with several metals have been widely used as
building blocks to produce a large variety of biologically
to that of tetracycline. H L and Cu(II) complex were
2
selected by NCI under Development Therapeutic Program
(NCI‐60 DTP Human Tumor Cell Line Screen) for
screening in human cancer cell lines. Further, their
cleavage behavior towards calf thymus DNA has been
studied using agarose gel electrophoresis method.
[5a,b]
active topologies.
The modularity, candid synthesis,
and stability towards hydrolysis of hydrazones can be
cited as reasons for their popularity. Functional diversity
of azomethine group in hydrazones, characterized by the
triatomic structure C‐N‐N enables its use in numerous
fields. Agile analysis of the structure of hydrazone
2
2
| EXPERIMENTAL
.1 | Materials and methods
Dehydroacetic acid received from Alfa‐Aeasar (Thermo
Fisher Scientific, Hyderabad, India) and other reagents
from Spectrochem (Spectrochem Pvt. Ltd., Mumbai,
India), were used as supplied. Solvents were purified
and dried according to standard procedures.
metal salts used were in their hydrated form except
anhydrous ZnCl , i.e., CoCl ·6H O, NiCl ·6H O and
(Figure 1) divulges that it has (i) an imine carbon that
has both electrophilic and nucleophilic character, (ii)
nucleophilic imine and amino‐type nitrogens, (iii) an
acidic N–H proton, and (iv) configurational isomerism
emanating from the innate nature of C¼N bond [6a–c].
Furthermore, Gelatinases shown in a number of
physiologic and pathologic conditions play an essential
role in inflammation. MMPs (matrix metalloproteinases)
are produced by activated inflammatory cells like
neutrophils, fibroblasts, macrophages, epithelial cells,
and vascular endothelial cells. Overexpression of MMPs
in higher grades may be associated with tissue damage
in chronic inflammatory diseases such as periodontitis,
[
10]
All the
2
2
2
2
2
CuCl ·2H O. Infrared (IR) spectra of the ligand and its
2
2
complexes were recorded in KBr discs in the region
4000–400 cm‐ on a Nicolet‐6700 FT‐IR spectrometer
(Thermo Fisher Scientific India Pvt. Ltd., Mumbai, India).
The CHN analysis was carried out using a Thermo quest
elemental analyzer (Mumbai, India). The H NMR spectra
were recorded on AGILENT VNMRS‐400 spectrometer
1
1
[7]
rheumatoid and osteoarthritis. Cancer chemotherapy
with platinum drugs has been used since the serendipi-
tous discovery of cisplatin's anti‐proliferate properties by
(Agilent Technologies India Pvt. Ltd., Bengaluru, India),
in DMSO‐d solvent. The solution state UV–Vis spectra
6
of all the compounds were recorded in the range of 200–
00 nm at 10‐ mol L in DMF to obtain π – π*, n – π*
5
‐1
5
‐3
‐1
transitions and in the range of 500–1000 nm at 10 mol L
in DMF to obtain d‐d transitions using JASCO V‐670 50
UV–Vis spectrophotometer (Antech, Bengaluru, India).
Thermal behavior of the complexes was analyzed on a
Universal V2.4F TA instrument (TA Instruments, Lukens
Drive, New Castle USA), from room temperature to a final
temperature of 1000 °C at the heating rate of 10 °C/min.
The molar conductivity measurements of 1 mM complex
solutions in DMF were carried out on Equiptronics EQ‐665
conductivity bridge (Equiptronics, Mumbai, India). The
FIGURE 1 The structural and functional diversity of hydrazone
scaffold

KENDUR ET AL.
3 of 21
mass spectrum of the ligand was recorded on an LC‐MS
Applied Biosystems MDS SCIEX‐API 4000 spectrometer
(m, N1‐H and N2‐H); 1695 (s, pyrone C18=O and lactone
C22¼O); 1668 (s, amide C14=O); 1651 (s, amide C7¼O);
1
(
Mangaluru, India). The ESI mass spectral data for all
1604 (m, C¼N). H NMR (DMSO‐d , 400 MHz)
6
the complexes were obtained using a Waters UPLC‐
TQD mass spectrometer (Waters Pvt. Ltd. Mumbai,
India).
δ(ppm):15.89 (s, 1H, O3‐H), 11.36 (s, 1H, N1‐H), 11.78
(s, 1H, N2‐H), 8.33 (d, 1H, ArH, J=8.4 Hz), 7.92 (d, 2H,
ArH, J=5.2 Hz), 7.82 (d, 1H, ArH, J¼8 Hz), 7.66‐7.55
(
m, 4H, ArH), 7.29 (t, 1H, ArH, J¼6.8 Hz), 5.85 (s,1H,
C19‐H), 2.61 (s,3H, C21‐H3), 2.11 (s,3H, C16‐H3).
+
LC‐MS (m/z): 406 ([M] ). UV/Vis (DMF) λmax, nm (logε,
2
2
.2 | Synthesis
L mol‐ cm ) transitions: 270 (7.66), 304 (7.57) π – π*,
1
‐1
.2.1 | Synthesis of (E)‐2‐benzamido‐N'‐(1‐
391 (7.87) n – π*.
(2‐hydroxy‐6‐methyl‐4‐oxo‐4H‐pyran‐3‐yl)
ethylidene) benzohydrazide (H L)
2
2
.2.2 | Synthesis of metal complexes
Schematic representation of the synthesis of ligand is
given in Scheme 1. First, methyl 2‐benzamidobenzoate
was obtained from acylation of methyl anthranilate with
Schematic depiction of synthesis of the complexes is given
in Scheme 2. Co(II) and Ni(II) complexes were obtained
by refluxing the respective hexa hydrated metal chlorides
(0.293 g, 1.2 mmol) with the methanolic solution of H2L
(0.500 g, 1.2 mmol) for 2 h. The crystalline product was
obtained by evaporating the solvent under reduced
pressure. Single crystals were obtained by evaporating
the methanolic solution of Ni(II) complex. To the metha-
[11]
an acyl chloride by the reported method.
In the next
step, methyl 2‐benzamidobenzoate (2 g, 7.8 mmol) was
refluxed in 20.0 ml of 80% hydrazine hydrate solution,
to obtain 2‐benzamidobenzohydrazide (1.12 g, Yield:
[12]
5
6%).
Finally, to the magnetically stirred methanolic
solution of 2‐benzamidobenzohydrazide (2 g, 7.8 mmol),
dehydroacetic acid (1.32 g, 7.8 mmol) in methanol was
added dropwise. The mixture was refluxed on the water
bath for 0.5 h. The progress of the reaction was moni-
tored by TLC. The colorless precipitate formed was fil-
tered and washed with hot methanol. The solid
product was dried in vacuo for 2 h. Crystals suitable
for single X‐ray diffraction (SC‐XRD) was obtained by
slow evaporation of the filtrate.
nolic solution of H L (0.500 g, 1.2 mmol), a methanolic
solution of CuCl .2H O (0.210 g, 1.2 mmol) was added
2
2
2
dropwise and the resulting suspension was stirred for
1 h at room temperature. The green precipitate obtained
was filtered off, washed with cold methanol and dried in
vacuo. Tiny single crystals suitable for SC‐XRD were
obtained by slow evaporation of the filtrate. Whereas,
Zn(II) complex was obtained by refluxing anhydrous
Yield: 78 %; m.p. 240 °C; Color: colouless. Anal. Calc.
for C H N O : C, 65.18; H, 4.72; N, 10.37. Found for
H L: C, 65.50; H, 4.97; N, 10.55. FTIR (cm ): ν= 3221
2
ZnCl (0.168 g, 1.2 mmol) with the methanolic solution
2
of H L (0.500 g, 1.2 mmol) for 3 h. The yellow product
22
19
3
5
2
‐
1
was filtered and washed with methanol.
2
SCHEME 1 Synthetic route for the preparation of H L

4
of 21
KENDUR ET AL.
SCHEME 2 Synthetic route for the preparation of complexes
[
Co(HL) ] (1)
[Cu(HL)Cl (H O)].H O (3)
2 2
2
Color: Tyrian purple, Yield: 68%. Anal. Calc. for
Color: Green, Yield: 70%. Anal. Calc. for
C H N O Co: C, 60.90; H, 4.18; Co, 6.79; N, 9.69.
Found: C, 60.79; H, 4.29; Co, 6.62; N, 9.58. FTIR (cm ):
C H N O ClCu: C, 48.98; H, 4.11; Cl, 6.57; Cu, 11.78;
44
36
6
10
22 22 3 7
‐
1
N, 7.79. Found: C, 48.75; H, 4.20; Cl, 6.73; Cu, 11.99; N,
‐
1
ν= 3295 (m, N1‐H and N2‐H); 1682 (s, lactone C22¼O);
7.65. FTIR (cm ): ν= 3377 (m, N1‐H and N2‐H); 1695
(s, lactone C22¼O); 1674 (s, pyrone C18¼O); 1645
(s, amide C7¼O); 1618 (s, amide C14¼O); 1592
(m, C=N). ESI‐MS (positive mode m/z) 545 ([Cu(HL)
1
656 (s, amide C7=O); 1614 (s, amide C14¼O); 1589 (m,
+
C¼N). ESI‐MS (positive mode m/z) 868 ([Co(HL) ‐H] ).
2
−
1
2
−1
Molar conductivity (Ohm
cm mol ): 5.2. UV/Vis
DMF) λmax, nm (logε, L mol‐ cm ) transitions: 270
8.27) π – π*, 380 (7.93) n – π*, 749 (4.064), 850 (4.22)
1
‐1
Cl(H O)]+Na] ),
+
522
([Cu(HL)Cl(H O)] ),
+
467
(
(
2
2
+
−1
2
−1
[Cu(HL) ]. Molar conductivity (Ohm
cm mol ):
32. UV/Vis (DMF) λmax, nm (logε, L mol‐ cm ) transi-
tions: 270 (7.88) π – π*, 371 (7.87) n – π*, 659 (5.17)
d–d transitions.
1
‐1
d–d transitions.
[
Ni(HL) ] (2)
2
Color: Fern green, Yield: 66%. Anal. Calc. for
C H N O Ni: C, 60.92; H, 4.18; N, 9.69; Ni, 6.77. Found
C, 60.92; H, 4.18; N, 9.69; Ni, 6.77. FTIR (cm ): ν= 3190
[Zn(HL) ] (4)
44
36
6
10
2
‐1
Color: Yellow, Yield: 60%. Anal. Calc. for C H N O Zn:
44
36 6 10
(
m, N1‐H and N2‐H); 1680 (s, lactone C22=O); 1665
C, 60.45; H, 4.15; N, 9.61; Zn, 7.48. Found: C, 60.65; H,
‐1
(
s, amide C7¼O); 1620 (s, amide C14¼O); 1585 (m,
4.02; N, 9.53; Zn, 7.39. FTIR (cm ): ν= 3323 (m, N1‐H
and N2‐H); 1677 (s, lactone C22=O); 1656 (s, amide
C7¼O); 1627 (s, amide C14=O); 1598 (m, C¼N). ESI‐MS
+
C¼N). ESI‐MS (positive mode m/z) 868 ([Ni(HL) ‐H] ).
2
−
1
2
−1
Molar conductivity (Ohm
cm mol ): 4.3. UV/Vis
DMF) λmax, nm (logε, L mol‐ cm ) transitions: 270
1
‐1
(positive mode m/z) 871 ([Zn(HL) ‐H] ). H NMR
+
1
(
(
2
7.63) π – π*, 385 (7.65) n – π*, 560 (5.46), 927 (5.52),
35 (5.53) d–d transitions.
(DMSO‐d6, 400 MHz) δ(ppm):11.80 (s, 1H, N1‐H), 12.65
(s, 1H, N2‐H), 8.40 (d, 1H, ArH, J=8.4 Hz), 7.91 (d, 2H,
9

KENDUR ET AL.
5 of 21
ArH, J=5.2 Hz), 7.61‐7.53 (m, 5H, ArH), 7.19 (t, 1H, ArH,
J=6.8 Hz), 5.76 (s,1H,C19‐H), 2.59 (s,3H, C21‐H3), 2.06
blended independently and afterwards brooded for
15‐30 min. Non reducing buffer in equal volume was
added, blended and 20 μL was filled in each well
employing gel loading pipette tips and 10 μL molecular
weight marker was filled in last well. 0.9% normal saline
with 50 μL of the tissue sample is used as the control.
Initially, the gel electrophoresis apparatus was run at
about 100 V until the bromophenol blue reached the bot-
tom of the plates. After electrophoresis, the equipment
was disassembled, the gel was gently detached and the
equipment was washed with zymogram renaturing
buffer and let the proteins to denature. Later, the gel
was incubated in zymogram incubation buffer at 37 °C
overnight and smeared with Coomassie blue R250 for
one hour. Presence of gelatinases appeared as white
bands, the upper bands are gelatinase‐B (MMP‐9) while
the lower bands are gelatinase‐A (MMP‐2). Using gel
documentation system, the percentage of inhibition was
assigned.
−
1
2
−1
(
7
s,3H, C16‐H3). Molar conductivity (Ohm cm mol ):
.6. UV/Vis (DMF) λmax, nm (logε, L mol‐ cm ) transi-
1
‐1
tions: 269 (8.08) π – π*, 379 (8.19) n – π*.
2.3 | X‐ray crystallography
Selected crystals of H L, 2 and 3 were mounted on the tip
2
of a 200 μm Mitagen loop with perfluorinated oil and
cooled rapidly to 100 K in a stream of cold nitrogen. Data
were collected on an Oxford Diffraction, (Agilent
Technologies, Santa Clara, USA), SuperNova X‐ray
diffractometer equipped with an Oxford Cryosystems
Cobra Low‐temperature device using Cu Kα radiation
(
λ = 154.178 pm) from a SuperNova Cu X‐ray micro
source and focusing mirror optics. The structures
2
were solved by direct methods and refined against F
by full‐matrix least‐squares using the program SHELXL‐
[13]
2
014/6.
2
.5.2 | NCI‐60 Human Cancer Cell Line
Screening methodology
2.4 | Hirshfeld surface analysis
Compounds H L and 3 were screened against a panel
2
Hirshfeld surfaces (HSs) and 2D fingerprint plots (FPs)
[14]
of 60 human cancer cell lines at NCI. Screening is a
two‐step process, first a single concentration is tested
against all 60 cell lines at a single dose of 10‐ M. If
the results obtained meet selection standards, then the
compound is tested once more against all 60 cell lines
in 5 x 10 fold dilutions with the top dose of 10‐ M.
Compounds consented for NCI60 testing are prepared
for both 1‐dose and 5‐dose testing at the same time.
The One‐dose data were reported as a mean graph of
the percent growth of treated cells. The number
reported for the One‐dose assay is growth relative to
the no‐drug control, and relative to the time zero num-
ber of cells. This allows the detection of both growth
inhibition (values between 0 and 100) and lethality
were generated using Crystal Explorer 3.1
based on
results of SC‐XRD studies. The function dnorm is a
ratio encompassing the distances of any surface point
to the nearest interior (d ) and exterior (d ) atom and
5
i
e
[
15, 16a]
the van der Waals radii of the atoms.
The
4
negative value of dnorm indicates the sum of d and de
i
is shorter than the sum of the relevant van der Waals
radii, which is considered to be the closest contact
and is visualized as red color in the HSs. The white
color denotes intermolecular distances close to van
der Waals contacts with dnorm equal to zero whereas
contacts longer than the sum of van der Waals radii
[
16b]
with positive dnorm values are colored with blue.
A plot of d versus d is a 2D fingerprint plot which
i
e
(
values less than 0). A value of 0 means no net growth
recognizes the existence of different types of
intermolecular interactions.
over the course of the experiment and a value of ‐100
[
18a–c]
means all cells are dead.
2
2
.5 | Pharmacology results
2
.5.3 | DNA cleavage studies
.5.1 | In vitro Anti‐inflammatory
Agarose gel electrophoresis
Cleavage results were analyzed by agarose gel electro-
phoresis method.
(NaCl 10, Peptone 10 and yeast extract 5 g L ). The
degree to which the ligand and its complexes can
function as DNA cleavage agents were examined using
calf‐thymus DNA as a target. 250 mg of agarose was dis-
solved in 25 ml of tris‐ acetate‐EDTA (TAE) buffer
screening
[
19]
Detection of MMP‐2 and MMP‐9 by gelatin
zymography through gel electrophoresis
In vitro anti‐inflammatory activity was carried out as
Nutrient broth media was used
‐1
[17]
described by Shastri et al.
10 mg of all synthesized
compounds were dissolved in 1 ml of DMSO, hence,
each μL contains 10 μg of the compound. 50 μL of
MMP extract and 50 μL of synthesized compounds were
‐1
(4.84 g tris base, pH 8.0; 0.5 M EDTA L ) by boiling,

6
of 21
KENDUR ET AL.
when the gel reaches ~55 °C, it was poured into gel cas-
sette fitted with a comb and left it to solidify. Then
comb was removed carefully and the gel was placed in
the electrophoresis chamber deluged with TAE buffer.
2.5.4 | Docking studies
To identify the potential structural features for anti‐
inflammatory activity and interaction at the active site
of a protein, molecular docking studies have been per-
formed. The crystal structure of celecoxib bound COX‐2
(PDB ID: 3LN1) derived from RSC PDB website
2
0 μL of DNA sample was filled (mixed with
bromophenol blue dye at 1:1 ratio) cautiously into the
wells, along with standard DNA marker with a constant
[
20]
[21]
5
0 V of electricity for 45 min. Finally, the gel was
(http://www.rcsb.org/pdb).
AutoDock
Vina
detached and cautiously stained with ethidium bromide
solution (10 μL ) for 15 min and the bands were
observed under UV transilluminator.
together with the AutoDock Tools was employed to per-
form blind docking calculations of ligand and complexes
binding to COX‐2.
‐1
2
TABLE 1 Crystal data and structure refinement details of H L, 2 and 3
Empirical formula
C
22
H
19
N
3
O
5
C
44
H
44
N
6
NiO14
C
22
H
3 7
22ClCuN O
Formula weight
405.40
100(1)
939.56
100(1)
539.41
Temperature/K
100(1)
Wavelength/Å
1.54184
1.54178
triclinic
P‐1
1.54178
Crystal system
monoclinic
P2 /n
monoclinic
P2 /n
Space group
1
1
a/Å
b/Å
c/Å
α/°
β/°
γ/°
9.68635(13)
10.97725(14)
18.1862(2)
90
8.9604(4)
14.4806(7)
16.9721(7)
19.4500(8)
90
14.8953(5)
17.0710(4)
101.758(3)
100.292(3)
100.872(3)
2134.01(13)
2
93.0043(12)
90
106.220(5)
90
3
Volume/Å
1931.08(4)
4
4589.9(4)
8
Z
3
ρcalc g/cm
1.394
1.462
1.561
μ/mm‐
1
0.835
1.316
2.850
F(000)
848.0
980.0
2216.0
3
Crystal size/mm
0.413 × 0.256
0.153
0.313 × 0.094
× 0.058
0.155 × 0.121
× 0.101
×
2Θ range for data collection/°
9.414 to 148.976
5.428 to 148.976
6.782 to 149.006
Index ranges
‐11 ≤ h ≤ 12,
‐10 ≤ h ≤ 11,
‐18 ≤ k ≤ 18,
‐21 ≤ l ≤ 20
‐18 ≤ h ≤ 16,
‐21 ≤ k ≤ 18,
‐18 ≤ l ≤ 24
‐
13 ≤ k ≤ 11,
‐
22 ≤ l ≤ 22
Reflections collected
8117
17303
21656
Independent reflections
3942 [Rint = 0.0149,
8712 [Rint = 0.0199,
9358 [Rint = 0.0192,
R
sigma = 0.0186]
3942/0/285
1.031
R
sigma = 0.0290]
8712/0/614
1.024
R
sigma = 0.0237]
9358/0/633
1.006
Data/restraints/parameters
2
Goodness‐of‐fit on F
a,b
R
1
1
,wR
2
2
[I>=2σ (I)]
R1 = 0.0347,
R1 = 0.0495,
wR2 =0.1370
R1 = 0.0350,
wR2 = 0.0883
= 0.0367,
= 0.0900
0.22/‐0.28
wR2 = 0.0973
= 0.0391,
wR = 0.1004
0.44/‐0.81
a,b
R
,wR
[all data]
R
1
R
wR
1
= 0.0535,
= 0.1416
R
1
wR
2
2
2
Largest diff. in peak and hole / e Å‐
3
0.95/‐0.78
a
R
1
= ||F
o
| – |F
c
|||F
o
|.
b
2
o
2
c
2
2
2 1/2
R
2
= [w(|F | ‐ |F |) /∑w |F | ]
.
o

KENDUR ET AL.
7 of 21
The coordinates of the complexes were taken from the
runs were carried out. A maximum of 50 conformers was
considered for each molecule, and the root‐mean‐square
cluster tolerance was set to 2.0 Å in each run. For each
docking cases, lowest energy docked conformation,
according to the AutoDock Vina scoring function was
selected as the binding mode. Visualization of the docked
crystal structures as a CIF file and converted to the PDB
format using Mercury software. For all the other
structures (where X‐ray structures are not available) the
geometry was optimized with ORCA (Quantum
[22]
Chemistry Program) package.
All calculations were
[26]
performed using the hybrid functional BP in combination
pose has been done by using Python Molecule Viewer
and Discovery Studio Visualizer.
[
23]
with Ahlrichs split‐valence double‐ξ basis set def2‐SVP
for all the atoms. The output of the calculations was
visualized using molecular visualizer tool Avogadro
3
| RESULTS AND DISCUSSION
.1 | Crystallographic study
[24]
1
.1.1.
The receptor and the ‘ligand’ (ligand and its
complexes) input files were prepared using UCCF
3
[25]
Chimera 1.11rc
and Autodock tools. In the docking
analysis, the binding site was assigned to include the entire
protein, which was enclosed in a box with a number of grid
points in x × y × z directions, 48 × 33 × 25 and a grid spac-
ing of 0.375 Å. After generation of the grid map, AutoDock
Vina was run by using parameters as follows: GA popula-
tion size, 150; maximum number of energy evaluations,
Single crystals of H L 2 and 3 suitable for SC‐XRD studies
were grown by slow evaporation technique. Summaries of
the crystallographic data, selected bond angles and bond
2
,
lengths, and hydrogen bond dimensions of H L, 2 and 3
2
are compiled in Tables 1–4, respectively. ORTEP repre-
sentations of the same showing 50% displacement ellip-
soids along with the numbering scheme are displayed in
2
,500,000; numbers of generations, 27,000. A total of 50
TABLE 2 Selected bond angles of H
2
L, 2 and 3
H
2
L
2
3
N2‐C14‐C13
C14‐N2‐N3
C15‐N3‐N2
N3‐C15‐C17
O2‐C14‐N2
O3‐C18‐C17
C18‐C17‐C15
115.1(9)
114.8(9)
121.8(9)
115.4(9)
121.1(9)
122.8(10)
119.6(9)
N2A‐C14A‐C13A
115.6(17)
116.4(18)
116.4(16)
117.8(18)
118.1(16)
118.9(18)
119.2(18)
119.1(19)
121.2(18)
121.1(18)
125.9(2)
126.8(2)
124.8(2)
123.9(19)
89.78(6)
89.45(6)
81.37(6)
80.81(6)
93.98(4)
94.85(4)
94.26(4)
90.65(4)
98.49(6)
101.2(6)
N2A‐C14A‐C13A
N2B‐C14B‐C13B
C14A‐N2A‐N3A
C14B‐N2B‐N3B
C15A‐N3A‐N2A
C15B‐N3B‐N2B
N3A‐C15A‐C17A
N3B‐C15B‐C17B
O2A‐C14A‐N2A
O2B‐C14B‐N2B
O3A‐C18A‐C17A
O3B‐C18B‐C17B
C18A‐C17A‐C15A
C18B‐C17B‐C15B
O8A‐Ni1A‐O3A
O3A‐Ni1A‐N6A
O3A‐Ni1A‐N3A
O3A‐Ni1A‐O7A
O8A‐Ni1A‐O2A
O8A‐Ni1A‐O3A
N6A‐Ni1A‐O2A
N3A‐Ni1A‐O2A
O7A‐Ni1A‐O2A
116.5(16)
116.6(17)
116.0(15)
115.3(15)
117.7(15)
117.6(15)
118.3(17)
118.7(16)
120.4(17)
120.6(17)
126.1(18)
126.1(17)
123.6(17)
123.4(16)
95.61(7)
96.81(7)
89.87(7)
90.85(7)
88.03(7)
95.61(7)
93.38(7)
79.50(6)
87.33(6)
C36A‐N5A‐N6A
C14A‐N2A‐N3A
N5A‐C36A‐C35A
C15A‐N3A‐N2A
C37A‐N6A‐N5A
N3A‐C15A‐C17A
N6A‐C37A‐C39A
O2A‐C14A‐N2A
O7A‐C36A‐C35A
O3A‐C18A‐C17A
O8A‐C40A‐C39A
C18A‐C17A‐C15A
C40A‐C39A‐C37A
O3A‐Cu1A‐N3A
O3B‐Cu1B‐N3B
N3A‐Cu1A‐O2A
N3B‐Cu1B‐O2B
O2A‐Cu1A‐Cl1A
O2B‐Cu1B‐Cl1B
Cl1A‐Cu1A‐O6A
Cl1B‐Cu1B‐O6B
O3A‐Cu1A‐O6A
O3B‐Cu1B‐O6B

8
of 21
KENDUR ET AL.
TABLE 3 Selected bond distances of H
2
L, 2 and 3
H
2
L
2
3
O3‐C18
N3‐C15
N2‐N3
1.273(13)
1.309(14)
1.387(12)
1.362(14)
1.232(13)
O3A‐C18A
1.275(3)
1.267(3)
1.298(3)
1.301(3)
1.401(2)
1.397(3)
1.344(3)
1.343(3)
1.253(2)
1.256(3)
1.969(16)
1.989(17)
2.007(17)
2.009(16)
2.072(16)
2.107(15)
O3A‐C18A
1.280(2)
1.280(2)
1.309(2)
1.311(2)
1.390(2)
1.393(2)
1.330(2)
1.335(2)
1.265(2)
1.260(2)
1.920(14)
1.915(13)
1.960(16)
1.971(16)
2.006(13)
2.007(13)
2.231(5)
2.247(5)
2.259(15)
2.259(15)
O8A‐C40A
N3A‐C15A
N6A‐C37A
N2A‐N3A
N5A‐N6A
N2A‐C14A
N5A‐C36A
O2A‐C14A
O7A‐C36A
Ni1A‐O8A
Ni1A‐O3A
Ni1A‐N6A
Ni1A‐N3A
Ni1A‐O7A
Ni1A‐O2A
O3B‐C18B
N3A‐C15A
N3B‐C15B
N2A‐N3A
N2B‐N3B
N2‐C14
O2‐C14
N2A‐C14A
N2B‐C14B
O2A‐C14A
O2B‐C14B
Cu1A‐O3A
Cu1B‐O3B
Cu1A‐N3A
Cu1B‐N3B
Cu1A‐O2A
Cu1B‐O2B
Cu1A‐Cl1A
Cu1B‐Cl1B
Cu1A‐O6A
Cu1B‐O6B
2
TABLE 4 Hydrogen bonds (Å, °) for H L, 2 and 3
a
D‐H···A interactions
d(D‐H)/Å
d(H···A)/Å
d(D···A)/Å
D‐H···A/°
H L
2
N1‐ H1B···O2
0.900(16)
0.914(16)
1.03(2)
1.890(16)
1.875(16)
1.53(2)
2.653(12)
2.784(12)
2.448(12)
141.3(14)
172.8(14)
145.1(18)
#1
N2‐H2B···O1
N3‐H3B···O3
2
N1A‐H1B···O2A
N2A‐H2B···O1A
N4A‐H4B···O7A
N5A‐H5B···O6A
0.82(3)
0.85(3)
0.81(3)
0.84(3)
2.10(3)
1.97(3)
2.08(3)
2.08(3)
2.783(2)
2.815(2)
2.719(2)
2.909(2)
140(2)
173(3)
136(3)
169(3)
#
#
2
3
3
O6A‐H6AA···O1C
N1A‐H1A···O2A
0.89
2.09
2.923(2)
2.748(2)
2.828(2)
3.171(2)
2.828(2)
2.930(3)
2.729(2)
156.3
135.5
146.6
138(3)
168(3)
166.5
131.4
0.88
2.05
#4
N2A‐H2A···O1A
0.88
2.05
O6A‐H6AB···O4B
O6A‐H6AB···O5B
O6B‐H6BA···O2C
N1B‐H1B···O2B
0.69(3)
0.69(3)
0.89
2.62(3)
2.15(3)
2.06
0.88
2.07
(Continues)

KENDUR ET AL.
9 of 21
TABLE 4 (Continued)
a
D‐H···A interactions
d(D‐H)/Å
0.88
d(H···A)/Å
2.08
d(D···A)/Å
2.920(2)
2.724(2)
3.219(18)
3.728(2)
3.138(3)
3.582(3)
D‐H···A/°
158.7
#5
N2B‐H2B···O1B
O6B‐H6BB···O5A
0.68(3)
0.87
2.05(3)
2.37
171(4)
164.4
O1C‐H1CA···Cl1A
#6
O1C‐H1CB···Cl1A
O2C‐H2CA···Cl1B
0.87
2.92
155.8
0.87
2.38
145.8
#7
O2C‐H2CB···Cl1B
0.87
2.74
162.2
D:donor; A:acceptor
a
Symmetry codes:
#
#
#
#
#
#
#
1
2
3
4
5
6
7
1
2
1
1
1
1
1
‐x,1‐y,‐z,
‐x,1‐y,2‐z;
‐x,‐y,1‐z,
‐x,1‐y,2‐z;
‐x,1‐y,1‐z;
‐x,2‐y,2‐z;
‐x,2‐y,1‐z.
Figures 2–4. Molecular packing diagrams and molecular
21.30° with one phenyl ring (mean of C8–C13), 55.12°
with another phenyl ring (mean of C1‐C6) and 13.08°
with DHA ring (mean C17‐C18‐C19‐C20‐O4‐C22),
respectively. Further, the azomethine ˃C¼N bond
distance (1.309(14) Å) agrees well with the values for
double bond character confirming the formation of imine
bond. The torsion angle of ‐9.21(14)° exhibited by N3–N2–
C14–O2, ‐2.72(16)° by C15‐C17‐C18‐O3 and 7.28(18)° by
C15–C17–C22–O5 indicate that N3,O2; C15,O3 and C15,
O5 are cis to each other, respectively, while the torsion
angle of 162.65 (9)° exhibited by C14–N2–N3–C15 and
planes of H L, 2 and 3 are presented in the Figures 5–7,
2
respectively.
3.1.1 | Crystal structure of H2L
H L crystallizes as colorless crystals were determined at
2
1
00 K is shown to be monoclinic with space group P2 /n
1
and R is found to be 3.43%. The asymmetric unit of
1
H L consists of one molecule. Azomethine and ˃C¼O
2
(mean of O2‐C14‐N2‐N3‐C15) form a dihedral angle of
2
FIGURE 2 ORTEP projection of H L
showing 50% probability ellipsoids

10 of 21
KENDUR ET AL.
FIGURE 3 ORTEP projection of 2 showing 50% probability ellipsoids
FIGURE 4 ORTEP projection of 3
showing 50% probability ellipsoids

KENDUR ET AL.
11 of 21
2
FIGURE 5 Molecular packing and molecular planes in H L
FIGURE 6 Molecular packing and molecular planes in 2
‐
177.94 (9)° by N2–N3–C15–C17 indicate that C14, C15
O3, where there exists a single bond character for
[
27]
and N2, C17 are trans to each other, respectively. The keto
form of the free ligand is evident from the single bond
nature of C14‐N2 bond and the double bond character
of C14‐O2 bond. The ligand is found to exist in zwitter-
ionic form and formally a neutral species as evident by
the presence of hydrogen atom (H3B) on N3 rather than
C18‐O3 bond.
Two intramolecular hydrogen bonds,
involving N1‐H1B with O2 and N3‐H3B with O3 are
observed. In addition, the molecule is also stabilized via
one intermolecular hydrogen bond: N2‐H2B···O1 (1‐x,‐1‐
y,‐z). Dimensions for hydrogen bonds are given in
Table 4 and shown in Figure S1.

12 of 21
KENDUR ET AL.
FIGURE 7 Molecular packing and molecular planes in 3
3
.1.2 | Crystal structures of 2 and 3
the ligand. The crystal is stabilized by two intramolecular
N1A‐H1B···O2A, N4A‐H4B···O7A and two intermolecu-
lar N2A‐H2B···O1A (2‐x,1‐y,2‐z), N5A‐H5B···O6A (1‐
x,‐y,1‐z) hydrogen‐bonding (Figure S1). In addition, the
complex molecule is stabilized by a number of intra/
inter‐molecular C‐H···π and π ···π stacking interactions
(Figure S2).
Complex 2 crystallizes as fern green colored crystals
belong to Triclinic crystal system having space group
P‐1, while 3 crystallizes as green colored crystals belong
to Monoclinic crystal system, in space group P2 /n.
1
Identical atom‐labelling schemes have been adopted for
both the structures for easy comparison of their relevant
metrical parameters.
Single‐crystal X‐ray structure of 3 was determined at
100 K and R is found to be 3.50%. The asymmetric unit
1
Complex 2 was determined at 100 K and R is found to
of 3 consists of two molecules namely A and B. These
two molecules A and B differ marginally from one
another in their bond distances and bond angles. Such
crystallographically independent and chemically similar
1
be 4.95%. The asymmetric unit of 2 consists of one
molecule. Complex 2 comprise of a neutral unit composed
of a central Ni(II) ion in a distorted octahedral environ-
ment surrounded by two tridentate mononegative
[29]
molecules are known as bond stretch isomers.
The
hydrazone (H L) bound in a mer fashion through amide
structure of 3 is a neutral molecule with one lattice held
water molecule. The ligand is coordinated to the central
Cu(II) ion in an ONO tridentate fashion through an
amide carbonyl oxygen (O2), azomethine nitrogen (N3)
and pyrone carbonyl oxygen (O3H) via deprotonation. In
addition, contains one coordinated chloride and one coor-
dinated water molecule. This way, 3 adopts a five‐coordi-
nate geometry. However, a five‐coordinate complex can
either adopt a square‐pyramidal or trigonal bipyramidal
(TBP) geometry. Addison et al. have devised a criterion
for assigning a definitive structure to five‐coordinate
complexes. The formula, τ = (β − α)/60 where, α and β
are the two biggest angles, defines the index of trigonality
(distortion from trigonal‐bipyramidal or square‐pyrami-
dal geometry) and has been successfully used to
distinguish between a square‐pyramidal and a TBP
configuration. When τ is 0, the structure is square‐pyrami-
dal but when τ is 1, the structure is TBP. Using this crite-
rion, the τ value of 3 came to be 0.179 indicating that the
2
carbonyl oxygen (O2), azomethine nitrogen (N3) and
pyrone carbonyl oxygen (O3H) via deprotonation. There
is some disordered solvent present in the lattice,
(currently modelled as oxygen for water). This solvent is
present in voids of the lattice. Approximately 12.5% of
the structure volume is void space [Figure S4]. The bonds
Ni1A–O2A (2.107 Å), Ni1A–N3A (2.009 Å), Ni1A–
O3A(1.989 Å), Ni1A–O7A(2.072 Å), Ni1A–N6A (2.007 Å)
and Ni1A–O8A (1.970 Å), forming pair of five‐membered
CN ONi and a pair of six‐membered C NONi chelate
[
30]
2
3
rings with bite angles of 79.50°, 79.97°, 89.87° and
8
9.84°, respectively, represents distortion from an ideal
[28]
octahedral geometry.
The bond lengths in 2 are:
O3A–C18A
= 1.275(3), N3A–C15A= 1.298(3) and
O2A–C14A= 1.253(2) Å, which are longer or shorter than
those of the corresponding distances in the free ligand,
O3–C18 = 1.273(13), N3–C15= 1.309(14) and O2–C14=
1
.232(13) Å is due to the bonding of the Ni(II) center with

KENDUR ET AL.
13 of 21
Cu(II) adopts a structure closer to square‐pyramidal. The
ONO donor sites of the tridentate ligand coordinate the
The dnorm is the normalized contact distance and is
defined by taking into account d and d and the van der
e
i
Cu(II) center forming one five‐membered CN OCu and
Waals radii of the atoms as below:
2
other six‐membered C NOCu chelate rings with bite
3
angles of 80.81° and 89.45°, respectively, represents slight
distortion from an ideal square pyramidal geometry. The
average bond lengths in the complex are: O3–C18 =
di r vi dW de−r ve dW
dnorm ¼
þ
vdW
vdW
r
r
i
i
1
.280(2), N3–C15= 1.310(2) and O2–C14= 1.263(2) Å,
Mapping dnorm on the HS gives a clear‐cut and
detailed picture of the interactions happening between
adjacent molecules that are shorter than the van der
Waals radii sum (visualized as red spots on the HS).
which are longer or shorter than those of the correspond-
ing distances in the ligand, suggesting considerable
delocalization of the charge on the chelate rings.
[31]
The
crystal is stabilized by three intramolecular O6‐H6···O1,
N1‐H1···O2, O1‐H1···Cl1 and two intermolecular
N2‐H2···O1 (1‐x,1‐y,2‐z), O2‐H2···Cl1 (1‐x,2‐y,1‐z)
hydrogen‐bonding [Figure S1]. In addition, the complex
molecule is stabilized by a number of intra /inter‐molecu-
lar C‐H···π and π ···π stacking interactions (Figure S3).
There are also two other potential donor sites in the
coordinated hydrazone ligand viz., oxygen of amide
carbonyl C7¼O1 and oxygen of lactone carbonyl
C22¼O5 which are not coordinated in both 2 and 3 due
to their non‐planarity with the three donor sites
The HSs of H L, 2 and 3, are illustrated in Figure S5,
2
showing surfaces that have been mapped with dnorm
,
shape index and curvedness. For a given crystal structure,
the HS is unique and suggests the possibility of obtaining
[
34]
additional acumen into the crystal.
The measureable
like area, asphericity, globularity and volume can also be
[
35]
calculated using HSs. The term, globularity
is found
to be less than unity for H L, 2 and 3 which indicate that
2
the molecular surface is more structured but not a sphere.
[
36]
The asphericity
is a measure of anisotropy which
decreases in the ensuing order for the compounds: H2L
> 3 > 2.
(Figure 5–7). In both the complexes metal‐oxygen (M‐O)
bond lengths are: M‐O3pyrone < M‐O2 probably due
In H L and 3, the DHA ring contributes more towards
C···H interaction seen as a moderate intense red spot in
amido
2
[32]
to the order of O→M π‐bonding.
The CIF files have
been deposited with CCDC No. 1579095 (H L), 1579100
the HS compared to that of 2 which is observed as light
2
(
2) and 1579096 (3).
red spot (Figure S5a). Further, the HSs of H L and 3 show
2
intense red spot on the d surface near the phenyl ring
e
which is due to close (ph)C···H(ph) contacts, while in case
of 2 is due to close (ph/DHA)C···H(ph). In addition to
this, O‐H···Cl and C‐H···Cl contacts are also seen as
intense red spots in 3. The crystal packing of 3 is mainly
controlled by dominant interactions between pyrone
‐OH and chloride atom observed as strong red spot. Shape
index and curvedness can also be used to identify the
characteristic packing modes and the ways in which the
nearby molecules contact one another. The shape index
3
.2 | Hirshfeld surface analysis
Hirshfeld surface analysis is rapidly gaining importance
as a useful technique in understanding the nature of
intermolecular interactions within a crystal structure
using a fingerprint plot. This allows easy identification
of characteristic interactions throughout the structure.
In order to measure various intermolecular interactions,
HSs and their associated FPs were generated using Crystal
Explorer 3.1. Even weak interactions, such as C−H···π,
C···H, and H···H contacts, which are hard to identify
and are requisite for crystal packing, can be distinctly
observed [16a, 33]. The Hirshfeld surface is defined by
w(r) = 0.5, where the weight function w(r) is given by
the following equation,
of H L, 2 and 3 shows a red concave region on the surface
2
around the acceptor atom and a blue region around the
[
37]
donor H‐atom.
Curvedness is a function of the root
mean square curvature of the surface and the maps of
curvedness on the HSs for H L, 2 and 3 show no flat
2
surface patches which indicate that there is no stacking
[
37]
interaction between the molecules (Figure 8c). A major
∑i εmoleculeρiðrÞ
wðrÞ ¼
contribution to HSs of H L, 2 and 3 comes from three
kinds of contacts, i.e., C···H, O···H and H···H. The finger-
2
∑i εcrystalρiðrÞ
print plots of H L, 2 and 3 features spike of various
2
The weight function represents the ratio of the sum of
spherical atom electron densities for a molecule to a
lengths and thickness, and the most prominent being
the presence of wing‐like peripheral spikes for C···H con-
tact at the top left and bottom right of each plot. The spike
at the top left correspond to the points on the surface
around the C–H donor, while those at the bottom right
correspond to the surface around the π acceptor and a
[16a]
similar sum for the entire crystal.
Several properties
of HS can be envisioned and cyphered, in particular, de
and d , which represent the distance from a point on the
i
HS to the nearest nucleus outside or inside, respectively.

14 of 21
KENDUR ET AL.
oxygen of OH group (pyrone ring) via deprotonation to
the Zn(II) ion. Two broad singlets at 11.78 and
11.36 ppm are assigned to protons of N2 and N1,
respectively. These signals have shifted to up‐field by
few ppm, revealing the breakdown of intramolecular
hydrogen bonding upon coordination. The signals due to
protons of O3, N1 and N2 are D O exchangeable. A singlet
2
observed at 5.85 ppm in free ligand ascribed to ‐C19H
corresponds to one proton. A doublet and triplet at 8.33
and 7.29 ppm in free ligand are assigned to ‐C12H and
‐C11H, respectively. The aromatic protons resonated as
multiplets in the region 7.66‐7.55 ppm in the free ligand
have suffered a slight downfield shift in 4. The ‐C16H3
and ‐C21H3 protons observed as singlets at 2.11 and
2.61 ppm in uncoordinated ligand have shifted to 2.06
and 2.59 ppm, respectively on complexation.
FIGURE 8 Graphical representation of % inhibition of all the test
compounds against MMP‐9 and MMP‐2
3.4 | Mass spectral (LC‐MS and ESI‐MS)
analysis
similar feature for C···H contact is also observed in FPs of
The LC mass spectrum of H L (Figure S8) has shown a
molecular ion peak [M+H] at m/z 406 corresponding
2
+
[34]
small organic molecules. In case of H L, 19.1% of inter-
2
molecular contacts are associated with C···H whereas in 2
and 3 it is of 19.2% and 15.0% of the HSs. The
non‐directional H···H contacts are characterized by
to its molecular mass. In the positive mode, ESI‐MS
(Figure S9) of 3 base peak observed at m/z 545 exactly
corresponds to the mass of [M+Na] species. Loss of
+
broader spikes in H L and its Ni(II) complex and
relatively sharper spikes in the Cu(II) complex [41.0%,
one coordinated chloride ligand, generating a mono‐pos-
itive ion is evident by the peak observed at m/z 485 and
followed by the loss of coordinated water molecule is
evident from the peak at m/z 467. This assignment is
in good agreement with the structure obtained from
SC‐XRD study for 3. In the mass spectra of 1 and 2
(Figure S10), peak observed at m/z 868 and 867
2
3
6.8% and 39.3% in H L, 2 and 3, respectively]. And, the
2
percentage contribution of H···H contact is also a measure
[38]
of the strength of the crystal lattice.
The longer and
thinner spikes reflect the O···H contacts (19‐28%) of the
hydrogen bonds present in H L, 2 and 3. In ligand,
2
+
2
4.3% of contacts are associated with O···H whereas in 2
respectively, is assigned to [M+H] ion. The ESI‐MS
and 3 it is of 27.9% and 19.6% of the HSs. The C···C and
N···H contacts are present only with a little contribution
of 4 (Figure S11) has shown a peak at 871, correspond-
ing to the ion [M‐H] . Further, the peak at 300 for all
+
of 4‐7% and 1‐3%, respectively, for H L, 2 and 3. By
comparing the brick red and blue region in Figure S5a,
it is seen that the relative contribution of C···H and
complexes, is due to the loss of a benzyol fragment of
the ligand indicating the ease of cleavage of C7–N1
bond. The peaks observed at m/z of 406 in all the com-
2
+
H···H contacts are comparable for H L and 3, while the
plexes corresponds to [M+H] species of the corre-
2
contribution is entirely different for 2. A visual inspection
sponding ligand.
of FPs for H L and 3 reveals that the two molecules are
2
distinct from each other and the main difference is the
3.5 | Electronic spectral studies
shortening of C···H contact of 3 relative to H L with a
2
concomitant increase in the H···H contact distance. Over-
all, the close contacts are dominated by O···H, C···H and
H···H interactions.
The electronic spectra of the ligand, as well as complexes,
were recorded in DMF solvent. Strong absorption in the
range of 265–275 nm exhibited by ligand is ascribed to
intra‐ligand π → π* transitions. This band has remained
almost unchanged in the complexes. The n → π* transi-
tion of azomethine functionality is observed between
304 and 391 nm and has suffered hypsochromic shift
upon complexation. This is an indication of coordination
of imine nitrogen to the metal ions. The d‐d transitions
1
3
.3 | H NMR spectral studies
1
H NMR spectra of H L (Figure S6) and 4 (Figure S7) are
2
provided as the supporting material. A broad singlet at
1
5.89 ppm in the spectrum of free ligand, ascribed to
4
‐OH proton is absent in 4, indicating the coordination of
observed at 749 and 850 nm for 1 are assignable to T
1
g

KENDUR ET AL.
4
15 of 21
4
4
(
F) → T2 (F) (ν ), and T (F) → A (F) (ν ) transi-
is involved in the binding of fibronectin to denatured
collagen, and in MMP‐2 and MMP‐9, it probably
augments the interaction with gelatin/gelatin‐like
g
1
1g
2g
2
tions, which are in support for an octahedral geometry
of the complex.
[39a,b]
Complex 2 has shown its lowest
[
40]
energy transition around 935 nm which is assignable to
substrates.
It is markedly useful for the assessment of
3
3
A2g (F) → T (F) (ν ). The other transition observed
two vital members of the matrix metalloproteinase family,
such as 72 kDa gelatinase A (MMP‐2) and 92 kDa
gelatinase B (MMP‐9), which have herculean gelatin‐
Gelatinases present in the physi-
ological system, play an essential role in inflammation
2g
1
3
around 560 nm are consistent with the energy of A
2g
1
(
F) → T1 (F) (ν ), indicating an octahedral transition
g
2
[
41]
for 2. The absorption spectrum of 3 has exhibited a d–d
electronic band around 659 nm. Absorptions in this
region are typical of species with square pyramidal
geometry around the Cu (II) ion.
π* and d–d transition bands exhibited by the ligand and
degrading properties.
[
42]
and autoimmunity conditions.
Activated inflammatory
[
39c]
The π → π*, n →
cells and dermal fibroblasts can express numerous
proteinases designated as matrix metalloproteinases
(MMPs) able to degrade all connective tissue macromole-
cules. Amongst these gelatinases, e.g., MMP‐2 and MMP‐9
together with interstitial collagenase have been presumed
to be of importance in connective tissue remodeling
its complexes are shown in Figures S12 and S13.
3.6 | Thermo gravimetric (TG) analysis
[
43]
consecutive to inflammation.
This method is used to
All the complexes were studied for TG and DTG analysis
over the temperature range of 25–1000 °C under nitrogen
atmosphere. The thermal decomposition pattern of 1 and
detect gelatinase activity, especially MMP‐2 and MMP‐9.
MMP‐2 and MMP‐9 remain inactive, while they are with
their pro‐domains and require denaturation to get
activated. Then, it could be detected on gelatin
zymograms as one or two white bands (pro and active
forms) after staining with coomassie blue. The in vitro
anti‐inflammatory activity results are attained from the
3
(Figure S14 & S15) are dealt in detail.
has remained thermally stable up to 313 °C, showing
1
the absence of any lattice held water/solvent molecules.
The weight loss of about 46.68% (Calc. 46.72%) in the
range of 314‐326 °C is due to the loss of one of the ligand
molecule. This is clearly evidenced in DTG curve in the
form of an endothermic peak at 321 °C. The second ligand
molecule has decomposed gradually with the increase in
temperature.
%
bands of MMP‐2 and MMP‐9 which was detected
for each sample screened from the gelatin zymogram
by gel electrophoresis techniques. The percentage of
inhibition of MMP‐2 and MMP‐9 for each sample is
calculated by subtracting from 100 with the % bands
of MMP‐2 and MMP‐9, respectively. The in vitro anti‐
inflammatory activity results of MMP‐2 and MMP‐9
are detected as white bands (Figure S16) and the
percentage of inhibition of the compounds are tabulated
in Table 5. The obtained results revealed that all the
compounds were active against MMP‐2. Similarly, the
The initial weight loss of about 3.33% (Calc. 3.34%) in
3
is due to the loss of lattice held water molecule. Further
in the temperature range of 120–240 °C, the complex has
lost 9.86% (Calc. 9.91%) of its weight due to the combined
loss of one chloride and one water molecules coordinated
to the metal ion. This process is further supported by
exothermic peaks in DTG curve at 234 °C. Above
compounds H L, 1 and 3 were active against MMP‐9,
2
2
41 °C, the complex has gradually lost its weight due to
whereas 2 and 4 showed slight inhibitory activity
against MMP‐9. The results are also represented as bar
diagram in Figure 8.
the decomposition of ligand moiety. The TG and DTG
analytical data of 1 and 3 are in good agreement with
the ascribed structures. The temperature ranges, stages
of decomposition, decomposition product loss as well as
the found and calculated weight‐loss percentages of the
complexes are summarized in Table S1 support the
suggested composition for the complexes.
TABLE 5 In vitro anti‐inflammatory results of H
2
L and its com-
plexes with % bands and % inhibition of MMP‐2 and MMP‐9
% Bands of MMP % Inhibiton of MMP
MMP‐2 MMP‐9 MMP‐2
Sample Code
MMP‐9
H
1
2
L
15
12
20
05
35
00
‐
55
45
65
30
45
00
‐
85
88
80
95
65
100
‐
45
3
3
.7 | Pharmacological studies
55
35
70
55
100
‐
.7.1 | In vitro anti‐inflammatory activity
2
Gelatin zymography is a modest yet strapping technique
to detect proteolytic enzymes capable of degrading gelatin
from various biological sources. The two gelatinases
3
4
Tetracycline
(MMP‐2 and MMP‐9) have gelatin‐binding domains that
DMSO Control
resemble an equivalent motif in fibronectin. This motif

1
6 of 21
KENDUR ET AL.
5
TABLE 6 Growth inhibition (GI %) in single dose assay (10‐
M
3
.7.2 | In vitro anticancer activity at one
‐5
concentration) for compound H
D‐797758/1)
2
L (NSC: D‐797749/1) and 3 (NSC:
dose (10 M concentration)
Two among the five newly synthesized compounds, H2L
and 3 were selected and submitted to in vitro anticancer
Growth Inhibition (GI %)
‐5
Panel/Cell line
Leukemia
H
2
L
3
screening in a single dose (10 M concentration) in the
[29–31]
full NCI 60 cell panel.
Using this data, it is possible
to anticipate the mechanism of action of each test
compound, or to define that the response pattern is
distinctive and not like any of the standard prototype
compounds included in NCI database. The single‐dose
data is graphed as the mean of the percent growth of
the treated cells, relative to the no‐drug control, and
relative to the time zero number of cells. This permits
detection of both growth inhibition and cytotoxicity.
The output from the single dose screen is available
CCRF‐CEM
K‐562
24.58
17.11
11.87
08.19
33.26
10.67
MOLT‐4
Non‐Small Cell Lung Cancer
A549/ATCC
EKVX
16.94
03.85
18.64
06.17
10.97
15.75
16.73
14.56
11.02
15.97
HOP‐62
NCI‐H23
NCI‐H522
Colon Cancer
HT29
[44,45]
for COMPARE analysis.
H L and 3 have been
2
evaluated by NCI, on all the 60 human cancer cell
lines organized into subpanels derived from nine differ-
ent human cancer types: leukemia, melanoma, lung,
colon, renal, ovarian, breast, prostate and CNS, at one
dose (10‐ M concentration) primary anticancer assay
01.58
16.67
CNS Cancer
SF‐268
5
24.72
06.27
(Table 6).
SNB‐75
06.45
14.24
The most sensitive cell lines for H L are Leukemia
2
Ovarian Cancer
OVCAR‐3
SK‐OV‐3
CCRF‐CEM (GI% 24.58), CNS Cancer SF‐268 (GI %
4.72), Melanoma UACC‐257 (GI % 30.20), Ovarian
Cancer OVCAR‐4 (GI% 53.08 or GP% 46.92) and
SK‐MEL‐5 (GI % 74.63 or GP% 25.37), Breast Cancer
MDA‐MB‐468 (GI % 23.30), Breast Cancer MDA‐MB‐
2
19.29
01.94
04.44
30.85
Breast Cancer
MCF7
19.56
19.76
2
2
31/ATCC (GI % 22.89) and Breast Cancer T‐47D (GI %
0.97) and for 3 are Leukemia K‐562 (GI% 30.26), Ovarian
T‐47D
20.97
19.95
Cancer SK‐OV‐3 (GI% 30.85) and Breast Cancer MCF7
GI% 19.76) (Table 6). Despite the average activity of 3
being less than that of H L, 3 outperformed H L against
(
experiment suggests that untreated DNA did not show
any notable DNA cleavage, even after a long exposure
time (lane A). Further, when the genomic DNA is allowed
2
2
several cell lines, namely K‐562 (Leukemia), EKVX
Non‐Small Cell Lung Cancer), HT29 (Colon Cancer),
(
to interact with H L and its complexes, a substantial
2
SNB‐75 (CNS Cancer), SK‐OV‐3 (Ovarian Cancer),
MCF7 (Breast Cancer) (Table 6). The tested compounds
decrease in the intensities of the bands for the ligand
and its complex bound DNA as compared to the untreated
show a different strength of anticancer activity, H L has
2
control DNA is observed, in case of H L, 1, 2 and 3 (lanes
2
moderate anticancer activity, but 3 possess a significant
influence on several cancer cell lines. This activity pattern
is likely due to distinctive molecular mechanisms of
action for the tested compounds.
C, D, E and F), shows a significant decrease in intensity
and bandwidth, indicating the sufficient cleavage of
CT‐DNA. Whereas, 4 (lane G) has shown a slight decrease
in the intensity and bandwidth compared to the control
due to moderate cleavage of CT‐DNA. These results
3.7.3 | DNA cleavage studies
suggest that H L and its complexes can cleave CT‐DNA
to different degrees. We conclude that 1 exhibits greater
2
The interactions between the free ligand and its com-
cleavage potential.
‐1
plexes (100 μg L ) with DNA were analyzed with the
aid of agarose gel electrophoresis method. The photo-
graph depicted in Figure 9 show bands with different
bandwidths compared to the marker and control, and this
is the differentiating criterion for cleavage abilities of the
compounds with CT‐DNA in this study. Control
3
.8 | Docking Study
Molecular docking studies are undertaken to envisage the
interaction between the synthesized prodrugs and a
protein, which would enlighten the behavior of the

KENDUR ET AL.
17 of 21
FIGURE 9 Photograph of gel
electrophoresis experiment of H L series
2
on Calf‐thymus DNA. Lane A, DNA
marker; lane B, untreated DNA; lane C,
2
H L; lane D, 1; lane E, 3; lane F, 2; lane G, 4
former in the binding site of target proteins to elucidate
the regulation of homologous biochemical processes.
The study aims to achieve an optimized conformation
for both the protein and drug with relative orientation
between them such that the free energy of the overall
system was minimized. The primary aim of the docking
Molecular surface visualization and crystallographic
studies revealed that the COX‐2 active site consists of
mostly hydrophobic residues. There are three main
pockets (S1, S2, S3) and one shallow pocket (S4) in
COX‐2 active site, wherein, Pocket S1 consists of the
amino acid residues His90, Ala516, Arg513, Gln192
and the backbone of Phe518, whereas Pocket S2 is
localized at the top of the channel and comprises of
several hydrophobic amino acid residues Met522,
Tyr348, Tyt385, Trp387 and Phe518. Pocket S3 confined
in the mouth of the active site and is delimited by
was to identify the preferred binding mode of H L and
2
its complexes with the COX‐2 enzyme. The calculations
were performed on Autodock Vina using the X‐ray crystal
structure of celecoxib bound at the COX‐2 active sites
(PDB code: 3LN1) as protein model.
FIGURE 10 (a) Docking conformation of H
of molecular interactions of H
2
L with amino acid residues at the active site of the enzyme. (b) 2D plot displaying various types
2
L with enzyme residues

18 of 21
KENDUR ET AL.
Tyr355, Leu359, Val116 and Arg120. Shallow pocket S4
is localized in a hydrophobic area close to the hydro-
phobic pocket S2 which has a lesser number of resi-
of hydrazone. In case of 1 and 2, the Gln356 exerts
dual H‐bonding tendency towards NH of hydrazine
(>N‐H‐‐‐O¼C<, 2.39 Å) and amidic proton (>N‐H‐‐‐
O¼C<, 2.52 Å). The other non‐coordinating amide
NH is in H‐bond bonding with Tyr108 which in turn
is in π‐ π interaction in T‐shape. Whereas for 3
oxygen of coordinated water molecule makes a short
distance H‐bonding with indole NH proton of Trp309
(>N‐H‐‐‐O¼C<, 1.85 Å). Adjacent to this is the Ser34
in a conventional H‐bonding distance of 2.68 Å with
metal coordinated oxygen of pyrone ring. The carbonyl
oxygen of Gly121 makes double H‐bond interactions
with NH of hydrazine and amide with bond distances
of 2.63 and 2.51 Å, respectively.
[46]
dues, including Ile345, Leu534 and Leu531
. The
inhibitors (H L and its complexes) were docked at
2
the active site of COX‐2 and various interactions have
been laid out (Figure 10–12). The most prominent
interactions were observed for 1 with the lowest bind-
ing energy of ‐12 kcal/mol amongst all other com-
pounds tested with the protein (Table 7). The
secondary amidic NH of 4 is in H‐bonding with the
oxygen of carbonyl group of Arg46 with a distance of
2
.39 Å. The Arg46, in addition, forms an alkyl and π‐
alkyl interactions with phenyl ring and methyl protons
FIGURE 11 (a) Docking conformation of 2 with amino acid residues at the active site of the enzyme. (b) 2D plot displaying various types of
molecular interactions of 2 with enzyme residues
FIGURE 12 (a) Docking conformation of 3 with amino acid residues at the active site of the enzyme. (b) 2D plot displaying various types of
molecular interactions of 3 with enzyme residues

KENDUR ET AL.
19 of 21
2
TABLE 7 Molecular docking results of H L and its complexes
Compound
Binding energy (kcal/mol)
PSA* at pH 7.4
No. of hydrogen bonds
Interacting residues
Distance (Å)
H
2
L
‐8.4
117
4
Arg29
Ser107
Ile110
Gln356
2.37
3.07
2.51
2.28
1
2
3
‐12.0
‐11.4
‐11.2
260
260
155
3
3
5
Tyr108
Gln356
2.31
2.43, 2.49
Tyr108
Gln356
2.62
2.39, 2.52
Ser34
2.68
Cys32
Gly121
Trp309
2.23
2.51, 2.63
1.85
4
‐11.5
260
2
Arg46
Gln356
2.37
2.59
*
PSA= Polar surface area
4
| CONCLUSIONS
ACKNOWLEDGMENTS
Authors thank USIC, Karnatak University, Dharwad for
IR, UV, TG/DTG analysis and Waters company for ESI
mass analysis. NCI‐USA is acknowledged for NCI‐60
Human Tumor Cell Lines Screen under Developmental
In the present work, we synthesized and characterized
a new tridentate ligand, H L and its complexes in good
2
yields. Analytical and spectroscopic data for the
complexes indicate a 1:1 (M:L) stoichiometry for 3
adopting a square‐pyramidal and 1:2 for 1, 2 and 4
adopting an octahedral geometry around the metal
1
Therapeutics Program. Recording of H NMR spectra
from IISC‐Bangalore is greatly acknowledged. One of
the authors, Umashri also thank Niranjan Acharya of
Sequent Scientific Limited for his generous help in mass
analysis. One of the authors, Geeta H. Chimmalagi
acknowledges UGC for providing RFSMS scholarship.
We acknowledge DST and UGC New Delhi, India, for
the financial support through UPE‐FAR‐I and
DST‐PURSE Phase II programmes.
ion. The organic motif, H L has coordinated through
2
an amide carbonyl oxygen (O2), azomethine nitrogen
(N3) and pyrone carbonyl oxygen (O3H) via deproton-
ation in case of all the complexes. Thus, H L acts as
2
a monobasic tridentate ligand. The tentative structures
for metal complexes are depicted in Scheme 2. All
interactions in crystal structures of H L, 2 and 3 have
2
studied by Hirshfeld surface analysis. H L and its com-
2
plexes have screened for their in vitro anti‐inflamma-
tory activity. The results showed that activity of H2L
has improved on complexation is probably due to the
ORCID
Kalagouda B. Gudasi
656
http://orcid.org/0000-0002-0063-
7
[47a–e]
greater lipophilic nature of the complexes.
Among
the complexes, 3 has shown highest activity. The differ-
ence in activity among the tested compounds may be
attributed to the electrostatic nature of ligand and cen-
tral metal ion. Among the 60 human cancer cell lines
REFERENCES
[1] B. Desoize, Crit. Rev. Oncol. Hematol. 2002, 42, 213.
[
2] a) M. Mohamadi, S. Y. Ebrahimipour, J. Castro, M. Torkzadeh‐
Mahani, J. Photochem. Photobiol. B 2016, 158, 219; b) M.
Mohamadi, S. Y. Ebrahimipour, M. Torkzadeh‐Mahani, S.
Foro, A. Akbari, RSC Adv. 2015, 122, 101063.
tested, both H L and 3 have moderately inhibited the
2
growth of K‐562 (Leukemia), EKVX (Non‐Small Cell
Lung Cancer), SNB‐75 (CNS Cancer), SK‐OV‐3 (Ovar-
ian Cancer), MCF7 (Breast Cancer). Further, the H2L
and its complexes were also tested for their potential
CT‐DNA cleavage activity. The molecular modelling
study of all the compounds with inhibitor bound
COX‐2 revealed that the molecules fit in the active site
of the receptor.
[3] a) S. Y. Ebrahimipoura, I. Sheikhshoaie, J. Castro, M. Dušek, Z.
Tohidiana, V. Eigner, M. Khaleghi, RSC Adv. 2015, (115),
9
5104; b) S. Y. Ebrahimipour, M. Mohamadi, M. T. Mahani, J.
Simpson, J. T. Mague, I. Sheikhshoaei, Eur. J. Med. Chem.
017, 140, 172; c) I. Sheikhshoaie, S. Y. Ebrahimipour, N. Lotfi,
J. T. Mague, M. Khaleghi, Inorganica Chim. Acta 2016, 442, 151;
2

20 of 21
KENDUR ET AL.
d) R. Takjoo, A. Akbari, S. Y. Ebrahimipour, M. Kubicki, M.
Mohamadi, N. Mollania, Inorganica Chim. Acta 2017, 455,
73; e) S. Y. Ebrahimipour, M. Mohamadi, I. Sheikhshoaie, S.
Suárez, R. Baggio, M. Khaleghi, Res. Chem. Intermed. 2016,
2, 611.
[21] O. Trott, A. J. Olson, J. Comput. Chem. 2010, 31, 455.
[
22] F. Neese, Wiley Interdiscip Rev Comput Mol Sci. 2012, 2, 73.
23] A. Schäfer, C. Huber, R. Ahlrichs, J. C. Phys. 1994, 100, 5829.
1
[
4
[24] M. D. Hanwell, D. E. Curtis, D. C. Lonie, T. Vandermeersch, E.
Zurek, G. R. Hutchison, Aust. J. Chem. 2012, 4, 1.
[
[
4] N. Bharti, M. R. Maurya, F. Naqvi, A. Bhattacharya, S.
Bhattacharya, A. Azam, Eur. J. Med. Chem. 2000, 35, 481.
[25] E. F. Pettersen, T. D. Goddard, C. C. Huang, G. S. Couch, D. M.
Greenblatt, E. C. Meng, T. E. Ferrin, J. Comput. Chem. 2004,
5] a) P. Krishnamoorthy, P. Sathyadevi, A. H. Cowley, R. R.
Butorac, N. Dharmaraj, Eur. J. Med. Chem. 2011, 46, 3376; b) P.
Krishnamoorthy, P. Sathyadevi, R. R. Butorac, A. H. Cowley,
N. S. P. Bhuvanesh, N. Dharmaraj, Dalton Trans. 2012, 41, 4423.
25, 1605.
[26] M. F. Sanner, J. Mol. Graphics Modell. 1999, 17, 57.
[
[
27] A. Djedouani, A. Bendaas, S. Boufas, M. Allain, G. Bouetd, M.
[
6] a) S. Y. Ebrahimipour, I. Sheikhshoaie, J. Simpson, H.
Ebrahimnejad, M. Dusek, N. Kharazmia, V. Eigner, New J.
Chem. 2016, 40, 2401; b) F. Heidari, S. J. A. Fatemi, S. Y.
Ebrahimipour, H. Ebrahimnejad, J. Castro, M. Dušek, V.
Eigner, Inorg. Chem. Commun. 2017, 76, 1; c) M. Mohamadi,
E. Faghih‐Mirzaei, S. Y. Ebrahimipour, I. Sheikhshoaie, W.
Haase, S. Foro, J. Mol. Struct. 2017, 1139, 418.
Khand, Acta Cryst. E 2007, 63, 1271.
28] R. Shakya, C. Imbert, H. P. Hratchian, M. Lanznaster, M. J.
Heeg, B. R. McGarvey, M. Allard, H. B. Schlegel, C. N. Verani,
Dalton Trans. 2006, (21), 2517.
[
[
[
[
[
29] (a) K. K. Narang, U. S. Yadav, Ind. J. Chem. 1979, 19A, 697.
(
b) K. K. Narang, U. S. Yadav, Ind. J. Chem. 1981, 20A, 404.
30] A. W. Addison, T. N. Rao, J. Reedijk, J. van Rijn, G. C.
[
[
[
7] A. A. Napoleon, F.‐R. N. Khan, Med. Chem. Res. 2014, 23, 4749.
Verschoor, Dalton Trans. 1984, 0, 1349.
8] B. Rosenberg, L. Vancamp, Nature 1969, 222, 385.
31] J. R. Dilworth, J. Hyde, P. Lyford, P. Vella, K.
9] D. Denoyer, S. Masaldan, S. La Fontaineab, M. A. Cater,
Venkatasubramaman, J. A. Zubieta, Inorg. Chem. 1979, 18, 268.
Metallomics 2015, 7, 1459.
32] D. Patra, N. Biswas, B. Kumari, P. Das, N. Sepay, S. Chatterjee,
[
[
10] (a) A. I. Vogel, Vogel's Textbook of Practicle Organic
Chemistry, 4th ed., ELBS, London 1978; (b) L. Wilfred, E.
Armarego, C. L. Lin Chai, Purification of Laboratory Chemicals,
M. G. B. Drewe, T. Ghosh, RSC Adv. 2015, 5 92456.
33] H. F. Clausen, M. S. Chevallier, M. A. Spackman, B. B. Iversen,
New J. Chem. 2010, 34, 193.
5
th ed., Butterworth‐Heinemann, Elsevier Science, Bodmin,
Cornwall, UK 2003.
[34] S. Y. Ebrahimipoura, B. Machura, M. Mohamadi, M. Khaleghi,
Microb. Pathog. 2017, 113, 160.
11] A. Kalusa, N. Chessum, K. Jones, Tetrahedron Lett. 2008,
4
9, 5840.
[35] A. Y. Meyer, Chem. Soc. Rev. 1986, 15, 449.
[
[
12] N. P. Peet, Synthesis 1984, 12, 1065.
[
[
36] A. Baumgärtner, J. Chem. Phys. 1993, 99, 7496.
13] G. M. Sheldrick, SHELXTL. Version 5.0, Bruker AXS Inc.,
37] S. K. Seth, D. Sarkar, A. Roy, T. Kar, CrystEngComm 2011,
Madison, WI, 2001.
13, 6728.
[
14] S. K. Wolff, D. J. Grimwood, J. J. McKinnon, M. J. Turner, D.
Jayatilaka, M. A. Spackman, CrystalExplorer 3.1, University of
Western Australia, Crawley, 2012.
[
[
38] S. Grabowsky, P. M. Dean, B. W. Skelton, A. N. Sobolev, M. A.
Spackman, A. H. White, CrystEngComm 2012, 14, 1083.
39] (a) U. Kendur, G. H. Chimmalagi, S. M. Patil, K. B. Gudasi, C. S.
Frampton, C. V. Mangannavar, I. S. Muchchandi, J. Mol Struct.
2018, 1153, 299; (b) N. Sathyanarayana, Electronic Absorption
Spectroscopy and Related Techniques, 1st ed., University Press
2001; (c) A. B. P. Lever, Inorganic Electronic Spectroscopy, 2nd
ed., Elsevier, Amsterdam, Netherlands 1984.
[
[
15] F. L. Hirshfeld, Theor. Chim. Acta 1977, 44, 129.
16] (a) M. A. Spackman, D. Jayatilaka, CrystEngComm 2009, 11, 19;
(
b) A. Massoud, V. Langer, Y. M. Gohar, M. A. M. Abu‐Youssef,
J. Jänis, G. Lindberg, K. Hansson, L. ÖhrstrÖm, Inorg. Chem.
013, 52, 4046.
2
[
[
17] N. S. Naik, L. A. Shastri, S. D. Joshi, S. R. Dixit, B. M. Chougala,
S. Samundeeswari, M. Holiyachi, F. Shaikh, J. Madar, R.
Kulkarni, V. Sunagar, Bioorganic Med. Chem. 2017, 25, 1413.
[40] W. C. Parks, C. L. Wilson, Y. S. López‐Boado, Nat. Rev.
Immunol. 2004, 4, 617.
[41] S. Loffek, O. Schilling, C. W. Franzke, Eur Respir J. 2011,
38, 191.
18] a) M. C. Alley, D. A. Scudiero, A. Monks, M. L. Hursey, M. J.
Czerwinski, D. L. Fine, B. J. Abbott, J. G. Mayo, R. H.
Shoemaker, M. R. Boyd, Cancer Res. 1988, 48, 589; b) M. R.
Boyd, K. D. Paull, Drug Dev. Res. 1995, 34, 91; c) M. R. Grever,
S. A. Schepartz, B. A. Chabner, Semin Oncol. 1992, 19, 622.
[42] U. Galm, S. Heller, S. Shapiro, M. Page, L. H. Shu‐Ming Li,
Antimicrob. Agents Chemother. 2004, 48, 1307.
[
[
43] S. Sakamoto, M. Sakamoto, Mol. Aspects Med. 1988, 10, 299.
44] K. D. Paull, R. H. Shoemaker, L. Hodes, A. Monks, D. A.
Scudiero, L. Rubinstein, J. Plowman, M. R. Boyd, J. Natl.
Cancer Inst. 1989, 81, 1088.
[
[
19] J. Sambrook, E. F. Fritsch, T. Maniatis, Molecular Cloning. A
Laboratory Manuals, 4th ed., Cold Spring Harbor Laboratory
Press, New York 1989.
[45] D. W. Zaharevitz, S. L. Holbeck, C. Bowerman, P. A. Svetlik,
20] J. L. Wang, D. Limburg, M. J. Graneto, J. Springer, J. R.
Hamper, S. Liao, J. L. Pawlitz, R. G. Kurumbail, T. Maziasz, J.
J. Talley, J. R. Kiefer, J. Carter, Bioorg. Med. Chem. Lett. 2010,
J. Mol. Graphics Modell. 2002, 20, 297.
[46] S. Bouaziz‐Terrachet, A. Toumi‐Maouche, B. Maouche,
S. Taïri‐Kellou, J. Mol. Model. 2010, 16, 1919.
2
0, 7159.

KENDUR ET AL.
21 of 21
[
47] (a) S. Chung‐Hang Leung, H.‐J. Z. Lin, D.‐L. Ma, Chem. Sci.
015, 6, 871; (b) R. S. Hoonur, B. R. Patil, D. S. Badiger, R. S.
2
How to cite this article: Kendur U, Chimmalagi
GH, Patil SM, Gudasi KB, Frampton CS. Synthesis,
structural characterization and biological
evaluation of mononuclear transition metal
complexes of zwitterionic dehydroacetic acid N‐
aroylhydrazone ligand. Appl Organometal Chem.
Vadavi, K. B. Gudasi, P. R. Dandawate, M. M. Ghaisas, S. B.
Padhye, M. Nethaji, Eur. J. Med. Chem. 2010, 45, 2277; (c) B.
G. Tweedy, Phytopathology. 1964, 55, 910; (d) T. D.
Thangadurai, K. Natarajan, Transition Met. Chem. 2001, 26,
5
00; (e) J. Joseph, K. Nagashri, G. A. B. Rani, J. Saudi Chem.
Soc. 2013, 17, 285.
2018;e4278. https://doi.org/10.1002/aoc.4278
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