Novel mixed-ligand complexes of coumarilate/N,N′-diethylnicotinamide with some transition metals: Synthesis and structural characterization

Article abstract of DOI:10.1007/s10973-017-6373-6

Coordination complexes of transition metal cations (Co^II, Ni^II, Cu^II and Zn^II) containing coumarilate and N,N′-diethylnicotinamide were synthesized. The structural characterization and thermal behaviour analysis

Full text of DOI:10.1007/s10973-017-6373-6

J Therm Anal Calorim
DOI 10.1007/s10973-017-6373-6
Novel mixed-ligand complexes of coumarilate/N,N0-
diethylnicotinamide with some transition metals
Synthesis and structural characterization
1
1
•
Ozge Daglı Dursun Ali Kose Gu¨lc¸in Alp Avcı2 Onur S¸ahin3
¨
•
•
˘
¨
Received: 23 November 2016 / Accepted: 26 March 2017
´
´
Ó Akademiai Kiado, Budapest, Hungary 2017
Abstract Coordination complexes of transition metal
cations (CoII, NiII, CuII and ZnII) containing coumarilate
and N,N0-diethylnicotinamide were synthesized. The
structural characterization and thermal behaviour analysis
of novel samples synthesized were conducted through
elemental analysis, magnetic susceptibility, solid-state
UV–Vis, direct and injection probe mass spectra, FTIR
spectra, thermoanalytic TG-DTG/DTA and single crystal
X-ray diffraction methods. The structural details of single
crystals of [Co(dena)2(H2O)4](coum)2 (I) and [Cu
(coum)2(dena)2(H2O)2] (III) complexes were resolved
completely. Moreover, the results of analysis obtained for
[Ni(coum)2(dena)2(H2O)2] (II) and [Zn(dena)2(H2O)4]
(coum)2 (IV) complexes were interpreted considering the
samples with crystal structures defined and made assump-
tions about the structural details. It was determined that the
complex of CoII metal cation has salt-type structure and the
coordination number of metal is accomplished to six as the
sum of 4 mol of water and also 2 mol of N,N0-diethylni-
cotinamide ligands in trans position located within the
coordination sphere. It was observed that 2 mol of
coumarilate anions are located outside the coordination
sphere and have stabilized to the charge (2?) of metal. The
CuII complex has totally molecular structure, and the
coordination sphere of metal cation was 6 as the sum of
2 mol of water, 2 mol of N,N0-diethylnicotinamide and
2 mol of monoanionic monodentate coumarilate ligands.
All ligands have been located in –trans position. The
geometry of both complex structures is distorted octahe-
dral. It is assumed that the NiII complex structure is
isostructural with CuII complex structure and also does ZnII
complex with CoII structure. It was determined that the
decomposition products obtained from thermal analysis are
the oxides of related metal cations.
Keywords Coumarilate Á N,N0-diethylnicotinamide Á
Mixed-ligand–metal complexes Á Crystal structure Á
Thermal analysis Á Structural analysis
Introduction
The coumarilic acid (coumarin-3-carboxylic acid, benzo
[b] furan carboxylic acid, HCCA, Fig. 1) which is the
derivative of coumarin is a ligand that shows monoanionic
monodentate or monoanionic bidentate binding features
through the carboxylic acid group it has. The benzo
[b] furan ring constituting the main body of the structure is
available in most of the compounds as a key pharma-
cophore and can be isolated from the natural sources [1]. It
is known that the benzo [b] furan and its derivatives exist in
different natural food sources such as fruits, herbs, and
vegetables [2]. It is also the major component of the drugs
(such as amiodarone and bergapten) synthesized and used
in many applications recently [3, 4].
Electronic supplementary material The online version of this
article (doi:10.1007/s10973-017-6373-6) contains supplementary
material, which is available to authorized users.
¨
& Dursun Ali Kose
dkose@hacettepe.edu.tr
1
Department of Chemistry, Hitit University, 19030 C¸ orum,
Turkey
2
Department of Molecular Biology and Genetics, Hitit
University, Ulukavak, C¸ orum, Turkey
3
It is well known that many of the heterocyclic com-
pounds containing oxygen in the ring structure exhibit
Scientific and Technological Research Application Centre,
Sinop University, 57000 Sinop, Turkey
123

¨
˘
O. Daglı et al.
diethylnicotinamide used in the synthesis of complexes were
obtained from the company Sigma-Aldrich. Structural
characterizations of these synthesized complexes were
characterized by elemental analysis, Fourier Transform
Infrared spectroscopy (FTIR), thermogravimetric analysis
(TG/DTA), single crystal X-ray diffraction diffractometry
(SC-XRD), solid ultraviolet–visible region spectroscopy (S-
UV–Vis) magnetic susceptibility and melting point deter-
mination methods. The biologic activation studies of the
elucidated molecules have been studied in cell culture
medium. Bacterial cultures of Enterecoccus faecalis ATCC
29212, Escherichia coli ATCC 25922, Staphylococcus aur-
eus ATCC 25923 and fungal culture of Candida albicans
ATCC 10231 were obtained from the culture collection at
Hitit University, Faculty of Science and Arts, Departments
of Molecular Biology and Genetics/Molecular Microbiol-
ogy. In this study, nutrient broth and agar (Diffco) for E. coli;
Tryptone-Yeast extract-Cystine (TYC) broth and agar for E.
fecalis and S. aureus; Eosin Methylene Blue (EMB, Merck)
broth and agar for P. aeroginosa and Sabouraud Dextrose
broth and agar (SD, Merck) for C. albicans were used for
growth of microorganisms. All strains stored at -20 °C in
appropriate medium containing 10% glycerol and regener-
ated twice before use.
OH
O
O
Fig. 1 Coumarilic acid
important biological features such as antiarrhythmic,
spasmolytic, antiviral, anticancer, antifungal, and anti-in-
flammatory activities [5–11]. This group of compounds
includes furobenzopyranone, benzofurane and benzopy-
rano systems.
This feature of coumarilic acid with a good ligand
behaviour in terms of coordination chemistry has made
many researchers focused on this ligand. There are studies
in the literature, in defiance of the limited number, about
the complex compound studies performed using metal
cations [12–14]. There are also studies showing that the
metal complex structures are more effective than ligand
structures (without any metal) biologically [15–21].
Although there are many studies conducted using
coordination complexes of coumarilic acid containing
transition metal cations [14, 22–27], the number of studies
on single crystal structure analysis is very limited in
amount [1, 25, 26]. Moreover, there is almost no study
concerned metal complexes with mixed ligand [1].
Therefore, the conditions of the coordination reaction of
coumarilic acid are important, and the researchers adjust
the different binding models of ligand ionized (as an
anion). Whether the binding of coumarilate ligand as a
monodentate-bridge or terminal ligand, or participating in
the coordination as bidentate chelator depends on reaction
conditions [22–24, 28–30].
The N,N0-diethylnicotinamide (nikethamide) is one of
the nicotinamide (B3 vitamin) derivatives, which is used as
a complementary ligand of mixed (ligand) complexes and
still used in medical field as a respiratory simulator [31].
The coordination compounds of anionic coumarilic acid
and N,N0-diethylnicotinamide ligands with CoII, NiII, CuII
and ZnII transition metal cations have been synthesized.
The structural features of molecules obtained were char-
acterized using single crystal X-ray diffraction (SC-XRD),
UV–Vis, FTIR and solid probe GC–MS methods, and TG-
DTG/DTA methods for the determination of thermal
behaviour.
Synthesis of mixed-ligand complexes
For the synthesis of mixed-ligand complexes, the sodium
coumarilate salt was obtained. After dissolving the
coumarilic acid of 0.005 mol in a beaker containing 50:50
(v/v) EtOH: H2O, NaHCO3 of 0.005 mol was added and
stirred until the gas evolution was ceased. Following this
process, the solution of the neutral ligand N,N0-diethylni-
cotinamide (0.005 mol in 25 mL H2O) was added to the
solution obtained and was stirred at room temperature for
approximately 30 min. Relevant metal cation nitrate salts
in the amount of 0.0025 mol of each was added to the final
solution obtained by mixing other two (Scheme 1). The
metal salts added in the form of solid were completely
dissolved and stirred at 55 °C over a hot plate for 3 h until
the solution becomes clear. The clear solutions obtained
were allowed to crystallize at room temperature. The pre-
cipitated crystals after approximately 3–5 weeks were
collected by filtration. The proportions of metal:ligand:li-
gand for Co, Ni, Cu and Zn transition metal complexes
were obtained as 1:2:2 basically.
Experimental
Results
Materials and methods
The elemental analysis results of metal–coumarilate/N,N0-
diethylnicotinamide mixed-ligand complexes are given in
Table 1. In addition, the melting point of the complexes,
The
chemicals
Co(NO3)2Á6H2O,
Ni(NO3)2Á6H2O,
´
Cu(NO3)2Á3H2O, Zn(NO3)2Á6H2O, coumarilic acid and N,N-
123

Novel mixed ligand complexes of coumarilate/N,N0-diethylnicotinamide with some transition…
O
HO
O
O
O
O
NaHCo
Na
CO
+ H O
2
3
2(g)
(1)
O
O
O
N
N
(H O)
M
O
2
4
2 NaNO
3
(s)
O
O
O
N
N
2
2
M: CoΙΙ and ZnII
Na
O
M(NO )
3 2
O
O
N
O
M
(H O)
2 NaNO
O
2
2
3
(s)
N
2
2
M: NiΙΙ and CuII
(2)
Scheme 1 Reaction of mixed-ligand complexes of coumarilate/N,N0-diethylnicotinamide
Table 1 Elemental analysis data of metal–coumarilate/N,N0-diethylnicotinamide mixed-ligand complexes
Complex
Sample mass/g mol-1 Yield Content/% experimental
(theoretical)
Colour Decomp. temp./K leff. (BM)
C
H
N
[Co(C10H14N2O)2(H2O)4](C9H5O3)2 809.72
[Co(dena)2(H2O)4](coum)2
79
86
92
87
20.06
4.26
11.33
Purple 368
Green 380
4.69
3.27
1.79
dia.
(19.74)
20.01
(4.94)
4.67
(11.52)
11.61
[Ni(C9H5O3)2(C10H14N2O)2(H2O)2] 773.45
[Ni(coum)2(dena)2(H2O)2]
(19.78)
21.24
(4.95)
3.96
(11.54)
12.06
[Cu(C9H5O3)2(C10H14N2O)2(H2O)2] 778.29
[Cu(coum)2(dena)2(H2O)2]
Blue
398
(20.90)
21.15
(4.36)
4.02
(12.13)
11.46
[Zn(C10H14N2O)2(H2O)4](C9H5O3)2 816.17
[Zn(dena)2(H2O)4](coum)2
White 438
(19.97)
(4.61)
(11.65)
magnetic susceptibility results, colours and yield estima-
tions can also be seen in the table.
1610 cm-1 are due to the C=O group of the carboxylic acid
in the metal complexes of CoII, NiII and CuII, whereas the
same peak was observed at 1612 cm-1 for ZnII complex.
The aromatic C=C stretching vibration was observed at
around 3065–3082 cm-1. The aromatic C–H stretching in
the complexes has provided stretching vibrations in
between 3279 and 3394 cm-1. The COO- asymmetric and
symmetric absorption bands of carboxylic acid were
Infrared spectroscopy
The data designating the significant stretching and bending
peaks owned by molecules are given in Table 2. The
intense and broad band observed near 3600–2900 cm-1 is
due to the presence of –OH groups in the structure of the
complexes. The stretching vibration peaks observed at
observed at (in order of) 1553–1579 and 1378–1402 cm-1
,
corresponding to the stretching vibration. The stretching
123

¨
˘
O. Daglı et al.
Table 2 IR spectra of metal–coumarilate/N,N0-diethylnicotinamide mixed-ligand complexes
Groups
CoII
NiII
CuII
ZnII
m(OH)H2O
3550–2900
3340
3600–2900
3394
3600–2900
3393
3600–2900
3279
m(=C–H)aromatic
m(C=C)aromatic
m(CH2)
3065
3082
3067
3073
2971, 2931
1610
2973, 2937
1610
2975, 2939
1610
2976, 2933
1612
m(C=O)carbonyl
m(COO–)asym
m(COO–)sym
Dmas-s
1553
1579
1556
1576
1389
1402
1378
1400
164
177
178
176
d(OH)H2O
1461
1461
1463
1476
m(C–N–C)pyridine
m(C–O–C)
1334
1343
1338
1329
1254/1181
1304
1253/1183
1305
1250/1183
1301
1254/1185
1302
m(C–O)carboxyl
mring of coumarilate
m(C–N)amide
m(M–N)
1104–820
940–704
584
1107–832
945–705
589
1104–831
943–703
590
1114–856
942–706
598
m(M–O)
433
530,427
514,445
431
vibration absorption bands belonging to the metal–oxygen
(M–O) binding were observed at 433 cm-1 for CoII; 427
and 530 cm-1 for NiII; 445 and 514 cm-1 for CuII; and
431 cm-1 for ZnII complexes. The vibrations of metal–
nitrogen (M–N) bonds were observed at 584 cm-1 for CoII;
589 for NiII; 590 for CuII; and 598 cm-1 for ZnII [32–34]
complexes.
pattern recorded in the wavelength range of 900–200 nm
(Fig. 2). According to these data, d–d transitions of CoII
complex were observed at the wavelengths of 479.72
(4T1g?4T2g) (F) and 450.03 nm (4T1g?4T1g) (P). The
three spin-allowed d–d transitions owned by NiII complex
were corresponded to the wavelengths at 807.12
(3A2g?3T1g) (P), 635.39 (3A2g?3T1g) (F) and 381.49 nm
(3A2g?3T2g) (F), and these transition bands provide the
The most significant proof of the monoanionic mon-
odentate binding of carboxylate group is the similarity of
the values obtained from the subtraction between the
asymmetric and symmetric stretching vibrations of car-
boxylate and that of sodium salt [31–33, 35]. The corre-
sponding m(COO–)asym –m(COO–)sym values for CoII, NiII,
CuII and ZnII structures are 164, 177, 178 and 176 cm-1
,
respectively. Because the subtraction is below the value of
200 cm-1, the monoanionic monodentate coordination of
carboxylate groups has been proved. The existence of two
different M–O binding stretching in the complexes II and
III is the proof of both salt-type and coordination bonds.
However, the single peak value for the M–O binding in
other complex structures may be presented as the confir-
mation of salt-type binding of coumarilate ligands in the
structures as a counter ion. The emerging shift values
belonging to the pyridine ring of N,N0-diethylnicotinamide
are the signal of the coordination of the pyridine through
nitrogen group.
(I)
(II)
(III)
(IV)
Solid UV–Vis spectroscopy
200
400
600
800 900
The electronic transition values of metal–coumarilate/N,N0-
diethylnicotinamide complexes with mixed ligands were
deduced according to the solid phase UV–Vis spectra
Wavelength/nm
Fig. 2 Solid UV–Vis spectra of complexes
123

Novel mixed ligand complexes of coumarilate/N,N0-diethylnicotinamide with some transition…
assumption that the d orbitals of NiII metal cations were
split to encourage the octahedral geometry. The multi-ad-
sorption band owned by CuII complex was formed by
overlapping peaks and having a broad view in a wide range
in between 869.43 and 497.36 nm. The maximum
absorption band of the broad spectrum of CuII complex
corresponds to approximately 622.81 nm (2Eg?2T2g).
Because the d orbitals in the last orbital of metal cation of
the ZnII complex with a diamagnetic feature detected from
the magnetic susceptibility data were fully engaged, there
was no any d–d electronic transition observed during any
octahedral split.
the DTG curve belonging to (I) complex with CoII mixed
ligand. Two of the four water ligands in the coordination
sphere were removed from the structure at 356–386 K
during the first step.
Â
Ã
CoðC10H14N2OÞ2ðH2OÞ4 ðC9H5O3Þ2ðsÞ
Â
Ã
356À386 K
À! CoðC10H14N2OÞ2ðH2OÞ4 ðC9H5O3Þ2ðsÞþ2H2OðgÞ
ð3Þ
The remaining 2 mol of water ligand in the coordination
sphere was completely removed from the structure at
decomposition step (120 °C) in the temperature range of
387–436 K.
The absorption bands observed at a lower wavelength
with high intensity do not belong to d–d transitions, but
metal–ligand (M ? L) charge transfer with higher energy.
The adsorption bands at 250.67 nm for CoII, 256.21 nm
NiII and 250.51 nm for CuII complexes do belong to metal–
ligand (M ? L) transition, whereas the intense peaks
observed at the wavelengths of 223.68 and 266.33 nm for
ZnII belong to ligand–metal (L ? M) charge transfer
[36, 37].
Â
Ã
CoðC10H14N2OÞ2ðH2OÞ2 ðC9H5O3Þ2ðsÞ
Â
Ã
387À436 K
À! CoðC10H14N2OÞ2 ðC9H5O3Þ2ðsÞþ2H2OðgÞ
ð4Þ
The N,N0-diethylnicotinamide and coumarilic acid ligand
of 2 mol each was concurrently removed from the structure
in the temperature range of 438–1062 K. The black-
coloured CoO compound remained as the decomposition
product.
Thermal analysis
Â
Ã
Â
438À1062 K
The thermal analysis curves are shown in Fig. 3, and
thermal decomposition steps are summarized in Table 3.
[Co(C10H14N2O)2(H2O)4](C9H5O3)2: There is four-step
decomposition observed at maximum temperatures of 382,
393, 456, 512 K and 587, 625, 661, 774, 918 K available in
CoðC10H14N2OÞ2 ðC9H5O3Þ2ðsÞ À! CoOðsÞ
ð5Þ
Ã
þ2C10H14N2OðdecompÞ þ 2C9H5O3ðdecompÞ
[Ni(C9H5O3)2(C10H14N2O)2(H2O)2]: It was determined
that there are four decomposition steps at maximum
Fig. 3 TG/DTA/DTG curves of
complexes; CoII (I), NiII (II),
100
80
100
CuII (III) and ZnII (IV)
80
60
60
40
20
0
TG
40
TG
DTA
DTA
DTG
DTG
20
0
273
473
673
873
1073
1273
273
473
673
873
1073
1273
Temperature/K
Temperature/K
(I)
(II)
100
80
60
40
20
0
100
80
60
40
20
0
TG
DTA
DTG
TG
DTA
DTG
273
473
673
873
1073
1273
273
473
673
873
1073
1273
Temperature/K
Temperature/K
(III)
(IV)
123

¨
˘
O. Daglı et al.
Table 3 Thermoanalytical data (TG-DTG/DTA) for the metal complexes
Complex
Temp.
range/°C
DTAmax/°C
Withdrawing
group
Mass/%
Residue/%
Decomp. Colour
product
Exp. Theor. Exp. Theor.
[Co(C10H14N2O)2(H2O)4](C9H5O3)2
[Co(dena)2(H2O)4](coum)2
(I)
Pink
1
2
3
4
356–386
387–436
438–571
382
2H2O
4.22
4.82
4.45
4.45
393
2H2O
809.72 g/mol
456, 512
2C10H14N2O
42.58 43.95
573–1062 587, 625,
661, 774,
918
C9H5O2;
C9H5O3
36.58 37.81 11.80
9.25 CoO
Black
Green
[Ni(C9H5O3)2(C10H14N2O)2(H2O)2]
[Ni(coum)2(dena)2(H2O)2]
(II)
1
2
3
4
385–423
424–470
471–591
414
H2O
2.10
2.41
2.33
2.33
436
H2O
773.45 g/mol
511, 571
2C10H14N2O
44.82 45.99
592–1170 606, 647,
670, 797,
1111
C9H5O2;
C9H5O3
37.81 39.60 12.86 9,66
NiO
Black
Blue
[Cu(C9H5O3)2(C10H14N2O)2(H2O)2]
[Ni(coum)2(dena)2(H2O)2]
(III)
1
2
3
312–353
358–414
416–798
332
368
H2O(nem)
2H2O
1.26
4.25
–
4.62
778.29 g/mol
482, 531,
601
2C10H14N2O
C9H5O2;
C9H5O3
77.91 79.50
4
901–1218 1028
CO2
5.12
5.65 11.36
10.22 CuO
Black
White
[Zn(C10H14N2O)2(H2O)4](C9H5O3)2
[Zn(dena)2(H2O)4](coum)2
(IV)
1
2
3
4
320–387
390–467
552–635
366
H2O(nem)
4H2O
1.23
8.62
–
425
8.82
816.17 g/mol
573, 593
2C10H14N2O
40.97 43.62
636–1094 648, 985
C9H5O2;
C9H5O3
36.22 37.52 12.96
9.97 ZnO
Grey
The N,N0-diethylnicotinamide and coumarilic acid ligand
of 2 mol each was concurrently removed from the structure
in the temperature range of 471–1170 K. The black-
coloured NiO compound remained as the decomposition
product.
temperatures
of
414,
436,
511;571 K and
606;647;670;797;1111 K available in the DTG curve
belonging to (II) complex with NiII mixed ligand. 1 of
2 mol of water ligand in the coordination sphere was
removed from the structure at 385–423 K during the first
step.
Â
Ã
NiðC9H5O3Þ2ðC10H14N2OÞ2
ðsÞ
h
i
Â
Ã
471À1170K
NiðC9H5O3Þ2ðC10H14N2OÞ2ðH2OÞðsÞ
À! NiOðsÞ þ2C10H14N2OðdecompÞ þ2C9H5O3ðdecompÞ
Â
Ã
385À423 K
À! NiðC9H5O3Þ2ðC10H14N2OÞ2ðH2OÞ ðs) þ H2OðgÞ
ð6Þ
ð8Þ
[Cu(C9H5O3)2(C10H14N2O)2(H2O)2]: Four decomposi-
tion steps are at maximum temperatures of 332, 368,
482;531;601 and 1028 K available in the DTG curve
belonging to (III) complex with CuII mixed ligand. The
humidity in the structure was removed from the structure at
312–353 K during the first step.
The remaining 1 mol of water ligand in the coordination
sphere was completely removed from the structure at the
decomposition step (436 K) in the temperature range of
424–470 K.
h
i
The 2 mol of water ligand in the coordination sphere
was completely removed from the structure at the decom-
position step (368 K) in the temperature range of 358–
414 K.
NiðC9H5O3Þ2ðC10H14N2OÞ2ðH2OÞðsÞ
Â
Ã
424À470 K
À! NiðC9H5O3Þ2ðC10H14N2OÞ2 ðs) þ H2OðgÞ
ð7Þ
123

Novel mixed ligand complexes of coumarilate/N,N0-diethylnicotinamide with some transition…
Â
Ã
monochromatic Mo-Ka radiation. The structures were
clarified by direct methods using SHELXS-97 and refined
by full-matrix least-squares methods on F2 using SHELXL-
97 [40] from within the WINGX [41] suite of software. All
non-hydrogen atoms were refined with anisotropic param-
eters. The H of C atoms were located from different maps
and then treated as riding atoms with C–H distances of
CuðC9H5O3Þ2ðC10H14N2OÞ2ðH2OÞ2
ðsÞ
Â
Ã
358À414 K
À! CuðC9H5O3Þ2ðC10H14N2OÞ2 ðs) þ 2H2OðgÞ
ð9Þ
The N,N0-diethylnicotinamide and coumarilic acid ligand
of 2 mol each was concurrently removed from the structure
in the temperature range of 416–798 K.
˚
0.93–0.97 A. The water H atoms were located on a dif-
Â
Ã
ferent map refined freely. Molecular diagrams were created
using the software MERCURY [42]. Supramolecular
analyses were performed, and the diagrams were prepared
with the aid of PLATON [43]. Details of data collection
and crystal structure determinations are given in Table 4.
Complex I: The molecular structure of I with atomic
label is shown in Fig. 4. The asymmetric unit of I contains
a CoII ion, a N,N0-diethylnicotinamide ligand, a non-coor-
dinated coumarilic acid ligand and two aqua ligands. The
CoII ion is located on the centre of symmetry and is
coordinated by two nitrogen atoms of two N,N0-diethylni-
cotinamide ligands and four oxygen atoms from aqua
ligands. The coordination geometry around the CoII ion can
be described as a distorted octahedral geometry. The Co–O
CuðC9H5O3Þ2ðC10H14N2OÞ2 416ÀÀ!798 K CuðCO3Þ
þ 2C9H5O3ðdecompÞ þ 2C10H14N2OðdecompÞ
2ðsÞ
ðsÞ
ð10Þ
It is believed that the CO2 was removed from the structure
at the 1028 K decomposition step in the temperature range
of 901–1218 K. The black-coloured CuO compound
remained as the decomposition end product
CuðCO3Þ2ðsÞ901ÀÀ!1218 K CuOðsÞ þ CO2ðgÞ
ð11Þ
[Zn(C10H14N2O)2(H2O)4](C9H5O3)2: The molecule has
four decomposition steps at maximum temperatures of 366,
425, 573;593 and 648;985 K available in the DTG curve
belonging to (IV) complex with the ZnII mixed ligand. It is
assumed that the first decomposition step is due to the
humidity in the structure at the maximum temperature of
366 K.
˚
bond lengths are 2.0678 (11) and 2.1034 (11) A, while the
˚
Co–N bond length is 2.1649 (12) A (Table 5).
Table 4 Crystal data and structure refinement parameters for com-
plexes I and III
The 4 mol of water ligand in the coordination sphere
was completely removed from the structure at the decom-
position step (425 K) in the temperature range of 390–
467 K.
Â
Crystal data
I
III
Empirical
formula
[Co(dena)2(H2O)4](coum)2 [Cu(coum)2(dena)2(H2O)2]
Ã
ZnðC10H14N2OÞ2ðH2OÞ4 ðC9H5O3Þ2ðsÞ
Formula mass 809.72
Crystal system Triclinic
778.29
Â
Ã
390À467 K
Monoclinic
P21
À! ZnðC10H14N2OÞ2 ðC9H5O3Þ2ðsÞþ4H2Og
Space group
P-1
ð12Þ
˚
a/A
7.9249 (5)
8.4475 (5)
16.6372 (10)
100.387 (2)
92.791 (3)
113.396 (2)
996.50 (11)
1
8.4196 (6)
12.2845 (9)
18.2399 (13)
90.00
˚
b/A
The N,N0-diethylnicotinamide and coumarilic acid ligand
of 2 mol each was concurrently removed from the structure
in the temperature range of 552–1094 K. The grey-
coloured ZnO compound remained as the decomposition
product.
˚
c/A
a/°
b/°
c/°
98.887 (2)
90.00
3
˚
V /A
1863.9 (2)
2
Â
Ã
ZnðC10H14N2OÞ2 ðC9H5O3Þ2ðsÞ552ÀÀ!1094 K ZnOðsÞ
Z
Dc /g cm-3
1.349
1.387
þ 2C10H14N2OðdecompÞ þ 2C9H5O3ðdecompÞ
ð13Þ
h range /°
Measured
refls.
3.2–28.4
46750
3.3–28.0
54225
The decomposition steps of mixed-ligand metal complexes
are consistent with the literature, and thermal degradation
product-related metal oxides were determined by IR
spectra [36–39].
Independent
refls.
4945
9280
Rint
0.027
0.048
S
1.09
1.03
X-ray diffraction analysis
R1/wR2
0.037/0.099
0.54/-0.53
0.037/0.081
0.33/-0.34
Dqmax/Dqmin
eA
/
-3
˚
Suitable crystals of I and III were analysed using a Bruker
APEX-II diffractometer equipped with
a
graphite
123

¨
˘
O. Daglı et al.
O1
C9
C10
C8
C3
N1
C6
N2
C7
C4
C5
C2
C1
O3
O4
i
O2
O2
Co1
C13
C19
i
C12
O3
C11
C14
C15
i
O5
N1
C16
O6
C18
C17
Fig. 4 Molecular structure of complex I showing the atom-numbering scheme
˚
Table 5 Selected bond distances and angles for complexes I and III (A, °)
Complex I
N1–Co1
2.1649 (12)
90.11 (5)
87.84 (5)
Co1–O2
O2–Co1–O3i
O3i–Co1–N1i
2.0678 (11)
89.89 (5)
93.65 (5)
Co1–O3
O2–Co1–N1i
O3–Co1–N1i
2.1034 (11)
92.16 (5)
86.35 (5)
O2–Co1–O3
O2–Co1–N1
Complex III
N1–Cu1
2.012 (2)
1.965 (2)
N3–Cu1
2.018 (2)
2.322 (3)
O1–Cu1
1.9679 (19)
2.729 (2)
O4–Cu1
Cu1–O10
Cu1–O9
O4–Cu1–O1
O1–Cu1–N3
174.42 (13)
88.49 (9)
O1–Cu1–N1
N1–Cu1–N3
89.83 (9)
O4–Cu1–N3
O4–Cu1–O10
90.75 (10)
92.76 (10)
172.77 (10)
Symmetry code: (i) -x, -y ? 1, -z ? 1 for I
The molecule of I is linked into the sheets by the
combination of O–HÁÁÁO and C–HÁÁÁO hydrogen bonds
(Table 6). The water O3 atom in the molecule at (x, y, z)
acts as a hydrogen bond donor, via atoms H3A and H3B, to
atoms O5i and O5v, and thus forms a centrosymmetric
R24(8) ring centred at (n, 1/2, 1/2) [n = zero or integer]
[(i) -x, -y ? 1, -z ? 1; (v) x - 1, y, z] (Fig. 5). Simi-
larly, water O2 atom in the molecule at (x, y, z) acts as a
hydrogen bond donor, via atom H2A, to atom O1iv, and
thus forms centrosymmetric R22(16) ring centred at (0, n,
1/2) [n = zero or integer] which is running parallel to the
[010] direction [(iv) x, y - 1, z] (Fig. 6).
water ligands. The coordination geometry of a CuII ion is a
distorted octahedron in which there are two oxygen atoms
of two different coumarilic acid ligands, two nitrogen
atoms of two N,N0-diethylnicotinamide ligands and two
oxygen atoms from aqua ligands. The Cu–Ocarboxyl bond
˚
lengths are 1.965 (2) and 1.968 (2) A. The Cu–Oaqua bond
˚
lengths are 2.322 (3) and 2.729 (2) A, while the Cu–N
bond lengths are 2.012 (2) and 2.018 (2) (Table 5). The O9
atom of aqua ligand is weakly coordinated to the CuII ion,
and the bond is longer than those of the Cu–O bonds due to
the Jahn–Teller effect.
Molecules of III are linked to the sheets by a combi-
nation of O–HÁÁÁO and C–HÁÁÁO hydrogen bonds (Table 6).
Water O10 atom in the molecule at (x, y, z) acts as a
hydrogen bond donor, via atom H10A, to atom O2ii, and
thus forms C(6) chain running parallel to the [010]
Complex III: The molecular structure of complex III,
with atom-numbering scheme, is shown in Fig. 7. The
asymmetric unit of III contains a CuII ion, two coumarilic
acid ligands, two N,N0-diethylnicotinamide ligands and two
123

Novel mixed ligand complexes of coumarilate/N,N0-diethylnicotinamide with some transition…
˚
thus forms C(8) chain running parallel to the [010] direc-
Table 6 Hydrogen bond parameters for complexes I and III /A, °
tion [(iii) -x ? 1, y ? 1/2, -z ? 1] (Fig. 9). All of these
intermolecular interactions give two-dimensional frame-
work results.
D–HÁ Á ÁA
D–H
HÁÁÁA
DÁÁÁA
D–HÁÁÁA
Complex I
C2—H2ÁÁÁO5ii
C7—H7BÁÁÁO4
C18—H18ÁÁÁO4iii
O2—H2AÁÁÁO1iv
O2—H2BÁÁÁO4
O3—H3AÁÁÁO5v
O3—H3BÁÁÁO5i
Complex III
0.93
0.97
0.93
2.57
2.46
2.54
3.386 (2)
3.241 (3)
3.427 (3)
146
137
160
Biological applications
0.82 (2) 1.94 (2) 2.7551 (18) 170 (2)
0.85 (2) 1.78 (2) 2.6175 (17) 173 (2)
0.82 (2) 1.93 (2) 2.7212 (16) 162 (2)
0.83 (2) 1.94 (2) 2.7760 (16) 176 (2)
The antimicrobial and antifungal effects of the synthesized
metal complexes I–IV were determined by the disc diffu-
sion method according to the Clinical and Laboratory
Standards Institute (CLSI) guidelines. First, 0.01 g of each
of the metal complexes was dissolved in 1 mL dimethyl-
sulphoxide (DMSO). The microorganisms were grown in a
suitable broth at 310 1 K for 24 h. All the Mueller-
Hinton agar (MHA) plates were prepared with a final depth
of 4 mm. Next 0.1 mL suspension of tested microorgan-
isms (106 cells mL-1; turbidity = McFarland barium sul-
phate standard 0.5) was spread on the agar plates. Then,
6-mm-diameter sterile filter paper discs (Whatman, no. 4)
were placed on the agar plates and impregnated with 15 lL
of metal complexes in DMSO. These plates were incubated
at 310 1 K for 24–48 h. DMSO without metal com-
C30—H30ÁÁÁO8i
C36—H36CÁÁÁO9ii
O9—H9AÁÁÁO2
O9—H9BÁÁÁO8iii
0.93
0.96
2.42
2.60
3.297 (4)
3.514 (7)
2.645 (5)
2.880 (5)
2.809 (4)
2.737 (4)
158
159
151
162
177
157
0.92 (3) 1.80 (4)
0.91 (3) 2.01 (4)
O10—H10AÁÁÁO2ii 0.86 (2) 1.95 (3)
O10—H10BÁÁÁO5
0.83 (2) 1.95 (3)
Symmetry codes: (i) -x, -y ? 1, -z ? 1; (ii) -x ? 1, -y ? 2,
-z ? 1; (iii) x ? 1, y, z; (iv) x, y - 1, z; (v) x - 1, y, z for I;
(i) -x ? 2, y ? 1/2, -z ? 1; (ii) -x ? 1, y - 1/2, -z ? 1; (iii)
-x ? 1, y ? 1/2, -z ? 1 for III
plexes
was
used
as
control.
Amoxicillin
(20 lg) ? Clavulanic acid (10 lg), amikacin (30 lg),
ampicillin (10 lg), gentamicin (25 lg), nystatin (25 lg)
and flucanazole (20 lg) were screened under similar con-
ditions as the standard antibiotic discs. At the end of the
incubation period, the inhibition zones around the discs
direction [(ii) -x ? 1, y - 1/2, -z ? 1] (Fig. 8). Simi-
larly, water O9 atom in the molecule at (x, y, z) acts as a
hydrogen bond donor, via atom H9B, to atom O8iii, and
Fig. 5 Formation of edge-fused R24(8) rings in I
123

¨
˘
O. Daglı et al.
Fig. 6 Formation of edge-fused R22(16) rings in I
C30
C31
C15
C14
C29
C13
C38
C37
C12
O6
C16
O9
N4
C32
C11
C17
N3
O2
C34
C18
C33
O8
C8
C35
C28
O4
O3
C10
O5
Cu1
C1
C9
C4
C36
O7
C27
C19
C2
C24
O1
C7
N2
N1
O10
C3
C25
C20
C6
C26
C5
C23
C21
C22
Fig. 7 Molecular structure of complex III showing the atom-numbering scheme
were measured as millimetres. The antimicrobial (an-
tibacterial and antifungal) test results of complexes syn-
thesized are given in Table 7.
aureus ATCC 25923, Enterococcus faecalis ATCC 29212
and Candida albicans ATCC 10231 and the complex
number II on Staphylococcus aureus ATCC 25923 and
Candida albicans ATCC 10231. The complexes number
III and IV were observed to have low rate inhibitory
effects on all microorganisms except for Staphylococcus
aureus ATCC 25923. In particular, it is seen that all metal
complexes are effective on Escherichia coli ATCC 25922
and Candida albicans ATCC 10231.
It was observed that the complexes of I, II, III and IV
have the antimicrobial effects towards the pathogenic
microorganisms on varying proportions. The effects of the
synthesized molecules on yeast, gram-positive and gram-
negative bacteria were observed. However, it has been
found that some mixed ligand complexes have more active
activity on specific microorganisms. The inhibitory effects
of complexes according to biological applications can be
referred as the complex number I on Staphylococcus
Total Antioxidant Capacity: The total antioxidant
capacity (TAC) of the metal complexes was determined
according to the procedures described in TAC Assay Kit
123

Novel mixed ligand complexes of coumarilate/N,N0-diethylnicotinamide with some transition…
Fig. 8 Formation of C(6) chain in complex III
Fig. 9 Formation of C(8) chain in complex III
123

¨
˘
O. Daglı et al.
Table 7 In vitro antimicrobial activity test results of metal complexes synthesized
Complexes
Antimicrobial activity (inhibition diameter, mm SD)
Staphylococcus aureus
Enterococcus faecalis
Escherichia coli
Pseudomonas aeroginosa
Candida albicans
I
7. 0 1.0
7.0 0.5
ND
6.5 0.5
4.0 1.0
5.0 1.0
4.0 1.0
ND
4.0 1.0
2.0 0.5
4.5 1.0
3.5 0.5
ND
ND
7.0 1.0
6.0 1.5
3.0 0.5
4.0 1.0
ND
II
ND
III
3.0 1.0
4.0 1.0
ND
IV
ND
AMC
AK
AMP
GN
NYS
FL
ND
20.0 2.1
17.4 1.2
9.5 2.0
ND
20.5 1.0
16.2 1.3
7.0 1.0
ND
18.8 2.8
15.8 1.2
8.75 2.25
ND
19.8 3.5
17.7 2.4
10.5 2.5
ND
ND
ND
ND
17.2 1.2
17.7 1.8
ND
ND
ND
ND
Culture codes of microbial strains; Enterecoccus faecalis ATCC 29212, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923 and
Candida albicans ATCC 10231
Standards: AMC Amoxicillin (20 lg) ? Clavulanic acid (10 lg), AK amikacin 30 lg), AMP ampicillin (10 lg), GN gentamicin (25 lg), NYS
nystatin (25 lg) and FL flucanazole (20 lg)
in the coordination sphere were coordinated to the metal.
Table 8 Total antioxidant capacity (TAC) of complexes synthesized
Moreover, it was confirmed that the structures number II
Metal complexes
TAC (lmol Trolox Eq/L)
and III is molecular, and there are also aqua, monodentate
N,N0-diethylnicotinamide and monoanionic monodentate
coumarilate ligands with the amount of 2 mol each
detected within the coordination sphere. The positions of
ligand in the coordinations of all structures have been
identified as –trans, and the coordination spheres of metal
cations were found to have octahedral structure. In addi-
tion, the structures have formed the network lattice struc-
tures via hydrogen bonding.
I
1.47
1.43
1.24
1.91
II
III
IV
(Rel Assay DiagnosticsÒ, Turkey). This method is a novel
automated colorimetric measurement method developed by
Erel (2004) [44]. As a result of this reaction, the bright
yellowish-brown dianisyl radical was obtained. Results
were expressed as micromolar Trolox equivalents per litre
(lmol Trolox Eq/L). The total antioxidant activity (TAC)
is given in Tables 7 and 8, respectively.
The reason for the black colour of decomposition end
products identified in all structures at the end of the thermal
decomposition and a few higher experimental data of
decomposition products as compared theoretical ones can
be the carbonized coal remained in the medium without
being totally fired depending on the inert nitrogen atmo-
sphere under which the process was carried out.
In the case that we look at the antioxidant activities of
the complexes, it is seen that all chemicals generally have a
certain amount of activity; especially, the activity of IV
seems one step ahead.
The electronic transition spectra and the magnetic sus-
ceptibility values of the metal cations have encouraged the
existence of ‘‘pseudo-octahedral’’ structures due to the
Jahn–Teller decomposition effect.
Conclusions
Supplementary material
The studies on the structural conformations of molecules,
binding properties and thermal decomposition steps were
performed. The metal:ligand:ligand proportions of mixed-
ligand complexes were determined as 1:2:2. The com-
plexes of I and IV were determined to have a salt-type
isostructure. It was found that the coumarilate anion is
located outside of the coordination sphere as the balancing
ions. It was observed that the 4 mol of aqua and 2 mol of
N,N0-diethylnicotinamide ligands bonded as monodentate
Crystallographic data for the structural analysis have been
deposited with the Cambridge Crystallographic Data Cen-
tre, CCDC No. 1465359 for I and 1465358 for III. Copies
of this information may be obtained free of charge from the
Director, CCDC, 12 Union Road, Cambridge CB2 1EZ, UK
(fax: ?44-1223-336033; e-mail: deposit@ccdc.cam.ac.uk
or www: http://www.ccdc.cam.ac.uk).
123

Novel mixed ligand complexes of coumarilate/N,N0-diethylnicotinamide with some transition…
Acknowledgements This study was financially supported by Sinop
14. Creaven B, Devereux M, Georgieva I, Karcz D, McCann M,
¨
University in Turkey (Project No. SUB-1901.14-01). The authors
Trendafilova N, et al. Molecular structure and spectroscopic
studies on novel complexes of coumarin-3-carboxylic acid with
Ni(II), Co(II), Zn(II) and Mn(II) ions based on density functional
theory. Spectrochim Acta A Mol Biomol Spectrosc. 2011;84(1):
275–85.
acknowledge Scientific and Technological Research Application and
Research Centre, Sinop University, Turkey, for the use of the Bruker
D8 QUEST diffractometer. This research was supported by the Sci-
ence Research Department of Hitit University (Project No:
FEF19004.15.005).
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