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American Chemical Science Journal
4(1): 117-137, 2014
SCIENCEDOMAIN international
www.sciencedomain.org
Synthesis, Characterization, Spectral (FT-IR, 1H,
13C NMR, Mass and UV) and Biological Aspects
of the Coordination Complexes of Sulfur Donor
Ligands with Some Rare Earth Elements
R. V. Singh1*, Pradeep Mitharwal1, Ritu Singh1 and S. P. Mital2
1Department of Chemistry, University of Rajasthan, Jaipur, 302 004, India.
2Department of Chemistry, D.A.V. P.G. College, Dehradun-248001, India.
Authors’ contributions
This work was carried out in collaboration between all authors. Author RVS designed the
study, performed the statistical analysis, wrote the protocol, and wrote the first draft of the
manuscript. Authors PM and RS managed the analyses of the study. Author SPM managed
the literature searches. All authors read and approved the final manuscript.
Received 17th September 2013
Accepted 16th October 2013
Published 9th November 2013
Original Research Article
ABSTRACT
Bio-potent ligands, 2-hydroxy-N-phenylbenzamide hydrazinecarbothioamide(HPHTSCZH2)
and 2-hydroxy-N-phenylbenzamide hydrazine carbodithioic benzyl ester (HPHCBESH2)
have been synthesized by the condensation of 2-hydroxy-N-phenylbenzamide with
hydrazinecarbothioamide and hydrazine carbodithioic benzyl ester, respectively and
reacted with hydrated lanthanide chlorides. The coordination moieties of the ligands have
been confirmed by various spectral studies. Elemental analyses suggested that the
complexes have 1:2 stoichiometry which were characterized further by magnetic moment,
infrared, EPR, electronic, 1H NMR, 13C NMR and mass spectral studies. TGA studies were
also conducted for one of the representative compound to analyze the presence of water
molecule. The spectral studies confirmed the proposed framework of the new lanthanide
complexes and indicated an octahedral geometry around the central metal atom. On the
basis of X-ray powder diffraction study one of the representative Sm complex was found
to have Hexagonal Lattice type, having Lattice Parameters: a = 18.528 Aº, b = 18.528 Aº
and c = 20.675 Aº and α = 90º, β = 90º and γ =120º. The free ligands and their metal
____________________________________________________________________________________________
*Corresponding author: Email: rvsjpr@hotmail.com;

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American Chemical Science Journal, 4(1): 117-137, 2014
complexes have been tested in vitro against a number of microorganisms in order to
assess their antimicrobial properties and in vivo for antifertility activity on male albino rats.
Both the ligands and their complexes were found to possess appreciable fungicidal,
bactericidal and antifertility activities.
Keywords: Rare earth elements; thiosemicarbazone; hydrazine carbodithioic acid; 2-
hydroxy-N-phenylbenzamide; microorganisms; antifertility activity; TGA; spectral
studies.
1. INTRODUCTION
Nowadays, the complexes of the rare earth ions are a subject of increasing interest in
bioinorganic and coordination chemistry [1]. A sustained research activity has been devoted
to lanthanide complexes, because of their successful application in the form of diagnostic
tools in biomedical analysis as MRI contrast agents [2,3]. The coordination chemistry of
lanthanide elements and important role of their complexes in chemical, medical and
industrial processes are enough to recognize them as worthwhile for the synthesis of the
new complexes. Apart from the structural diversities and bonding interactions, the multitude
applications of lanthanide complexes make it an exciting arena in coordination chemistry
[4,5]. Imines are important class of ligands due to their synthetic flexibility, their selectivity
and sensitivity towards the central metal atom, structural similarities with natural biological
substances and also due to the presence of the imine group (>C=N) which imparts in
elucidating the mechanism of transformation and racemisation reaction in biological system
[6].
The chemistry of thiosemicarbazones has received considerable attention in view of their
variable bonding modes, promising biological implications, structural diversity, and ion-sensing
ability [7-8]. They have been used as drugs and are reported to possess a wide
variety of biological activities against bacteria, fungi, and certain type of tumors and they are
also a useful model for bioinorganic processes [9,10]. Metal complexes of imines derived
from S-alkyl/aryl esters of dithiocarbazoic acid [11] have received considerable attention
because of the presence of both hard nitrogen and soft sulfur donor atoms in the backbones
of these ligands. It is well known that lanthanide ions have high affinity to hard donor atoms,
and thus ligands containing oxygen or nitrogen atoms have been extensively used in the
synthesis of lanthanide complexes [12].
Recently, there has been a growing interest in the lanthanide imines complexes owing to the
important applications of both metals and ligands. Hirayama, et al. [13] extracted the trivalent
lanthanide selectively as anionic imine complexes. Bastida, et al. [14] studied the lanthanide
complexes with macrocyclic Schiff base ligands and obtained complexes of 18 and 15-
membered macrocycles. Exhibiting a broad spectrum of biological activities and outstanding
optical properties, complexes of rare-earth metals with imines derived from amino acids
attract a great interest of researchers in recent years [15].
Keeping all these facts under consideration, during the present investigations we have
synthesized, characterized and screened the biologically potent ligands and their lanthanide
complexes against a variety of pathogenic fungal and bacterial strains. Further, the
complexes were also tested for their antifertility activity in male albino rats and the results
were indeed positive.
118

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American Chemical Science Journal, 4(1): 117-137, 2014
2. EXPERIMENTAL
The hydrated lanthanide chlorides as well as 2-hydroxy-N-phenylbenzamide were purchased
from Alfa Aesar and used as such. All the chemicals and solvents used were of analytical
grade. Hydrazine carbodithioic acid was prepared in the laboratory by the literature method
[16]. All the solvents were dried and distilled before use. The metal contents were estimated
complexometrically with EDTA using Erichrome Black T as an indicator. Sulfur and nitrogen
were estimated by the Messenger’s and Kjeldahl’s method, respectively. IR spectra were
recorded on a Perkin-Elmer model 577 grating spectrophotometer, in the range 4000–200
cm-1 in KBr discs. 1H NMR and 13C NMR spectra were recorded on a JEOL-AL-300 FT NMR
spectrometer in DMSO-d6 using TMS as the internal standard. EPR spectra of the
complexes were monitored on Varian E- 4X band spectrometer. The electronic spectra were
recorded on a Varian–Cary/5E spectrophotometer and mass spectra were recorded on
JEOL GCmate spectrometer. Molecular weight determinations were carried out by the Rast
Camphor Method. Magnetic susceptibility measurements were made at room temperature
with the Faraday balance using Hg[Co(NCS)4] as calibrant.
2.1 Synthesis of the Ligands
Both of the ligands, 2-hydroxy-N-phenylbenzamide hydrazinecarbothioamide (HPHTSCZH2)
and hydroxy-N-phenyl benzamide hydrazine carbodithioic benzyl ester (HPHCBESH2) were
prepared as reported in the literature [17]. Their physical properties and analytical data are
given in Table 1. Synthetic route and structures of the ligands are given in Fig. 1.
119
C O
HN
OH
H2N C
NH
NH2
S
H2N C
NH
SCH2C6H5
S
C N
HN
OH
NH
C
NH2
S
HPHTSCZH2
C N
HN
OH
NH
C
SCH2C6H5
S
HPHCBESH2
Ethanol, H2O
Ethanol, H2O
Fig. 1. Synthesis and structures of the ligands

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American Chemical Science Journal, 4(1): 117-137, 2014
120
Table 1. Analytical data and physical properties of the ligands and their complexes
Compound Colour Melting
point (ºC)
Found (Calcd.) (%) μeff
(B.M)
Mol. wt.
found
(Calcd.)
Yield (%)
N S Ln
HPHTSCZH2 Light pink 124 19.51
(19.57)
11.13
(11.20)
- - 267.46
(286.35)
80
HPHCBESH2 Grey 133 10.56
(10.68)
16.34
(16.30)
- - 407.70
(393.53)
82
[La(HPHTSCZH)(HPHTSCZ)].3H2O Black 210-218 14.39
(14.63)
7.67
(7.96)
19.34
(18.14)
.00 751.01
(762.63)
72
[Pr(HPHTSCZH)(HPHTSCZ)].3H2O Dirty yellow 160-165 14.43
(14.59)
8.52
(8.35)
17.22
(18.35)
3.53 747.98
(764.62)
74
[Nd(HPHTSCZH)(HPHTSCZ)].3H2O Sandy brown 178-180 11.65
(11.76)
6.69
(6.70)
14.99
(15.50)
3.47 779.06
(767.96)
76
[Sm(HPHTSCZH)(HPHTSCZ)].3H2O Sandy brown 140-142 14.23
(14.47)
8.12
(8.28)
18.35
(19.42)
1.44 768.56
(774.07)
70
[La(HPHCBESH)(HPHCBES)].3H2O Light brown 150-158d 8.78
(8.85)
13.42
(13.51)
13.87
(14.63)
.00 967.53
(948.93)
75
[Pr(HPHCBESH)( HPHCBES)].3H2O Brown 230-240d 8.96
(8.83)
13.60
(13.48)
13.99
(14.81)
3.71 932.86
(950.93)
71
[Nd(HPHCBESH)( HPHCBES).3H2O Grey 90-100 8.57
(8.80)
13.34
(13.44)
14.98
(15.11)
3.62 947.49
(954.26)
68
[Sm(HPHCBESH)(HPHCBES)].3H2O Chocolate
brown
100-110 8.81
(8.75)
13.42
(13.35)
14.79
(15.65)
1.52 956.14
(960.37)
71

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American Chemical Science Journal, 4(1): 117-137, 2014
2.2 Synthesis of the Sodium Salt of the Ligands
Sodium metal was taken corresponding to the weight of the ligand in 2:1 molar ratios. Now
both the sodium metal and ligand were dissolved in minimum amount of methanol
separately. Ultimately these two solutions had been dissolved to prepare sodium salt of the
ligand. In this process the sodium metal first reacts with methanol and form sodium
methoxide. This sodium methoxide in the next step reacts with the ligand and replaces acidic
proton from the enolic form of the ligand with the sodium metal and form sodium salt of the
particular ligand (Fig. 2). The ligands may be used as such but the rate of reaction will be
slow as compared to the sodium salt. Removal of chloride from the metal chloride is easy
with sodium as compared to hydrogen.
2.3 Synthesis of the Lanthanide (III) Complexes
The methanolic solution of the hydrated lanthanide chloride LnCl3.6H2O (2 g, 5.48 - 5.66
mmol) was mixed with methanolic solution (50 mL) of the sodium salt of the ligand (3.13 –
4.45 g, 10.96 – 11.32 mmol) in 1:2 molar ratios. The mixture was then heated under reflux
for about 13-16 h. On cooling, the sodium chloride which formed in this reaction was filtered
through the alkoxy funnel and the excess of solvent from mother liquor was removed under
reduced pressure. The physical properties and analytical data of these complexes are
recorded in Table 1. The suggested structure of the complexes is given in Fig. 2.
121
C N
HN
O
N
S
C R
C
N
NH
O
R C N
SH
Ln
.3H2O
Fig. 2. Structure of the metal complexes
Where, Ln = La, Pr, Nd and Sm , R = -NH2 or –SCH2C6H5

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2.4 Biological Activity
2.4.1 Antifungal activity
The antifungal activity of both the ligands and the synthesized complexes was evaluated
against Aspergillus fumigatus and Aspergillus niger using Czapek’s agar medium having the
composition, glucose 20g, starch 20g, agar-agar 20g and distilled water 1000 mL. To this
medium was added requisite amount of the compounds after being dissolved in
dimethylformamide so as to get a certain concentrations (50, 100 and 200 ppm). The
medium then was poured into petri plates and the spores of fungi were placed on the
medium with the help of inoculum’s needle. These petri plates were wrapped in polythene
bags containing a few drops of alcohol and were placed in an incubator at 30 + 2ºC. The
controls were also run and three replicates were used in each case. The linear growth of the
fungus was recorded by measuring the diameter of the fungal colony after 96 h and the
percentage inhibition was calculated by the equation:
122
% Inhibition = (C-T)100 / C
Where C and T are the diameters of the fungal colony in the control and the test plates,
respectively [18].
Fig. 3. Antifungal activity of the ligands and their complexes
.

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American Chemical Science Journal, 4(1): 117-137, 2014
2.4.2 Antibacterial activity
Both of the ligands and their corresponding metal complexes were tested for their
antibacterial activity against Escherichia coli and Salmonala typhi using the paper disc plate
method [19]. The nutrient agar medium (peptone, beef extract, NaCl and agar-agar) and
5mm diameter paper discs of Whatman filter paper No.1 were used. The compounds were
dissolved in methanol for obtaining the concentrations of 500 and 1000 ppm. The filter paper
discs were soaked in these solutions, dried and then placed in the petri plates previously
seeded with the test organisms. The plates were incubated for 24 h at 28 + 2ºC and
inhibition zone around each disc was measured.
123
Fig. 4. Antibacterial activity of the ligands and their complexes
2.4.3 Antifertility activity
The activity of the synthetic products towards the biological systems is an important feature
of the current research, and the Schiff base metal complexes play a significant role in this
direction. In view of such potential interest in these biologically active compounds, the
antifertility activity of some selected compounds has been studied on male albino rats.
Healthy adult male albino rats (Ratus norvegicus) of an average body weight 190-200 g
were used for experimentation. The animals were kept in clean polypropylene cages
covered with chrome plates grills and maintained in an airy room with controlled room
temperature (20 ± 5ºC) with 12:12 hours light and dark cycle. The animals were fed with
food pellet procured from Ashirwad Industries, Chandigarh as well as germinated/sprouted
gram and wheat seeds as an alternative feed. Tap water was supplied ad libitum.
Animals were divided into six groups containing 6 animals each. Group A animals were kept
control and were administered olive oil only. The animals in group B received ligand
(HPHCBESH2) whereas the animals in groups C, D, E and F received La(III), Pr(III), Nd(III),

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American Chemical Science Journal, 4(1): 117-137, 2014
Sm(III) metal complexes of ligand (HPHCBESH2), respectively. The animals were
maintained under perfect supervision and in accordance to the guidelines of committee for
the purpose of control and supervision of experiment on animals (CPCSEA) for the
regulations of scientific experiments on animals. The experimental protocol has approval of
the institutional ethical committee Dept of zoology UOR Jaipur. In the group B, the ligand 30
mg/kg body weight suspended in olive oil was given orally through the mouth by pearl point
needle for a period of 60 days. The animals of groups C, D, E and F received same doses of
respective compound for the same period. It was then administered orally through the mouth
by pearl point needle. No rat mortality occurred during the study period. The mating
exposure test was done on day 55th of the experiment. The rats were sacrificed after 24 h of
the last dose (61st day) to perform various tests. At the end of experiment, the rats were
weighed and sacrificed under light ether anesthesia. The male reproductive organs were
removed, washed with distilled water, dried, weighed and processed for biochemical studies.
Sperm mobility in cauda epididymis and sperm density in testes and cauda epididymis were
assessed. The protein, sialic acid, testicular glycogen acid and alkaline phosphatase of
testes, and serum testosterone were determined by standard laboratory techniques. Results
were analysed statistically using student’s t-test.
3. RESULTS AND DISCUSSION
The reactions of hydrated lanthanide chlorides with bibasic tridentate ligands have been
shown by the following general equation:
124
MeOH
LnCl3.6H2O+ 2LH2 + 4Na [Ln(L) (LH)].3H2O + 3NaCl + NaOH + 3H2O
Where, Ln = La, Pr, Nd and Sm, L= HPHTSCZ and HPHCBES
The newly synthesized complexes have been obtained as coloured solids which exhibit their
solubility in methanol, DMSO and DMF. The monomeric nature of these products has been
confirmed by the molecular weight determinations.
3.1 Electronic Spectra
The electronic spectra of the ligands and their metal complexes have been recorded in dry
methanol. The electronic spectra of the ligands exhibit three bands in the regions 238-242,
272-277 and 330-355 nm. The bands in the regions 238-242 nm and 272-277 nm are
assignable to -* transitions of the azomethine group. The considerable hypsochromic
shifting of the third band viz. 330-355 nm in the spectra of the metal complexes attributed to
the coordination of the azomethine nitrogen to the metal atom. The electronic spectra of the
complexes are dominated by the ligands bands with the slight shift of spectral bands to the
lower energy level. This slight shift was attributed to the effects of crystal field upon the
interelectronic repulsion of 4f electrons. The absorption bands appear in the spectra of
Pr(III), Nd(III) and Sm(III) are due to transitions from the ground levels 3H4, 4I9/2 and 6H5/2 to
the excited ‘J’ levels of 4f configuration, respectively. The nephelauxetic parameter (β) [20],
bonding parameter (b1/2) [21] and Sinha’s covalency parameter () [22] and angular
covalency (η) for the Pr(III), Nd(III) and Sm(III) complexes are presented in Table 2. The
Sinha’s parameter () suggests the degree of covalency and is obtained by the equation,

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American Chemical Science Journal, 4(1): 117-137, 2014
125
 = (1- βav)/ βav .100
Where βav is the average value of the ratio of vcomplex/ vaquo. The magnitude of the bonding
parameters (b1/2) suggests the degree of involvement of 4f orbitals in metal–ligand bonding
and is related to nephelauxetic ratio (β) by the equation,
b1/2 = [(1-βav)/2]1/2
Angular covalency (η) = (1-βav)1/2/ βav
1/2
The intensity of the f–f transitions presents an interesting observation. The intensity of the
normal f–f transitions does not show much change. However, the hypersensitive transitions
(environment sensitive transitions) are found to show large changes in intensity. According
to Karraker [23] the shape and intensity of these transitions indicate the geometry of the
complex. In the present complexes, nephelauxetic ratio (β) being less than one and positive
values of b1/2 and  indicate slight covalent bonding between metal and ligand.
3.2 Infrared Spectra
The infrared spectra of the ligands show the most significant band in the region 1622-1618
cm-1 assignable to (C=N) group which shifted to the lower frequency in the complexes
suggesting the coordination of the azomethine nitrogen to the metal atom (Table 3). The
band in the region 3200-3050 cm-1 due to the (NH/OH) mode disappears in the complexes.
The coordination of the azomethine nitrogen, phenolic oxygen and bonding of the thiolic
sulfur to the metal ion is supported by the appearance of three absorption bands in the
regions 530-515, 620-580 and 420–355 cm-1 in the complexes which may be assigned to
(MN), (M-O) and (M-S) vibrations, respectively. However, two strong bands in the
regions 3475-3460 and 3365-3350 cm-1 due to the asymmetric and symmetric vibrations of
NH2 group remain unaltered in the spectra of the complexes indicating the non-involvement
of this group in the coordination. In the ligand HPHCBESH2, a doublet at 2895 and 2945
cm-1 is assigned to symmetric and asymmetric vibrations of S-CH2-C6H5 grouping and is
reduced to a weak doublet in the spectra of the complexes. The characteristic band due to
v(SH) at 2610–2540 cm-1 present in spectra of the ligands was also seen in the complexes
showing that one ligand moiety of both type of ligands form coordinate bond in place of
simple covalent bond to the metal atom. The broad band present in the region 3600-3568
cm-1 may be assigned to (OH) stretching indicating the presence of water molecules.

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126
Table 2. Electronic spectral data of Ln(III)complexes
Complex Assignment Vmax of Ln+3
ion (cm-1)
Vmax of
complexes
(cm-1)
β 1-β b1/2 δ η
[Pr(HPHTSCZH)(HPHTSCZ)].3H2O 3H4 – 1D2
- 3P0
- 3P1
- 3P2
17401
20945
21450
22820
17241
20833
21276
22727
.9908
.9946
.9918
.9959
.0092
.0054
.0082
.0041
.0678
.0519
.0640
.0452
.9285
.5429
.8267
.4116
.0963
.0736
.0908
.0641
[Nd(HPHCBESH)(HPHCBES).3H2O 4I9/2 - 4G5/2,2G7/2
- 2G9/2
- 4G11/2
16830
19795
21913
16666
19607
21739
.9902
.9905
.9920
.0098
.0095
.0080
.0700
.0689
.0632
.9896
.9591
.8064
.0993
.0978
.0897
[Sm(HPHCBESH)(HPHCBES)].3H2O 6H5/2 – 4I13/2
- 4F9/2
- 4I9/2
- 6P3/2
21450
25825
26520
28733
21276
25641
26315
28571
.9918
.9928
.9922
.9943
.0082
.0072
.0078
.0057
.0640
.0600
.0624
.0533
.8267
.7252
.7256
.5732
.0908
.0851
.0886
.0756

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American Chemical Science Journal, 4(1): 117-137, 2014
3.3 1H NMR Spectra
The 1H NMR spectra of both the ligands and their La(III) complexes were recorded in
DMSO-d6 (Table 4). In the ligands, the signal in the region 10.05-12.10 ppm due to -OH
disappears in the complexes and this confirms the deprotonation and complexation through
this functional group. The signal due to the -NH proton attached to the phenyl ring remains
unaltered in the complexes. In the spectra of La(III) complex, the -NH2 signal remains
unpurturbed at  2.58-2.60 ppm indicating the non involvement of this group in the
complexation. The signal of -NH proton in the ligands in the range  8.59-8.78 ppm
disappears in the spectra of the corresponding complexes. The free ligands show multiplets
in the region  6.70-8.32 ppm attributable to aromatic protons, which appear almost in the
same position in their respective complexes. The signals appearing at 5.50-4.51 ppm are
due to the SH proton. The appearance of this signal in the complexes showing that one
ligand moiety of both type of ligands form coordinate bond in place of simple covalent bond
to the metal atom.
3.4 13C NMR Spectra
The 13C NMR spectra of the ligands and their lanthanum complexes were recorded in
DMSO-d6 and the assignments are shown in Table 4. The signals due to azomethine carbon
appeared at δ152.81-153.43 ppm and on complexation they have shown downfield shift to
δ156.26-158.05 ppm due to the resonance and also have given proof that nitrogen is
involved in coordination. The spectra of the ligands exhibit a strong peak at δ175.02-176.24
ppm due to C=S group which undergoes downfield shift in metal complexes suggesting the
involvement of sulfur in coordination to the metal atom.
3.5 Magnetic Properties and EPR Spectra
The La(III) complexes are diamagnetic as expected. The room temperature magnetic
moments of the complexes do not show much deviation from Van Vleck values [24]
indicating that there is no significant participation of the 4f electrons in bonding since they
are well shielded by the 5s2 5p6 octet. However in case of Sm(III) complexes a slight
variation from Van Vleck values was observed [25]. Due to the low J–J separation, the
energy level between the ground state and the next higher level being only of the order of
KT, the excited states are also populated leading to anomalous magnetic moments. This is
known as the first order Zeeman Effect [26]. The EPR spectra (both at RT and LNT) were
broad having similar 'g' value of 1.98, which is nearly equal to the free electron value
(g = 2.00277). Similar line widths at both the temperatures indicate spin–lattice and spin–
spin relaxation processes contribute equally to line width.
3.6 Thermogravimetrical Analysis (TGA)
The TGA method was conducted to demonstrate the nature and number of the H2O
molecules in the complexes. Table 5 listed the losses in mass (Found and Calculated) of the
[Pr(HPHTSCZH)( HPHTSCZ)].3H2O complex.
127

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128
Table 3. IR (cm-1) spectral data of the ligands and their corresponding complexes
Compound ν(C=N) (NH/OH) v(NH2) (SCH2C6H) v(SH) v(OH) ν(M→N) ν(M→O) ν(M→S)
vsym vasym vsym vasym
HPHTSCZH2 1618 3050 3350 3475 - - 2540 - - - -
HPHCBESH2 1622 3200 3365 3460 2895 2945 2610 - - - -
[La(HPHTSCZH)(HPHTSCZ)].3H2O 1600 - 3348 3472 - - 2535 3600 530 620 420
[Pr(HPHTSCZH)( HPHTSCZ)].3H2O 1598 - 3342 3469 - - 2532 3572 524 615 412
[Nd(HPHTSCZH)(HPHTSCZ)].3H2O 1610 - 3339 3470 - - 2538 3585 518 586 358
[Sm(HPHTSCZH)(HPHTSCZ)].3H2O 1608 - 3345 3465 - - 2536 3591 515 580 360
[La(HPHCBESH)(HPHCBES)].3H2O 1602 - 3362 3452 2890 2940 2608 3576 526 618 417
[Pr(HPHCBESH)(HPHCBES)].3H2O 1607 - 3356 3458 2885 2940 2600 3598 529 584 414
[Nd(HPHCBESH)(HPHCBES).3H2O 1594 - 3363 3453 2889 2935 2598 3583 523 596 355
[Sm(HPHCBESH)(HPHCBES)].3H2O 1612 - 3359 3457 2878 2936 2605 3568 520 585 356
Table 4. 1H NMR and 13 CNMR (, ppm) spectral data of the ligands and their La(III) complexes.
Compound 1HNMR 13CNMR
-OH
(s)
-NH
(bs)
-SH
(bs)
-NH2
(s)
-S-CH2
(s)
-NH
(s)
Aromatic
proton
(m)
Thiolo
carbon
>C=N Aromatic
carbon
HPHTSCZH2 10.05 8.59 - 2.60 - 10.64 6.75-8.32 175.02 152.81 159.76, 136.99, 129.15,
127.79, 126.98, 125.58,
122.44, 119.68, 117.94,
116.89
HPHCBESH2 12.10 8.78 - - 1.92 10.75 6.70-8.19 176.24 153.43 158.72, 137.74, 133.81,
127.82
[La(HPHTSCZH)
(HPHTSCZ)].3H2O
- - 4.51 2.58 - 10.59 6.61-8.03 179.74 156.26 160.66, 138.89, 130.08,
127.99, 129.85, 123.58,
120.94, 120.48, 118.99,
118.09
[La(HPHCBESH)
(HPHCBES)].3H2O
- - 5.50 - 1.89 10.69 6.99-7.68 182.64 158.05 160.62, 137.84, 130.81,
127.94

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American Chemical Science Journal, 4(1): 117-137, 2014
129
Table 5. Thermogravimetrical analysis data for the metal complex
Complex formula Dehydration stage Start of
decom-position
Oxide formation
metallic residues/%
Temperature
range /ºC
H2O loss Temp.
/ºC
Calc. Found
Calc. Found
[Pr(HPHTSCZH)
(HPHTSCZ)].3H2O
120-200 7.0683 7.0687 300 700 18.42 18.38
The complex decomposes in three steps. The initial mass loss within the range 120-200ºC
corresponds to the removal of three H2O molecules resulting in anhydrous complexes. The
facts that the water molecule was lost at a low temperature suggest that the water is a
crystal hydrate. The second and third subsequent decomposition steps start at 300ºC and
continue upto 650ºC. Based on the above TGA results, the following three steps of the
thermal decomposition may be proposed for the lanthanide imine complex.
[Pr(HPHTSCZH)( HPHTSCZ)].3H2O
Dehydration at
[Pr(HPHTSCZH)(HPHTSCZ )] + 3H2O
[Pr(HPHTSCZH)(HPHTSCZ)
120-200 0C
Partialdecomposition
300-450 0C
Intermediate
Intermediate
Final decomposition
500-650 0C
Metal Oxide
Step - 1
Step - 2
Step - 3
3.7 Mass Spectra
The elemental analyses data of Nd(III) and Pr(III) complexes obtained are in agreement with
the formula [Nd(HPHCBESH)(HPHCBES)].3H2O and [Pr(HPHCBESH)(HPHCBES)].3H2O.
The suggested formulae were further confirmed by mass-spectral fragmentation analysis.
Many lanthanides possess several isotopes and the MS peak patterns are therefore
characteristic of the nature of the cation present. Neodymium and Praseodymium have
several isotopes and the peak pattern of the compounds containing these metals therefore
much more complicated. The spectra (although with low intensity) showed isotopic patterns
centered around m/z (%) 954.26 and 950.93 for Nd and Pr, respectively, corresponding to
the mass weights of the complexes. The results thus obtained are in agreement with metal:
ligand ratio, 1:2.
3.8 X-ray Powder Diffraction Studies
The possible geometry of the finely powdered product has been deduced on the basis of X-ray
powder diffraction studies. The observed interplanar spacing values (’d’ in Å), have been
measured from the diffractogram of these compounds and the Miller indices h, k and l have

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American Chemical Science Journal, 4(1): 117-137, 2014
been assigned to each d value and 2θ angles are reported in Table 6 and Fig. 5. The results
show that the compound belongs to ‘Hexagonal’ crystal system having unit cell parameters
as a = 18.528 Aº, b =18.528 Aº and c = 20.675 Aº maximum deviation of 2θ = 0.04 and α =
90º, β = 90º and γ =120º.
130
Fig. 5. XRD-diffraction pattern of [Sm(L1H)(L1)].3H2O
Table 6. X-ray spectral data of [Sm(L1H)(L1)].3H2O.
H K l 2Theta
(Exp.)
2Theta
(Calc.)
2Theta
(Diff.)
d(
Exp.)
d(
Calc.)
Intensity
(Exp.)
3 0 4 30.190 30.193 -.003 3.71720 3.71680 30.23
4 1 2 33.898 33.942 -.044 3.32056 3.31639 40.34
4 0 5 39.287 39.292 -.005 2.87958 2.87920 64.48
5 1 4 45.227 45.235 -.009 2.51755 2.51708 12.96
6 1 0 46.608 46.607 .001 2.44689 2.44695 15.62
4 4 5 57.265 57.249 .016 2.02011 2.02064 53.13
7 2 2 60.304 60.346 -.042 1.92720 1.92597 16.60
6 2 7 65.997 66.005 -.009 1.77744 1.77723 11.57
8 2 1 67.370 67.408 -.038 1.74535 1.74449 15.47
5 2 9 68.862 68.840 .022 1.71207 1.71254 11.05
8 1 6 71.901 71.893 .008 1.64885 1.64900 44.81
5 1 11 75.865 75.887 -.022 1.57471 1.57431 26.92
5 5 8 80.019 80.011 .008 1.50567 1.50580 12.45
9 0 8 82.525 82.543 -.017 1.46778 1.46753 13.86
7 6 1 85.902 85.919 -.017 1.42069 1.42046 19.73
7 6 3 87.943 87.932 .011 1.39424 1.39438 22.59

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American Chemical Science Journal, 4(1): 117-137, 2014
3.9 Biological Results and Discussion
Antimicrobial activity of the synthesized ligands and their corresponding metal complexes
(Tables 7 and 8) on selected fungi, Aspergillus fumigatus and Aspergillus niger and two
bacteria Escherichia coli and Salmonala typhi, were carried out (Figs. 3 and 4) [27]. The
results of antimicrobial activity show that the metal complexes exhibit antimicrobial
properties and it is important to note that they show enhanced inhibitory activity compared to
the parent ligand. It has been suggested [28] that the ligands with nitrogen and sulfur donor
systems might inhibit enzyme production, since the enzymes which require these groups for
their activity appear to be especially more susceptible to deactivation by the metal ions upon
chelation. Chelation reduces the polarity [29] of the metal ion mainly because of the partial
sharing of its positive charge with the donor groups and possibly the π-electron
delocalization within the whole chelate ring system thus formed during coordination. This
process of chelation thus increases the lipophilic nature of the central metal atom, which in
turn favours its permeation through the lipid layer of the membrane.
131
Table 7. Antifungal activity of the ligands and their complexes
Compound Diameter of inhibition zone (mm)
Aspergillus fumigates, Aspergillus niger
50
100
200
50
100
ppm
ppm
ppm
ppm
ppm
200
ppm
HPHTSCZH2 27 33 45 31 39 47
HPHCBESH2 33 39 49 35 41 52
[La(HPHTSCZH)(HPHTSCZ)].3H2O 48 58 69 46 60 65
[Pr(HPHTSCZH)( HPHTSCZ)].3H2O 46 55 62 52 61 68
[Nd(HPHTSCZH)(HPHTSCZ)].3H2O 41 48 56 51 58 66
[Sm(HPHTSCZH)(HPHTSCZ)].3H2O 40 45 53 50 64 61
[La(HPHCBESH)(HPHCBES)].3H2O 57 65 74 54 63 66
[Pr(HPHCBESH)( HPHCBES)].3H2O 50 62 68 56 64 70
[Nd(HPHCBESH)( HPHCBES).3H2O 43 50 60 52 60 68
[Sm(HPHCBESH)(HPHCBES)].3H2O 42 48 59 53 66 63
Flucanazole 90 100 100 95 100 100
Table 8. Antibacterial activity of the ligands and their complexes
Compound Diameter of inhibition zone (mm)
E. coli, S. typhi
500 ppm 1000 ppm 500 ppm 1000 ppm
HPHTSCZH2 4 8 5 8
HPHCBESH2 6 9 6 9
[La(HPHTSCZH)(HPHTSCZ)].3H2O 8 9 7 9
[Pr(HPHTSCZH)( HPHTSCZ)].3H2O 7 10 6 10
[Nd(HPHTSCZH)(HPHTSCZ)].3H2O 9 9 6 11
[Sm(HPHTSCZH)(HPHTSCZ)].3H2O 6 8 8 11
[La(HPHCBESH)(HPHCBES)].3H2O 10 11 9 12
[Pr(HPHCBESH)( HPHCBES)].3H2O 9 13 10 12
[Nd(HPHCBESH)( HPHCBES).3H2O 13 12 8 10
[Sm(HPHCBESH)(HPHCBES)].3H2O 11 14 11 13
Tetracyclin 16 20 15 18

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American Chemical Science Journal, 4(1): 117-137, 2014
The results of antifertility showed that administration of ligand and its metal complexes did
not affect the body weights of treated groups. However, a significant reduction in the weight
of testes, epidydymis, seminal vesicle and ventral prostate was observed after treatment
with ligand (HPHCBESH2) and its La(III), Pr(III), Nd(III), Sm(III) metal complexes. (Table 9)
A significant decrease in motility of spermatozoa in cauda epidydymis and sperm density in
cauda epidydymis and testes have been observed in rats treated with ligand and its metal
complexes. (Table 10) The reduction in the weights of these sex accessory organs may be
due to the decreased production of androgen [30].
Oral administration of ligand and its metal complexes caused a significant reduction in
testicular glycogen and sialic acid contents where as cholesterol, sialic acid and alkaline
phosphatase contents of testes were increased after treatment with in ligand and metal
complexes (Table 11). Sialic acids are concerned with changing the membrane
Surface of maturing spermatozoa as well as with the development of their fertilizing capacity
[31]. The results demonstrate a marked decrease in testicular glycogen, which may be due
to interference during glucose metabolism [32]. Inhibition of glycogen synthesis eventually
affects the protein synthesis and thus inhibits spermatogenesis [33].The serum testosterone
concentrations were decreased significantly (P ≤ .01 to .001) after treatment with ligand
(HPHCBESH2) and its La(III), Pr(III), Nd(III) and Sm(III) metal complexes (Table 11).
A marked reduction in testosterone content, in association with a highly reduced circulating
level of this hormone, confirmed alterations in the reproductive physiology of the rats. These
results suggested that the ligand and its complexes exert inhibitory effects on testicular
function and lead to the infertility in male rats. Further, addition of a metal ion to the ligand
enhances the activity.
132

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American Chemical Science Journal, 4(1): 117-137, 2014
133
Table 9. Effects of ligand and its complexes on body and reproductive organ weight of male rats
Group Treatment Body Weight Organ Weight (mg/100 g b.wt.)
Initial Final Testes Epidydymis Seminal
Vesicle
Ventral
Prostrate
A Control (olive oil) 221.0±16.4 231.0±14.5 1280.0±30.2 470.0±12.9 461.0±14.3 451.0±21.7
B HPHCBESH2 226.0±10.3 237.0±13.3ns 1010.0±25.3a 359.0±13.2a 394.0±25.4a 398.0±19.7a
C [La(HPHCBESH)(HPHCBES)].3H2O 204.0±12.4 228.0±11.9ns 722.0±15.8b 281.0±11.2b 253.0±26.5b 279.0±17.9b
D [Pr(HPHCBESH)(HPHCBES)].3H2O 216.0±13.4 231.0±16.3ns 800.0±19.4b 293.0±14.1b 231.0±27.3b 251.0±30.3b
E [Nd(HPHCBESH)(HPHCBES).3H2O 218.0±15.4 238.0±16.5ns 710.0±20.4b 270.0±14.3b 222.0±26.9b 261.0±30.2b
F [Sm(HPHCBESH)(HPHCBES)].3H2O 209.0±9.8 225.0±14.3ns 652.0±30.2b 275.0±10.5b 228.0±28.3b 267.0±15.2b
Values are mean ± SEM of 6 determinations
a = p ≤ .01
b= p ≤ .001
ns = p= Non Significant
Group B, C, D, E and F compared with Group A
Table 10. Altered sperm dynamics and fertility of ligand and its various complexes treated male rats
Group Treatment Sperm Mortility (%) Sperm Density (million/mL) Fertility (%)
Cauda Epidydymis Testes Cauda Epidydymis
A Control (olive oil) 71.5±4.5 4.78±0.7 60.4±3.70 100(+ve)
B HPHCBESH2 58.5±4.7 a 3.20±.5 a 52.4±2.90 a 40(-ve)
C [La(HPHCBESH)(HPHCBES)].3H2O 34.0±6.5 b 1.97±.3 b 25.0±2.10 b 82(-ve)
D [Pr(HPHCBESH)(HPHCBES)].3H2O 31.0±5.4 b 1.80±.3 b 28.0±2.20 b 85(-ve)
E [Nd(HPHCBESH)(HPHCBES).3H2O 33.0±5.1 b 1.50±.4 b 20.0±1.90 b 88(-ve)
F [Sm(HPHCBESH)(HPHCBES)].3H2O 32.0±3.9 b 1.30±.3 b 22.3±2.10 b 85(-ve)
Values are mean± SEM of 6 determinations
a = p ≤ .01
b= p ≤ .001
Group B, C, D, E and F compared with Group A

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134
Table 11. Testicular biochemistry and serum testosterone levels of ligand and its various complexes treated rats
Group Treatment Protein Sialic Acid Cholesterol Glycogen Acid
Phosphatase
Alkaline
Phosphatase
Serum
Testosterone
(mg/ml)
A Control(olive oil) 228.5±10.5 4.24±.70 8.0±.90 3.24±.39 3.21±.19 10.2±.60 2.90±.67
B HPHCBESH2 281.0±5.3 a 3.18±.75 a 11.2±.70 a 2.71±.19 a 4.81±.20 a 14.1±.20 b 2.20±.72 a
C [La(HPHCBESH)
(HPHCBES)].3H2O
336.0±2.9 b 1.91±.72 a 13.8±.39 b 1.48±.11 b 5.34±.16 b 17.2±.20 b 1.35±.10 b
D [Pr(HPHCBESH)
(HPHCBES)].3H2O
332.0±3.6 a 1.82±.69 b 13.2±.35 a 1.42±.17 b 6.11±.32 b 17.6±.30 b 1.60±.30 b
E [Nd(HPHCBESH)
(HPHCBES).3H2O
339.0±4.3 b 1.6±.75 b 13.6±.31 b 1.31±.13 b 6.22±.39 b 17.3±.40 b 1.28±.10 b
F [Sm(HPHCBESH)
(HPHCBES)].3H2O
327.0±4.5 a 1.7±.60 b 13.7±.43 b 1.34±.14 b 5.74±.12 b 16.5±.35 b 1.15±.15 b
Values are mean ± SEM of 6 determinations
a = p ≤ .01
b= p ≤ .001
Group B, C, D, E and F compared with Group A

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American Chemical Science Journal, 4(1): 117-137, 2014
4. CONCLUSION
On the basis of the analytical data and spectral studies, it has been observed that the
ligands coordinated to the metal atoms in a bibasic tridentate manner and thus possess
octahedral geometry. On the basis of X-Ray powder diffraction study [Sm(L1H)(L1)].3H2O
complex was found to have hexagonal lattice type. The biological screening data of the
ligands and their complexes indicate that the complexes are more potent than the parent
ligands.
ACKNOWLEDGMENTS
The authors are thankful to CSIR, New Delhi, India through grant no.
09/149(0594)/2011/EMR-I for financial assistance.
COMPETING INTERESTS
Authors have declared that no competing interests exist.
REFERENCES
1. Kostova I, Momekov G, Tzanova T, Karaivanova M. Synthesis, characterization, and
cytotoxic activity of new lanthanum(III) complexes of bis-coumarins. Bioinorg. Chem.
Appl., 2006; Article ID 25651:1.
2. Picard C, Geum N, Nasso I, Mestre B, Tisnès P, Laurent S, Muller RN, Elst LV. A dual
lanthanide probe suitable for optical (Tb3+ luminescence) and magnetic resonance
imaging (Gd3+ relaxometry). Bioorg. Med Chem Lett. 2006;16:5309.
3. Aime S, Crich SG, Gianolio E, Giovenzana GB, Tei L, Terreno E. High sensitivity
lanthanide (III) based probes for mr-medical imaging. High Coord Chem Rev.
2006;250:1562-1579.
4. Mohanan K, Devi SN. Synthesis, characterization, thermal stability, reactivity, and
antimicrobial properties of some novel lanthanide(III) complexes of 2-(N-salicylideneamino)-
3-carboxyethy l-4,5,6,7-tetrahydrobenzo [b] thiophene. Russian J
135
Coord Chem. 2006;32:600.
5. McCleverty JA, Meyer TJ. Comprehensive Coord. Chem. II, Eds., Oxford: Pergamon
2004;3:93.
6. Elzahany EA, Khaled HH, Safaa K, Khalil H, Youssef NS. Synthesis, characterization
and biological activity of some transition Metal complexes with Schiff bases derived
from 2-formylindole, Salicyladehyde, and N-amino Rhodanine. Australian J Basic Appl
Sci. 2008;2:210.
7. Casas JS, Garcia-Tasende MS, Sordo. Corrigendum to main group metal complexes
of semicarbazone and thiosemicarbazone. J Coord Chem Rev. 2000;209:197.
8. Mishra D, Naskar S, Drew, MGB, Chattopadhyay SK. Synthesis, spectroscopic and
redox properties of some ruthenium(II) thiosemicarbazone complexes: Structural
description of four of these complexes. Inorg Chim Acta. 2006;359:585-592.
9. Chandra S, Tyagi M, Refat MS. Spectroscopic, thermal and antibacterial studies on
Mn(II) and Co(II) complexes derived from thiosemicarbazone J .of Serbin Chem Soc.
2009;74:907-915.
10. Singh NK, Singh SB, Shrivastav A, Singh SM. Spectral, magnetic and biological
studies of 1,4-dibenzoyl-3-thiosemicarbazide complexes with some first row transition
metal ions. Proceed Indian Acad of Sci Chem Sci. 2001;113:257.

20.
American Chemical Science Journal, 4(1): 117-137, 2014
11. Ali MA, Mirza AH, Tan AL, Wei LK, Bernhardt PV. The preparation and
characterization of seven-coordinate tin (IV) complexes of the 2, 6-diacetylpyridine
Schiff bases of S-alkyl/aryl-dithiocarbazates and the X-ray crystal structure of the [Sn
(dapsme)I2] complex (dapsme = doubly deprotonated form of the 2, 6-diacetylpyridine
Schiff base of S-methyldithiocarbazate, Polyhedron. 2004;23:2037.
12. Kapoor P, Fahmi N, Singh RV. Microwave assisted synthesis, spectroscopic,
electrochemical and DNA cleavage studies of lanthanide (III) complexes with coumarin
based imines. Spectrochim. Acta Part A, 2011;83:74-81.
13. Hirayama N, Takeuchi I, Honjo T, Kubono K, Kokusen H. Ion-pair extraction system
for the mutual separation of lanthanides using divalent quadridentate schiff bases.
Anal Chem. 1997;69:4814.
14. Bastida R, Blas A, Castro P, Fenton DE, Macias A, Rial R, Rodriguez A, Rodriguez-
Blas T. Complexes of lanthanide(III) ions with macrocyclic ligands containing pyridine
head units. J Chem Soc Dalton Trans. 1996;1493.
15. Xi XL, Li ZC, Ji YF. Synthesis and characterization of neodymium sulphate compiexes
with Schiff-base of salicylidene amiao acids, Chinese Rare Earths (in Chinese).
2002;23:6.
16. Das M, Livingstone SE. Metal chelates of dithiocarbazoic acid and its derivatives. IX.
Metal chelates of ten new Schiff bases derived from S-methyldithiocarbazate. Inorg
Chim Acta. 1976;19:5.
17. Ali MA, Bose RN. Metal complexes of Schiff bases formed by condensation of 2-
methoxybenzaldehyde and 2-hydroxybenzaldehyde with S-benzyldithiocarbazate. J
Inorg Nucl Chem. 1977;39:265.
18. Chaudhary A, Singh RV. Biologically relevant tetraazamacrocyclic complexes of
manganese: synthetic, spectral, antimicrobial, antifertility and antiinflammatory
approach. J Inorg Biochem. 2004;98:1712.
19. Gaur S, Fahmi N, Singh RV. Coordination behavior of unsymmetrical ligand
complexes of diorganotin and diorganosilicon derived from Schiff bases. Phosphorus,
Sulfur and Silicon, and the Related Elements, 2007;182:853.
20. Jorgenson CK. The Nephelauxetic Series, Progress in Inorganic Chemistry. New York,
136
NY: Interscience publishers, Division of John Wiley, Cotton FA ed. 1962;4:73.
21. Henrie DE, Choppin GR. Environmental effects on f–f transitions. II. “hypersensitivity”
in some complexes of trivalent neodymium. The J Chem Phys. 1968;49:477.
22. Sinha SP. Spectroscopic investigation of some neodymium complexes.
Spectrochimica Acta. 1966;22:57.
23. Karraker DG. Hypersensitive transitions of six, seven, and eight-coordinate
neodymium, holmium, and erbium chelates. Inorg Chem. 1967;6:1863.
24. Van Vleck JH, Frank A. The effect of second order zeeman terms on magnetic
susceptibilities: errata Phys. Rev. 1929;34:1494.
25. Sinha SP. “Complexes of Rare Earths”, Pergamon, New York, 1966; 14.
26. Syamal A, Dutta RL. “Elements of Magnetochemistry,” 5th ed., Affiliated East-West
Press Pvt Ltd. New Delhi, 1993.
27. Gour, K. Synthesis and characterization of lanthanide complexes with isovanillin
thiosemicarbazone. Ultra Scientist of Physical Sciences, 2002; 14(1):119-122
(English).
28. Chohan ZH. Antibacterial and antifungal ferrocene incorporated dithiothione and
dithioketone compounds. Appl Organomet Chem. 2006;20:112.
29. Chohan ZH, Arif M, Shafiq Z, Yaqub M, Supuran CT. Metal-based antibacterial and
antifungal agents: synthesis, characterization, and in vitro biological evaluation of
Co(II), Cu(II), Ni(II), and Zn(II) complexes with amino acid-derived compounds. J
Enzyme Inhibit Med Chem. 2006;21:95.

21.
American Chemical Science Journal, 4(1): 117-137, 2014
30. Joshi SC, Goyal R, Jain S. Effect of organochlorine pesticide Methoxychlor (1,1,1-
trichloro-2,2-bis (4-methoxypheny1) ethane) on reproductive function of male albino
rat. Asian J Exp Sci. 2005;19(2):23.
31. Verma RJ, Chinoy NJ. Effect of papaya seed extract on microenvironment of cauda
137
epididymis. Asian J Androl. 2001;3(2):143.
32. Yeung CH, Oberlander G, Cooper TG. Effects of the male antifertility agent ornidazole
on sperm function in vitro and in the female genital tract. J Reprod. Fertil.
1995;103(2):257.
33. Cooper TG, Yeung CH, Skupin R, Haufe G. Antifertility potential of ornidazole
analogues in rats. J Androl. 1997;18(4):431.
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