Synthesis and voltammetric study of some new macrocyclic sulfur compounds for use as chelating agents for separation of arsenic (III) in wastewater and as molluscicidal agents against Biomophalaria Alexandrina Snails

Article abstract of DOI:10.1016/j.crci.2012.05.004

A series of some new nanomeric molecules of cyclic 5- methoxy -5, 6-diaryl -4,5-dihydro -2H-1,2,4-triazin -3-thiones (1-3) has been synthesized. The interaction of compounds 1-3 with HgCl₂ in 1:1 and 1:2 molar ratios was used for the synthesis

Full text of DOI:10.1016/j.crci.2012.05.004

C. R. Chimie 15 (2012) 617–626
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´
Full paper/Memoire
Synthesis and voltammetric study of some new macrocyclic sulfur
compounds for use as chelating agents for separation of arsenic (III)
in wastewater and as molluscicidal agents against Biomophalaria
Alexandrina Snails
1
*
M.S.T. Makki , R.M. Abdel-Rahman, M.S. El-Shahawi
Department of Chemistry, Faculty of Science, King Abdulaziz University, PO. Box 80203, 21589 Jeddah, Kingdom of Saudi Arabia
A B S T R A C T
A R T I C L E I N F O
Article history:
A series of some new nanomeric molecules of cyclic 5- methoxy -5, 6–diaryl -4,5-dihydro -
2H-1,2,4–triazin -3-thiones (1-3) has been synthesized. The interaction of compounds 1-3
with HgCl2 in 1:1 and 1:2 molar ratios was used for the synthesis of the macrocyclic Schiff
base [5,6, 11,12 - tetraaryl -1,2,4,7,8,10- hexa-aza cyclododoeca -4,6,10,12- tetraene -3,9-
dithione] (4), macrocyclic thioethers 5 and/or complex 6. Chemical structures of the
compounds were determined from elemental analysis and spectral measurements. The
compounds were screened as molluscicidal agents against Biomophalaria Alexandrina
Snails which cause Bilhariziasis. Cyclic voltammetry of selected compounds showed well-
defined irreversible electrode couple suggesting application of these compounds as
chelating agents for separation of arsenic in industrial wastewater samples. Compound 1
was physically immobilized onto polyurethane foams (PUFs) and was successfully used for
complete removal of arsenic (III) & (V) species from wastewater.
Received 11 May 2011
Accepted after revision 3 May 2012
Available online 29 June 2012
Keywords:
Nanomeric sulfur compounds
Molluscicidal activity
Voltammetry
Removal of arsenic
Wastewater
ß 2012 Acade´mie des sciences. Published by Elsevier Masson SAS. All rights reserved.
1. Introduction
ions and catalysis [12–14]. Crown ethers of Schiff bases
and their complexes (Fig. 1) have great potential to
Synthesis of macrocyclic molecules and their applica-
tions as chelating agents for separation and/or determina-
tion of toxic metal ions have been reported [1–4]. These
systems also possess bacteriostatic properties in vitro and
facilitate the iron mobilization from 59Fe labeled reticu-
locytes [5]. Nanomers, e.g. macrocyclic ligands allow
selective complexation and extraction of metallic cations
and anions of environmental importance [6–11].
Recently, nanomeric molecules and macrocyclic tran-
sition metal complexes in which structural changes have
made to the basic crown ethers in an attempt to enhance
the selectivity of such class of compounds towards metal
generate novel metabolites and act as fungitoxic than free
ligands [14]. These compounds could also be used as
selective agents for the maintenance of animal or human
health from infections [15–17].
Nanomeric systems as strain allowed have been
synthesized from heterocyclization of aryl - 1,3-dicarbox -
aldehyde with 2-acetylpyridine in ethanolic sodium hy-
droxide. The resultant compound was refluxed with
ammonium acetate-glacial acetic acid afforded 1,3-bis-
compound 1 [17]. Reaction of compound 1 with RuCl3.xH2O
in successive steps has produced a type of nanomer
(Fig. 2) [17].
The compounds 3-thioxo -1,2,4–triazines and their
macrocyclic Schiff bases have great importance as
medicinal and pharmacological agents [18–21]. Blanco
et al., 2002 [22] have reported the nanomers derived from
thiosemicarbazide and a cyclic bicarbonyl compounds.
Therefore, the present article is focused on:
* Corresponding author.
E-mail address: mmakki@kau.edu.sa (M.S.T. Makki).
1
Permanent address: Department of Chemistry, Faculty of Science at
Damiatta, Mansoura University, Mansoura, Egypt.
1631-0748/$ – see front matter ß 2012 Acade´mie des sciences. Published by Elsevier Masson SAS. All rights reserved.
http://dx.doi.org/10.1016/j.crci.2012.05.004

618
M.S.T. Makki et al. / C. R. Chimie 15 (2012) 617–626
excellent biocidal reagents, the present investigation
O
O
O
O
reports the preparation and spectroscopic characteriza-
tion of macromolecules as nanomer systems to be used as
Molluscicidal agents against Biomophalaria Alexandriaa
Snails responsible for Bilharzias. Thus, treatment of
methanolic acyclic 1,2–bicarbonyl compounds such as
benzil, 4,40–dimethoxybenzil and 4,40 -difluorobenzil
with methanolic thiosemicarbazide in hot concentrated
HCl with stirring afforded 5- methoxy -5,6-diaryl-4,5-
dihydro-1,2,4- triazine -3-thiones (1-3) (Scheme 1). The
compounds were characterized by elemental analysis and
spectral measurements.
O
N
O
N
O
N
O
N
H2O
M
HO
O
O
OH
M = Mn, Fe, Ni, Co, Cu, Zn
Fig. 1. Macrocyclic transition metal complexes.
IR spectra of compound
1 in solid state and in
chloroform showed the disappearance of NH and/or SH
groups in the solution suggesting formation of a type of
oxidation and/or complex formation products on treat-
ment with HgCl2. Structure of compound 1 was deduced
from elemental analysis and spectral data as given below:
ꢀ
synthesis of some new nanomeric sulfur compounds
derived from thiosemicarbazide and acyclic bicarbonyl
compounds;
ꢀ
ꢀ
testing their toxicity properties as molluscicidal agents
against Biomophalaria Alexandrina Snails;
studying the redox behavior of selected compounds for
use as chelating agents in stripping voltametric analysis
of arsenic;
ꢀ
ꢀ
UV absorption spectrum in DMF recorded lmax at 325,
280 and 210 nm assigned to due to n–
sigma electronic transitions;
IR spectrum showed characteristic bands at IR:
p
,
p
-
p
and n-
n
cmꢁ1
3180 (NH), 2946 and 2835 (aliphatic CH), 1488 and 1446
(deformation of CH3), 1056 (C-O-Me), 976 and 886 cmꢁ1
(phenyl groups);
ꢀ
application of compound 1 for separation of arsenic (III)
& (V) species from industrial wastewater.
ꢀ
Mass spectrometry recorded the molecular ion M+ at m/z
298 (12.5), M + 1 at 299 (3.8) with a base peak at m/z 77
(Scheme 2).
2. Results and discussion
2.1. Chemistry
Treating
5-methoxy-5,6–diaryl-4,5-dihydro-2H-
1,2,4-triazin -3-thions (1-3) with HgCl2 in methanol at
1:2 molar ratio at room temperature under stirring,
produced a type of macro cyclic thioether Schiff base 4
In continuation to our previous work on the prepara-
tion of sulfur organic compounds [18–21] to be used
CH3
N
N
N
N
N
N
N
N
N
N
M
2
M
N
1
H3C
N
CH3
N
N
N
N
N
N
N
N
N
N
M6
N
M
N
3
H3C
N
N
M
N
CH3
N
N
N
N
N
N
N
N
M5
N
4
CH3
Fig. 2. Formation of strain allowed nanomeric species.

M.S.T. Makki et al. / C. R. Chimie 15 (2012) 617–626
619
Ar
Ar
O
Ar
Ar
Ar
O
O
C
C
Ar
H2NNHCSNH2
C
MeOH
H+
HO
C
N
MeOH/HCl
O
NH2
OMe
HCl
HN
MeOH
HCl
S
Ar
Ar
N
H
S
Ar
OMe
OH
N
C
- H2O
C
Ar
N
N
H
N
H
H
OMe
HN
Hg(NO
3
)
/MeOH
/Δ
2
Hg(NO3
(1 : 1)
)
2
MeOH
(2 M : 2L)
S
1- 3
Δ
H
X
X
Ar
Ar
N
S
N
N
N
Ar
Ar
X
X
Ar
Ar
N
N
N
Ar
N
N
N
N
S
H
N
Ar
S
S
a, X = OMe
Hg
5
b, X = H
c, X = F
4
Scheme 1. Formation of 1–5.
Ph
N
NH +
118(5.4)
N+
Ph
Ph
Ph
Ph
N
NH
HN
S
73(1.5)
N
178(78.2)
179(13.7)
N
H
S
MeO
1
N
M/e =298 (12.5)
M+1 =299 (3.8)
Ph
Ph
N
SH
180(2.7)
MeOCN
N
N
N
- N 2 H
2
57(1.7)
Ph
Ph
N
+
NH
77(100) Ph+
54(1.0)
+
N
S
H
267(8.8)
190(1.2)
192(1.1)
268(3.3)
Scheme 2. Mass fragmentation of compound 1.
as [5,6,11,12–tetraaryl -1,2,4,7,8,10–hexa-aza cyclodo-
doeca -4,6,10,12–tetraene -3,9-dithione] (Scheme 3).
Mass spectrum of compound 4 showed two peaks
which are assigned to [C34H28N6S2O4]Hg fragment and to
the molecular ion of selective ligand C34H28N6S2O4,
respectively. IR spectrum of [Hg(ligand)3(Cl) 2] recorded
lack of both NH and SH functional groups, suggesting
hydrogen bonding between the ligand molecules in the

620
M.S.T. Makki et al. / C. R. Chimie 15 (2012) 617–626
Ar
N
N
complex of metal/organic-ligand 1:2 - stoichiometry
(2 : 1)
+
Mx2
Ar
SH
N
H
OMe
Ar
Ar
N
N
Ar
N
N
N
H
N
H
Ar
OMe
S
S
MeO
M
Ar
2-
Ar
Ar
-2 MeOH
N
N
Ar
Ar
Ar
N
N
N
S
M2+
N
NH
N
N
S
N
N
N
Ar
Ar
S
S
M
Ar
Ar
N
N
N
Ar
Ar
N
N
N
S
S
M
Scheme 3. Formation of 4.
formed complex. 1H NMR spectra of the isolated complex
species showed the absence of amine nitrogen’s and OMe
groups through complexation. 13C NMR spectrum of the
formed complex also showed lacks of carbons of OCH3 and
two imino carbons confirming the proposed structure.
On treatment compounds 1-3 with HgCl2 in 1:1 molar
ratios in methanol at room temperature, compounds 5 a-c
were isolated. Formation of these compounds may take
place via simple–oxidation through mercuric ions. IR
spectrum of compound 5c showed lacks of both NH and SH
functional groups as well as M/z recorded M + 2, M + 1 and
M+ at 608, 606 and 602 with a base peak at 214 (Scheme 4).
It is interesting to noting that, on treating compound 3
with HgCl2in 1:1 molar ratio in methanol and stirring at
room temperature, bis (5, 6–diaryl-5-methoxy-2,4-dihy-
dro-1,2,4–triazin-3-thiato) mercury was separated out as
solid complex 6, while complex 5c was soluble in the
filtrate. A possible mechanism of formation of the complex
6 was suggested via addition of metal salts on C3 = N4 of
1,2,4- triazine (Scheme 5), while complex 5c was formed
via oxidation of mercapto group followed by elimination of
methanol molecules. IR spectrum of compound 6 recorded
8.8 and 8.5 ppm afforded to four NH with a signals due to
aromatic protons at 7-7.3, 7.5 -7.7 in addition at 3.45 -
3.25 ppm of 4-OMe. On the other hand, compounds 1-3
with HgCl2 gave the corresponding complexes of metal-
ligand in 1:2 stiochiometry.
2.2. Molluscicidal activity
Based upon the earlier work by Ali et al. [23] on the
synthesis of phosphono-3- substituted -5, 6-diphenyl -
1,2,4- triazine derivatives and their molluscicidal activities
against Biomophalaria Alexandrina Snails responsible for
Bilharziasis diseases, the prepared compounds were tested
as molluscicidal agents against Biomophalaria Alexandrina
Snails (shell in diameter 5–8 mm). The intermediate host of
Sohistosoma mausoni in Giza Govern state that was not
treated with molluscicides. The snails were adapted to
laboratory conditions for two weeks before being used in
toxicity tests to be sure that the snails are strong and
healthy. Snails were kept in plastic aguaria filled with de
chlorinated tap water at room temperature (25–27 oC).
Stock solutions (500 m
g mLꢁ1) of the tested compounds
peaks at
n
cmꢁ1 3210, 3165 cmꢁ1 of two NH, in addition at
were prepared in the least volume of ethanol and
completed to the required volume with de - chlorinated
tap water on the basis of weight/volume. A series of more
diluted solutions were then prepared following the
1507, 1372, 1158 and 1039 cmꢁ1 due to presence of
thiocarbamide, -C-OMe functional groups. 1H NMR spec-
trum in DMSO recorded resonated signals at: d: 12.5, 10.7,

M.S.T. Makki et al. / C. R. Chimie 15 (2012) 617–626
621
F
F
F
H
N
N
S
S
N
N
N
N
H
F
+
5 c, M
M
M
602 (5.15)
+1
+2
606 (3.90)
608 (0.80)
F
F
N
N
N
S
H
301 (46.35)
F
C
C
N
N
S
N
86 (1.11)
214 (100)
F
Scheme 4. Mass fragmentation pattern of compound 5c.
Ar
Ar
N
OMe
NH
S
N
H
M
)
2
Ar
Ar
Ar
Ar
OMe
OMe
2 M
MX2
MeOH
(3 : 1, L : M)
+
N
NH
S
N
NH
S
and 5 c
N
N
H
H
)
X + Cl
3
Ar
Ar
Ar
Ar
N
+
OMe
O
+ Me
M
N
NH
S
NH
S
N
N
H
2M
)
H
)
2
Scheme 5. Mechanism of formation of compound 6 from 3.

622
M.S.T. Makki et al. / C. R. Chimie 15 (2012) 617–626
Table 1
The Molluscicidal activity of the prepared systems.
Compound No
Mortality of Snails at
various concentrations,
ppm
50
20
100
100
100
100
80
1
2
50
3
40
4a
40
4a
70
100
100
100
5b
30
Reference standard, Baylucide
100
instructions given by WHO organization [24,25]. The
results given in Table 1 revealed high activity towards
snails and the following sequences:
4a > 5b > 5a and 3 > 2 > 1 were achieved. Total elec-
tron barrier of molecular distribution of the evaluated
systems led to inhibition of enzymatic effect on the living
processes for the tested Snails thereby causing break of a
vital-cyclic of snails. The presence of Hg and/or F atoms in
system 4 enhanced the toxicity and a deposition of protein
in the vital-cell of snails. The fact that Hg2+ ions are most
likely able to react with protein containing sulfur forming
stable chelate causing deposition of the vital-cell of the
snails.
2.3. Voltammetric behavior
Compounds 1 and 4a were selected for cyclic voltam-
metric studies as representative for organic macromole-
cule 1 and its mercuric (II) complex. The choice of the two
compounds was based upon the influence of mercury (II)
on the redox characteristic of the resulting species. The CVs
of compound 1 in DMF–tetramethylammonium chloride
(TMA+.Clꢁ) as supporting electrolyte at Pt working
electrode vs. Ag/AgCl reference electrode at various scan
rates are demonstrated in Fig. 3. Two well-defined anodic
peaks at –1.0 and + 0.75 V coupled with two cathodic peaks
at –1.25 and –0.75 V were noticed. An ill-defined anodic
peak at –0.55 V was also noticed at 100 mV sꢁ1 (Fig. 3)
suggesting the irreversible nature of the observed elec-
trode couples. On increasing the scan rates from 100 to
Fig. 4. CVs of compound
1 at 50 (I), 100 (II) and 1000 (III) mV/s
500 mV sꢁ1 in the potential window -2 to 0.0. V vs. Ag/AgCl electrode.
1000 mV sꢁ1, the cathodic and anodic peaks were shifted
cathodically and anodically, respectively (Fig. 4). These
results confirmed the irreversible nature of the electrode
couples [26,27]. Continuous scan of the CV significantly
decreased the peak current and the signal was hardly
discernible from the baseline, indicating passivity of the
surface of the Pt working electrode via formation of
polymeric oxidation product or fouling of the electrode by
the reduction products.
The CVs of compound 4 a in DMF-TMA+.Clꢁ at various
scan rates (Fig. 5) showed one well-defined cathodic and
anodic peaks in the range ꢁ1.2 – 0.8 V with peak–peak
potential separation (60 mV) suggesting reversible elec-
trochemical process [26]. The plot of anodic (at –0.91 V) or
cathodic (-0.97 V) peak current vs. square root of the scan
rate increased linearly on increasing the scan rate,
indicating that, the electrochemical reduction process is
diffusion controlled electro–chemical process [26,27]. The
Fig. 3. CVs of compound 1 at 100 mV sꢁ1 in the potential window -1.5 to
+1. V vs. Ag/AgCl reference electrode.

M.S.T. Makki et al. / C. R. Chimie 15 (2012) 617–626
623
80
60
40
20
0
0
40
80
120
Time, min
Fig. 6. Influence of shaking time on arsenic (III) sorption from aqueous
solution onto the unloaded (–) and compound 1 immobilized (–) PUFs
from aqueous solutions of pH 3-4.
emission spectrometry (ICP-OES. Preliminary investiga-
tion revealed considerable retention of arsenic (III) species
onto compound 1 treated PUFs). Therefore, the influence of
shaking time, pH and acidity on arsenic (III) uptake by PUFs
was investigated. The sorption profile of an aqueous
solution of arsenic (yyy) at pH 3 by untreated PUFs and
compound 1 loaded PUFs at room temperature was
studied. Arsenic (yyy) in the aqueous phase after equilibri-
um was determined by ICP-MS. The extraction percentage
(%E) and the distribution ratio (D) of arsenic (yyy) reached
maximum within 90 minutes (Fig. 6). Thus, a shaking time
of 90 min was adopted in the subsequent work.
The sorption profile of arsenic (III) ions at 10.0 m
g mLꢁ1
Fig. 5. CVs of compound 4a at 50 (I) and 200 (II) mV sꢁ1 V vs. Ag/AgCl
concentration level from the aqueous solutions (50 mL) at
different pH by the immobilized PUFs (0.2 ꢂ 0.01 g) was
investigated after 90 min shaking time. The sorption profile
of arsenic (III) by the immobilized PUFs decreased on
increasing the solution pH and maximum sorption percent-
age was achieved at pH 3. At pH > 3, the decrease in the
uptake of arsenic (III) by the loaded PUFs is most likely due to
the instability or the hydrolysis of the produced complex
species formed between arsenic (III) and the reagent
immobilized PUFs. The retention of arsenic (yyy) in pH 2-3
is most likely attributed to the protonation of the ether (_
electrode.
plot of the cathodic peak potential vs. log scan rate was also
linear on raising the scan rate. The current function (ip, c/to
)
decreased on raising the square root of the scan rate
continuously. Thus, the first reduction processes of the
compound preceded according to the well-known elec-
trode- coupled chemical reaction mechanism of type EC
[26,27]. These results suggested the possible use of
compound 1 and its derivatives as complexing agent in
stripping voltammetric determination and also in solid
phase extraction for separation of arsenic (III, V) ions in
industrial water.
CH2 OH+_ CH2_) and/or urethane linkages group (- NH2
-
_
+
COO-) available in the PUFs sorbent membrane. Thus, the
retention of analyte proceeded via ‘‘solvent extraction and/or
weak base anion exchange mechanism’’ [28,29]. The pKa of
2.4. Retention profile of arsenic (III) by reagent 1 immobilized
the protonated ether group (_ CH2_ OH+_ CH2
)foam and amide
_
polyurethane foams
group (- NH2+- COO-) foam are _ 3 and _ 6, respectively [28,29].
Thus, the uptake of arsenic (III) is easily proceeded via ether
group of the PUFs than the protonated amide group of the
PUFs.
Polyurethane foams (PUFs) sorbent represent one of the
most effective solid sorbent due to its high available
surface area, aerodynamic, cellular and membrane struc-
ture and extremely low cost [28,29]. A recent literature
survey revealed no data on the use of compound 1 or its
derivatives as chelating agents for metal separation and/or
determination in different matrices. Thus, considerable
attention was focused on preconcentration of trace and
ultra trace concentrations of arsenic (III) ions in water by
compound 1 physically immobilized onto PUFs prior its
determination by inductively coupled plasma-optical
2.5. Performance of the reagent 1 treated polyurethane foams
packed column
The performance of compound 1 loaded PUFs packed
column was determined via critical (CC) and breakthrough
capacities (BC) [31,32]. The CC was defined as the amount
of arsenic (III) that could be retained on the PUFs column at
2 mL minꢁ1 flow rate until the arsenic (III) was first

624
M.S.T. Makki et al. / C. R. Chimie 15 (2012) 617–626
100
80
60
40
20
0
sample solutions to the electro-chemical cell. The data
were recorded at room temperature and the peak current
heights were measured using the ‘‘tangent fit method’’.
3.2. Reagents and materials
Analytical chemicals and reagents grade quality were
purchased from BDH chemicals. Low density polyethylene
(LDPE) bottles, Nalgene were used for the collection of the
different water samples. LDPE bottles and electrochemical
cell were carefully cleaned first with hot detergent, soaked
in 50% HCl (Analar), HNOBB3 BB(2.0 mol lPPꢁ1PP), subse-
quently washed with dilute HCl (0.5 mol lPPꢁ1PP) and
finally rinsed with distilled water. The sample solution was
stored in LDPE bottles and stored at -20 8C. Stock solutions
(0.1%w/v) of the reagent were prepared in the appropriate
solvent. A stock BDH stock solution of metal ions to be
analyzed (1.0 mg/mL) in dilute nitric acid was used.
Commercial white sheets of open cell PUFs based polyether
type were used as solid sorbent for the separation of the
tested metal ions. The foam cubes were then washed with
acetone in a Soxhlet extractor for 6 hours, and dried at
80 8C in an oven for 2 hours. The dried foam cubes were
then stored in dark low density polyethylene bottles.
0
50
100
150
200
250
300
350
Feed aqueous solution, ml
Fig. 7. Breakthrough curve of aresnic (III) uptake onto compound 1
loaded PUFs (1.0 ꢂ 0.01 g) packed columns at 5.0 mL min.ꢁ1
.
detected in the effluent. Practically, this value equal the
actual volume of the effluent collected just before first
appearance of arsenic (III) in the effluent minus the free
column volume. The calculated values of CC and BC of
arsenic (III) ions from the breakthrough (S–shaped) curve
(Fig. 7) were found equal 0.55 and 0.88 mg g
flow rate of 2 mL minꢁ1 [28,29].
ꢁ1
to be at a
The reagent PUFs packed column was tested for
retention and recovery of arsenic (III) from wastewater
samples (1.0 L). The sample was spiked with arsenic (III)
3.3. Organic preparation
3.3.1. 5- Methoxy -5,6-diaryl -4,5-dihydro-2 H-1, 2, 4-
triazine -3-thiones (1-3)
(5–10 mg) and percolated through PUF column at
2.0 mL minꢁ1 flow rate. Complete recovery of the retained
arsenic (III) species was achieved by percolating acetone
(10 mL) at 2.0 mL minꢁ1 flow rate as indicated from the
ICP-OES analysis of arsenic before and after extraction.
Arsenic (V) can also be preconcentrated by the developed
treated PUFs packed column after reduction with SO2 gas
to arsenic (III) in water.
A solution of thiosemicarbazide (12.50 mmol) in dry
methanol (150 mL) was added drop wise to a solution of
benzil and 4, 4–di(methoxy/fluoro) benzil (12.5 mmol) in
absolute methanol with concentrated HCl (25 mL,
2 mol Lꢁ1) with constant stirring for 8 hours. The solution
was left to cool overnight. The formed precipitates were
filtered off, washed and dried to give 1-3, respectively.
Compound 1 was crystallized from ethanol as yellow
crystals. Yield = 75%, m.p. 190 oC. Analytical data: Found:
C = 64.39, H = 4.99, N = 13.98, S = 10.53%; Calculated for
3. Experimental
3.1. Apparatus
C
16H15N3SO: C = 64.64, H = 5.05, N = 14.14, S = 10. 77%; m/z
298 (C16H15N3SO +1, 35%) IR:
cmꢁ1 = 3184, 3131 (NH),
1608 (C = N), 1550, 846 (thioamide I & II). 1H NMR (DMSO):
: 12.0 (1 H, s, NH), 10.0 (1 H, s, NH), 7.5 (2 H, m, 5- H), 7.7 -
n
The following apparatuses were afforded by the
Chemistry Department, Faculty of Sciences, King Abdulaziz
University. A Perkin Elmer (Lambda EZ-210) double beam
spectrophotometer (190–1100 nm) with 1 cm (path
width) quartz cell was used for recording the electronic
spectra of the compounds. A Perkins Elmer model RXI-FT-
IR system 55529 was used for recording the IR spectra of
the compounds. A Brucker advance DPX 400 MHz model
using TMS as an internal standard was used for recording
the 1HNMR and 13C NMR spectra (Chemical shift in ppm) of
the compounds on deuterated DMSO. A GC-MS-QP 1000-
Ex model was used for recording the mass spectra of the
compounds. Melting points were determined with an
electro thermal Bibbly Stuart Scientific Melting Point SMPI
(US). Molecular weights and C, H, N analysis of the
compounds was performed on Micro analytical center,
Cairo University, Egypt. Cyclic voltammetric measure-
ments were carried out on a Metrohm 757 VA trace
analyzer and 747 VA stand (Basel, Switzerland). A digital-
d
7.2 (8 H, m, diphenyl), 3.1 (3 H, s, OCH3).
Compound 2 was crystallized from ethanol as yellow
crystals. Yield (65.2%), m.p. 183 -185 oC. Analytical data:
Found: C = 59.49, H= 5.85, N = 11.74, S = 8.97%; Calculated
for C18H19N3SO3: C = 60.14, H = 5.35, N = 11.74, S = 8. 97%;
m/z 359 (C18H19N3SO3 +2, 15%) IR:
(NH), 1610(C = N), 1560, 860 (thioamide I & II), 1050 (-C-O-
Me). 1H NMR (DMSO):
: 12.3, 10.8 (each 1 H,s, NH), 7.8 -
7.3 (8 H, m, aryl protons),3.55 (6 H,s, two OCH3), 3.35 (3H,s,
– OCH3), 13C NMR 29.35 – 30.39, 55.74 – 56.25, 106.94,
115, 125.91 – 133.09, 146.72, 160.39, 166.01, 180.37 and
194.48 and 197.64.
Compound 3 was crystallized from ethanol as faint
yellow crystals. Yield (82%), m.p. 225-226 0C. Analytical
data: Found: C = 57.25, H = 3.85, N = 12.46, S = 9.49;
n
cmꢁ1 = 3210, 3190
d
F = 11.27%. Calculated for C16H13N3SF2O:
H = 3.95, N = 12.94, S = 9. 67; F = 11.41 %; m/z 334.
(C16H13N3SF2O +1, 26%) IR: 2850
cmꢁ1 = 3250
C =57.61,
micro-pipette 10–100
m
L (Volac) was used for transferring
n
–

M.S.T. Makki et al. / C. R. Chimie 15 (2012) 617–626
625
(b, NH, aromatic & aliphatic CH), 1610 (C = N), 1485
(deformation CH3), 1530, 880 (thioamide I, II), 1200 (C = S),
separated out, filtered off, washed with methanol and
dried to give 5c.
1060 (-C-O-Me), 680 (C-F). 1H NMR (DMSO):
d
: 11.2, 10.8
Compound 5c was crystallized from THF as pale yellow
crystals. Yield (45%), m.p. 280 oC. Analytical data: Found:
C = 59.50, H = 2.90, N = 13.70, S = 10.35, F = 12.45%. Calcu-
lated for C30H18N6S2F4, C = 59.80, H = 2.99, N = 13.95,
S = 10.63, F =12.62%. M/z 602 (M+, 5.15), 606 (M + 1,
3.901, 608) (M + 2, 0.80), 301 (46.35), 214 (100) and 86
(1.11).
(each 1 H,s, NH), 7.8 – 7.2 (8 H, m, aryl protons), 3.35 (3H,s,
– OCH3), 13C NMR 29.58,31.09, 36.23, 40.85, 162.86 and
206.45.
3.3.2. 5,6,11,12–Tetraaryl -1,2,4,7,8, 10 hexaaza–
cyclododeca -4, 6,10,12–tetraene -3,9-dithiones (4)
A
solution of mercuric chloride (0–70 mmol) in
Compound 6 was crystallized from ethanol as yellow
crystals. Yield (40%), m.p. 190 Analytical data: Found:
C = 40.90, H = 2.84, N = 8.18, S = 6.09, F = 8.31%, M/z = 938.
Calculated for C32H26N6S2F4O2HgCl2, C = 40.93, H = 2.87,
methanol (50 mL) was added to a solution of compound
2 (1.4 mmol) in absolute methanol (50 mL). The reaction
mixture was stirred for 4 h at room temperature. The solid
precipitate was filtered off, washed with methanol and
dried to give 4. Dilution of the filtrate yielded the cyclic
thioether 5. The solution was filtered and crystallized from
methanol. This compound was crystallized from methanol
as yellow crystals. Yield (45%), m.p. 110 oC. Analytical data:
Found: C = 47.52, H = 3.26, N = 9.78, S = 7.45%, Calculated
N = 8.95, S = 6.82, F = 8.39%. IR:
NH), 1507, 1372 (thiocarbamide), 1156 (C = S) and 1039 (C-
O-Me); 1H NMR (DMSO):
: 12.5 (1H, s, NH), 10.7 (1 H,s,
n
cmꢁ1 3210, 3165 (NH,
d
NH), 8.8 & 8.5 (1 H, each s, NH), 7.7–7.5 (4 H, m, aryl), 7.3 –
7.0 (4 H, m, aryl) and 3.45 (6 H, each s, O- CH3); 13C NMR
29.35, 30.39 (O- CH3); 116.45,116.71 (C-N), 131 -134 (aryl
carbons), 206.19 (C = S).
for [C34H28N6S2O4]Hg,: C = 48.5, H = 3.29, N = 9.95,
=7.53%; IR:
cmꢁ1 lacks of both NH, SH; 1H NMR (DMSO):
: 3.15, 10.8 (4 s, OCH3), 7.07, 7.1,7.2, 7.3, 7.5, 7.6, 7.7 and
S
n
d
3.4. Analytical applications
7.8 (each s, 8 H, 8 H aryl protons).
3.4.1. General cyclic voltammetry
3.3.3. Cyclic thioether 5a
The general procedure for recording cyclic voltam-
metric at differential sweep rates was carried out as
follows. An accurate concentration (10 mmol) of the test
compound and supporting electrolyte tetra methyl am-
monium chloride (100 mmol) in DMF were transferred
into the voltammetric cell. The solution was stirred with
nitrogen for 15 minutes to release oxygen. The voltammo-
grams were then recorded in the potential ranges e -1.5 to
1.V at Pt working electrode versus Ag/AgCl reference
electrode.
A
solution of mercuric chloride (0–70 mmol) in
methanol (50 mL) was added to a solution of compound
2 (0–70 mmol) in absolute methanol (50 mL). The reaction
was stirred for 4 hours at room temperature and the solid
precipitate was filtered off, washed with methanol and
dried.
Compound 5a was crystallized from ethanol as pale
yellow crystals. Yield (35%), m.p. 130 Analytical data:
Found: C = 62.29, H = 4.56, N = 12.79, S = 9.49%. Calculated,
for (C34H30N6S2O4) C = 62.76, H = 4.61, N = 12.92, S =9.84%.
IR:
n
cmꢁ1 lacks of both NH, SH with peaks at 1620 (C = N),
: 8.8 (2 H,
3.4.2. Preparation of polyurethane foam packed column
Compound 1 was physically immobilized onto PUFs as
follows: PUFs cubes (1.0 cm3) were shaken well with
compound 1 for 10 minutes as reported [28].An accurate
weight (1.0 ꢂ0.01 g) of the reagent 1 immobilized PUFs was
packed in a column (1000 ꢃ 10 id mm) using the vacuum
method of foam packing [28,29]. The aqueous solutions (0.1 L)
containing arsenic (III) at concentrations < 10 mg mLꢁ1 were
percolated through the PUFs packed column at 5 mL minꢁ1
flow rate after adjustment the solution to pH = 2–3 with B-R
buffer. The sample and blank PUFs packed columns were then
washed with 100 mL of B-R buffer solution at the same pH.
Quantitative retention of arsenic (III) took place on the
immobilized PUFs asindicated fromthe ICP-AESmeasurement
of arsenic in the effluent solutions. The retained arsenic (III)
species were then recovered quantitatively from the foam
column with acetone 910 mL at 5 mL minꢁ1 flow rate.
1180 (C-S), 1055 (C-O-Me); 1H NMR (DMSO):
d
s< H-C5 of 1,2,4–triazine), 7.7 -7.0 (16 H, m, aryl protons),
3.65 -3.55 (12 H, s, 4-OCH3).
3.3.4. Cyclic thioether, 5b
Compound 5b was prepared as mentioned using
compound 1 and mercuric chloride salt in 1: 1 molar
ratio and crystallized from ethanol as yellow crystals.
Yield (80%), m.p. 120. Analytical data: Found: C = 67.37,
H = 4.10,
N = 15.67,
30H22N6S2: C = 67.9, H = 4.15, N = 15.84, S = 12.07%. IR:
cmꢁ1 2704 (N-S-N), 1525, 1329 (cyclic amide I, II),
S = 11.94%.
Calculated
for
C
n
1024 (C-S-N), 867, 807 (phenyl CH), 1H NMR (DMSO):
d
:
7.3 -7.8 (22 H, m, phenyl & H–C5 of 1,2,4–triazine), 13C
NMR 167 (CS), 156, 1, 156.0 (C-N), 131.31 and 128.84
(carbon - phenyls).
3.3.5. Bis [5,6- di (4-flurophenyl)-5-methoxy-2,4-dihydro-
1,2,4- triazin-3-thiato] – mercury, 6 and cyclic thioether, 5c
A methanolic solution of mercuric chloride (0.01 mmol)
in methanol (50 mL) was added to a solution of compound
3 (0.03 mmol) in absolute methanol (50 mL). The reaction
mixture was stirred for 8 hours at room temperature. The
solid precipitate was filtered off and dried to give a type of
complex 6. On diluting the filtrate, a solid compound was
Acknowledgement
The authors would like to thank the Deanship of
Scientific Research, King Abdul Aziz University, Kingdom of
Saudi Arabia for the financial support under the grant
number MX/11/20 and the Chemistry Department for the
facilities provided.

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