Complexes of Co(II), Ni(II), Cu(II), and Pd(II) with sulfametrole- cyclodiphosph(V)azane derivatives

Article abstract of DOI:10.1080/10426500802016661

Novel [1,3-di-[N1-4-methoxy-1,2,5-thiadiazole-3-yl- sulfanilamide(sulfametrole)]-2,,4-bis-[1,3-dithiole-2-thione-4,5-dithiolate] -2′,4′-dichl-orocyclodiphosph(V)azane] (III), was prepared and their coordinating behavior towards the metal ions Co(II), Ni(I

Full text of DOI:10.1080/10426500802016661

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Complexes of Co(II),
Ni(II), Cu(II), and Pd(II)
with Sulfametrole-
Cyclodiphosph(V)azane
Derivatives
A. M. A. Alaghaz a
a Chemistry Department, Faculty of Science , Al-
Azhar University (for Boys) , Nasr City, Cairo, Egypt
Published online: 10 Oct 2008.
To cite this article: A. M. A. Alaghaz (2008) Complexes of Co(II), Ni(II), Cu(II), and
Pd(II) with Sulfametrole-Cyclodiphosph(V)azane Derivatives, Phosphorus, Sulfur, and
Silicon and the Related Elements, 183:11, 2807-2826
To link to this article: http://dx.doi.org/10.1080/10426500802016661
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Phosphorus, Sulfur, and Silicon, 183:2807–2826, 2008
Copyright © Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500802016661
Complexes of Co(II), Ni(II), Cu(II), and Pd(II) with
Sulfametrole-Cyclodiphosph(V)azane Derivatives
A. M. A. Alaghaz
Chemistry Department, Faculty of Science, Al-Azhar University (for
Boys), Nasr City, Cairo, Egypt
Novel [1,3-di-[N -4-methoxy-1,2,5-thiadiazole-3-yl-sulfanilamide(sulfametrole)]-
1
2,,4-bis-[1,3-dithiole-2-thione-4,5-dithiolate]-2ꢀ,4ꢀ-dichl-
orocyclodiphosph(V)azane] (III), was prepared and their coordinating behavior
towards the metal ions Co(II), Ni(II), Cu(II), and Pd(II) was studied. The structures
1
of the isolated products are proposed based on elemental analyses, IR, UV, H,
31
and P NMR, ESR, magnetic susceptibility, molar ratio, conductometric titration
and electrical conductivity measurements. The prepared complexes showed high to
moderate bactericidal activity compared with the ligand.
Keywords complexes; Cyclodiphosph(V)azane; dithiolate; sulfametrole;
INTRODUCTION
Sulfonamides are the oldest class of antimicrobials and are still the
drug of choice for many diseases such as cancer and tuberculosis.1,2 Cy-
clophosphamide and its derivatives are examples of phosphorus com-
pounds that are some of the most effective anticancer agents with
proven activity against a large variety of human cancers.3 The reaction
of hexachlorocyclodiphosph(V)azanes with amino compounds, active
methylene containing compounds and bifunctional reagents have been
investigated in some details.4,5 Little is known about the interaction
of sulfametrole-hexachlorocyclodiphos-ph(V)azane with 1,3-dithiole-2-
thione-4,5-disodiumthiolate and their metal complexes. The proposed
structure for III is shown in Scheme 1.
Received 6 November 2007; accepted 27 February 2008.
Address correspondence to A. M. A. Alajhaz, Chemistry Department, Faculty of
Science, Al-Azhar University (for Boys), Nasr-City, Cairo, Egypt. E-mail: aalajhaz@
hotmail.com
2807

2808
A. M. A. Alaghaz
SCHEME 1 Proposed structure of III ligand III: 1,3-di-[ N1-4-methoxy-1,2,5-
thiadiazole-3-yl- sulfanilamide]-2,,4-bis-[1,3-dithiole-2-thione-4,5-dithiolate]-
2ꢀ,4ꢀ dichlorocyclodiphosph(V)azane (III).
RESULTS AND DISCUSSION
The ligand was found to be soluble in CHCl3, acetonitrile, acetone,
ethanol, THF, methanol, DMSO, DMF, ethyl acetate, and insoluble in
diethyl ether and water, slightly soluble in benzene andn-hexane. The
structure of the ligand (III) was elucidated by elemental analyses, IR,
1
electronic, H, and 31P NMR techniques. The assignment of the pro-
posed structure for III is based on the elemental analyses data listed
in Table I. The UV spectra of III in DMF showed absorption bands at
284 nm, which is characteristic for phosphazo four-membered rings.6
The infrared spectra of the III ligand showed the characteristic bands
which are summarized in Table II. The 1H NMR spectrum of the ligand
(III) showed the following characteristic proton signals at: δ (7.20) ppm
is assigned for aromatic protons Ar-H and abroad signal at δ (10.54)
ppm is assigned for N H proton, which disappeared on the addition of
D2O due to the proton exchange. The 31P NMR of the ligand records a
signal at δ = 25.93 ppm, which supports the phosphazo ring structure.
Further insight concerning the structure of the ligand was obtained
from its mass spectra. The mass fragmentation pattern of the ligand
showed a base peak at m/z 92 (100%), together with peaks at m/z 155

2809

2810

Complexes of Co(II), Ni(II), Cu(II), and Pd(II)
2811
(72%) and m/z 161 (76%). The other possible fragmentations are given
in Scheme 2.
SCHEME 2 Possible fragmentation pathways of III ligand.
Spectrophotometric Measurements of Solution
Stoichiometry
The absorption values of the Co2+, Ni2+, Cu2+, and Pd(II) complexes
are shown in Table III. The diagrams in Figure 1, consist of two linear
portions intersecting at 1: 2 [ligand]/[M2+], where M2+ corresponding
to Co2+, Ni2+, Cu2+, and Pd(II) respectively, indicating the formation
of 2 M: 1 L species.7 This is in agreement with the elemental analyses
and conductometric analyses data.
Conductometric Titration
In order to follow up the behavior of the ligand in solution with
Co2+, Ni2+, Cu2+, and Pd(II), we investigated these systems using

2812
A. M. A. Alaghaz
TABLE III Absorption Data of Ligand (III) Solution with the
Addition of Metal M2+ (M2+ = Cu) Solution, Where [Cu2Cl4(III)] (IVc)
Molar ratio(M+2: III)
Conc. of III (10−4M)
Conc. of III (10−4M)
Cu(II)
0
0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
0.159
0.163
0.170
0.174
0.180
0.181
0.182
0.182
0.182
0.183
0.183
0.183
0.183
2:0.25
2:0.50
2:0.75
2:1.00
2:1.25
2:1. 50
2:1.75
2:2.00
2:2.25
2:2.50
2:0.75
2:3.00
0.25
0.50
0.75
1.0
1.25
1.50
1.75
2.0
2.25
2.50
2.75
3.0
conductometric titration method.7 In this method, 50 ml (10−4M) of
M(II), where M(II) is Co(II), Ni(II), and Cu(II) solution in absolute
ethanol was titrated with (10−3M) of ligand solution absolute ethanol
at room temperature 25oC and represented in Figure 2. The curves
were plotted between the conductance of the solution and the volume
of ligand added. The results show that the break in the curve occurred
when the 2: 1 (M: L) species are formed in solution. The conductance of
the reaction mixture was increase continuously with complexes under
investigation. The reason for increase in conductivity after 2: 1 (M: L)
complexes forms may be due to the presence of the ligand in ionic form
in the medium (ethanol) which a rises the conductivity.
Cu(II)
0.185
0.18
0.175
0.17
0.165
0.16
0.155
0
1
2
3
4
[lig]/[Cu(II)]
FIGURE 1 Results of molar ratio method for Cu(II) complex.

Complexes of Co(II), Ni(II), Cu(II), and Pd(II)
2813
Cu(II)
25
20
15
10
5
0
0
2
4
6
8
Volume of ligand (ml)
FIGURE 2 Conductometric titrations for Cu(II) complex.
Metal Complexes
All the complexes are polycrystalline solids and the elemental analy-
sis results (Table I) agree well with the binuclear structure shown in
Scheme 3. The purities of all these compounds were checked by TLC
by dissolving the appropriate complex in DMF and using ethyl acetate
(80%) - methanol (15%) - acetic acid (5%) as eluant. Only one spot was
observed in each case after developing in an iodine chamber, indicating
SCHEME 3 Suggested structures of III metal complexes.

2814
A. M. A. Alaghaz
that the compounds were pure. All the complexes have high melting
points (>360◦C) suggesting the existence of a strong covalent bonding
between the Co(II), Ni(II), Cu(II), or Pd(II) ions and the ligand under
investigation.
The chemical behavior of III towards transition-metal cations was
our goal in this article. The metal cations selected for this purpose were
Co(II), Ni(II), Cu(II), and Pd(II). When a mixture of one mol of III in ace-
tonitrile was reacted with two moles of the metal salts in acetonitrile, a
change in color was observed and the complex compounds precipitated.7
The products were purified by washing with acetonitrile, and gave ele-
mental analysis compatible with the general formula:
[M2X4III(H2O)m],
(1)
where:
M(II)
X−
m
Co
Ni
Cu
Pd
Cl
Cl
Cl
4
4
4
0
NO3
Accordingly, the complexes are prepared following the general
equation:
acetonitrile (solvent)
ꢀ
ꢁ
2 MX2 + III = H2O −−−−−−−−−−−→ [M2X4III H2O
]
(2)
m
reflux for 2hours
where;
M(II)
X−
m
Co
Ni
Cu
Pd
Cl
Cl
Cl
4
4
4
0
NO3
The analytical data of the isolated complexes are listed in Table I.
Further, the proposed structures of the complexes of III is confirmed
using different physico-chemical tools such as IR, molar conductance,
UV-Vis, molar ratio, ESR, magnetic moment, conductometric titration,

Complexes of Co(II), Ni(II), Cu(II), and Pd(II)
2815
and electrical conductivity measurements. Biological activities of III
and its metal complexes were done and compared with standard drugs.
IR Spectra
A comparative study of the IR spectra of the complexes with that of
the free ligand and those of the complexes of related ligands gives
some positive information regarding the binding sites of the sulfadrug-
cyclodiphosph(V)azane. The IR data are listed in Table II. The SO2
group modes of the ligand appear as medium to small bands at 1401
cm−1 (νasym) and 1080 cm−1 (νsym). In the complexes, the asymmetric
and symmetric modes are shifted to 1378–1392 cm−1 and 1060–1072
cm−1 for the asymmetric and symmetric modes, respectively, upon coor-
dination to the transition metals.8 The stretching vibration band ν(NH)
of the sulfonamide group, which in the free ligand is found at about
3183cm−1, disappeared or was hidden under the broad bands at 3486–
3324 cm−1 in the spectra of the isolated complexes, as the result of the
presence of coordinated water molecules. The presence of coordinated
water molecules renders it difficult to confirm the enolization of the sul-
fonamide group. The blue shift of the SO2 stretching vibration to lower
frequencies may be attributed to the transformation of the sulfonamide
to the enol form as a result of complex formation to give a more stable
six-membered ring. This transformation would result in the loss of the
amide proton and the appearance of the absorption peak for enol ν(OH)
stretching mode at 2922–2976 cm−1 for the complexes, together with
a change in position and intensities of the sulfone group. This is sup-
1
ported by the H NMR data. The enolic OH group is formed through
the following tautomerism.4,5,9
The lower frequencies of the enolic OH groups can be taken as ev-
idence for the participation of this group in complex formation. The
strong band located at 1638 cm−1 is assigned to the ν(C N) stretch-
ing vibrations of thiadiazole N atom. After complexation, this band
is shifted to lower wavenumbers (24–38 cm−1), indicating coordina-
10
tion via the thiadiazole N atom, as previously reported. However, a

2816
A. M. A. Alaghaz
medium intensity band in the 480−570 cm−1 region may reasonably be
assigned to the M-N stretching vibration.11 Bands appearing in the re-
gions 2880−2920 and 1410−1440 cm−1 in all the complexes may be due
to ν(C H) and δ(C H), respectively. The spectrum of [Pd2(III)(NO3)2]
shows bands at 1450 cm−1 (υ1), 1030 cm−1 (υ2), 1362 cm−1 (υ4), and 710
cm−1 (υ5) with υ1–υ4 separation of 88 cm−1, characteristic of monoden-
tate nitrato group.12 Bands appearing in the chloro complexes in the
regions 270−318 cm−1 are assignable to ν(M Cl).11 Another band ap-
peared between 230 and 240 cm−1, which is assigned to the interaction
of enolic sulfonamide OH oxygen to the metal atom, i.e., the stretching
vibrationsν(M O).7 The appearance of a medium-to-strong band in the
stretching vibration region between 820–860 cm−1and 780–794 cm−1
in the spectra of the metal complexes were attributed to coordinated
water molecules.13 The band at 1375−1378 cm−1 in all the complexes
is due to the ν(CH3) frequency, is not affected upon complexation. The
aliphatic protons are not greatly affected upon complexation. This is
supported with the observed characteristic νM
band. Moreover, the
O
characteristic vibrational bands corresponding to the νPNP, νP N, νP
,
S
νP Cl, νC S, νC
and νC
which were associated with all the com-
C
S
plexes under investigation are given in Table II. It is obvious from the
IR data that III behaves as a neutral bidentate ligand coordinated to
the metal ions through the thiadiazole N and enolic sulfonamide OH
atoms.
1H and 31P–NMR Spectra
The 1H–NMR spectrum of the diamagnetic Pd(II) complex showed the
same characteristic proton signals for the III ligand and the data are
listed in Table IV. The signal characteristic for amide NH proton (δ =
7.72 ppm) disappeared in the spectrum of the isolated Pd(II) complex
and a new band appeared at δ = 11.11 ppm. The absence of this sig-
nal is attributed to the transformation of the amide-NH group to the
enolic form. This is also supported by the disappearance of the band at
δ = 11.11 ppm when using deuterated solvent.9 The 31P NMR of the
TABLE IV 1H and 31P-NMR Spectra of III and Its Pd(II) Complex
δ,ppm
1H -NMR
31P-NMR
OH
NH
ArH
OCH3
phosphazo ring
III
—
11.11
10.54
—
7.20
7.67
3.47
3.82
25.93
24.32
[Pd2(NO3)4(III)]

Complexes of Co(II), Ni(II), Cu(II), and Pd(II)
2817
Pd(II) complex records a signal at δ = 24.32 ppm, which supports the
phosphazo ring structure.
From the above IR and 1H NMR studies, we suggest that the ligand
III is present in the complexes in the enol form.
Magnetic and Electronic Spectral Studies
On complexation the lower-energy band observed at 355 nm in the
spectrum of the free ligand III, which was assigned to n-π* transition
is shifted to a red shift, while the other one at 284 nm of the π − π*
transition is slightly shifted to a blue shift.
The magnetic susceptibility measurement at room temperature of
the green Co(II) complex IVa, gave magnetic moment value µeff of 5.14
B.M.,11 this high value may be due to orbital contribution correspond-
ing to three unpaired electrons are expected for a week field ligand.
4
Two peaks at 705 nm and 554 nm, which may be assigned to T1g(F)
4
4
4
→ A1g(F) and T1g(F) → T1g(P) and is consistent with the octahedral
geometry. 11 The peaks observed at 255 nm, 310 nm, and 380−405 nm
regions, were assigned to π → π* and n→ π* transitions, respectively.
Finally, the low value of molar conductance (11.33 ꢀ−1cm2 mol−1) sug-
gests a non-electrolytic nature of this complex in DMSO.12
The electronic spectrum of the Ni (II) complex IVb shows absorption
4
4
band at 702 nm which may be investigated to the A2g(F) → T1g(F),
week bands observed on the high and low energy sides of the 710 nm
band have been assigned to spin forbidden bands.11 The value of mo-
lar conductance in DMSO (10.34 ꢀ–1cm2mol–1) indicating a non elec-
trolytic nature around the Ni (II) ion.11 Also, the value of magnetic
moment (2.87 B. M.) is taken as additional evidence for the presence of
octahedral geometry around the Ni(II) ion. 11
The Cu(II) complex IVc gave a band at 560 nm, suggesting the ex-
istence of a transition from dxy →d2z and dxz →dyz transfer to the anti-
bonding and half-filled d2x−dy2 level which is consistent with an octahe-
dral configuration.11 The observed magnetic moment of the Cu(II) com-
plex is 1.76 B.M.,11 which confirms the octahedral structure of this com-
plex. Also, the value of molar conductance in DMSO (8.20 ꢀ–1cm2mol
)
–1
suggests a non-electrolytic nature of this complex.12
Palladium complex (IVd) has three spin allowed singlet–singlet d–
1
1
1
1
d transitions, which are A1 → A2 (662 nm), A1 → B1 (495 nm), and
1A1 → E (443 nm).14 These transitions are from the lower lying d orbital
1
to the empty dx2−y2 orbital. The strong band at 375 nm is assignable to
a combination of M→L (charge transfer) and d–d bands. The molar
conductance value of the Pd(II) complex (6.93 ꢀ–1cm2mol–1) indicates
12
that this complex in DMSO is non electrolyte in nature.
Also, the

2818
A. M. A. Alaghaz
diamagnetic nature of this complex is taken as additional evidence for
the presence of square-planar geometry around the Pd(II) ion. 13
ESR Spectrum of Cu(II) Complex
X-band ESR spectrum of the Cu(II) (IVc) complex, was recorded in
the solid state at 25◦C. The spectrum exhibits one broad band with g =
2.11 for complex (IVc). The shape of the spectrum is consistent with
the octahedral geometry around the Cu(II) environment in the complex
(IVc).15
Thermal Studies
Thermogravimetric studies (TGA) for the complexes were carried out
within a temperature range from room temperature up to 1000◦C. TGA
results are in a good agreement with the suggested formulae resulted
from microanalyses data (Table I). The determined temperature ranges
and percent losses in mass of the solid complexes on heating are given
in Table V, which revealed the following findings:
The Co(II) complex of III (IVa) gives a decomposition pattern as
follows; the first stage is one step within the temperature range of 30–
175◦C, representing the loss of four coordinated water and HCl gas
with a found mass loss of 7.34% (calcd. 7.53%). The second stage is
four steps between (175–1000◦C) representing the decomposition of the
organic part with losses of 3HCl gas with found mass loss of 82.45%
(calcd. 82.07%). At a temperature higher than 1000◦C, and at the end
of the thermogram, the metal oxide 2CoO was the residue 10.21% (calcd.
10.40%), which is in good agreement with the calculated metal content
obtained and the results of elemental analyses (Table I).
The thermogram of the Ni(II) complex of III (IVb) shows that the
first weight loss is between 125 and 230◦C representing the loss of four
coordinated water molecules and HCl gas with a found mass loss of
7.52% (calcd. 7.53%) and second stage at (230–1000◦C) representing
the decomposition of the organic part in addition to the loss of 3HCl
with a found mass loss of 82.14% (calcd. 82.10%) leaving behind nickel
oxide as the product of decomposition, found 10.34% (calcd. 10.37%).
The Cu(II) complex of III (IVc) is thermally decomposed in two
stages. The first stage corresponds to a mass loss of 14.64% (calcd.
14.72%) within the temperature range 25–240◦C represents the loss
of four coordinated water, 3 HCl and O2 gases. The second stage, 240–
1000◦C with a found mass loss of 74.53% (calcd. 74.31%), is reasonably
accounted for the decomposition of the organic part of the complex and
HCl gas leaving out 2CuO as a residue with a found mass loss of 10.83%
(calcd. 10.97%).

2819

2820
A. M. A. Alaghaz
The Pd(II) complex of III (IVd) is thermally decomposed in two
stages. The first stage corresponds to a mass loss of 10.00% (calcd.
10.06%) within the temperature range 30–245◦C represents the loss of
two nitric acid and O2 gases. The second stage, 230–1000◦C with a found
mass loss of 74.57% (calcd. 74.35%), is reasonably accounted for the de-
composition of the organic part of the complex and HNO3 gas leaving
out 2PdO as a residue with a found mass loss of 15.43% (calcd. 15.59%).
From the above thermogravimetric analyses, the overall weight
losses for the Co(II), Ni(II), Cu(II) and Pd(II) complexes agree well
with the proposed formulae obtained by elemental analyses, IR, 1H
and 31P NMR, EPR, solid reflectance, magnetic susceptibility molar ra-
tio method, and conductometric titration measurements.
From the above findings, we propose that the coordination occurs
through the nitrogen of the heterocyclic ring and the enolic OH group
to give the structures shown in Scheme 3.
Solid-State Electrical Conductivity
Figure 3 shows the relation between log σ against 1/T for (III) compound
and its complexes. A linear behavior was obtained for all samples. The
conductivity of the free ligand is increased on complexing with transi-
tion metal ions. This behavior is attributed to the inclusion of the var-
ious metal cations in the π-electron delocalization of the ligand.20 The
observed conductivities follow the order Co < Ni < Cu < Pd. Theoreti-
cally, if we consider the charge/radii, the stability of the metal complexes
FIGURE 3 Plots of In σ versus 1000/T for Co2+ complex (IVa).

Complexes of Co(II), Ni(II), Cu(II), and Pd(II)
2821
increases as the size of the metal ion decreases or the value of the ratio
charge/radii increases. This means that the stability increases towards
the copper complex. It is apparent that increasing stability of the com-
plexes will increase the number of dislocated electrons on the ligand
molecule and then increase the conductivity21 as given in (Table VI).
To explain the conduction mechanism of the ligand and its complexes,
it is necessary to determine the mobility of charge carriers µ. If the
density of charge carriers is known, then the mobility can be calculated
using the relation σ =eNm, eis the electron charge. The charge carrier
concentration was determined using the relation,
n = 2[2µm∗ kT/h2]1/2 exp(−E/kT),
(3)
where m∗ is the effective mass of charge carrier. The calculated mobili-
ties are ranged from 10−5 to 10−9 cm2/Vs, suggesting that the conduction
of sulfadrug-cyclodiphos (V)azane ligand and its metal complexes takes
place by hopping mechanism.22
Biological Activity
The disc diffusion method was used to measure the antimicrobial ac-
tivity of the complexes.23 The compounds under test were dissolved in
dimethylformamide (DMF) (2% w/v) and added at a concentration of
0.5 mL/disc to Whatman number 3 filter paper, 5 mm diameter. The
biological activity of the III, its complexes and traivid and tavinic (as
standard compounds), were tested against bacteria because bacteriums
can achieve resistance to antibiotics through biochemical and morpho-
logical modifications.24 The antimicrobial activity was examined with
different species of Gram-positive bacteria such as Staphylococcue pyo-
gones, Gram-negative bacteria, such as Pseudomonas aereuguinosa,
and Escherichia coli, and fungi (Candida). The data obtained are sum-
marized in Table VII. The data obtained reflect the following findings.
TABLE VI Values of the Electrical Conductivity (σ) and
Thermal Activation Energy of the Ligand (III) and Its
Co(II), Ni(II), Cu(II), and Pd(II) Complexes at 303 K
Compound
σ(Ohm−1 cm−1
)
E(eV)
n(cm−3
)
III
1.53 × 10−8
1.72 × 10−8
2.13 × 10−8
2.62 × 10−8
3.24 × 10−8
0.32
0.38
0.43
0.56
0.76
9.26 × 1019
12.85 × 1018
1.74 × 1018
1.29 × 1016
0.79 × 1016
Co2(III)Cl4
Ni2(III)Cl4
Cu2(III)Cl4
Pd2(III) (NO3)4

2822
A. M. A. Alaghaz
1. The III ligand has moderate activity in comparison with Staphylo-
coccus Pyogones and is less active in comparison with Escherichia
coli and Pseudomonas aereuguinosa. The remarkable activity of the
ligand may arise from the isoxazole-N and the enolic OH of sulfon-
amide groups, which may play an important role in the antibacte-
rial activity,25 as well as the presence of two imine groups, which is
important in elucidating the mechanism of transformation reaction
in biological systems.26
2. Antibacterial activity of the complexes towards the different organ-
isms shows a high-to-moderate activity.
3. The activity of the ligand and its complexes increases as the concen-
tration increases because it is a well known fact that concentration
plays a vital role in increasing the degree of inhibition.26
EXPERIMENTAL
All chemicals used were of analytical reagent grade. They included
CoCl2·6H2O, NiCl2·6H2O, CuCl2·2H2O, and Pd(NO3)2.2H2O, sulfamet-
role and phosphorus pentachloride supplied from BDH. The solvents
used were acetonitrile, CHCl3, acetone, ethanol, dimethyformamide
(DMF), tetrahydrofuran (THF), methanol, ethyl acetate, diethyl ether,
benzene, n-hexane, and deutrated dimethyl sulfoxide (DMSO). The 1,3-
dithiole-2-thione-4,5-disodiumthiolate (II) was prepared by the litera-
ture method.23
Preparation of Ligand
A solution of 1,3-dithiole-2-thione-4,5-disodiumthiolate (II) (2.42 g,
0.01 mmol) was added to a well-stirred mixture of 1,3-di-[N1-4-methoxy-
1,2,5-thiadiazole-3-yl-sulfanilamide]-2,2,2,4,4,4-hexachlorocyclodipho-
sph(V)azane (I) (4.21 g, 0.005 mmol) as a base in 100 ml of acetonitrile.
After completing the addition, the reaction mixture was heated under
reflux for 3 h. The solid formed (sodium chloride) was filtered off, and
the filtrate was evaporated under vacuum to give a solid compound
that was recrystallized from DMF to obtain a red crystalline compound
(III). The whole process of the chemical reactions and the structures
of compoundsI, II and III are shown in Scheme 1.
Preparation of Complexes
A hot solution (60oC) of the metal salts [CoCl2·6H2O (0.47 g; 0.002 mol)],
[NiCl2·6H2O (0.47 g; 0.002 mol)], [CuCl2·2H2O (0.34 g; 0.002 mol)], or

2823

2824
A. M. A. Alaghaz
[Pd(NO3)2·2H2O (0.50 g; 0.002 mol)]in 50 mL acetonitrile was added
dropwise to a hot solution of III (1.09 g; 0.001 mol) in 100 mL acetonitrile
in a 2:1 metal-to-ligand molar ratio at room temperature with continu-
ous stirring. After complete addition of the hot, metal-salt solution, the
reaction mixture was heated under reflux for about 2 h under dry condi-
tions. The resultant polycrystalline solid products (IVa−d) were filtered
and recrystallized from DMF. The analytical data of both ligand and its
metal complexes are listed in Table I.
METHODS
Elemental analyses were determined at the Microanalytical Unit of
Cairo University (Egypt) using CHNS-932 (LECO) Vario EL elemen-
tal analyzers. The phosphorus content was determined gravimetrically
as phosphoammonium molybdate.24 Analyses of metal ions after the
dissolution of the solid complex in hot concentrated nitric acid, HNO3,
then diluting with distilled water and filtering to remove the precipi-
tated ligand. The solution was neutralized with ammonia solution and
the metal ions were then titrated with EDTA.25 The infrared spectra
were recorded on a Shimadzu FT-IR spectrometer using KBr discs.
1H NMR spectra were obtained on a Varian Gemini 200 MHz spec-
trometer. The samples were dissolved in DMSO-d6 using tetramethyl-
silane as an internal standard. 31P NMR spectra were run, relative
to external H3PO4 (85%), with a Varian FT-80 spectrometer at 365
MHz. The solid reflectance spectra were measured using a Shimadzu
PC3101 UV-VIS-NIR scanning spectrophotometer. The mass spectra
were obtained by a Shimadzu-Ge-Ms-Qp 100 EX mass spectrometer
(Shimadzu, Japan), using the direct inlet system, at Cairo University
(Egypt). The conductometric measurements in solutions were carried
out using conductivity TDS model 72. The magnetic susceptibilities of
the complexes in the solid state were recorded on a Sherwood Scien-
tific magnetic susceptibility balance. Diamagnetic corrections were cal-
culated from Pascal’s constants. ESR spectra recorded on the Bruker,
Model: EMX, X-band spectrometer. The magnetic field was calibrated
with a 2,2-diphenyl-1-picrylhydrazyl sample. The thermogravimetric
analyses (TGA) were recorded on a Shimadzu TGA-50H. TGA was car-
ried out in a dynamic nitrogen atmosphere (20 mL min−1) at a heating
rate of 10◦C min–1. The ultraviolet spectra were recorded on a Perkin
Elmer Lambda 3B UV-VIS spectrophotometer. Conductivity measure-
ments were made on discs having 1-mm thickness of III, and its com-
plexes were sandwiched between two copper electrodes. The conduc-
tivity cell used was the same as that reported before.26 The electri-
cal conductivity was measured in the temperature range 30◦C –150◦C.

Complexes of Co(II), Ni(II), Cu(II), and Pd(II)
2825
The activation energies were calculated using the equation σ = σ◦
exp (-E/2kT). The biological activity experiments were carried out at
Bab-Al-Sheria University Hospital (Al-Azhar Microbiology Laboratory
University).
CONCLUSION
From all of the above observations, the structure of these com-
plexes may be interpreted in accordance with complexes of ligand III
with a similar distribution of sites such coordination hexachlorocy-
clodiphosph(V)azanes of sulfadimidine and sulfametrole.5 The struc-
tural information from these complexes is in agreement with the data
1
reported in this article based on the IR, molar conductance, H, 31P
NMR, UV-Vis, mass, thermal analysis, and magnetic-moment measure-
ments. The Co(II), Ni(II), and Cu(II) complexes of this ligand have octa-
hedral structure. III ligand always coordinates via the isoxazole-N and
enolic sulfonamide-OH forming two-binding chelating sites.
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