Polymer complexes. LIV. Structural and spectral studies of supramolecular coordination polymers built from Ni(II), Fe(II) and Pd(II) with sulphadrug

Article abstract of DOI:10.1016/j.molstruc.2011.01.015

Polymer complexes of p-acrylamidyl sulphaguanidine (HL) with Ni(II), Fe(II) and Pd(II) salts have been prepared. The structures of the polymer complexes were elucidated using elemental analysis, ¹H NMR, UV-Vis, IR spectroscopies, magnetic moment, molar conductance and thermal analysis. The polymer complexes were isolated in 1:1 and 1:2 (M:L) ratios. The solid monocomplexes (1:1) (M:L) were isolated in the general formula [Fe(HL)O ₂SO₂(OH₂)₂]. The biscomplexes (1:2) (M:L) solid chelates found to have the general formula [Ni(HL)₂X ₂]_n (X = Cl^-, Br^-, I^-, NO₃, NCS^- ), [Fe(HL)(en)(OSO₃)(OH ₂)]_n and [Ni(HL)₂(Py)₂] _nX₂, while {[Pd(L)X]₂}_n (1:1) (X = Cl^- or Br^-). In all the polymer complexes the ligand and anions were found to be coordinated to the Ni(II) and Fe(II) ions. The bidentate nature of the ligand is evident from IR spectra. The magnetic and spectroscopic data indicate a octahedral geometry for complexes. The thermal behaviour of these chelates shows that the hydrated complexes loss water molecules of hydration in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps.

Full text of DOI:10.1016/j.molstruc.2011.01.015

Journal of Molecular Structure 990 (2011) 26–31
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Polymer complexes. LIV. Structural and spectral studies of supramolecular
coordination polymers built from Ni(II), Fe(II) and Pd(II) with sulphadrug
a,
⇑
b
a
a
A.Z. El-Sonbati , A.A.M. Belal , M.A. Diab , R.H. Mohamed
a
Chemistry Department, Faculty of Science, (Demiatta), Mansoura University, Egypt
Chemistry Department, Faculty of Science, Port Said University, Egypt
b
a r t i c l e i n f o
a b s t r a c t
Article history:
Polymer complexes of p-acrylamidyl sulphaguanidine (HL) with Ni(II), Fe(II) and Pd(II) salts have been
Received 1 December 2010
Received in revised form 2 January 2011
Accepted 2 January 2011
prepared. The structures of the polymer complexes were elucidated using elemental analysis, 1H NMR,
UV–Vis, IR spectroscopies, magnetic moment, molar conductance and thermal analysis. The polymer
complexes were isolated in 1:1 and 1:2 (M:L) ratios. The solid monocomplexes (1:1) (M:L) were isolated
Available online 22 January 2011
in the general formula [Fe(HL)O
the general formula [Ni(HL)
Py) , while {[Pd(L)X]
2
SO
2 2 2
(OH ) ]. The biscomplexes (1:2) (M:L) solid chelates found to have
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
2
X
2
]
n
(X = Cl , Br , I , NO , NCS ), [Fe(HL)(en)(OSO
3
3
)(OH
2 n 2
)] and [Ni(HL) -
Keywords:
ꢀ
ꢀ
(
2
n
] X
2
2 n
} (1:1) (X = Cl or Br ). In all the polymer complexes the ligand and anions
p-Acrylamidyl sulphaguanidine
Polymer complexes
Characterization
were found to be coordinated to the Ni(II) and Fe(II) ions. The bidentate nature of the ligand is evident
from IR spectra. The magnetic and spectroscopic data indicate a octahedral geometry for complexes.
The thermal behaviour of these chelates shows that the hydrated complexes loss water molecules of
hydration in the first step followed immediately by decomposition of the anions and ligand molecules
in the subsequent steps.
Ó 2011 Elsevier B.V. All rights reserved.
1
. Introduction
Sulphadrugs have attracted special attention from their thera-
and the formation of chelates with various compositions has been
suggested on the basis of spectroscopic data [11–22].
In continuation to our work on sulphadrugs, this article involves
the synthesis of polymer complexes of p-acrylamidyl sulphaguani-
dine with Ni(G), Fe(G) and Pb(G) salts. The solid products were
characterized by elemental analysis, IR, molar conductance, mag-
netic moments and reflectance spectra measurements.
peutic importance as they were used against a wide spectrum of
bacterial aliments [1]. Some sulphadrugs have been used in the
treatment of cancer, malaria, leprosy and tuberculosis [2,3]. Also,
the importance of metal ions in biological system is well known
[
4]. The coordination chemistry of sulphadrug and its derivatives
2
. Experimental
have attracted much attention by virtue of their applicability as po-
tential ligands for a large number of metal ions [5]. Sulphadrug li-
gands are widespread among coordination compounds and are
important components of biological transition metal complexes
2.1. Materials
Sulphaguanidine and acryloyl chloride (AC) (Aldrich Chemical
[
6]. The metal chelates thus produced have wide application in
Co., Inc.) were used without further purification.
the chemistry, as analytical reagents for determination of metals
and in biological uses [7]. Sulphadrug complexes are considered
to be among the most important stereochemical models in main
group and transition metal coordination chemistry due to their
preparative accessibility and structural variety [8–13].
As a part of our systematic studies of the coordination chemis-
try of the early actinides and transition elements, we recently pub-
lished several papers on the structural chemistry of sulphadrug
polymer complexes of Cu (G), Ni (G) and uranium (VI) [14,15]. A
number of studies have been undertaken with both ligand system
0
2
,2 -Azobisisobutyronitrile (AIBN) (Aldrich Chemical Co., Inc.)
was purified by dissolving in hot ethanol and filtering [23]. The
solution was left to cool. The pure material then being collected
by filtration and dried.
ꢀ
ꢀ
ꢀ
ꢀ
NiX
oven at 80 °C for 2 h. The left-out products were kept in a vacuum
desiccator over fused CaCl for 48 h. Anhydrous Ni(G) salts were
obtained as microcrystalline solid compounds.
2
ꢁnH
2
3
O (X = Cl , Br , I and NO , n = 3–6) were dried in an
2
2
.2. Preparation of p-acrylamidyl sulphaguanidine (HL) monomer
⇑
Corresponding author. Tel.: +20 60081581; fax: +20 502254000.
E-mail address: elsonbatisch@yahoo.com (A.Z. El-Sonbati).
HL monomer was prepared by the reaction of equimolar
amounts of AC and sulphaguanidine in dry benzene until the
0
022-2860/$ - see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.molstruc.2011.01.015

A.Z. El-Sonbati et al. / Journal of Molecular Structure 990 (2011) 26–31
27
evolution of hydrogen chloride ceased. The IR spectrum of the
monomer showed the presence of an NH absorption band at
for 4 h at room temperature. The reaction mixture was heated
(80 °C) under reflux for 16–18 h under anhydrous conditions with
continuous stirring. The reaction mixture was cooled to room tem-
perature. The product, in each case, was filtered off, then washed
several times with dry alcohol and dry diethyl ether and finally
ꢀ1
3
165 cm . Microanalysis for C10
12 4 3
H N O S. Found C, 44.8; H, 4.0;
N, 15.9; S, 11.5%. Cal. C, 44.6; H, 4.1; N, 15.6; S, 11.9%.
2
dried in a desiccator over fused CaCl .
2.3. Preparation of poly (p-acrylamidyl sulphaguanidine) (PHL)
homopolymer
2.4.3. Ni(II) thiocyanate polymer complex 5
PHL homopolymer was prepared by free radical initiation of HL
using 0.1 w/v% AIBN as initiator and DMF as solvent for 6 h. The
polymer product was precipitated by pouring in distilled water
and dried in a vacuum oven for several days at 40 °C. The PHL
Method C: Ni(II) thiocyanate polymer complex was obtained by
method B, refluxing the corresponding chloro complex with potas-
sium thiocyanate in dry ethanol medium for 20 min and filtering
off the precipitated potassium chloride. The solution was concen-
trated on water bath followed by cooling at room temperature.
The product, was filtered off, then washed several times with alco-
hol and dry diethyl ether and finally dried in a desiccator over
1
homopolymer has been characterized by IR, H NMR. The inherent
viscosity (
level viscometer at 30 ± 0.01 °C, using chloroform as solvent is
inh = 1.23.
ginh = lnr/c, C = 0.5 g/dl), in a Desreux–Bishoff suspended
g
2
fused CaCl .
2
2
.4. Preparation of the polymer complexes
2.4.4. Fe(II) polymer complex 6
Method D: Equimolar amounts of monomer (HL) and FeS-
.4.1. Ni(II) polymer complexes 1–4
Method A: The Ni(II) chelates with monomer (HL) was prepared
O
4
2
ꢁ7H O were dissolved in 50 ml DMF with 0.1% (w/v) AIBN as ini-
tiator. The reaction mixture was stirring for 2 h at room
temperature, and then heated under reflux for about 8 h under
dry condition. The hot solution was precipitated by pouring in a
large excesses of distilled water containing dilute hydrochloric
acid, to remove the metal salts that were incorporated into the
polymer complexes. The polymer complex (6, see Table 1) was fil-
tered, washed with water, and dried in a vacuum oven at 40 °C for
several days.
by refluxing anhydrous Ni(II) salt (0.001 mol) with the correspond-
ing ligand (0.002 mol) in 20 ml DMF as a solvent, and 0.1% (w/v)
AIBN as initiator. The resulting mixture was heated at reflux for
8
h. The hot solution was precipitated by pouring in a large ex-
cesses of distilled water containing dilute hydrochloric acid, to re-
move the metal salts that were incorporated into the polymer
complexes. The polymer complexes (1–4, see Table 1) were
filtered, washed with water, and dried in a vacuum oven at 40 °C
for several days.
2.4.5. Nickel/Iron mixed ligand polymer complexes 7–9
Method E: The product (7–9) were obtained by reacting pyri-
2
.4.2. Ni(II) polymer complexes 1–4
Method B: The products 1–4 were obtained by another method
dine (Py) and/or ethylenediamine (en) with the calculated amount
of trans-[Ni(HL) Cl ](X = Cl or Br ) according to the following pro-
2 2
ꢀ
ꢀ
according to the following procedure: A solution of Ni(II) salts
0.001 mol) in dry alcohol (30 ml); monomer (HL) (0.001 or
.002 mol) and 0.1% w/v AIBN as initiator were mixed and stirred
cedure: A solution of Py(0.5 ml)/en (2 ml) in 5 ml of DMF was
added to a stirred suspension of (1, 2 and/or 6) in 20 ml of the same
solvent. After 24 h, Et O (5 ml) was added at room temperature
2
(
0
Table 1
Analytical data of the polymer complexes (for molecular structure see Fig. 1)b.
a
Complexc
No.
Method of preparationd
Experimental (calcd.)%
C
H
N
(S/Cl)e
Molar ratio
1:2
[
1
Ni(HL)
2
2
2
2
2
Cl
2
]
n
A, B
A, B
A, B
A, B
C, B
D
36.3
3.6
17.1
(16.8)
14.5
(14.8)
13.4
(13.1)
11.4
(11.7)
19.4
(19.7)
12.6
9.4/(9.6)
10.9/(10.7)
8.1/(8.5)
21.5/(21.2)
7.7/7.5
(36.1)
31.7
(3.6)
3.0
[
Ni(HL)
Br
2
]
n
1:2
2
(31.8)
28.0
(3.2)
2.8
[
Ni(HL)
I
2
]
n
1:2
3
(28.2)
33.5
(2.8)
3.2
30.5/(30.3)
8.7/8.9
[
Ni(HL)
(ONO
(SCN)
SO (OH
2
)
2
]
n
1:2
4
(33.4)
37.3
(3.3)
3.3
[
Ni(HL)
2
]
n
13.3
(13.5)
14.5
1:2
5
(37.2)
28.0
(3.4)
3.6
[
Fe(HL)O
2
2
2
)
]
2 n
1:1
6
(27.8)
43.6
(3.7)
4.0
(13.0)
17.2
(14.8)
8.0
{
[Ni(HL)
2 2
(Py) ]Cl
2
}
n
E
1:2:2
1:2:2
1:1:1
1:1
7
(43.7)
39.5
(39.4)
28.6
(28.5)
29.4
(29.4)
26.6
(4.1)
3.6
(3.7)
4.4
(4.4)
2.8
(2.8)
2.4
(17.0)
10.5
(15.4)
16.8
(16.6)
13.9
(13.7)
12.6
(7.8)
7.3
(7.0)
12.9
(12.7)
8.0/(7.8)
8.9/(8.7)
7.3/(7.1)
7.5/(17.7)
{
[Ni(HL)
2
(Py)
2
]Br
2
}
n
E
8
[
Fe(HL)(en)OSO
3
ꢁOH
2
]
n
E
9
{
[Pd(L)Cl]
2
}
n
F
1
0
{
[Pd(L)Br]
2
}
n
F
1:1
1
1
(26.5)
(2.4)
(12.4)
a
b
c
Microanalytical data as well as metal estimations are in good agreement with the stoichiometry of the proposed complexes.
The excellent agreement between calculated and experimental data supports the assignment suggested in the present work.
HL are the ligand as given in Fig. 1 and L is the anion; air stable; no-hygroscopic; insoluble in water; soluble in coordinating solvents such as DMF and DMSO.
See text.
Estimated gravimetrically.
d
e

2
8
A.Z. El-Sonbati et al. / Journal of Molecular Structure 990 (2011) 26–31
and the resulting mixed polymer complexes (7–9) were isolated,
filtered off and washed with EtOH and dried in a vacuum oven at
under investigation were found to have molar conductance values
ꢀ1
ꢀ1
2
in the range from 3.95 to 12.95 O mol cm which indicated the
non-ionic nature of these polymer complexes and they were con-
sidered as non-electrolytes. This is in accordance with the fact that
4
0 °C for several days.
ꢀ
1
ꢀ1
conductivity values for a non-electrolyte are below 50 O mol
2
.4.6. Pd(II) polymer complexes 10, 11
2
ꢀ
cm in DMSO solution [15,16]. Hence the sulphate in iron(II) and
chloride/bromide in palladium(II) polymer complexes are coordi-
nation sphere. In nickel(II) polymer complexes two (chlorides, bro-
mides, iodides, nitrates, thiocyanates) are in coordination sphere.
Method F: An ethanolic solution of 0.01 mol of PdX
2
(X = Cl or
ꢀ
Br ) was mixed with the appropriate weight of the corresponding
ligand (HL, monomer) in ethanol (25–40 ml) and 0.1 w/v AIBN as
initiator. The reaction mixture was boiled with stirring until the
corresponding solid complex separated. On cooling the crystalline
product formed was filtered off, washed several times with dry
ethanol and dry diethyl ether and finally dried in a desiccator over
3
3
.3. Characterization of the monomer (HL)
fused CaCl
2
.
.3.1. HL ligand
HL monomer used in this study is elucidated by different tools
2
.5. Measurements
as, the elemental analysis, which indicated that the ligand has the
molecular formula C10 S and IR spectrum supported the
structure in Fig. 1. H NMR spectrum is the final confirming tool
12 4 3
H N O
1
C, H, and N microanalyses were carried out at the Cairo Univer-
sity Analytical Center, Egypt. The metal content in the polymer
complexes was estimated by standard methods [20–22]. The
NMR spectrum was obtained with a Jeol FX90 Fourier transform
spectrometer with DMSO-d as the solvent and TMS as an internal
reference. Infrared spectra were recorded using Perkin–Elmer 1340
spectrophotometer. Ultraviolet–Visible (UV–Vis) spectra of the
polymer were recorded in Nujol solution using a Unicam SP 8800
spectrophotometer. The magnetic moment of the prepared solid
complexes was determined at room temperature using the Gouy‘s
for the ligand structure and displayed peaks for C@NHNH , SO NH
2
2
1
1
H
and AC@NH. H NMR spectrum of HL [d(DMSO-d ] displayed a sin-
6
glet peak at d = 7.44 ppm by integration assigned to 4H referring to
the phenyl group. Also, the three singlet peaks at 11.3, 7.26 and
7.48 ppm, each peak by integration assigned to the three hydrogen
6
atoms aggregated from CONH, SO NH and AC@NH groups. The rel-
2
ative down field appearance of the third peak (d = 7.48 ppm) may
be due to the intramolecular hydrogen bonding between NH and
S@O groups [25,26]. The broad medium signal centered at
method. Mercury(II) (tetrathiocyanato)cobalt(II), [Hg{Co(SCN)
4
}],
d = 5.45 ppm which could be assigned to the ANH protons. These
2
was used for the calibration of the Gouy’s tubes. Diamagnetic cor-
rections were calculated from the values given by Selwood [24]
signals disappeared on repeating the measurements in the pres-
1
ence of D O. The H NMR spectrum of HL monomer showed the ex-
2
and Pascal’s constants. Magnetic moments were calculated using
pected peaks and pattern of the vinyl group (CH @CH), 6.25 ppm
(dd, J = 17, 11 Hz) for the vinyl CH proton and proton d 5.12 ppm
2
coor 1/2
the equation,
l
eff. = 2.84 [T
v
M
]
. The halogen content was
determined by combustion of the solid complex (30 mg) in an oxy-
gen flask in the presence of a KOH–H mixture. The halide con-
tent was then determined by titration with a standard Hg(NO
(AM part of AMX system dd, J = 17, 1 Hz) for the vinyl CH protons,
respectively. These peaks disappeared on polymerization while a
triplet at d 1.86 ppm (t, J = 7 Hz) and a doublet at 1.80 ppm (d,
2
2
O
2
3
)
2
solution using diphenyl carbazone as an indicator [20,21]. The con-
ductance measurement was achieved using Sargent Welch scien-
tific Co., Skokie, IL, USA.
CH
2
CH
C
CH
2
CH
C
O
O
OH
3
. Results and discussion
NH2
NH
N
3.1. General
o
Benzene, 0 C, N
2
O
acryloyl chloride
The reaction of ligand (HL, monomer) with different nickel (II)
O
S
HN
S
S
H
salts, iron sulphate and the reaction of the isolated polymer com-
plexes with pyridine/en (7,8/9) as described in Section 2 are shown
in Table 1. All the polymer complexes are coloured and air stable.
They are soluble in solvents like DMF and DMSO but insoluble in
common organic solvents. The composition, coordination mode
and geometry of the polymer complexes were established on the
basis of spectral analyses, thermal analysis, conductivity measure-
ments and magnetic properties and are discussed in detail in the
following sections.
O
O
O
NH
HN
HN
NH
N
NH
2
NH
2
NH
2
HL
CH2 CH
CO
n
3.2. Molar conductance of the polymer complexes
NH
The molar conductance of 10ꢀ3 M of solutions of the polymer
complexes in DMSO was calculated as 25 ± 2 °C. It was concluded
from the results that Ni(II) chelates {[Ni(HL) (Py) ]X [X = Cl (7)
or Br (8)] were found to have molar conductance values of 205
and 190 O mol cm of HL, respectively, indicating the ionic
nature of these polymer complexes. It, also, indicated the non-
bonding of chloride and bromide anions to the Ni(II) ions. So, the
Ni(II) chelates were considered 1:2 electrolytes with HL ligand
O
2
2
2 n
}
S
O
ꢀ1
ꢀ1
2
HN
NH
NH
PHL
Fig. 1. Structure of the monomer (HL) and homopolymer (PHL).
2
[
14]. On the other hand, the molar conductivity values of
Ni(II)(1–5), Fe(II)(6 + 9) and Pd(II)(10 + 11) chelates with HL ligand

A.Z. El-Sonbati et al. / Journal of Molecular Structure 990 (2011) 26–31
29
Table 2
Palladium chloride under the same condition, give a polymer
complex containing the homopolymer as a monoanion, having lost
one proton from C@NH group, while nickel(II) salts and iron(II) sul-
phat form polymer complexes in which the homopolymer is neu-
tral. This indicates that the polymer complexes composition is
dependent on the nature and strength of the metal–homopolymer
bond.
Characteristic 1H NMR spectra for HL, PHL and Pd(II) complex (ppm vs. TMS).a
Compound
HL
Chemical shift d (ppm)
Assignment
7.44
d, 4H, ArH’s
11.30
5.45
7.26
7.48
6.25
5.12
d, 1H, CONH
br, 2H, AC@NHNH
2
br, 1H, ASO
s, 1H, AC@NH
Vinyl CH (CH
2
Vinyl CH (CH @CH)
2
NH
The 1H NMR spectra of HL and Pd-diamagnetic complex (10)
2
@CH)
6
was recorded in dimethylsulphoxide (DMSO-d ) using trimethylsi-
2
lane (TMS) as internal standard. The chemical shifts of the different
types of protons of HL and diamagnetic Pd-complex are listed in
Table 2. The signal characteristic for AC@ (NH) group disappeared
in the spectrum of the isolated polymeric complex indicating coor-
dination via deprotonated AC@NH atom. Also, the signal character-
PHL
7.44
d, 4H, ArH’s
d, 1H, CONH
1
5
7
7
1.30
.45
.26
.48
br, 2H, AC@NHNH
br, 1H, ASO NH
2
2
s, 1H, AC@NH
{
1
[PdClꢁL]
2
}
n
7.22
11.15
d, 4H, ArH‘s
d, 1H, CONH
br, 2H, AC@NHNH
2
br, 1H, ASO NH
s, 1H, AC@NH
br, coordinated H
2
istic for ANH group shifted to lower frequencies due to the
0
complexation. Construction of molecular models suggest that the
formation of a stable six-membered ring system with the central
metal ion having OANH/OAN donor function taking one of oxygen
4
7
–
3
.48
.17
2
.54
2
O proton
2
of O@S@O and nitrogen of the AC@NH(NH ) and/or the imino
nitrogen (NH/N) of the guanidine residue as bonding sites is the
most probable proposition; this substantiated through the present
a
The excellent agreement experimental data supports the assignment suggested
in the present work.
ꢀ1
IR spectral studies recorded down to 200 cm
.
IR spectrum of the homopolymer showed three medium broad
J = 7 Hz) appeared, indicating that the polymerization of HL mono-
mer occurs on the vinyl group [21,27]. It is worth noting that the
ꢀ1
bands at 3165, 3280 and 3440 cm which consist of overlapping
stretching vibration assigned to (NAH) and as(NH and NH
groups). The band width further indicates that the NH group is in-
t
s
t
2
rest of the proton spectrum of the monomer and polymer remain
almost without change. The 1H NMR spectrum of the ligand (HL,
2
volved in intramolecular hydrogen bonding [29]. Also, the IR spec-
trum of uncomplexed polymer shows absorption bands at
monomer) showed characteristic protons, which are listed in Table
2, and the proposed structure for the ligand is shown in Fig. 1.
ꢀ
1
ꢀ1
3
350 cm and 1630 cm due to ANH and CO groups respectively,
In the present work, the synthesis of polymer complexes with
ꢀ1
the absorption singles 3015 cm
shows ACH of benzene ring
homopolymer sulphadrug was investigated. The influence of the
position of the O@S@O and AC@NH groups of the side residue of
the monomer, on their stereochemistry and chain flexibility was
explored. For this purpose, different techniques such as elemental
stretching frequency, the absorption signals at 2980 and 2935
shows ACH@CHA stretching frequency. The ligand shows C@N
and C@C stretching frequency bands. All these results prove that
1
the ligand have been successfully synthesized. The SO
2
group
)) and
analysis, H NMR, UV–Vis, IR spectroscopies, magnetic moment,
ꢀ1
modes of the HL appear as a bands at 1315 cm
(t
asym(SO
2
molar conductance and thermal analysis were adopted.
ꢀ1
1
036 cm
2
(tsym(SO )), respectively.
In the polymer complexes, the asymmetric and symmetric
3
3
.4. Characterization of polymer complexes
ꢀ1
modes are shifted to higher frequencies, at 1330 cm
and
ꢀ1
1
085 cm [30]. Also, The stretching vibration mode characteristic
.4.1. Metal polymeric complexes
All the isolated polymer complexes are air stable for extended
ꢀ1
2
for t(NH) of AC@(NH)(NH ) moiety at 3175 cm in HL was shifted
ꢀ1
to higher frequencies (ꢃ3195–3215 cm ) upon coordination to
periods and remarkably soluble in DMSO and DMF. The molar con-
ductivities in DMF solution indicate that the polymer complexes
are in the range expected for no electrolytes except complexes 7
and 8 [28]. This can be account for by the satisfaction of the bi-
valency of the metal by the chloride, bromide, iodide, nitrate, thio-
cyanate, and sulphate. This implies the coordination of the anions
to the metal ion centers. The analytical data of the isolated polymer
complexes are listed in Table 1. Further, confirmation of the pro-
posed structures of the chelates of HL with metal salts was done
using different physico-chemical methods shows below. The for-
mation of these complexes may proceed according to the following
equation
the transition metals via deprotonated NH group [30]. The
t
(C@N) stretching bands of the guanidine part of the ligand
ꢀ1
appearing around 1645 cm has been found to experience a neg-
ꢀ1
ative shift of ꢄ8 cm pointing to the probable participation of the
imino nitrogen/nitrogen of the guanidine moiety of the ligand
in complexes [31]. The spectrum of ethylenediamine containing
4 2
complex [Fe(HL)(en)(SO )(H O)] (9) display additional splitted
ꢀ1
broad band at ꢃ3230 cm (at lower wavenumber relative to that
2
of free ethylenediamine) characteristic of coordinated ANH to the
iron(II) ion.
New bands were found in the spectra of the polymer complexes
ꢀ
1
ꢀ1
in the regions 450–470 cm and 495–520 cm which were as-
signed to (MAN) and (MAO) stretching vibrations, respectively
9–14,31]. Also, in the 7 and 8 complexes a new band appears in
NiX
2
þ HL ! ½NiðHLÞ X
2
ꢂ ;
t
t
2
n
[
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
where X = Cl (1), Br (2), I (3), NO3 (4), or SCN (5).
FeSO ÞðOH Þ ꢂ ð6Þ
þ HL ! ½FeðHLÞðSO
ꢀ1
the region 1612–1618 cm attributable to coordinated pyridine
ꢀ1
[18]. Free pyridine shows a strong band at 1585 cm . Thus, the
nitrogen of the pyridine is coordinated to metal ion. These
stretches were not present in the spectrum of the ligand.
4
4
2
2
n
½
NiðHLÞ X ꢂ þ Py ! ½NiðHLÞ ðPyÞ ꢂ X
2
2
;
2
n
2
2 n
The presence of water molecules in the above mentioned com-
plexes [(6) and (9)] is assigned by the appearance of a broad band
ꢀ
ꢀ
where X = Cl (7), Br (8).
FeðHLÞðSO ÞðOH Þ ꢂ þ en ! ½FeðHLÞðenÞðSOÞ ÞðOHÞ ꢂ ð9Þ
ꢀ
1
within the range 3440–3300 cm , which is attributed to
2
m(OH ) of
½
4
2
2
n
4
2 n
the water molecules associated with the complex formation. Also,
bending vibration of the water molecules; d(OH
range 960–925 cm . The other bending vibration of the water
2
), is found in the
PdX þ HL ! ½½PdðLXÞꢂ ꢂ ;
where X = Cl (10), Br (11).
2
2
n
ꢀ1
ꢀ
ꢀ
ꢀ1
2
molecules; d(OH ), is usually around 1600 cm
which always

3
0
A.Z. El-Sonbati et al. / Journal of Molecular Structure 990 (2011) 26–31
interferes with the skeleton vibration of the benzene ring (C@C
vibration).
Table 3
Electronic spectral data cm of Ni(II) polymer complexes.
ꢀ
1
Complexes
1
t
2
/
t
1
State
Electronic spectral data
3
.4.2. Bands due to anions
In the IR spectrum of nitrato complex (4) three bands are ap-
1.78
1.69
1.48
1.83
1.54
1.64
1.7
Reflectance
DMF
Reflectance
DMF
Reflectance
DMF
Reflectance
DMF
Reflectance
DMF
Reflectance
DMF
Reflectance
DMF
8580, 15,320, 25,005
8960, 13,960, 23,610
8450, 14,330, 23,900
8850, 14,330, 23,600
9850, 14,590, 24,400
8850, 14,010, 23,600
8650, 15,800, 21,500
8950, 14,150, 23,800
9999, 15,360, 24,100
8888, 16,350, 25,100
9100, 14,900, 25,250
9260, 16,100, 24,500
9100, 15,500, 21,100
8850, 14,050, 23,100
ꢀ
1
peared at ꢃ1430, 1325 and 1018 cm . The position of these bands
2
3
4
5
6
7
suggests that both the nitrate groups are coordinated to the metal
ꢀ
1
ion in a unidentate fashion (
trum of Fe(II) sulphato complex (6) absorption bands are appeared
at ꢃ1105, ꢃ1062 and ꢃ1040 cm suggesting bidentate behaviour
of the sulphate ion but in the case of compound (9) absorption
Dt < 150 cm ) [32]. In the IR spec-
ꢀ
1
ꢀ
1
bands are appeared at ꢃ1182, ꢃ1022 and ꢃ945 cm suggesting
unidentate behaviour of the sulphate ion [33]. Furthermore, the
complex [Fe(HL)SO
(H
4 2
O)
2
] (6) and [Fe(HL)(en)(SO
4
)(H
2
O)] (9) dis-
play bands, before and after heating at 160 °C for 4 h, confirming
the presence of coordinating water molecules rather than water
of crystallization [34]. The sulphato complex (6) shows the four
bands at 1211, 1131, 1028, and 965 cm due to t and t stretch-
3 1
ing vibrations of sulphate anion which indicates that the sulphate
ꢀ
1
2 2 2 n 2 1
and [Ni(HL) (ONO ) ] , it is observed that the respective t /t ratio
Table 3) have come down to the pseudo-octahedral range (1.55–
(
1
anion coordinates in bridging bidentate manner [35].
.58). The data reasonably suggest that there might be an effective
symmetry due to solvation effects. The fol-
2
The IR spectra of [Pd(L)X] , [X = Cl (10), Br (11)] exhibit strong
change from D4h to O
h
ꢀ
1
bands at 280 and 225 cm , characteristic of bridging Cl and/or
Br, respectively [18]. According to the electronic and IR spectral
of these complexes the following structure could be assumed. This
lowing schematic formulation may be represented to express the
extensive solvolysis which might be responsible for the observed
2+
conductance
data.[Ni(HL)
2 2
X ] + DMF ? [Ni(HL)
2
2
(DMF) ]
+ 2X,
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
is supported by the presence of
t
PdAN and
t
PdAO.
[
X = Cl /Br /I /NCS /NO ]
3
Furthermore, PdABr/
t
t
PdACl lie in the range 0.67–0.70 cmꢀ1,
The relatively high intensity of these absorptions is attributed
to both metal-centered d–p mixing excepted for non-symmetrical
polymer complexes and the covalency effects [41]. The spectral
supporting the assumed square-planar symmetry.
The diagnostic band frequencies of the other counter ions (X),
ꢀ
ꢀ
ꢀ
ꢀ1
(
X = Cl /Br )
t
(MACl) (285–290 cm
)
and
t
(MABr) (260–
3
3
bands given in Table
3 are assigned to [ A2g(F) ? T2g(F)],
1
ꢀ
ꢀ
2
65 cm ), indicate the coordinated nature of Cl and Br ions
3
3
3
3
[
A
2g(F) ? T1g(F)] and [ A2g ? T1g(P)] transition denoted as
1
t –
respectively. In the thiocyanato complex (5), the very strong band
t
3
, according to increasing energy, respectively. It is showed that
the band positions are in the sequency, NO
ꢀ1
observed at 2084 cm corresponds to
t
(C@N). Bands observed at
are assigned to (C@S), d(NCS) and
(NiAN), respectively. These facts indicate that thiocyanate group
is N-coordinated to nickel [36].
3
> Cl > Br > I, in case
ꢀ1
7
t
78, 479 and 459 cm
t
ꢀ
of [Ni(HL)
2
X
2
]. The absorptions of [Ni(HL)
2
(Py)
2
]X
2
, X = Cl or
ꢀ
Br , are found to be at the same wavenumbers indicating that
the ligand field around the nickel(II) in these complexes is the
same and the non-bonding nature of the counter ions. It is noted
that the d–d transition energy of these complexes are order as
3.4.3. Magnetic and electronic spectral studies
The room temperature magnetic moment values for all the
[
Ni(HL)
Ni(HL)
ure of the coordinating atoms X or Py.
2
(Py)
2
]Cl
2
> [Ni(HL)
2
2
(Py) ]Br
2
> [Ni(HL)
2 2
(ONO) ] > [-
Ni(II) polymer complexes are magnetically normal 6-coordinate
complexes [ eff = 2.74–2.99 B.M.]. The electronic spectrum of the
free HL displays bands due to
respectively. In all polymer complexes, the first band is replaced
by a new intense one assignable to
sition [37]. The new band (shoulder) in the spectra of all polymer
complexes is assigned to
due to n ?
complexes centered that can be assigned as composite of the
remaining n ?
Electronic spectral data indicate that most of the Ni(II) polymer
complexes probably belong to O or D4h or a group of lower sym-
metry [38] (Table 3]. The diffuse reflectance spectra of the polymer
complexes were characterized by three main bands in the region
2
(Cl) ] > [Ni(HL)
2
2
(Br)
2
] > [Ni(HL)
2
(I) ], depending on the nat-
2
l
ꢅ
ꢅ
p
?
p
and n ?
p transitions,
The electronic spectrum of the Fe(II) polymer complex (6) con-
sisted of a pair of low intensity bands at 13,160, 17,640 cm and
also for polymer complex (9) at 15,340 and 19,010 cm which
are arising from
for distorted octahedral complexes. The band at 25,730 cm could
be assigned to L ? M charge transfer. The doublet is attributed to
Jahn–Teller distortion in the excited state [43] and could also be
correlated with solution oxidation giving characteristic bands for
Fe(III) in the 17,000–19,000 cm range. At the room temperature,
the magnetic moment [5.2 (6) and 5.5 (9) BM] corresponding to
ꢀ1
(N) ? M2 charge transfer tran-
+
r
ꢀ1
5
5
T
2g ? Eg transition [42], similar to those found
+
p
(O) ? M2 CT transition [37]. The band
ꢀ1
ꢅ
p
transition is merged into a broad band in all polymer
ꢅ
2+
p and r(O) ? M and other LMCT transitions.
ꢀ1
h
octahedral symmetry (Fig. 2).
3
3
3
3
8
600–10,500 [ A2g(F) ? T2g(F)], 14,300–15,700 [ A2g(F) ? T1g(F)]
3
.4.4. Thermogravimetric analyses
The thermal decomposition studies of the complexes were car-
ried in temperature range 30–700 °C. The complexes (6) and (9)
ꢀ
1
3
3
and 21,300–25,000 cm [ A2g ? T1g(P)] transitions in an ideal-
ized O symmetry. For the polymer complexes [Ni(HL)
h
ꢀ
2 2 n
X ]
ꢀ
ꢀ
[
X = Br , I , SCN ] and
characterize them as essentially pseudo-octahedral in the solid
state. However, values for the rest of the Ni(II) species are
2 1
t /t ratio lying between 1.54 and 1.69
2 1
t /t
SO
O
3
H
2
H
N
found to fall in the range 1.78–1.83 indicating appreciable degree
of tetragonal distortion in these octahedral species [39]. Electronic
spectral data of the polymer complexes in DMF solutions commen-
surate that no gross change occurs in the electronic or geometric
structures of the complexes on dissolution in the said solvent
OH
Fe
2
2
X
O
O
O
O
O
N
N
O
O
S
Fe
Ni
N
O
N
H
N
H
OH
OH
2
H2
X
H
ꢀ1
and show three principal bands, in the range 8880–9500 cm
X = Cl (1), Br (2), I (3), ONO
2
(4), NCS (5), Py(7, 8)
ꢀ
1
ꢀ1
(t
1
), 14,050–16,450 cm
(
t
2
) and 22,950–25,000 cm
(t
3
) [40].
Cl
In case of electronic spectra of the DMF solution of [Ni(HL)
2
2
]
n
Fig. 2. Structure formulae of HL-metal polymer complexes.

A.Z. El-Sonbati et al. / Journal of Molecular Structure 990 (2011) 26–31
31
undergo first step decomposition in the temperature range 220–
50 °C due to the loss of the coordinated water molecules. All the
[2] A. Tantawy, F. Goda, A.M. Abdelal, Chin. Pharm. J. 47 (1995) 37.
[
[
[
3] A.C. Ojha, R. Jain, Pol. J. Chem. 56 (1982) 1553.
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5] C.Y. Wu, L.H. Chen, W.S. Hwang, H.S. Chen, C.H. Hung, J. Organomet. Chem. 689
(2004) 2192.
2
complexes show the second step decomposition between 380
and 430 °C due to removal of uncoordinated and/or coordinated
anions and half part of the ligand. Finally the complexes undergo
decomposition between 500 and 650 °C due to loss of remaining
part of ligand. The final residue was analyzed by IR spectra and
identified as MO.
[
6] (a) T. Semba, Y. Funahashi, N. Ono, Y. Yamamoto, N.H. Sugi, M. Asada, K.
Yoshimatsu, T. Wakabayashi, Clin. Cancer Res. 10 (2004) 1430;
(
b) D.B. Clyson, J.A.S. Pringle, G.M. Ranses, Biochem. Pharmacol. 16 (1967) 614.
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8] A.K. Gadad, M.N. Noolyi, R.V. Karpoomath, Bioorg. Med. Chem. 12 (2004) 5651.
9] A.Z. El-Sonbati, M.A. Diab, M.S. El-Shehawy, M.M. Makpel, Spectrochim. Acta A
75 (2010) 394.
4
. Concluding remarks
[10] A.Z. El-Sonbati, A.A. Al-Sarawy, M. Moqbel, Spectrochim. Acta A 74 (2009) 463.
[
[
11] A.T. Mubarak, A.Z. El-Sonbati, Polym. Bull. 57 (2006) 683.
12] A.Z. El-Sonbati, R.M. Issa, A.M. AbdEl-Gawad, Spectrochim. Acta A 68 (2007)
Series of Ni(II), Pd(II) and Fe(II) polymer complexes with
1
34.
[13] J.A. Dean, Lange’s Hand Book of Chemistry, 14th ed., MEGRAW-Hill, New York,
992. p. 35.
ligand (HL) have been prepared and fully characterized. The
coordination behaviour of the anions is also discussed on the ba-
sis of IR and molar conductance measurements. It was observed
that coordination of anions with metal was effected by number
of coordination sites, which was further confirmed by molar
conductance.
The geometries of the polymer complexes are also affected by
number of coordination sites. The ligand (HL) has two coordination
sites and formed different geometrical complexes with different
anions.
1
[
[
14] W.J. Geary, Coord. Chem. Rev. 7 (1971) 81.
15] L.K. Thompson, F.L. Lee, E.J. Gabe, Inorg. Chem. 27 (1988) 39.
[16] A.Z. El-Sonbati, A.A. El-Bindary, R.M. Issa, H.M. Kera, Desig. Mon. Polym. 7
2004) 445.
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93.
[18] A.Z. El-Sonbati, A.A. El-Bindary, M.A. Diab, Spectrochim. Acta A 59 (2003) 443.
(
[
2
[
[
[
[
19] A.Z. EL-Sonbati, A.A. EL-Bindary, R.M. Issa, H.M. Kera, Desig. Mon. Polym. 7
2004) 445.
20] A.Z. EL-Sonbati, M.A. Diab, M.M. El-Halawany, N.E. Salam, Spectrochim. Acta A
77 (2010) 755.
(
21] A.Z. El-Sonbati, A.A. El-Bindary, M.A. Diab, S.A. Mazrouh, Mon. Chem 124
(
1993) 793.
(
1) The ligand (HL) has a high affinity for chelation with metal
ions under study accordance to the increasing charge den-
sity of the metal ion and hence to the increasing of their
coordination affinities.
22] A.Z. El-Sonbati, M.A. Diab, M.M. El-Halawany, N.E. Salam, Mater. Chem. Phys.
123 (2010) 439.
[23] D.M. Grant, N. Grassie, Polym. Sci. 42 (1960) 587.
[
[
24] P.W. Selwood, Magneto Chemistry, Interscience Pub. Inc., New York, 1956.
25] A.Z. El-Sonbati, A.A. El-Bindary, R.M. Ahmed, Spectrochim. Acta A 57 (2003)
(
2) HL is bonded to the metal ion in bidentate fashion through
oxygen (of O@S@O group) and nitrogen atom [of imino
nitrogen (NH/N) of the guanidine group] as inferred from
333.
[26] A.Z. El-Sonbati, M.A. Diab, R.H. Mohamed, Spectrochim. Acta A 77 (2010) 795.
[
[
27] A.Z. El-Sonbati, A.A. El-Bindary, M.A. Diab, M.A. El-Ela, S.A. Mazrouh, Polym.
Deg. & Stab. 4 (1993) 1.
28] C.M. Sharaby, Spectrochim. Acta A 62 (2005) 326.
1
IR and H NMR spectra.
(
(
3) These results also confirm the non-reactivity of the
ACONHA group in coordination (see Fig. 1).
4) HL has a high affinity for chelation with metal ions under
study accordance to the increasing charge density of the
metal ion and hence to the increasing of their coordination
affinities.
[29] A.G. Raso, J.J. Fiol, S. Rigo, A.L. Lopez, E. Molins, E. Espinosa, E. Borras, G. Alzuet,
J. Borras, A. Castineiras, Polyhedron 19 (2000) 991.
[
[
30] C.M. Sharaby, G.G. Mohamed, M.M. Omar, Spectrochim. Acta A 66 (2007) 935.
31] J.R. Ferraro, Low Frequency Vibrations of Inorganic and Coordination
Compounds, first ed., Plenum Press, New York, 1971. pp. 168–196.
[
[
[
[
32] M. Shakir, O.S.M. Nasem, A.K. Mohamed, S.P. Varkey, Ind. J. Chem. 32 (2007)
240.
33] K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination
Compounds, Wiley Interscience, New York, 1970.
34] A.Z. El-Sonbati, M.A. Diab, M.F. Kotb, H.M. Killa, Bull. Soc. Chim. Fr. 128 (1991)
(
5) According to the electronic spectra and magnetic data, there
is a continuous transition between distorted octahedral and
octahedral stereochemistry of the polymer complexes stud-
623.
35] K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination
Compounds, third ed., Wiley Interscience, New York, 1978.
ied.
p-electron acceptor mixed ligand (Py) stabilize the
polarizable ligand (
p
-electron donor ligand, e.g. halide ion)
[36] D.X. West, G. Ertem, R.M. Makeever, Trans. Met. Chem. 10 (1986) 41.
[
37] A.K. Shehata, G.Y. Ali, A. Soyed, A. El-Dissouky, Trans. Met. Chem. 21 (1996)
17.
38] A.B.P. Lever, J. Lewis, R.S. Nyholm, J. Chem. Soc. (1964) 4761.
and prefers the octahedral structure leads to irregular
deformed coordination, suggesting that the bonding effect
of the ligand in the axial position cannot be ignored.
1
[
[39] A.B.P. Lever, Coord. Chem. Rev. 3 (1968) 119.
[
[
40] K.C. Patel, D.E. Goldberg, J. Inorg. Nucl. Chem. 34 (1972) 637.
41] A.B.P. Lever, Inorganic Electronic Spectroscopy, second ed., Elsevier, New York,
Further studies with the title ligand, using different metal ions,
are in progress and will be published in course.
1984.
[42] F.A. Cotton, G. Wilkinson, C.A. Murillo, M. Bochmann, Advanced Inorganic
Chemistry, sixth ed., Wiley, New York, 1999.
[
43] A.B.P. Lever, Inorganic Electronic Spectroscopy, second ed., Elsevier,
Amsterdam, 1984.
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