Spectrophotometric study of complexation between some new N 2O2-schiff bases and some transition metal ions in nonaqueous solvents

Article abstract of DOI:10.1155/2011/437621

The complexation reaction between some transition and heavy metal cations and some new N₂O₂ Schiff bases in acetonitrile (AN) or methanol (MeOH) as nonaqueous solvents at 25 °C and 0.05 M tetraethylammonium perchlorate (TEAP) were in

Full text of DOI:10.1155/2011/437621

ISSN: 0973-4945; CODEN ECJHAO
E-Journal of Chemistry
http://www.e-journals.net
2011, 8(2), 495-506
Spectrophotometric Study of Complexation
Between Some New N2O2-Schiff Bases and Some
Transition Metal Ions in Nonaqueous Solvents
A. SHOKROLLAHI*, M. GHAEDI, M. MONTAZEROZOHORI,
A. H. KIANFAR, H. GHAEDI, N. KHANJARI, S. NOSHADI and S. JOYBAR
Chemistry Department
Yasouj University, Yasouj, 75918-74831, Iran
ashokrollahi@mail.yu.ac.ir
Received 27 April 2010; Accepted 17 July 2010
Abstract: The complexation reaction between some transition and heavy metal
cations and some new N2O2 Schiff bases in acetonitrile (AN) or methanol
(MeOH) as nonaqueous solvents at 25 ºC and 0.05 M tetraethylammonium
perchlorate (TEAP) were investigated by spectrophotometric method. The
stoichiometry and overall stability constants of complexes have been evaluated
by computer refinement of abs-mole ratio data, using the KINFIT program. All
investigated metal ions form 1:1 ML, 1:2 ML2 or 2:1 M2L complexes with
studied ligands. The effect of structure on the complexation was investigated.
Keywords: Complexation, N2O2-Schiff bases, Acetonitril, Transition metal ion.
Introduction
During the past two decades, considerable attention has been paid to the chemistry of the
metal complexes of Schiff bases containing nitrogen, oxygen and sulfur donor atoms1-3. This
may be attributed to their stability, biological activity and potential applications in many
fields such as oxidation catalysis and electrochemistry. Azomethine compounds have wide
applications in many biological aspects, viz., proteins4, visual pigment5. Schiff base
transition metal complexes are one of the most versatile and thoroughly studied systems6,7.
Particularly, complexes of divalent transition metal ions involving derivatives of
salicylaldehyde and aliphatic amines are important, because of their similarity to the
biological dioxygen carriers8,9, their applications in the clinical10, analytical fields11,12 and
non-enzymatically controlled transamination reactions13..
The study of complexation reaction of these ligands in non-aqueous matrices could be
used as an efficient strategy to design the analytical systems such as potentiometric sensor14-16
bulk and supported liquid membrane transport17,18, optical sensor19, solid phase and cloud
,

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A. SHOKROLLAHI et al.
point extraction20,21 and biochemistry fields22. Thus, the studies of complexation reaction of
these Schiff bases with metal ions, not only result effective information about complexation,
but also lead to a better understanding of the selectivity of these ligands toward different
metal cations.
It is important for an analytical chemist to know what kind of complexes with what
stability may be expected. Knowledge of the composition of a solution in terms of the
species formed is of importance in many parts of solution chemistry: in understanding
analytical procedures, industrial process, pollution of natural waters and biological fluids.
Knowledge of the equilibria is also of importance for interpretation of the kinetics of
reactions in solution.
The aim of comparative studies of the various equilibrium processes in virtually all
cases is to find a correlation between the values of the equilibrium constants and the
parameters reflecting the chemical properties of the components participating in the process.
Basically two types of the parameters reflecting the chemical properties are distinguished:
(a) physical parameters due to the interaction of the component in question with physical
fields (e.g. ionization potential, electroaffinity, ionic potential, polarizability) and (b)
correlation coefficients expressing the connection between the various chemical properties,
which can be determined from a large number of studies (e.g. Hammet σ value,
electronegativity, data reflecting the hard-soft nature, etc.)23.
We have used the Kinfit and Best program20,24-27, for evaluating the stability constant of
complexes using the spectrophotometric and potentiometric data respectively28-32. Of
particular interest have been those involving Schiff base since they reveal surprising
molecular diversity not only in coordination geometry but in more subtle changes in the
ligands.
In the present work the authors decided to investigate spectrophotometric study and the
effect of the ligands structure on the stability constants of the complexation of the some
metal ions with various salophen and salpn derivatives. Based on this data, one can focus to
synthesize new ligands with proper stability constant toward metallic ions for the selective
and sensitive determination of metal ions.
Experimental
Analytical grade nitrate salts of Cu(II), Ni(II), Co(II), Zn(II), UO2(II), La(III), Ce(III) and Th(IV)
ions are purchased from Merck Company and used without any further purification.
Tetraethylammonium perchlorate (TEAP) was synthesized according to literature33. The ligands,
including bis(hydrosalicylate) 1,3-propanediimine (BSAPD), bis(salicylaldehyde) 1,2-
phenylenediimine (BSPHEN), bis(salicylaldehyde) 4-nitro1, 2-phenylenediimine (BSNPHEN),
bis(salicylaldehyde)4-carboxylic-1,2-phenylendiimine (BSCPHEN) was synthesized according
to literature34-36 and the ligands bis(2-hydroxyphenyl) 1,2-phthaldimine (BHPPDI), bis(2-
hydroxyacetophenone) ethylenediimine (BHAED), bis(2-hydroxyacetophenone)-1,4-
butanediimine (BHABDI) prepared according to procedure given below.
Preparation of bis(2-hydroxyphenyl)1,2-phthaldiimine (BHPPDI)
5 mmol of 2-Aminophenol and 2.5 mmol of phthaldialdehyde in 25 mL ethanol was
gradually added to a 25 mL ethanolic solution and the reaction mixture was refluxed. The
progress of the reaction was monitored by TLC (Thin layer chromatography). After 8 h,
50 mL cooled water was added to reaction mixture. Deep yellow precipitate was filtered
and washed with water and ethanol/water mixture. Thus bis(2-hydroxyphenyl) 1, 2-phthaldiimine

Spectrophotometric Study of Complexation
497
o
(BHPPDI) was obtained in 76% yield. M.p is 117-120 C. Elemental analysis: calculated
(%) C20H16N2O2: C 48.93; H 4.62; N 7.13. Found: C 49.27; H 4.72; N 6.96. Characteristic
IR(KBr, cm-1): 3306 (bs, νOH), 3061 (w, CH- Aromatic), 2976(w, CH-imine), 1634(vs,
νC=N- imine) 1493(s),1586(s), 1453(s, νC=C, aromatic ring), 1331(m), 1302(m), 1274(m),
1209 (m, νC-N), 1146(m), 1123(w), 1033(m, C-O), 928(w), 896(m), 747(s), 727(s), 657(m),
566(w), 471(m). UV (CH2Cl2, λmax): 223 and 306 nm. 1H NMR (DMSO-d6, ppm): 10.22(bs, 1H),
8.88 (bs, 1H), 7.57 (m, 4H), 7.16 (m, 2H), 6.93(m, 2H), 6.61(m, 2H) and 6.35(m, 4H) ppm.
Preparation of bis(2-hydroxyacetophenone)ethylenediimine (BHAED)
To 1 mmol (0.12 g) of eyhylenediamine in 50 mL ethanol, 2 mmol (0.544 g) of 2-hydroxy
acetophenone was added in 50 mL ethanol. The reaction mixture was refluxed for 7 h. Then
the mixture was kept in refrigerator overnight and then filtered to give the product as yellow
crystals (86% yield). The product was characterized by physical and spectral data.
IR (KBr, cm-1) : 3444(bs, νOH), 3053(w, CH- Aromatic), 2935(w, CH- aliphatic), 2837
(w, CH- aliphatic), 1609 (-C=N), 1575 (C=C), 1507 (m, C=C), 1445, 1366 (s), 1325 (m),
1312 (s), 1292 (s), 1261 (m, νC-N), 1240 (m), 1198 (m), 1160 (s), 1128 (m), 1064 (s,C-O),
1024 (s,C-O), 947 (m), 859 (m), 836 (m), 757 (s), 743 (m), 648 (m), 557 (m), 524 (m), 503
1
(m), 467 (m), 451 (m), 440 (m), 407 (m). H NMR (CDCl3): 15.64 (s, 2H), 7.32 (t, 2H, J=
7.95Hz, J= 6.95Hz), 7.04 (m, 2H), 6.62 (d, 2H, J= 8.30Hz), 6.57 (t, 2H, J= 7.20Hz, J=
7.90Hz), 3.75 (s, 4H), 2.16 (s, 6H) ppm. 13C NMR (CDCl3/DMSO): 173.01, 163.36, 132.62,
128.51, 119.68, 118.52, 117.59, 77.91(t, CDCl3), 50.34, 40.37 (q, DMSO-d6), 15.07 ppm.
UV-Vis (CHCl3): 308, 370 nm. M.p 58 oC.
Preparation of bis(2-hydroxyacetophenone)-1,4-butanediimine (BHABDI)
2 mmol of 2-Hydroxy acetophenone was added to 1.0 mmol of 1,4-butanediamine and the
reaction mixture was refluxed for 6 h. Then the mixture was kept in refrigerator overnight
and filtered to obtain yellow crystals of product (89% yields). The product was characterized
by different analytical techniques. Elemental analysis, C20H24N2O2: (theoretical values of C
74.04%; H 7.46%; N 8.64%), while found: C 74.21%; H 7.38% and N 8.69%. Infra red
spectra (KBr, cm-1): 3433(br s, m OH),3048 (w, CH–aromatic), 2933 (w, CH–aliphatic),
2866 (w, CH–aliphatic),1613 (–C≡N), 1554 (C=C), 1492 (m, C=C), 1444 (m),1382 (w),
1325 (m), 1311 (m), 1231 (m), 1261 (m, mC–N), 1159 (s),1130 (m), 1068 (m, C–O), 1009 (m,
C–O), 948 (m), 841(s), 836 (m),761 (s), 746 (s), 633 (m), 560 (m), 526 (m), 474 (m) and 443 (w).
Spectrophotometric titration
Standard stock solutions of ligand (1.0×10−3 M) and the metal ions (1.0×10−3 M) were
prepared by dissolving appropriate and exactly weighed (with an accuracy of 0.0001 g)
amount of pure solid compounds in pre-calibrated 25.0 mL volumetric flasks and diluted to
the mark with solvent. Working solutions were prepared by appropriate dilution of the stock
solutions. According to the spectra reported (Figures 1-5), titration of the ligand solution (for
sample 3.8 × 10−5 M, 2.6 mL) was carried out by the addition of micro-liter amounts of a
concentrated standard solution of the metal ion (1.0-2.5×10−3 M) using a pre-calibrated
micro-syringe, followed by absorbance intensity reading at 25.0 oC and 0.05 M TEAP.
Results and Discussion
Complexation of transition and heavy metal cations with donor atoms such as nitrogen and
sulfur or hard atoms such as oxygen is favored, These ligands, play a key role in the
speciation of metal ions in various media and in controlling its physicochemical behavior,

498
A. SHOKROLLAHI et al.
biological availability, accumulation and mobility. Depending on the pH value, presence of
salts (ionic strength effect) and degree of saturation of binding sites, ligands substances can
form either soluble or insoluble complexes with various metal ions and play a double role in
various matrixes The stability of a transition metal complex with a polydentate chelate
ligand depends on a range of factors including: number and type of the donor atoms present
and the number and size of the chelate rings formed on complexation37. In addition, the
stability and selectivity of complexation strongly depend on the donor ability and dielectric
constant of the solvent38 and shape and size of the solvent molecules39.
In detail the complexation of some transition metal ions with some ligands including
BHAEDI, BSAPD, BHABDI, BSPHEN, BSNPHEN, BSCPHEN, BHPPDI (Table 1) and
their stability constant and stoichiometry has been calculated using KINFIT program.
Table 1. Structure of ligands
Ligand
Structure
λ
max, nm
Transition for ligand
N
N
250
314
π→π* (phenolic ring)
π → π * (C=N)
BHAED
OH
HO
N
N
252
308
π→π * (phenolic ring)
π → π* (C=N)
BSAPD
OH
HO
N
N
247
311
π →π* (phenolic ring)
π → π* (C=N)
BHABDI
OH
HO
π→π*(phenolic ring)
π→π* (C=N)
N
N
270
340
BSPHEN
OH
HO
Contd…

Spectrophotometric Study of Complexation
499
NO2
285
370
π→ π* (phenolic ring)
π→ π* (C=N)
N
N
BSNPHEN
OH
HO
COOH
280
370
π→ π* (phenolic ring)
π→ π* (C=N)
N
N
BSCPHEN
OH
HO
π→ π* (C=N)
N
N
BHPPDI
330
OH
HO
Investigation of complexation
Nonaqueous solvents usually are more inert toward ions than water. It would seem that the
more intrinsic properties of solutes could be more readily established in non-aqueous media,
since many of the unusual properties of water as a solvent are absent in the former media.
Nonaqueous studies would be useful also in understanding the nature of solutes that have only
a limited solubility in water. In addition the pH of solution must be controlled in water solution
for reasons such as the above; studies of nonaqueous solutions systems have been undertaken.
The interaction of some Schiff bases with the metal ions was studied by adding various
ratio of metal ions solution in acetonitrile or methanol. The structure of studied Schiff base
ligands and abbreviation of their names and spectra characteristic are summarized in Table 1.
The complexation of these ligands was carried out spectrophotometrically in methanol and
acetonitrile medium by mole ratio method. In these experiments, ligand concentration was
kept constant and metal ion concentration was increased of M/L ratio from 0-4 in excess.
The respective curves are presented in Figures 1-5. The increase in the concentration of the
transition metal ions causes that one of the original peaks of the Schiff base ligand at about
250-285 nm gradually vanished and the other original peak around 300-380 nm shifted to
lower wavelengths with the increase in its intensity and a new peak appeared at about
400-500 nm its intensity increases with the increase in the concentration of metal ions with
very clear isosbestic points. As it was reported in Table 1, one of the bands in 300-370 nm
range in the spectrum of the ligand was assigned to π→ π* transition of the imine nitrogen atom
in conjugation with the phenoxy group40. The other absorption bands associated with the π→ π*
transition of the phenoxy group shifted by about 10 nm the bathochromic shifting of ligand peaks
indicate coordination of metal ion with the ligand chromophoric groups.

500
A. SHOKROLLAHI et al.
(a’)
(a)
Wavelength, nm
Wavelength, nm
Wavelength, nm
Wavelength, nm
(b)
(b’)
ML
ML
M/L
M/L
(c’)
(c)
Figure 1. UV-Vis spectra for titration of BHAED (a) and BSPHEN (a´ ) (3.8×10-5 M) with
2+
UO2 ion in acetonitrile (T = 25 ˚C, I= 0.05 M and 0.05 M TEAP) and the corresponding
absorbtion mole ratio curves at 362, 420 nm respectively (b,b’) and curve fitting (c,c΄ ).
(a)
(a’)
Wavelength, nm
Wavelength, nm
Wavelength, nm
Wavelength, nm
(b’)
(b)
ML
ML
M/L
M/L

Spectrophotometric Study of Complexation
501
(c)
(c’)
Figure 2. UV-Vis spectra for titration of BHABD (a) and BSAPD (a´ ) (3.8×10 -5M) with
Co2+ ion in acetonitrile (T = 25 ˚C, I= 0.05 M and 0.05M TEAP) and the corresponding
absorbtion mole ratio curves at 372, 272 nm respectively (b,b΄ ) and curve fitting(c,c΄ )
Wavelength, nm
Wavelength, nm
Wavelength, nm
Wavelength, nm
Figure 3. Uv-Vis spectra for titration of BSNPHEN (3.8×10-5 M) with metal ions (1.0×10-3M)
(a) Cu2+, (b) Ni2+, (c) Co2+ and (d) UO22+ ion in acetonitrile (T=25 ˚C and I= 0.05 M TEAP)
Wavelength, nm
Wavelength, nm
Wavelength, nm
Wavelength, nm
Figure 4. UV-Vis spectra for titration of BSCPHEN (3.8 × 10-5 M) with metal ions containing
(1.0×10-3) (a) Cu2+, (b) Ni2+, (c) Co2+ and (d) UO22+ in acetonitrile (T=25 ˚C and I= 0.05 M TEAP)

502
A. SHOKROLLAHI et al.
Wavelength, nm
Wavelength, nm
Wavelength, nm
Figure 5. UV-Vis spectra for titration of BHPPDI (3.8 × 10-5 M) with metal ions containing
(1.0×10-3) (a) Cu2+, (b) Ni2+ (c) and Co2+ ion in acetonitrile (25 ˚C and I = 0.05 M TEAP)
The appearance of band at higher wavelength with higher intensity may be attributed to
coordination of imine nitrogen atoms to the metal ion with an additive effect due to
deprotonated phenolate groups upon chelation. The absorption at about 400-550 nm is
assigned to a ligand-metal d- π* charge transfer transition41-43. Additional band at 254 nm is
inter-ligand (π-π*) transition centered on coordinated Sciff base. The band at about 280 nm
was assigned to a phenyl ring π -π* transition44,45. The shifting of ligand peaks towards lower
energy on deprotonation of the chelating units can be explained by two ways: (i) the
interaction of enolimine with a hydrogen-bond forming solvent would presumably reduce
the O- H bond strength and facilitate proton transfer to the nitrogen center favouring the
formation of the ketoamine, which gives characteristic n→π* transition at longer wavelength
than the corresponding enolimine; (ii) on deprotonation, formation of phenolate ion from
phenol stabilized the π→π* excited state due to charge delocalization and brings the lowest
excited state closer to the highest ground state and thus permits a lower energy (longer
wavelength) for transition. Analyses of spectra using KINFIT whole at maximum
wavelengths gave the best fit of absorbance moleratio data (for sample Figure 1-c,c´ and 2-
c,c´) for ML and ML2 complex and its formation constants with their standard deviations are
given in Tables 2 and 3 for sample of plot fitting are brought The possibility of other type of
formulations in Figures 1, 2- c, c´ were ruled out due to absence of any extra peak in the
higher wavelengths, which was further confirmed as inclusion of additional species in the
model The complexation through two tertiary imine groups followed by two phenolate
groups to give a uncharged four-coordinated ML species with distorted octahedral structure,
where two-coordination sites are occupied solvent water molecules at cis-position in solid
state. It has been shown for a (N, O-donor) tetradentate Schiff base ligand, the relative
flexibility of these ligands allow formation of metal complexes to give a ‘umbrella’ or
‘stepped’ like geometry the stoicheimetry of complex for metal ions are ML or ML and
ML2. The authors think that the uranyl ion formation of M2L complex with BSCPHEN is
due to the probability of inserting one uranyl ion to the ligand cavity and the another interact

Spectrophotometric Study of Complexation
503
with carboxilate to form ML. About the ligand BHPPDI, the stoichiometry for copper(ΙΙ),
nickel(ΙΙ) and cobalt(ΙΙ) is ML and ML2 .This fact may be due to steric distortion of ligand so
that the ligand acts as a bidentate that lead to formation of ML2 in agreement to previously
reports46-49
Table 2. The overall stability constants of complexation between some metal ions with BHAED,
BHABDI and BSAPD at 25 ˚C and 0.05 M TEAP in acetonitrile or methanol solvent
Ligand
solvent
Metal ion
Cu2+
log β1
log β2
9.33 0.01
8.04 0.01
M/L
6.02 0.01
4.03 0.01
4.99 0.02
5.00 0.01
4.06 0.01
5.78 0.01
4.00 0.02
5.23 0.02
6.11 0.20
5.00 0.24
0.2625.01
4.89 0.23
5.92 0.29
4.99 0.26
5.01 0.42
5.00 0.01
5.76 0.01
5.56 0.01
6.06 0.43
3.95 0.01
4.59 0.12
1:1&1:2
1:1&1:2
1:1
1:1&1:2
1:1&1:2
1:1&1:2
1:1&1:2
1:1
Ni2+
Co2+
Mn2+
Cd2+
9.00 0.01
7.93 0.01
9.80 0.01
7.01 0.05
AN
BHAED
2+
UO2
Th4+
La3+
Fe3+
Cu2+
Ni2+
Co2+
Zn2+
Fe3+
Cr3+
Co2+
Zn2+
Cu 2+
Ni2+
Pb2+
Cr3+
MeOH
AN
1:1
1:1&1:2
1:1&1:2
1:1&1:2
1:1&1:2
1:1&1:2
1:1&1:2
1:1&1:2
1:1&1:2
1:1&1:2
1:1
9.01 0.47
BHABDI
BSAPD
MeOH
9.01 0.56
4.00 5.01
10.51 0.0
8.72 0.01
AN
6.96 0.01
1:1&1:2
1:1
MeOH
The Schiff base ligands BSCPHEN and BSHNPDI and substituted BSPHEN were
chosen according to their structures by changing both the aldehyde and the amine parts and
changing the substitution in order to study their influence on the metal coordination sphere.
The differences among the stability constants values are probably due to the change in the
nature of the metal environment in the four complexes and the interior core of desired
complexes. In our view, the higher core of BSPHEN and flexibility suitable and superior it
for complexation with metal ions in comparison to BHPPDI. In fact, the presence of the
primary amine nitrogen in the metal coordination sphere may lead to ligand distortion in the
both complexes, unlike the less rigid BHNPDI complexes reduce the stability constant. The
result of stability constant of Schiff base with metal ion show that salophen has higher
stability in comparison to other derivatives such as BSNPHEN and BSCPHEN, that may be
atributed to the fact that withdrawing group such as carboxilic and nitro in the ligand reduce
their activity for complexation. The order for stability constant of the mentioned ligands for
every metal ion is as following BSCPHEN<BSNPHEN<BSPHEN. As it can be seen from
Table 3, the complex between BSCPHEN and metal ion has lower stability constant with
respect to other ligands. In a view glance to the result of stability constant one can notice
that the stability constant for BSNPHEN is higher than respective value for BSCPHEN. This
can be explained that in the presence of nitro with higher electron withdrawing property the
intra- molecular hydrogen bond will be weakened. In the salophen ligand, a strong intra-

504
A. SHOKROLLAHI et al.
molecular hydrogen bond between iminic nitrogen and phenolic hydrogen exist that will be
distroyed by complexation. Nitro group with higher electron withdrawing tendency decrease
the strength of intra-molecular hydrogen bond, therefore facilitate the complex formation
and lead to higher stability constant due to decrease in activity of BSCPHEN ligand.
In Schiff base ligands of BSPHEN and BHPPDI the more resonance and interior core of
ligands favor their complexation with metal ion, while more rigidity and higher interior core
of ligands in BSPHEN increased the complexation probability and its stability constant.
Table 3. The overall stability constants of complexation between some metal ions with
BSPHEN, BSNPHEN, BSCPHEN and BHPPDI at 25 ˚C and 0.05 M TEAP in acetonitrile
Ligand
Metal ion
Cu2+
log β1
8.30 0.30
----
7.40 0.14
5.80 0.11
8.01 0.23
----
6.80 0.20
4.72 0.20
7.01 0.12
5.81 0.10
----
log β2
----
9.91 0.40
----
----
----
8.92 0.15
----
M/L
1:1
2:1
1:1
1:1
1:1
2:1
1:1
1:1
1:1
1:1
1:2
2:1
Ni2+
BSPHEN
Co2+
2+
UO2
Cu2+
Ni2+
Co2+
BSNPHEN
2+
UO2
----
----
----
Cu2+
Ni2+
Co2+
BSCPHEN
BHPPDI
10.20 0.21
9.88 0.15
9. 00 0.10 1:1 & 1:2
8.15 0.14 1:1 & 1:2
7.90 0.11 1:1 & 1:2
2+
UO2
----
Cu2+
Ni2+
Co2+
6.00 0.10
5.15 0.12
4.90 0.08
As it is seen from Table 2, the results of complexation between the L1 (BHAED), L2
(BHABDI) and L3 (BSAPD) ligands and metal ion revealed the order of stability L2>L1>L3
almostly. The low stability complexes of L3 relative to L2 and L1 refer to the presence of two
methyl group, in the structure of L1 and L2. In comparing complexes of L1 and L2 with metal
ions, the stability constants of L2 is relatively high to L1, due to the presence of longer
hydrocarbon chain, which causes to distort of flexibility in structure. The order for stability
of metal ion-Schiff base complexes, are agreement with the Irving Williams50 order, but this
ranking in some cases was not observed.
References
1.
Başoǧlu A, Parlayan S, Ocak M, Alp H, Kantekin H, Özdemir M and Ocak U,
Polyhedron, 2009, 28, 1115-1120.
2.
3.
4.
Demir I, Bayrakci M, Mutlu K and Pekacar A I, Acta Chim Slov., 2008, 55, 120.
Seleem H S, El-Shetary B A, Khalil S M E and Shebl M, J Serb Chem Soc., 2003, 68, 729.
Choi K H, Lai V, Foster C E, Morris A J, Tolan D R and Allen K N, Biochem., 2006,
45, 8546-8555.
5.
Al-Dilaimi S K, Aumiller J C, Johnson R H and Blatz P E, Photochem Photobiol,
1987, 46(3), 403-412.
6.
7.
8.
Dixit P S and Srinivasan K, Inorg Chem., 1988, 27, 4507-4509.
Nishinaga A, Itahara T and Matsuura T, Tetrahedron Lett., 1974, 15, 4481.
Golcu. A, Tumer M, Demirelli H and Wheatley R A, Inorg Chim Acta, 2005, 358(6),
1785-1797.

Spectrophotometric Study of Complexation
505
9.
Khandar A A, Nejati K and Rezvani Z, Molecules, 2005, 10, 302-311.
10. Sun R W Y and Che C M, Coord Chem Rev., 2009, 253, 1682-1691
11. Rouhollahi A, Zolfonoun E and Salavati-Niasari M, Sep Purif Technol., 2007, 54(1), 28-33.
12. Shemirani F, Jamali M R, Kozani R R and Niasari M S, J Anal Chem., 2006, 61, 124-128.
13. Tang B, Zhang G Y, Liu Y and Han F, Anal Chim Acta, 2002, 459, 83.
14. Gupta V K, Goyal R N and Sharma R A, Talanta, 2009, 78, 484-490
15. Gupta V K, Goyal R N, Jain A K and Sharma R A, Electrochim Acta., 2009, 54,
3218-3224
16. Gupta V K, A. K. Singh A K and Pal M K, Anal Chim Acta., 2008, 624, 223-231.
17. Fathi S A M, Parinejad M and Yaftian M R, Sep Purif Technol., 2008, 64, 1.
18. Yoshikawa M, Mori Y, Tanigaki M and Eguchi W, Bull Chem Soc Jpn., 1990, 63, 304.
19. Gupta V K, Pal M K and Singh A K, Anal Chim Acta., 2009, 631, 161-169.
20. Ghaedi M, Tavallali H, Shokrollahi A, Zahedi M, Montazerozohori M and Soylak M,
J Hazard Mater, 2009, 166, 1441-1448.
21. Dehghan Abkenar Sh, Hosseini M and Salavati-Niasari M, Asian J Chem., 2008,
20, 4291,
22. Bassov T and Sheves M, Biochem., 1986, 25, 5249.
23. Dwyer F P and Mellor D P, Chelating Agents and Metal Chelates; Academic Press
Inc., London, UK, 1964.
24. Seleem H S, El-Shetary B A, Khalil S M E and Shebl M, J Serb Chem Soc., 2003, 68, 729.
25. Safavi A and Rastegarzadeh S, Anal Sci., 1999, 15, 173.
26. Moghimi A, Shokrollahi A, Shamsipur M, Aghabozorg H and Ranjbar M, J Mol
Struct., 2004, 701, 49-66.
27. Moghimi A, Alizadeh R, Shokrollahi A, Aghabozorg H, Shamsipur M and Shockravi A,
Inorg Chem., 2003, 42, 1616-1624.
28. Gao H W and Zhao J F, Croat Chim Acta, 2003, 76, 1.
29. Martell A E and Motekaitis R J, Determination and Use of Stability Constants, VCH,
Publishers, New York, 1992, 28, 11.
30.. Machado C M M, Cukrowski I, Gameiro P and Soares H M V M, Anal Chim Acta.,
2003, 493, 105.
31. Bakr M F, J Chin Chem Soc., 2003, 50, 339.
32. Wang Y M, Cheng T H and Liu G C, J Chin Chem Soc., 2000, 47, 1083.
33. Kolthoff I M and Bruckenstein S, J Am Chem Soc., 1957, 79, 1-7.
34. Baran Y and Erk B, J Tur Chem., 1996, 20, 312.
35. Sarvestani A H, Asadi M and Abbasi M, J Chem Res., 2007, 56-59.
36. Illingsworth M L and Rheingold A L, Inorg Chem., 1987, 26, 4312.
37. Popov A I and Lehn J M, In Coordination Chemistry of Macrocyclic Compounds,
Melson G.A. Ed., Plenum Press, New York, 1985.
38. Strasser B O and Popov A I, J Am Chem Soc., 1985, 107, 7921-7924.
39. Popov A I, Pure Appl Chem., 1979, 51, 101.
40. Sharma R K, Singh R V and Tandon J P, J Inorg Nuclear Chem., 1980, 42, 1382-1384.
41. Biradar N S, Karajagi G V, Aminabhavi T M and Rudzinski W E, Inorg Chim Acta,
1984, 82, 211.
42.
Estiu G L, Jubert A H and Costamagena J and J Vargas, Inog Chem., 1996,
35(1), 263-266.
43. Ortiz B and Park S M, Bull Korean Chem Soc., 2000, 21, 405.
44. Iqbal M and Khurshid S J, Can J Chem., 1993, 71, 629.
45. Bosnich B, J Am Chem Soc., 1968, 90, 627.

506
A. SHOKROLLAHI et al.
46. Han H, Ruan W J, Zhao X J, Hu G H and Zhu Z A, Synth React Inorg Met-Org
Chem., 2003, 33, 1011.
47. Sakiyan I, Logoglu E, Arslan S, Sari N and Sakiyan N, Bio Metals., 2004, 17, 115.
48. Khalil S M E and Bashir K A, J Coord Chem., 2002, 55(6), 681.
49. Mederos A, Domi nguez S, Herna ndez-Molina R and Sanchiz F and J Brito
Chem Rev., 1999, 193-195, 857.
,
Coord
50. Irving H and Williams R J P, J Chem Soc., 1953, 8, 3192.

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