Complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) with 4-chloro-2-methoxybenzoic acid anion: Physico-chemical properties

Article abstract of DOI:10.1007/s10973-005-7379-z

The complexes of 4-chloro-2-methoxybenzoic acid anion with Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺ were obtained as polycrystalline solids with general formula M(C₈H ₆ClO₃)

Full text of DOI:10.1007/s10973-005-7379-z

Journal of Thermal Analysis and Calorimetry, Vol. 86 (2006) 3, 783–789
COMPLEXES OF Mn(II), Co(II), Ni(II), Cu(II) AND Zn(II) WITH
4-CHLORO-2-METHOXYBENZOIC ACID ANION
Physico-chemical properties
WiesÓawa Ferenc1*, B. Cristóvão1 and J. SarzyÕski2
1Faculty of Chemistry, Maria Curie-SkÓodowska University, 20-031 Lublin, Poland
2Institute of Physics, Maria Curie-SkÓodowska University, 20-031 Lublin, Poland
The complexes of 4-chloro-2-methoxybenzoic acid anion with Mn2+, Co2+, Ni2+, Cu2+ and Zn2+ were obtained as polycrystalline solids
with general formula M(C8H6ClO3)2·nH2O and colours typical for M(II) ions (Mn – slightly pink, Co – pink, Ni – slightly green, Cu – tur-
quoise and Zn – white). The results of elemental, thermal and spectral analyses suggest that compounds of Mn(II), Cu(II) and Zn(II) are
tetrahydrates whereas those of Co(II) and Ni(II) are pentahydrates. The carboxylate groups in these complexes are monodentate. The hy-
drates of 4-chloro-2-methoxybenzoates of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) heated in air to 1273 K are dehydrated in one step in
the range of 323–411 K and form anhydrous salts which next in the range of 433–1212 K are decomposed to the following oxides:
Mn3O4, CoO, NiO and ZnO. The final products of decomposition of Cu(II) complex are CuO and Cu. The solubility value in water
at 293 K for all complexes is in the order of 10–3 mol dm–3. The plots of cM vs. temperature of 4-chloro-2-methoxybenzoates of Mn(II),
Co(II), Ni(II) and Cu(II) follow the Curie–Weiss law. The magnetic moment values of Mn2+, Co2+, Ni2+ and Cu2+ ions in these complexes
were determined in the range of 76-303 K and they change from: 5.88–6.04 mB for Mn(C8H6ClO3)2·4H2O, 3.96–4.75 mB for
Co(C8H6ClO3)2·5H2O, 2.32–3.02 mB for Ni(C8H6ClO3)2·5H2O and 1.77–1.94 mB for Cu(C8H6ClO3)2·4H2O.
Keywords: 4-chloro-2-methoxybenzoic acid, 4-chloro-2-methoxybenzoates of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), IR spectra,
magnetic moments, thermal stability
Introduction
research on the compounds of methoxybenzoic [16]
and chloromethoxybenzoic acids [17], we decided to
synthesise and investigate the complexes of 4-chloro-
2-methoxybenzoic acid anion with Mn(II), Co(II),
Ni(II), Cu(II) and Zn(II). These types of compounds
maybe find the application in medicine as components
of drugs or they may be used in technique as magnetic
materials depending on their magnetic properties. The
physico-chemical properties of 4-chloro-2-methoxy-
benzoates of d block elements were determined by
thermal stability in air atmosphere during heating
to 1273 K, IR spectral data, X-ray powder investiga-
tions, solubility in water at room temperature and mag-
netic properties. Thermal stability investigations give
information about the ways of complex decomposi-
tions and the endo- or exo-effects connected with such
processes as: dehydration, melting, polymorphic
changes, crystallization, oxidation or reduction. The
magnetic properties of 4-chloro-2-methoxybenzoates
of Mn(II), Co(II), Ni(II) and Cu(II) were investigated
in the range of 76–303 K in order to study the kind of
coordination of central ions and the nature of bonding
between central ions and ligands. If the effective mag-
netic moment meff is known, the number of unpaired
electrons can be calculated. This may also give infor-
4-Chloro-2-methoxybenzoic acid having formula
C8H7ClO3 is a white crystalline solid, weakly soluble
in water. The reaction of 4,2-Cl(MeO)C6H3CO2H with
H2NCH2CH2NEt2 carried out at a temperature of
80–90°C in HCl medium and catalysed by PCl3 gave
4,2-Cl(MeO)C6H3COHNCH2CH2NEt2·HCl,
which
has practical application as antiemetic [1]. The
4-chloro-2-methoxybenzoic acid was used also by
other scientists to obtain compounds having antiemetic
and psychotropics properties [2, 3]. From the survey of
literature it follows that there are papers on various or-
ganic ligands with d block elements [4–7] but the com-
pounds of 4-chloro-2-methoxybenzoic acid anion with
various cations are not known. There are no papers on
its properties and its salts obtained as solids. Recently,
we have prepared the complexes of 5-chloro-2-
methoxybenzoic acid anion with following selected
cations of d and f block elements: La(III), Ce(III),
Pr(III), Nd(III), Sm(III), Eu(III), Gd(III), Tb(III),
Dy(III), Ho(III), Er(III), Tm(III), Yb(III), Lu(III),
Y(III), Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) as sol-
ids and have examined some of their physico-chemical
properties [8–15]. This time, as a continuation of our
*
Author for correspondence: wetafer@hermes.umcs.lublin.pl
1388–6150/$20.00
Akadémiai Kiadó, Budapest, Hungary
Springer, Dordrecht, The Netherlands
© 2006 Akadémiai Kiadó, Budapest

FERENC et al.
mation on the oxidation state of the metal ion or the
heated in platinum crucibles in static air to 1273 K with
a sensitivity of TG – 100 mg, DTG and DTA sensitivi-
ties were regulated by computer Derill programme. The
products of decomposition were calculated from TG
curves and verified by the diffraction pattern and IR
spectra registration.
central atom of a complex, on the electron configura-
tion and, hence, on the nature of the bonding between
the metal and the ligands. The determination of the
number of unpaired electrons of the central atom al-
lows to establish whether the complex investigated is
of low or high spin and whether the ligand field is
strong or weak.
Magnetic susceptibilities of polycrystalline sam-
ples of 4-chloro-2-methoxybenzoates of Mn(II),
Co(II), Ni(II) and Cu(II) were investigated in the tem-
perature range of 76–303 K. The measurements were
carried out using the Gouy method. The calibrant em-
ployed was Hg[Co(SCN)4] for which the magnetic
susceptibility was assumed to be 1.644×10–5 cm–3 g–1.
Correction for diamagnetism of the constituent atoms
was calculated by the use of Pascal’s constants [18].
Solubility of 4-chloro-2-methoxybenzoates of
Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) in water was
measured at 293 K. Saturated solutions of the ob-
tained compounds were prepared under isothermal
conditions. The contents of Mn(II), Co(II), Ni(II) and
Cu(II) were determined by using ASA 880 spectro-
photometer (Varian).
Experimental
The complexes of the 4-chloro-2-methoxybenzoic acid
anion with Mn2+, Co2+, Ni2+, Cu2+ and Zn2+ were ob-
tained by the addition of equivalent quantities of 0.1 M
ammonium 4-chloro-2-methoxybenzoate (pH~5) to a
hot solution containing the nitrates(V) of respective
metal ions and crystallizing at 293 K. The solids were
filtered off, washed with hot water and ethanol to re-
move ammonium ions and dried at 303 K.
The C, H analysis was performed using a
CHN 2400 Perkin Elmer analyser.
The contents of metals were calculated from TG
curves.
The IR spectra of complexes were recorded over
the range 4000–400 cm–1 using M–80 spectrophoto-
meter (Carl-Zeiss, Jena). Samples for IR spectra mea-
surements were prepared as KBr discs.
Results and discussion
4-Chloro-2-methoxybenzoates of Mn(II), Co(II),
Ni(II), Cu(II) and Zn(II) were obtained as poly-
crystalline solids with a metal ion to ligand ratio of 1:2
and a general formula M(C8H6ClO3)2·nH2O (where
M=Mn, Co, Ni, Cu, Zn and n=4 for Mn(II), Cu(II),
Zn(II) and n=5 for Co(II), Ni(II), respectively). Their
colours are typical for the corresponding divalent ions
of d block elements i.e. is slightly pink in the case of
Mn(II), pink for Co(II), slightly green for Ni(II), tur-
quoise for Cu(II) and white for Zn(II). The compounds
were characterized by elemental analysis (Table 1) and
IR spectra (Table 2). 4-Chloro-2-methoxybenzoates of
Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) in solid state
show similar IR spectra. As anticipated, the character-
istic wavenumbers corresponding to the carbonyl
group are altered markedly when going from acid to
the complex. The band at 1684 cm–1 originating from
COOH group, present in the IR spectrum of the acid, is
replaced in the spectra of d-block element complexes
The X-ray powder diffraction were taken on a
HZG-4 (Carl Zeiss-Jena) diffractometer using Ni fil-
tered CuKa radiation. The measurements were made
within the range 2q=4–80° by means of the
Debye–Scherrer–Hull method.
The thermal stability and decomposition of Mn(II)
and Co(II) complexes were studied in air using a
Setsys 16/18 TG, DTA instrument. The experiments
were carried out under air flow in the temperature range
of 297–1273 K. Samples 5.07 mg of Mn(II) and
4.96 mg of Co(II) complexes were heated in Al2O3 cru-
cibles. The thermal analysis of 4-chloro-2-methoxy-
benzoates of Ni(II), Cu(II) and Zn(II) were determined
by Paulik–Paulik–Erdey Q-1500D derivatograph with
Derill converter, recording TG, DTG and DTA curves.
The measurements were made at a heating rate of
10 K min–1 with a full scale. The samples (100 mg) were
Table 1 Elemental analysis data of 4-chloro-2-methoxybenzoates of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)
H/% C/% M/%
Compound
calcd.
4.02
4.23
4.23
3.95
3.93
found
3.83
4.04
4.08
3.76
3.79
calcd.
38.55
36.92
36.93
37.90
37.75
found
38.76
37.05
37.19
37.90
38.01
calcd.
11.03
11.33
11.30
12.53
12.86
found
11.20
11.40
11.50
12.40
12.50
Mn(C8H6ClO3)2×4H2O
Co(C8H6ClO3)2×5H2O
Ni(C8H6ClO3)2×5H2O
Cu(C8H6ClO3)2×4H2O
Zn(C8H6ClO3)2×4H2O
784
J. Therm. Anal. Cal., 86, 2006

COMPLEXES OF Mn(II), Co(II), Ni(II), Cu(II) AND Zn(II)
Table 2 Wavenumbers (cm–1) of COO– bands in 4-chloro-2-methoxybenzoates of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), sodium
and of the COOH band in 4-chloro-2-methoxybenzoic acid
Compound
nC=O
nas(OCO)
ns(OCO)
DnOCO
nM–O
Mn(C8H6ClO3)2×4H2O
Co(C8H6ClO3)2×5H2O
Ni(C8H6ClO3)2×5H2O
Cu(C8H6ClO3)2×4H2O
Zn(C8H6ClO3)2×4H2O
C6H3ClOCH3COOH
NaC8H6ClO3
–
–
–
–
1604
1596
1596
1608
1604
–
1420
1412
1416
1416
1424
–
184
184
180
192
180
–
500
500
500
512
505
–
1684
–
1580
1404
176
–
by two bands at 1608–1596 and 1424–1412 cm–1, due
to asymmetric and symmetric vibrational modes of the
COO– group, respectively. The bands with the maxima
at 3488–3416 cm–1 characteristic for nOH vibrations,
and the narrow band of dOH at 1608–1596 cm–1 confirm
the presence of crystallization water molecules in the
complexes. The bands of nC–C ring vibrations appear
at 1608–1596, 1488–1456 and 1032–1024 cm–1. The
bands of CH3, d , antisymmetric and symmetric vi-
CH 3
brations are observed at 1488–1456 and
1384–1376 cm–1, respectively. The bands at
1252–1248 and 1032–1024 cm–1 were assigned to C–O
bond, (nas(C–O–C) and ns(C–O–C), respectively) in ether
compounds. The valency nC–Cl vibration bands occur
at 704–696 cm–1 and the bands at 512–500 cm–1 con-
firm the metal–oxygen bond [19, 20]. The magnitudes
of separation, Dn, between the frequencies of nas(OCO)
and ns(OCO) in the complexes are higher
(DnOCO=192–180 cm–1) than in the sodium salt
(DnOCO=176 cm–1). Accordingly, the carboxylate ion in
the analysed coordination compounds appears to be a
monodentate [20, 21].
In order to evaluate, if the 4-chloro-2-methoxy-
benzoates of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)
are crystalline or amorphous compounds, their X-ray
powder diffraction measurements were carried out.
The analysis of the diffractograms suggests that the
obtained complexes are polycrystalline compounds
(Fig. 1). Their comparison shows that 4-chloro-
2-methoxybenzoates of Co(II), and Ni(II) are proba-
bly isostructural compounds. The structures of the
complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)
have not been determined, because their single crys-
tals have not been obtained.
In order to verify the compositions of the com-
plexes, to determine the temperature ranges of their
thermal stability, and decomposition during heating in
air, to estimate the intermediate and final products of
their decomposition and to evaluate the type of pro-
cesses that occur during heating, the thermal stability of
4-chloro-2-methoxybenzoates of Mn(II), Co(II), Ni(II),
Cu(II) and Zn(II) was studied in the range of
293–1273 K. Some results are presented in Table 3, and
Fig. 1 Relationships between I/I0 and 2q for 4-chloro-2-methoxy-
benzoates of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)
J. Therm. Anal. Cal., 86, 2006
785

FERENC et al.
Table 3 Decomposition data for 4-chloro-2-methoxybenzoates of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) in air atmosphere
and their solubility in water at 293 K
Mass loss/%
calcd. found
Mass loss/%
calcd.
DT1/K
DT2/K
Compound
n
Solubility/mol dm–3
found
84.50
86.00
85.80
86.50
85.90
Mn(C8H6ClO3)2×4H2O
Co(C8H6ClO3)2×5H2O
Ni(C8H6ClO3)2×5H2O
Cu(C8H6ClO3)2×4H2O
Zn(C8H6ClO3)2×4H2O
364–400
360–408
359–409
330–395
323–411
14.46
17.31
17.31
14.21
14.16
14.20
17.35
17.37
14.00
14.28
4
5
5
4
4
433–851
503–1212
489–973
473–1016
473–903
84.69
85.75
85.63
84.31
83.99
1.80×10–3
2.20×10–3
2.10×10–3
1.50×10–3
1.60×10–3
DT1 – temperature range of dehydration process; n – number of crystallization water molecules being lost in one endothermic step;
DT2 – temperature range of complex decomposition
364–400 K
Mn(C8H6ClO3)2·4H2O ¾¾¾®
433–851 K
Mn(C8H6ClO3)2 ¾¾¾® Mn3O4
Fig. 2. The results reveal that the complexes of Mn(II),
Cu(II) and Zn(II) are tetrahydrates whereas those of
Co(II) and Ni(II) are pentahydrates. These results were
also confirmed by the elemental analysis (Table 1), and
the IR spectra data. The complexes are stable up
to 323–364 K. Next they dehydrate in one step losing 4
or 5 molecules of crystallization water and form anhy-
drous compounds. The losses of mass calculated from
TG curves (14.00–17.37%) correspond to the losses of 4
and 5 molecules of water (the theoretical values are
equal to 14.16–17.31%). The tetrahydrate of 4-chloro-
2-methoxybenzoate of Mn(II) is the most thermally sta-
ble complex since its initial temperature of dehydration
is equal to 364 K, while tetrahydrate of Zn(II) has less
thermal stability (323 K). The dehydration process is ac-
companied by endothermic effect seen in the DTA
curves. The anhydrous complexes of Mn(II), Co(II),
Ni(II), Cu(II) and Zn(II) in air are stable up to
411–503 K and heated further they decompose to the re-
spective oxides: Mn3O4, CoO, NiO, ZnO and to mixture
of CuO and Cu. 4-Chloro-2-methoxybenzoate of Co(II)
(Fig. 2) decomposes to CoO with intermediate forma-
tion of Co3O4. The process of Co3O4 reduction to CoO is
connected with endo-effect to be seen in DTA
curve [22–24]. The combustion of the organic ligand is
accompanied by strong exo-effect seen on DTA curves.
The final products of decomposition of 4-chloro-
2-methoxybenzoates of Mn(II), Co(II), Ni(II), Cu(II)
and Zn(II) were calculated from TG curves and experi-
mentally verified by the X-ray diffraction pattern and IR
spectra registration. The mass losses calculated from TG
curves are equal to 84.50–86.50% (the theoretical val-
ues are 83.99–85.75%). In the case of Cu(II) and Zn(II)
complexes the found values of the losses of mass are
greater than the theoretical value. This is probably con-
nected with properties of ZnO at higher temperature and
with chemical transformation of Cu(II) complex with
increasing temperature.
360–408 K
Co(C8H6ClO3)2·5H2O ¾¾¾®
503–838 K 1181–1212 K
Co(C8H6ClO3)2 ¾¾¾® Co3O4 ¾¾¾® CoO
359–409 K
Ni(C8H6ClO3)2·5H2O ¾¾¾®
489–973 K
Ni(C8H6ClO3)2 ¾¾¾® NiO
330–395 K
Cu(C8H6ClO3)2·4H2O ¾¾¾®
473–1016 K
Cu(C8H6ClO3)2 ¾¾¾® CuO, Cu
323–411 K
Zn(C8H6ClO3)2·4H2O ¾¾¾®
473–903 K
Zn(C8H6ClO3)2 ¾¾¾® ZnO
The solubility of 4-chloro-2-methoxybenzoates
of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) in water
at 293 K was measured (Table 3). Its values amount
to: 1.8·10–3 mol dm–3 (for Mn(II) complex), 2.2·
10–3 mol dm–3 (for Co(II) complex), 2.1·10–3 mol dm–3
(for Ni(II) complex), 1.5·10–3 mol dm–3 (for Cu(II)
complex) and 1.6·10–3 mol dm–3 (for Zn(II) complex).
The complex of Co(II) is the most soluble salt while
that of Cu(II) is the least soluble one.
The magnetic susceptibility of 4-chloro-2-
methoxybenzoates of Mn(II), Co(II), Ni(II) and Cu(II)
was measured in the temperature range of 76–303 K
(Table 4). All the complexes show paramagnetic prop-
erties and essentially obey the Curie–Weiss law, since
The obtained results indicate that the thermal de-
composition of 4-chloro-2-methoxybenzoates of
Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) in air pro-
ceeds in the following steps:
Fig. 2 TG, DTG and DTA curves of 4-chloro-2-methoxy-
benzoate of Co(II)
786
J. Therm. Anal. Cal., 86, 2006

COMPLEXES OF Mn(II), Co(II), Ni(II), Cu(II) AND Zn(II)
Table 4 Values of meff and ccMorr for 4-chloro-2-methoxybenzoates of Mn(II), Co(II), Ni(II) and Cu(II)
Mn(C8H6ClO3)2×4H2O
Co(C8H6ClO3)2×5H2O
Ni(C8H6ClO3)2×5H2O
Cu(C8H6ClO3)2×4H2O
T/K
ccMorr×106
meff/mB
T/K
ccMorr×106
meff/mB
T/K
ccMorr×106
meff/mB
T/K
ccMorr×106
meff/mB
76
123
133
143
153
163
173
183
193
203
213
223
233
243
253
263
273
283
293
303
58579
36712
33217
30360
28254
26551
24949
23661
22507
21532
20031
19673
18788
18082
17421
16951
16379
15965
15483
15013
5.97
6.01
5.95
5.90
5.88
5.89
5.88
5.89
5.90
5.92
5.85
5.93
5.92
5.93
5.94
5.98
5.98
6.02
6.03
6.04
76
123
133
143
153
163
173
183
193
203
213
223
233
243
253
263
273
283
293
303
25701
18628
17412
16447
15659
14930
14193
13544
13029
12543
12093
11622
11172
10804
10487
10185
9942
3.96
4.28
4.31
4.34
4.38
4.41
4.43
4.46
4.49
4.52
4.54
4.56
4.57
4.59
4.61
4.63
4.66
4.70
4.73
4.75
76
123
133
143
153
163
173
183
193
203
213
223
233
243
253
263
273
283
293
303
8828
6745
6366
6061
5806
5585
5389
5184
5030
4867
4717
4554
4408
4283
4183
4112
3999
3907
3824
3749
2.32
2.58
2.60
2.63
2.67
2.70
2.73
2.76
2.79
2.81
2.84
2.85
2.87
2.89
2.91
2.94
2.96
2.98
3.00
3.02
76
123
133
143
153
163
173
183
193
203
213
223
233
243
253
263
273
283
293
303
5402
3245
2967
2750
2631
2453
2324
2196
2097
2057
1928
1849
1810
1721
1681
1661
1602
1532
1612
1473
1.81
1.79
1.78
1.77
1.80
1.79
1.79
1.79
1.80
1.83
1.81
1.82
1.84
1.83
1.85
1.87
1.87
1.86
1.94
1.89
9750
9522
9301
the values of their magnetic susceptibility decrease
with increasing temperature. The paramagnetic
dependences of magnetic susceptibility values of the
complexes as a function of temperatures are presented
in Table 4 and those only for Co(II) complex in Fig. 3.
The experimental data suggest that the 4-chloro-2-
methoxybenzoates of Co(II), Ni(II) and Mn(II) are
high-spin complexes of octahedral coordination with a
weak ligand field (Tables 4 and 5). From the data pre-
sented in Tables 4 and 5 it follows that there is no sig-
nificant orbital contribution to the magnetic moments
of the complexes (spin only for complexes of Mn(II)
and Ni(II)), or its contribution is essential (complex of
Co(II)). In the case where no orbital contribution to the
magnetic moments is to be expected its experimentally
measured values differ from the spin-only moment.
The values of meff=5.88–6.04 mB obtained for Mn(II)
4-chloro-2-methoxybenzoate suggest that it is
high-spin compound with LK=6. In the coordination
sphere of Mn(II) ion there are probably four molecules
of water and two monodentate groups of acid anions.
This was confirmed by the IR spectral analysis and it
appears that the carboxylate groups are monodentate.
The magnetic moment values of Ni(II) 4-chloro-2-
methoxybenzoate change from 2.32–3.02 mB. This in-
dicate that in the solid state the Ni2+ ion exists in an oc-
tahedral triplet ground state with the five molecules of
water and probably with one monodentate carboxylate
group coordinated to the cation. The IR spectrum re-
veals that the carboxylate groups in this compound are
in fact monodentates. The effective magnetic moments
calculated for the complex of Co(II) are equal to
3.96–4.75 mB. The values indicate that it is also a
high-spin complex with octahedral structure. In the co-
Fig. 3 Dependence of magnetic susceptibility values vs. tem-
perature for 4-chloro-2-methoxybenzoate of Co(II)
J. Therm. Anal. Cal., 86, 2006
787

FERENC et al.
Table 5 Magnetic moments of complexes with the central ions of Mn(II), Co(II), Ni(II) and Cu(II) with octahedral coordination
Central atom
Mn2+
5
Co2+
7
Ni2+
8
Cu2+
9
Number of d electrons
High-spin complexes
Number of unpaired electrons
Spin-only moment (mB)
Magnetic moment (mB)
5
3
2
1
5.92
3.88
2.83
1.73
5.32–6.10
4.30–5.20
2.80–3.50
1.70–2.20
Low-spin complexes
Number of unpaired electrons
1
1
0
–
–
–
Magnetic moment (mB)
1.80–2.10
1.80
References
ordination sphere of Co(II) ion there are probably five
molecules of water and one monodentate carboxylate
group. Such character of carboxylate groups was also
confirmed by the IR spectral analysis. The magnetic
and X-ray powder diffraction measurements indicate
that complexes of Co(II) and Ni(II) have probably the
same structure. The results of thermal analysis of com-
plexes of Mn(II), Co(II) and Ni(II) show that mole-
cules of water are lost in one step which suggests that
they may be bound in the same way. The changing
magnetic moment values of Cu(II) complex from 1.77
to 1.94 mB, the decreasing of magnetic susceptibility
data with rising temperature, and the interpretation of
IR spectra may suggest it to be monomeric com-
pound [14, 25–32].
1 V. Aldea and E. R. Oltenau, Patent – Rom. 62,894
(Cl. C07C103/29), 25 Aug. 1977, Appl. 77,645,
12 Feb. 1974, p. 3.
2 M. Ogata and H. Matsumoto, Patent – Ger. Offen.
2,803,651 (Cl. C07D207/08), 03 Aug. 1978, Japan,
Appl. 77/8,443, 27 Jan, 1977, p. 34.
3 M. Thominet, J. Acher and J. C. Monier, Patent – Ger.
Offen. 2,901,170 (Cl. C07D207/08), 26 Jul. 1979, Fr.,
Appl. 78/1,633, 20 jan. 1978, p. 86.
4 J. Skoršepa, E. Godoºiková and J. ‡ernák,
J. Therm. Anal. Cal., 75 (2004) 773.
5 F. C. D. Lemos, M. Muraro, J. Zukerman-Schpector,
É. T. G. Cavalheiro and R. R. Dockal, J. Therm. Anal. Cal.,
75 (2004) 599.
6 I. Labadi, I. Lakos, G. Kenessey and G. Liptay,
J. Therm. Anal. Cal., 76 (2004) 829.
7 K. Györyová, J. Chomi¹ and J. Ková¹ová,
J. Therm. Anal. Cal., 80 (2005) 375.
Conclusions
8 W. Ferenc, B. Bocian and B. Czajka, ACH-Models Chem.,
136 (1999) 571.
4-Chloro-2-methoxybenzoates of Mn(II), Co(II),
Ni(II), Cu(II) and Zn(II) were characterized by ele-
mental analysis, thermal stability in air atmosphere,
IR spectral data, X-ray powder investigations, solu-
bility in water at room temperature and magnetic
properties. The obtained results indicate that com-
plexes crystallize as tetra- or pentahydrates. When
heated they dehydrate to form anhydrous salts which
next are decomposed to the oxides of the respective
metals. The solubility of the analysed compounds of d
block elements in water is of the order of
10–3 mol dm–3. The complexes of Mn2+, Co2+, Ni2+
and Cu2+ with 4-chloro-2-methoxybenzoic acid anion
obey the Curie–Weiss law, since the values of their
magnetic susceptibility decrease with rising tempera-
ture. The obtained meff values for Mn(II), Co(II) and
Ni(II) complexes may suggest that they are high-spin
complexes with octahedral coordination and with the
weak electrostatic field of ligands in the coordination
sphere of central ion.
9 W. Ferenc and B. Bocian, J. Therm. Anal. Cal., 62 (2000) 831.
10 W. Ferenc, B. Bocian and B. Czajka, ACH-Models Chem.,
137 (2000) 659.
11 B. Bocian, B. Czajka and W. Ferenc, J. Therm. Anal. Cal.,
66 (2001) 729.
12 B. Czajka, B. Bocian and W. Ferenc, J. Therm. Anal. Cal.,
67 (2002) 631.
13 B. Bocian and W. Ferenc, J. Serb. Chem. Soc., 67 (2002) 605.
14 W. Ferenc and B. Bocian, J. Therm. Anal. Cal., 74 (2003) 521.
15 W. Ferenc and B. Bocian, Annals of the Pol. Chem. Soc.,
2 (2003) 541.
16 W. Ferenc, A. Walków-Dziewulska and B. Bocian,
J. Therm. Anal. Cal., 79 (2005) 145.
17 W. Ferenc, B. Bocian and A. Walków-Dziewulska,
J. Therm. Anal. Cal., 76 (2004) 179.
18 E. König, Magnetic Properties of Coordination and
Organometallic Transition Metal Compounds,
Springer Verlag, Berlin 1966.
19 E. Pretsch, T. Clerc, J. Seibl and W. Simon, Tables of
Spectral Data for Structure Determination of Organic
Compounds, Springer Verlag, Berlin 1989.
20 K. Nakamoto, Infrared and Raman Spectra of Inorganic
and Coordination Compounds, John Wiley and Sons,
Toronto 1997.
788
J. Therm. Anal. Cal., 86, 2006

COMPLEXES OF Mn(II), Co(II), Ni(II), Cu(II) AND Zn(II)
21 S. Manhas and A. K. Trikha, J. Indian Chem. Soc.,
29 M. Hvastijova, J. Kohout, J. MroziÕski and L. Jäger,
59 (1982) 315.
Pol. J. Chem., 69 (1995) 852.
22 J. Garcia-Oricain and A. Fuster Camps, J. Thermal Anal.,
29 (1984) 793.
30 M. Melnik and J. MroziÕski, Mater. Sci., 14 (1988) 3.
31 M. Melnik, D. MroziÕska and J. MroziÕski, Mater. Sci.,
4 (1989) 65.
23 D. Dollimore and D. L. Griffiths, J. Thermal Anal.,
2 (1970) 229.
32 M. Melnik, Z. Sabova, J. MroziÕski and A. Szymaszek,
J. Mol. Struct., 240 (1990) 285.
24 D. Czakis-Sulikowska, A. Malinowska and J.
RadwaÕska-Doczekalska, Pol. J. Chem., 74 (2000) 607.
25 S. F. A. Keetle, Inorganic Physical Chemistry, PWN,
Warszawa 1999 (in Polish).
Received: September 30, 2005
Accepted: November 8, 2005
OnlineFirst: May 23, 2006
26 C. I. O. O’Connor, Progress in Inorganic Chemistry,
Wiley, New York 1982.
27 J. MroziÕski, Mater. Sci., 14 (1988) 23.
28 J. MroziÕski and L. Natkaniec, Mater. Sci., 14 (1988) 69.
DOI: 10.1007/s10973-005-7379-z
J. Therm. Anal. Cal., 86, 2006
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