Thermal and other properties of complexes of Mn(II), Co(II) and Ni(II) with 2,2′-bipyridine and trichloroacetates

Article abstract of DOI:10.1023/A:1026371029185

Complexes of the general formulae Mn(2-bpy)₂(CCl₃CCOO)₂, Co(2-bpy)₂(CCl₃COO)₂ ·H₂O and Ni(2-bpy)₂(CCl₃COO)₂·2H₂O (where: 2-bpy=2,2′-bipyridine) have been prepared and characterized by VIS and IR spectroscopy, conductivity and magnetic measurements. The thermal properties of complexes in the solid state were studied under non-isothermal conditions in air atmosphere. During heating the complexes decompose via different intermediate products to the oxides MN₃O₄, CoO and NiO. A coupled TG-MS system was used to detection the principal volatile products of thermal decomposition and fragmentation processes of obtained compounds. The principal volatile products of thermal decomposition of complexes are: H₂O⁺, CO₂⁺, Cl₂⁺ and other.

Full text of DOI:10.1023/A:1026371029185

Journal of Thermal Analysis and Calorimetry, Vol. 74 (2003) 349–360
THERMAL AND OTHER PROPERTIES OF
COMPLEXES OF Mn(II), Co(II) AND Ni(II) WITH
2,2’-BIPYRIDINE AND TRICHLOROACETATES
D. Czakis-Sulikowska* and A. Czylkowska
Institute of General and Ecological Chemistry, Technical University, ˜ódŸ, Poland
(Received February 19, 2003; in revised form March 22, 2003)
Abstract
Complexes of the general formulae Mn(2-bpy)2(CCl3COO)2, Co(2-bpy)2(CCl3COO)2·H2O and
Ni(2-bpy)2(CCl3COO)2·2H2O (where: 2-bpy=2,2’-bipyridine) have been prepared and characterized
by VIS and IR spectroscopy, conductivity and magnetic measurements. The thermal properties of
complexes in the solid state were studied under non-isothermal conditions in air atmosphere. During
heating the complexes decompose via different intermediate products to the oxides Mn3O4, CoO and
NiO. A coupled TG-MS system was used to detection the principal volatile products of thermal de-
composition and fragmentation processes of obtained compounds. The principal volatile products of
thermal decomposition of complexes are: H2O+, CO2+ , Cl2+ and other.
Keywords: 2,2’-bipyridine complexes, conductivity, mass spectrometry, thermal decomposition,
trichloroacetate, VIS-IR spectra
Introduction
In earlier publications, we have reported the synthesis and characterization of
mixed-ligand complexes of Mn(II), Co(II), Ni(II) and Cu(II) with 4,4’-bipyridine
(4-bpy) and mono- and trichloroacetates [1, 2]. Some conclusions of their structure
were drawn. The thermal behaviours of these compounds (in the temperature range
20–1000oC) were studied using TG/DTA, and TG-MS techniques in air.
In connection with our investigation into the 4,4’-bipyridine–trichloroacetato
complexes of the transition metals [2] a comparative study of the corresponding
2,2’-bipyridine–trichloroacetato compounds seemed of interest.
The influence of bipyridine isomers and halogenoacetates species on the several
behaviours of these type of complexes was not studied. The bipyridine isomers fa-
vour mainly types of coordination: as an example, 2-bpy is potential bidentate chelat-
ing ligand; 4-bpy can coordinate as bidentate bridging ligand; 2,4’-bipyridine acts as
monodentate ligand [3, 4]. The influence of nitrogen atom position from the bi-
pyridine was observed on thermal stability of mixed bipyridine–oxalato complexes
with several metals(II) [5, 6]. The complexes of 2-bpy and 4-bpy are more stable,
than those containing 2,4’-bipyridine.
*
Author for correspondence: E-mail: ich@zto.pw.plock.pl
1388–6150/2003/ $ 20.00
Akadémiai Kiadó, Budapest
© 2003 Akadémiai Kiadó, Budapest
Kluwer Academic Publishers, Dordrecht

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CZAKIS-SULIKOWSKA, CZYLKOWSKA: Mn(II), Co(II) AND Ni(II) COMPLEXES
The interesting aspect of title complexes lies also in the fact, that the
halogenoacetate ion can coordinate metal(II) ions in various ways: as a simple
unidentate ligand, or as a bidentate bridging or chelating, symmetric or asymmetric
group [7–12]. However, studies on the metal(II) complexes with 2,2’-bipyridine and
trichloroacetates are not reported yet in literature. Only the complex of Zn(II) with
2-bpy and trichloroacetates was described in [13]. Several mixed-ligand complexes
of Co(II), Ni(II) and Cu(II) with trichloroacetates and other N-donors also have been
synthesized and characterized [12, 14–16]. Shova et al. [17, 18] prepared trichloro-
acetates of manganese(II) and cobalt(II). The molecular structure of these com-
pounds was determined. Therefore, in this paper we describe the results of our inves-
tigations on Mn(II), Co(II) and Ni(II) complexes with 2,2’-bipyridine and trichloro-
acetates. This report is concerned predominantly on the nature of metal-ligand bond
and thermal decomposition of obtained compounds.
Experimental
Materials, synthesis and analysis
2,2’-Bipyridine (m.p. 72°C) and other chemicals were the same as described in our
previous papers [2, 6].
The complexes were synthesized by reacting water solutions of M(CCl3COO)2
(M(II)=Mn, Co, Ni) with solution of 2,2’-bipyridine in 96% v/v ethanol. The procedure
was similar to that used for the 4,4’-bipyridine compounds [2]. The chemical formulae of
obtained complexes have been established analytically. The solid thermal decomposition
products at different temperatures were identified using derivatographic curves, analyti-
cal and IR data or X-ray diffractograms. Obtained X-ray diffractometric results were ana-
lyzed using the Powder Diffraction File [19]. Metal(II) in mineralized samples was deter-
mined complexometrically; C, H and N – by standard elemental analysis with V2O5 as
oxidizing agent.
Physical measurements
Molar conductivities (ΛM) of complexes were measured [20] on 1.0⋅10–3 mol L–1 solu-
tions in methanol, DMSO and DMF at 25 0.05°C. The magnetic susceptibility of pre-
pared complexes was measured on a magnetic balance (Sherwood scientific MSB MK I)
using Co[Hg(SCN)4] as a calibrant, and experimental magnetic susceptibilities were cor-
rected for diamagnetism [21]. Thermal behaviours of title complexes were investigated
by techniques: TG/DTA, DTG with derivatograph OD-102/1 500°C. The samples of 100
mg were heated in ceramic crucible in air static atmosphere. α-Al2O3 was used as stan-
dard material. TG-MS system consisting of derivatograph TG/DTA SETSYS-16/18,
coupled to a mass spectrometer (QMS-422), model ThermoStar Balzers Instruments;
platinum crucible 100 µL; dynamic measurements were carried out in air or in argon at-
mosphere at flow rate of 1 L h–1 ; sample of mass in the range ca. 9–11 mg (Figs 2 and 3);
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CZAKIS-SULIKOWSKA, CZYLKOWSKA: Mn(II), Co(II) AND Ni(II) COMPLEXES
351
an ion source temperature of ca. 150°C by using 70 eV electron impact ionization. All
thermal investigations were carried between 20–1000°C, at heating rate 10°C min–1.
Results and discussion
Reactions of metal trichloroacetates with 2,2’-bipyridine in ethanol (75% v/v) – water so-
lution yield solid complexes of the composition Mn(2-bpy)2(CCl3COO)2,
Co(2-bpy)2(CCl3COO)2⋅H2O and Ni(2-bpy)2(CCl3COO)2⋅2H2O. The analytical, conduc-
tivity and magnetic data of compounds are collected in Table 1. The complexes of Co(II)
and Ni(II) are right soluble in water; the compound of Mn(II) is fairly soluble
(1.25⋅10–2 mol L–1). The analysis of the diffractograms proved that these complexes are
crystalline. Complex Ni(2-bpy)2(CCl3COO)2⋅2H2O shows higher symmetry than other
compounds. The molar conductance values of complexes in methanol fall within the gen-
erally acceptable range for electrolytes 1:1 [22]. Conductivity data suggested that all
compounds in DMSO and Co(II) and Ni(II) complexes in DMF present intermediate be-
haviour between those of non- and 1:1 electrolytes. Higher than anticipated ΛM values are
usually due to the displacement of trichloroacetate ligand by a molecule of solvent. Simi-
lar behaviours were observed for Mn(II), Co(II) and Ni(II) complexes with 4-bpy and
mono- or trichloroacetates [1, 2], and other metal(II) complexes with several amines
[20, 23]. The very low molar conductance value indicate the non- electrolytic nature of
the Mn(2-bpy)2(CCl3COO)2 in DMF. The room temperature effective magnetic moment
µeff of Ni(II) complex corresponds to two unpaired electrons. The Ni(II) complex shows
magnetic moment value of 3.84 M.B., which is in the range expected for octahedral com-
plexes [12, 24]. The µeff value for the Co(II) complex is 3.65 M.B., which is lower than
observed range for octahedral complexes (µeff.cald. 3.88 M.B., observed in the range
4.30–5.20 M.B.). Sub-normal magnetic moment in the present compound suggests the
possibility of at best a very weak interaction between the paramagnetic centres [25].
Electronic absorption spectra
These spectra of solid Co(II) and Ni(II) complexes in Nujol mulls exhibit strong band
above 26 000 cm–1 which may be assigned to charge transfer transition. The ligand field
spectra of these complexes are entirely consistent with a distorted octahedral donor envi-
ronment around the metal ions [26]. The main absorption band at 20 800 cm–1, observed
4
in spectra of Co(II) complex, can be attributed to the T1g(P)←4T1g(F) and shoulder at
4
16 000 cm–1 as A2g←4T1g(F) transitions. The d–d bands of the Ni(II) complex are as-
3
signed to the following transitions: T1g(F)←3A2g (17600 cm–1) and 1Eg←3A2g
(12 800 cm–1, shoulder). The Rule of Average Environment (RAE) [26] has been applied
to indicate of chromophores in the obtained solid complexes of cobalt(II) and nickel(II).
The comparison of the values of νcalcd=21 000 cm–1 (for transition 4T1g(P)←4T1g(F)) and
ν
calcd=17 400 cm-1 (for 3T1g(F)←3A2g) with the experimental ν and supported by IR data,
indicate that the following chromophores are presented in the compounds: CoN4O2 and
NiN4O2 (where: O-form carboxylate groups).
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CZAKIS-SULIKOWSKA, CZYLKOWSKA: Mn(II), Co(II) AND Ni(II) COMPLEXES
353
Infrared spectra
The IR spectrum of free 2-bpy changes owing to complex formation [27]. The most char-
acteristic ring stretching C–C, C–N, C–Ci.r. str. (symmetry A1) and C–N, C–C str. (sym-
metry B1) frequencies, appearing at 1579 and 1553 cm–1 in a free ligand are observed in
these compounds in the ranges 1604.7–1596.6 cm–1 and 1575.7–1568.4 cm–1, respec-
tively. The pyridine ‘breathing’ frequency is shifted by about 33–24 cm–1 towards higher
values. The characteristic out-of-plane hydrogen deformation modes in unbonded 2-bpy
are observed of 753 and 738 cm–1; the complexes exhibit very strong absorptions at
769.5–761.3 and 736.8–731.0 cm–1. The IR data at all isolated complexes show that they
are cis–2,2’-bipyridine chelates [27, 28].
Table 2 Principal IR bands (cm–1) for 2-bpy and OCO group in obtained complexes
Complex
CCl3COONa
Assignment
[29]
Mn(II)
Co(II)
Ni(II)
Coordinated 2-bpy modes
1604.7
1596.6
1604.7
1600.8
C–C, C–N, C–Ci,r str.
C–N, C–C str.
–
1598.9
1575.7
1568.8
1575.7
1568.4
–
1569.0
761.3
731.0
765.7
732.9
769.5
736.8
C–H out of plane bend
Pyridine ‘breathing’
–
–
1014.5
1020.3
1024.1
Carboxylate group modes
1700.3
1687.6 pd
1708.8 pd
1688.5
1718.8
1688.7
as(OCO)
s(OCO)
1677.0
1354.9
1329.2
1350.1
1317.3
1363.6
1338.5
1353.0
324.0
348.1
358.4
358.7
371.2
353.2
350.2
=
as(OCO– s(OCO)
pd – poorly resolved doubler; i.r. – inter-ring bands
The IR spectra of studied complexes revealed also absorptions of the carboxylate
group. Principal concern are the positions of the asymmetric (νas) and symmetric (νs)
stretching frequencies and their separation (∆ν=νas–νs). These are listed in Table 2 for
complexes, together with data for sodium salt. The asymmetric bands lie between
1718.8–1687.6 cm–1 and are in all complexes, higher than the νas(OCO) of the
CCl3COONa. Calculated from examined spectra values of ∆ν of complexes are in the
range 348–371 cm–1 and are higher than for sodium salt. This suggests the presence of
thermal carboxylate groups in obtained complexes [7–12]. IR spectra of all complexes
exhibit two clearly separated bands in the symmetric stretching frequency νs(OCO) re-
gion. This would seem to indicate that the complexes have a cis-configuration [12]. A
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CZAKIS-SULIKOWSKA, CZYLKOWSKA: Mn(II), Co(II) AND Ni(II) COMPLEXES
strong and broad band in the water stretching region (ca. 3050–3450 cm–1) and only the
shoulder in the water bending region (ca. 1625 cm–1) for Ni(2-bpy)2(CCl3COO)2⋅2H2O
complex are observed.
Thermal properties of complexes in air
The solid intermediate products of decomposition were determined from TG curve
and were confirmed by recording the IR spectra of sinters. IR spectra for sinters (pre-
pared during the heating of sample of complex up to definite temperature from TG)
occur the bands of 2-bpy and carboxylate groups (for intermediate products of
Co(2-bpy)2Cl1.5(CCl3COO)0.5) or only bands of 2-bpy products of the type
M(2-bpy)nCl2. In the sinters presence of anions Cl– was investigated. They were in all
intermediate products. The final solid products of decomposition were calculated
from TG curve and verified by X-ray diffraction patterns registration. The thermal
decomposition data of the obtained complexes are collected in Table 2. All the com-
plexes decompose progressively. The anhydrous complex Mn(2-bpy)2(CCl3COO)2
begin decompose at about 95oC. Thermoanalytical curves of Mn(2-bpy)2(CCl3COO)2
in air is shown, as an example, in Fig. 1. A sudden mass loss was observed between
95–160°C, which corresponded to the composition, Mn(2-bpy)2Cl2 with trace of not
burned carbon. The appropriate exothermic peak on DTA is at 115°C. Next, the step-
Fig. 1 Thermoanalytical curves of Mn(2-bpy)2(CCl3COO)2; mass sample 100 mg
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CZAKIS-SULIKOWSKA, CZYLKOWSKA: Mn(II), Co(II) AND Ni(II) COMPLEXES
355
wise elimination of 2-bpy begins and Mn2O3 forms. The deamination processes are
partly overlap; on TG curve show only the bendings. According to the DTG curve
[30] is probably, than 2-bpy is lost in three stages and intermediate forms
Mn(2-bpy)1.5Cl2 and Mn(2-bpy)0.5Cl2. Above 680°C the slow conversion Mn2O3 to
Mn3O4 takes place (only diffraction lines characteristic of Mn3O4 were detected). The
very strong and broad exothermic effect on the DTA curve with centers is associated
with the combustion of the organic ligands. The Scheme 1 of thermal decomposition
of Mn(II) compound in air is:
awith ca. 1.5% C; bby projecting minimum of the DTG curve on TG curve
On Schemes 1–3 are shown below the arrows the mass values (%) found (with-
out brackets) and those calculated (in brackets). Above the arrows there are presented
ranges of decomposition and peaks from DTA (°C).
Hydrate complexes are stable up to 100oC (Co) and up to 80°C (Ni). The rapid
mass loss observed on TG in range 100–180°C (Co) and 80–240°C (Ni) is connected
with the dehydration and decomposition of trichloroacetates. Following intermediate
compounds were detected: Co(2-bpy)2Cl1.5(CCl3COO)0.5 (clearly separated step) and
Ni(2-bpy)2Cl2 with trace of ca. 1.5% C. Between 180–260°C Co(2-bpy)2Cl2 is
formed. This stage of decomposition is followed by exothermic peak at 220°C for Co
and broad exoeffect with center at ca. 300°C for the nickel complex. The intermediate
complexes M(2-bpy)2Cl2 (where: M(II)=Co, Ni) appeared to more stable than the
corresponding Mn(2-bpy)2Cl2 complex. The intermediate compounds M(2-bpy)2Cl2
deaminate in two stages. At first 1 mol of 2-bpy was eliminated to form M(2-bpy)Cl2
(temperature range 260–440°C for Co and 240–490°C for Ni). In the case of the
nickel compound this step is not clearly separated on the TG curve. On temperature
elevation, Co(2-bpy)Cl2 decompose via Co3O4 to CoO. A horizontal mass level for
NiO begins at 738°C. These oxides of metals(II) were verified by X-ray diffraction
patterns registration. DTA curves present mixture of several endo- and exothermic
peaks. The very strong exothermic maxima with center at: 405, 640, 720°C (Co) and
broad exothermic effects in the range 240–310, 640–720°C (Ni) correspond to pyrol-
ysis of organic ligands. Schemes of thermal decomposition of Co(II) and Ni(II) com-
plexes can be expressed as:
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CZAKIS-SULIKOWSKA, CZYLKOWSKA: Mn(II), Co(II) AND Ni(II) COMPLEXES
awith trace of ca. 1.5% C; bby projecting minimum of the DTG curve on TG curve; sh-shoulder;
br-broad
Thermal stability of obtained complexes in argon atmosphere was not analyzed.
Mass spectrometric analysis
Mass spectrum measured obtained during thermal decomposition and fragmentation
processes in air of complexes showed presence of several ion signals intensities. The
m/z values are given based on: 1H, 12C, 16O, 14N and 35Cl.
In air atmosphere major maxima of ion current signals are observed at ca. 183
and 430–450°C for Mn(II) compound. The MS peaks coincide with mass decrease
appeared on TG. In the temperature ca. 183°C, dominate in gases the molecular ions
CO+2 (m/z=44), formed probably by decomposition of carboxylate groups. In this re-
gion of temperatures, ion signals was detected also for: Cl+2 (m/z=70) and traces of
other signals. At higher temperatures ca. 430–450°C further maxima for CO +2 occur;
additional signals with m/z= 30, 76, 78 (NO+, N2O3+ and 2-bpy·+ radical) were ob-
served. Many ion signals in these temperatures correspond to total decomposition of
trichloroacetate anions; next probably release and pyrolysis of 2-bpy takes place.
Maximum rates of forming NO+ at 478, 536°C and N2O+3 at 451°C are observed.
The total amount and relative aboundance of ions current for Co(II) and Ni(II) com-
plexes are sufficiently similar to those detected for Mn(II) complex. In the case of Co(II)
compound many maxima of signals take place at ca. 164–180 and 385–420°C, and for
Ni(II) complex at ca. 148 and 359–376°C. Generally, varieties in the ion currents for
Mn(2-bpy)2(CCl3COO)2, Co(2-bpy)2(CCl3COO)2⋅H2O and Ni(2-bpy)2(CCl3COO)2⋅2H2O
complexes are following: in the case of Co(II) complex many maxima for ion currents
are shifted by ca. 20°C for Ni(II) complex by ca. 50–70°C to lower temperatures. MS
peaks of H2O+ (m/z=18) appeared at ca. 164, 500°C (Co) and 179, 376°C (Ni). The strong
peaks CO+2 (m/z=44) were observed at: 242, 421, 551°C for Co(II) complex and 290, 372
and 480°C (Ni). The peaks of NO+ appeared at 425, 555°C (Co) and 373°C (Ni). Correla-
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CZAKIS-SULIKOWSKA, CZYLKOWSKA: Mn(II), Co(II) AND Ni(II) COMPLEXES
357
tion of some m/z observed by MS with TG curves for Mn(II) and Ni(II) compounds is
shown as an example in Fig. 2.
Fig. 2 TG curve and ion current detected by the MS in air for:
Mn(2-bpy)2(CCl3COO)2, sample mass 11.61 mg, m/z: 1–30; 2–44; 3–70;
a – order of the magnitude of ion currents/A: E-10, E-09, E-12, respectively,
Ni(2-bpy)2(CCl3COO)2·2H2O, sample mass 9.04 mg, m/z: 1–18; 2–30; 3–44;
b – order of the magnitude of ion currents/A: E-09, E-10, E-09, respectively
In argon the main peaks of MS occur in region of lower temperatures at ca.
165–170oC (Mn), 243–268°C (Co), 167–193 and 278–284°C for Ni(II) complex. MS
data detected only some ions signal. Major profiles for ions current are observed with
m/z:18 (only for Co(II) and Ni(II)), 27, 44 and traces of 70 and 78. At higher tempera-
tures only certain smaller peaks are observed. Additionally in argon atmosphere the
elimination of signal with m/z=28 (which corresponds to CO+ or N2+ ) is observed. The
MS peaks with m/z=28 appeared at: 168, 843°C (Mn), 265, 520, 613, 731°C (Co) and
278, 517°C for Ni(II) complex; on the other hand, the main peaks of CO +2 appeared
at: 168°C (Mn), 260°C (Co) and 282, 511°C for Ni(II) compounds. The maximum
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CZAKIS-SULIKOWSKA, CZYLKOWSKA: Mn(II), Co(II) AND Ni(II) COMPLEXES
Fig. 3 TG curve and ion current detected by the MS in argon for:
Mn(2-bpy)2(CCl3COO)2, sample mass 8.47 mg, m/z: 1–28; 2–44; 3–70;
a – order of the magnitude of ion currents/A: E-09, E-09, E-12, respectively,
Co(2-bpy)2(CCl3COO)2·H2O, sample mass 9.37 mg, m/z: 1–18; 2–28; 3–44;
b – order of the magnitude of ion currents/A: E-09, E-10, E-09, respectively
rate of elimination of H2O+ occurs at around 188°C (Co) and 193°C (Ni). TG coupled
with MS data for some m/z are presented in Fig. 3.
Conclusions
New mixed-ligand complexes of general formulae M(2-bpy)2(CCl3COO)2⋅nH2O (where
n=0 for Mn, n=1 for Co and n=2 for Ni) were prepared as crystalline compounds. The
complexes of M(II) with trichloroacetate and 2-bpy or 4-bpy have analogous molar ratio
of metal to organic ligands 1:2:2 (anhydrous or hydrate) except
Mn(4-bpy)(CCl3COO)2⋅H2O. The obtained compound Ni(2-bpy)2(CCl3COO)2⋅2H2O is
new complex with ligand isomerism. Previously we described a similar complex with
4-bpy [2].
IR data show, that obtained compounds M(2-bpy)2(CCl3COO)2 nH2O are cis-bis
2,2’-bipyridine chelates. The carboxylate group acts as monodentate in these complexes.
In the case of mixed-ligand complexes of Mn(II) and Co(II) with 4,4’-bipyridine and
trichloroacetates, the carboxylate ion is bonded as a bidentate chelating ligand [2]. The
way of metal-carboxylate coordination probably depends on bipyridine structure. Hence
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CZAKIS-SULIKOWSKA, CZYLKOWSKA: Mn(II), Co(II) AND Ni(II) COMPLEXES
359
the complexes have different structures and different thermal properties. The complex
Ni(2-bpy)2(CCl3COO)2⋅2H2O is thermally more stable than analogous complex with
4-bpy; for complex with 2-bpy the step of elimination of water was not observed. The
stoichiometry of intermediate products of thermal decomposition also depends on the na-
ture metal-ligand bonds. In the case of mixed-ligand 2-bpy complexes M(2-bpy)2Cl2 as
intermediate solid compounds were detected. These compounds lose 2-bpy in several
stages, and convert to oxides. The mixed 4-bpy complexes decompose to oxides via un-
identified products and MnCl2 or CoCl2 (formation of NiCl2 was not observed). The MS
data show, that the principal profiles with m/z detected at the temperature range
20–1000°C for metal(II) complexes with 2-bpy (or 4-bpy) and trichloroacetates are very
similar only major maxima of ion current are a little shifted. Other observations made in
this paper are similar to those made in the case of metal(II) complexes with 4-bpy and
trichloroacetates [2, 31].
* * *
This work was supported by KBN, project no. 4 TO9B 103 22. We thank Ph.D. R. Mrozek for the
magnetic measurements.
References
1 D. Czakis-Sulikowska, A. Czylkowska and J. Radwañska-Doczekalska, J. Therm. Anal. Cal.,
63 (2001) 387.
2 D. Czakis-Sulikowska, A. Czylkowska and A. Malinowska, ibid. 65 (2001) 505;
ibid. 67 (2002) 667.
3 I. S. Ahuja, R. Singh and C. L. Yadava, J. Mol. Struct., 74 (1981) 43.
4 T. Bartczak, D. Czakis-Sulikowska and J. KaÓuüna, J. Therm. Anal. Cal., 46 (1998) 193.
5 D. Czakis-Sulikowska, A. Malinowska and M. Markiewicz, J. Therm. Anal. Cal., 60 (2000) 151.
6 D. Czakis-Sulikowska and A. Czylkowska, ibid. in press.
7 K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination Compounds, John
Wiley and Sons, New York 1997.
8 B. S. Manhas and A. K. Trikha, J. Indian Chem. Soc., LIX (1982) 315.
9 W. Brzyska and W. O¿ga, J. Therm. Anal. Cal., 60 (2000) 123; ibid.,
61 (2000) 135 and references therein.
10 W. Brzyska, Z. Rz¹czyñska and A. Kula, Monatsh. Chem., 120 (1989) 211.
11 M. Melnik, Coord. Chem. Rev., 36 (1981) 1 and references therein.
12 A. B. P. Lever and D. Ogden, J. Chem. Soc., 17 (1967) 2041.
13 S. Sen, S. Mitra, P. Kundu, M. K. Saha, C. Krüger and J. Bruckmann, Polyhedron,
16 (1997) 2475.
14 U. Tupeinen, R. H¬m¬l¬inen and Reedijk, ibid. 6 (1987) 1603.
15 J. A. Moreland and R. J. Doedens, Inorg. Chem., 17 (1978) 674.
16 R. Grobelny, T. GÓowiak and J. MroziÕski, XIVth Summar School on Coordination Chemistry,
Polanica Zdrój, 6-12. VI. 1999.
17 S. G. Shova, L. G. Turyatke, G. V. Novitsky, M. D. Mazus and A. P. Gulya, Koord. Khim.,
22 (1996) 517.
J. Therm. Anal. Cal., 74, 2003

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CZAKIS-SULIKOWSKA, CZYLKOWSKA: Mn(II), Co(II) AND Ni(II) COMPLEXES
18 S. G. Shova, G. V. Novitsky, M. D. Mazus and A. P. Gulya, Dokl. Akad. Nauk. SSSR,
337 (1994) 348.
19 Pasder Diffraction File. International Center of Diffraction. JCTDS-JCDD. 1990.
20 D. Czakis-Sulikowska, J. Ka³uüna, J. Therm. Anal. Cal., 58 (1999) 51.
21 E. Konig, Magnetic Properties of Coordination and Organometallic Transition Metal Com-
pounds, Springer, Berlin 1966.
22 W. I. Geary, Coord. Chem. Rev., 7 (1971) 81.
23 N. M. Karayannis, A. N. Speca, D. E. Chasan and L. L. Pytlewski, ibid., 20 (1976) 37.
24 Saiyid Aftab Ahmad Zaodi, Shahjahan and Khwaja Saluhuddin Siddiguin, Trans. Met. Chem.,
18 (1993) 51.
25 Indra Rani, K. B. Pandeya and R. P. Singh, J. Indian Chem. Soc., 59 (1982) 235.
26 A. B. P. Lever, Inorganic Electronic Spectroscopy, Elsevier, Amsterdam, 1984.
27 J. S. Strukl and J. L. Walter, Spectrochim. Acta, 2717 (1971) 299; ibid., 27 (1971) 223.
28 W. R. Mc Whinnd and J. D. Miller, Advances in Inorg. Chem. Radiochem., 12 (1965) 137.
29 E. Spinner, J. Chem. Soc., (1964) 4217.
30 L. E. Erdey and G. Liptay, Periodica Polytechnica (Budapest), 7 (1963) 223.
31 D. Czakis-Sulikowska and A. Czylkowska, Thermal decomposition of complexes of Co(II)
with 4,4’-bipyridine and halogenoacetates in argon atmosphere, VIII-th Conference
‘Prof. St. Bertsznajdera’, P³ock 2002, p. 267.
J. Therm. Anal. Cal., 74, 2003