Thermal kinetic TG-analysis of the mixed-ligand copper(II) and nickel(II) complexes of N-(1-phenyl-3-methyl-4-benzylidene-5-pyrazolone) p-nitrobezoylhydrazide and pyridine

Article abstract of DOI:10.1016/j.tca.2004.11.027

Thermal behaviors of three mixed-ligand complexes, [Ni(PMBP-PNH)(Py) ₃], [Ni(PMBP-PNH)Py] and [Cu(PMBP-PNH)Py] (PMBP-PNH = N-(1-phenyl-3-methyl-4-benzylidene-5-pyrazolone) p-nitrobezoylhydrazide; Py = pyridine), were studied by TG and DTG in dy

Full text of DOI:10.1016/j.tca.2004.11.027

Thermochimica Acta 429 (2005) 31–42
Thermal kinetic TG-analysis of the mixed-ligand copper(II) and nickel(II)
complexes of N-(1-phenyl-3-methyl-4-benzylidene-5-pyrazolone)
p-nitrobezoylhydrazide and pyridine
∗
Guan-Cheng Xu, Li Zhang, Lang Liu, Guang-Fei Liu, Dian-Zeng Jia
Institute of Applied Chemistry, Xinjiang University, Urumqi, 830046, PR China
Received 1 August 2004; received in revised form 1 November 2004; accepted 22 November 2004
Available online 29 December 2004
Abstract
3
Thermal behaviors of three mixed-ligand complexes, [Ni(PMBP-PNH)(Py) ], [Ni(PMBP-PNH)Py] and [Cu(PMBP-PNH)Py] (PMBP-
PNH = N-(1-phenyl-3-methyl-4-benzylidene-5-pyrazolone) p-nitrobezoylhydrazide; Py = pyridine), were studied by TG and DTG in dynamic
air atmosphere. The complexes show the loss of pyridine molecule which is followed by the decomposition of the PMBP-PNH anion and
give respective metal oxides as residues. Meanwhile, the Ozawa-Flynn-Wall model-free analyses and multivariate non-linear regression were
applied to perform single and overall steps optimization. Kinetic parameters were given and the most probable mechanism functions were
suggested in this study.
©
2004 Elsevier B.V. All rights reserved.
Keywords: Thermal analyses; Kinetic studies; Non-linear regression; Mixed-ligand complexes
1
. Introduction
ties of mixed-ligand complexes, we report in this paper the
phenomenological, kinetic and mechanistic aspects of ther-
mal decomposition of the nickel(II), copper(II) complexes of
PMBP-PNH and containing pyridine as co-ligand.
Pyrazolone-5, especially 4-acyl pyrazolones, form an im-
portant class of organic compounds and widely used in bio-
logical, analytical applications, catalysis and extraction met-
allurgy [1–5]. Furthermore, 4-acyl pyrazolone derivatives
have a potential to form different types of coordination com-
pounds due to the several electron-rich donor centers [6–9]
and tautomeric effect of enol form and keto form [10–12].
Meanwhile, compounds containing hydrazide moieties and
their complexes also possess biological activities, especially
serving as potential inhibitors for many enzymes [13–15].
During the course of our research, we have synthesized
a series of 4-acyl pyrazolone derivatives [16–18] and re-
ported several transition metal complexes [19–22], but no
detailed studies on thermal degradation and thermal kinet-
ics have been carried out so far. Hence, As a continuation
of our earlier study and the interest on the thermal proper-
2. Experimental
2.1. Reagents
The ligand PMBP-PNH was synthesized according to the
procedure described in the literature [23]. Other chemicals
and solvents were analytical grade and commercially avail-
able.
2.2. Instrumental
Elemental analyses of C, H and N were performed
using a PE-2400C analyzer. Thermogravimetric measure-
ments were carried out on a Netzsch STA 449C Model
instrument. An alumina crucible was used in dynamic air
∗
Corresponding author. Tel.: +86 991 8580032; fax: +86 991 8581006.
E-mail address: jdz@xju.edu.cn (D.-Z. Jia).
0
040-6031/$ – see front matter © 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.tca.2004.11.027

3
2
G.-C. Xu et al. / Thermochimica Acta 429 (2005) 31–42
3
−1
3
. Results and discussion
atmosphere (30 cm min ). The rate of heating was 20, 10
◦
−1
and 5 C min and sensitivity of the instruments is 0.1 ␮g.
The crystal structure was determined by a Siemens P4 diffrac-
tometer and SHELXTL-97 crystallographic software pack-
age of molecular structure.
The elemental analysis results for the mixed-ligand com-
plexes were listed in Table 1. The results agree well with the
given formulae of the compounds. The complexes are stable
in air and soluble in most of organic solvents.
3
3
.1. Thermal decomposition
2
.3. Syntheses of the complexes
.1.1. [Ni(PMBP-PNH)(Py)3]
The TG and DTG curves of the [Ni(PMBP-PNH)(Py)3]
The mixed-ligand complexes were synthesized us-
ing solvothermal method. The synthetical procedure of
are represented in Fig. 1. The decomposition of the mixed-
ligand complex undergoes in four stages. Degradation of
two pyridine molecules takes place in the first stage be-
tween 100 C and 205 C with a mass loss of 21.56% (Calc.:
2
[Ni(PMBP-PNH)(Py)3] [22] is as follows:
Equimolar PMBP-PNH and Ni(Ac)2·4H2O were grinded
evenly and dissolved by moderate methanol. The clear solu-
tion was then removed in a Teflon bomb, adding 1 ml acetoni-
trile and 1 ml pyridine into the mixture. The bomb was heated
◦
◦
1.51%). The maximum rate of mass loss is indicated by
◦
◦
the DTG peak at 170 C. The residue at the first stage was
found to be [Ni(PMBP-PNH)Py] and the second stage be-
to 120 C and maintained at this temperature for 2 days. After
slowly cooling down to the room temperature, the red-black
block crystals were collected by filtration and dried in air.
The [Cu(PMBP-PNH)Py] was synthesized in the same
condition. However, an interesting aspect of the experiments
is that [Ni(PMBP-PNH)Py] was obtained when the reaction
◦
◦
tween 205 C and 360 C corresponds to decomposition of
the remaining pyridine molecule. The observed mass loss
is 11.57% which is consistent with the theoretical value
of 10.75%. With heating, the decomposition of the ligand
(PMBP-PNH) was followed. Two well-separated peaks are
displayed on the DTG curve, this indicates that the de-
composition of the ligand (PMBP-PNH) divides into two
steps. The third stage, which occurs in the temperature range
◦
temperature is maintained at 150 C.
2
.4. The theoretical base of the kinetics estimation of the
◦ ◦
60–425 C with a DTG peak at 403 C, corresponding to
3
thermal decomposition
the decomposition of the Ph NO2 group, the observed
mass loss (16.23%) is roughly coincide with the calculated
value (16.60%). The fourth stage, occurs between 425 C and
According to non-isothermal kinetic models, the com-
monly used kinetic equation of solid thermal decomposition
is given as follows:
◦
◦
5
40 C, corresponding to the further decomposition of the
ligand, the mass loss (39.67%) is as against the theoretical
value (40.97%). The maximum rate of mass loss is indicated
by the DTG peak at 453 C. The final residue, estimated as
nickel oxide, has the observed mass 10.90% as against the
calculated value of 10.16%.
Thedecompositionprocedurecanalsobedemonstratedby
the crystal structure of the complex (Fig. 2) [22]. With regard
to the bond distances, the Ni N (pyridine) (Ni N6, Ni N7
andNi N8)distancesarelongerthanothercoordinatingbond
lengths (Table 2). In theory, these bonds are less stable and
easy to be broken down. Therefore, the pyridine molecules
were considered to be expelled before the degradation of the
PMBP PNH anion. Among the three pyridine molecules,
ꢀ
ꢁ
dα
dT
A
−Ea
◦
= β exp
f(α)
(1)
RT
where α is fractional extent of reaction at time t, β the heat-
ing rate, Ea the apparent activation energy, dα/dT the rate of
the reaction, A the pre-exponential factor, and f(α) is kinetic
differential function. Its integral form is as follows:
ꢂ
ꢂ
ꢀ
ꢁ
α
T
dα
A
= β
−Ea
G(α)
exp
dT
(2)
f(α)
RT
0
0
The 15 reaction models and mechanism functions [24]
were used to fit kinetics curves. The kinetic software from
Netzsch was used in this analysis [25,26].
˚
Ni N7 and Ni N8 bond lengths (2.159 (2), 2.194 (2) A)
are longer than Ni N6 bond length (2.088 (2) A), indicating
that the bond strengths of pyridyl nitrogen coordinated to
˚
Table 1
The elemental analyses for the mixed-ligand complexes
Compound
Formula weight
Found(Calcd.) (%)
C (%)
H (%)
N (%)
[Ni(PMBP-PNH)(Py)3]
[Ni(PMBP-PNH)Py]
[Cu(PMBP-PNH)Py]
735.42
577.22
582.08
63.86(63.70)
60.76(60.34)
59.78(59.84)
4.21(4.39)
3.57(3.84)
3.89(3.81)
14.94(15.24)
13.83(14.56)
13.95(14.44)

G.-C. Xu et al. / Thermochimica Acta 429 (2005) 31–42
33
Fig. 1. The TG-DTG curves of [Ni(PMBP-PNH)Py3]. Scanning rate 10 C min−1. (—) TG curve, (-·-·) DTG curve.
◦
Ni(II) are different and Ni N6 is stronger than Ni N7 and
Ni N8. Thus, Ni N6bondwasconsideredtobebrokendown
followingNi N7andNi N8bonds. TheTGcurveshowsthat
two pyridine molecules were lost first and the removal of the
remaining pyridine molecule was followed.
ment, three-step decomposition is proposed for this complex.
◦
◦
The first stage starts at 200 C and ends at 358 C. The ob-
served mass loss (14.65%) is attributed to the decomposition
of one pyridine molecule (theoretical mass loss: 13.70%).
◦
◦
The second stage starts at 358 C and ends at 428 C, the cor-
responding mass loss (21.17%) is due to the degradation of
the Ph NO2 group of the PMBP-PNH anion, which is in
well agreement with the calculated value (21.15%). The DTG
Therefore, the thermal decomposition process of
[Ni(PMBP-PNH)(Py)3] complex can be expressed by the fol-
lowing scheme:
◦
peak corresponding to this stage is 403 C. The third stage,
which occurs in the temperature range 428–560 C with a
DTG peak at 457 C, corresponding to the decomposition
[Ni(PMBP-PNH)(Py)3] → [Ni(PMBP-PNH)(Py)]
◦
◦
→
[Ni(PMBP-PNH)] → NiO
of the remaining part of the ligand, the observed mass loss
(
50.62%) coincides with the theoretical value (52.20%). The
3
.1.2. [Ni(PMBP-PNH)Py]
The typical TG-DTG curves of [Ni(PMBP-PNH)Py] are
final residue, estimated as nickel oxide, has the observed mass
1
3.26% as against the calculated value of 12.94%.
shown in Fig. 3. From the TG curve, decomposition starts at
◦
2
00 C and shows almost a continuous weight loss in the tem-
◦
3
.1.3. [Cu(PMBP-PNH)Py]
The thermal model of decomposition of the complex is
perature range of 200–560 C. Based on the percentages of
weight losses, the DTG curve and the complexation sustain-
shown in Fig. 4 and it indicates that it is thermally sta-
ble up to 160 C. The thermal decomposition takes place
in two distinct stages. In the first stage between 160 C to
2
◦
◦
◦
78 C, the co-ligand pyridine degrades as shown as one max-
◦
imum in the DTG curve at 186 C with a 13.58% mass loss
(Calc.: 13.60%). The second stage is related to decomposi-
tion of the PMBP-PNH anion in the temperature range of
◦
3
7
00–620 C, accompanied by a mass loss of 72.01% (Calc.:
2.74%). In the light of the DTG curve and the mass loss,
Table 2
Partial bond distances of [Ni(PMBP-PNH)(Py)3]
Bond
Bond distance ( A˚ )
Bond
Bond distance ( A˚ )
Ni O1
Ni N3
Ni N7
2.0390(17)
1.9965(19)
2.159(2)
Ni O2
Ni N6
Ni N8
2.0467(17)
2.088(2)
2.192(2)
Fig. 2. The molecular structure of [Ni(PMBP-PNH)(Py)3].

3
4
G.-C. Xu et al. / Thermochimica Acta 429 (2005) 31–42
Fig. 3. The TG-DTG curves of [Ni(PMBP-PNH)Py]. Scanning rate 10 C min−1. (—) TG curve, (-·-·) DTG curve.
◦
we judge that decomposition of the ligand PMBP-PNH is
a consecutive procedure and can’t be separated as the for-
to select a specific kinetic model and hence any dependence
on this choice. The Netzsch thermokinetics software package
has the capacity to perform model-free kinetic analyses. Ac-
cording to our experience, the significance of the model-free
analyses lies in its function as preliminary stage of non-linear
regression. Thedeterminationofkineticparametersbymeans
of the non-linear regression is an iterative process. The pre-
set of start values for the parameters is necessary. Here the
model-free estimation of the activation energy means a great
help for the non-linear regression for being able to deliver
start values. Anyway the multi-step feature of a process of-
ten canonlybe detectedfrom the dependence ofthe activation
energy on the reaction degree.
mer two complexes. Weight constancy is attained at around
◦
5
80 C. The end product, estimated as CuO, has the ob-
served mass of 14.22% compared with the calculated value of
1
3.67%.
3
.2. Kinetic analyses
The apparent activation energy of the decomposition
process in non-isothermal conditions can be calculated by
model-free isoconversional method [27–31]. The model-free
kinetic analyses have the advantage of alleviating the need
Fig. 4. The TG-DTG curves of [Cu(PMBP-PNH)Py]. Scanning rate 10 C min−1. (—) TG curve, (-·-·) DTG curve.
◦

G.-C. Xu et al. / Thermochimica Acta 429 (2005) 31–42
35
Table 3
The optimized mechanism functions and kinetic parameters of three mixed-ligand complexes
−
−1
)
Complexes
Steps
Mechanism
F1
Ea (kJ mol 1)
log A (s
11.70
Reaction order n
Exponent α
1.42E−5
Correction coefficient
0.99944
[Ni(PMBP-PNH)(Py)3]
I
115.48
1.00
II
Fn
Bna
Fn
89.81
100.05
25.97
6.05
6.93
1.27
3.50
0.91
0.90
0.99760
III
I
F1
Bna
240.1167
138.1133
16.6092
12.8156
1.00
0.6449
0.99935
0.99898
0.9483
[
Ni(PMBP-PNH)Py]
Cu(PMBP-PNH)Py]
Fn
Bna
Fn
174.99
70.99
112.14
13.72
3.88
8.44
8.09
0.38
0.72
5.74E−6
II
F1
Bna
224.4565
153.2284
15.4067
10.8757
1.00
0.5750
0.99950
0.8035
[
I
Fn
Fn
467.5126
102.1752
53.2179
9.4775
4.7143
1.6953
0.99941
0.99939
II
Fn
Fn
264.98
125.45
20.56
6.91
2.00
0.72
In this study, the Ozawa–Flynn–Wall model-free analyses
single reaction mechanism was used to fit, the results were
satisfied (Fig. 6).
and multivariate non-linear regression were applied to per-
form single and overall steps optimization. Kinetic parame-
ters were given and the most probable mechanism functions
were suggested (Table 3).
Fig. 7showstheactivationenergywasvariedwiththereact
conversion, this demonstrates that the second step reaction
contains at least three steps. Therefore, three-step mechanism
model was applied in the non-linear regression. The results
were shown in Fig. 8 and Table 3.
3
.2.1. Thermal kinetic TG-analysis of
[
Ni(PMBP-PNH)(Py)3]
The TG data for the first, second and third steps of this
We based on the variation of activation energy with the re-
action fraction α for the third step of [Ni(PMBP-PNH)(Py)3]
(Fig. 9), andtriedtousemulti-stepreactionmechanismmodel
to fit. The results were shown in Fig. 10.
complex were analyzed by model-free method and non-linear
fit to 15 mechanism functions.
Fig. 5 shows that the activation energy and pre-exponential
factor of the first step are independent of the extend of con-
From Table 3, we see that the decomposition of first
step adopted the one-step reaction model, and the reaction
mechanism was F1, relevant Ea was 115.48 kJ mol .The
−
1
−1
version, the activation energy value is about 110 kJ mol
.
This indicates that the first step is a single-step reaction. So
value was agree well with that from OFW analysis.
Fig. 5. A plot of Ea and log A as a function of α for the first step of [Ni(PMBP-PNH)(Py)3] based on the OFW model-free method using TG results. The error
limits specified by bars.

3
6
G.-C. Xu et al. / Thermochimica Acta 429 (2005) 31–42
Fig. 6. Fit of the first step of the TG curve of [Ni(PMBP-PNH)(Py)3], simulated with reaction type F1. Signs measured, (—) calculated.
The second step adopted A → B → C → D sequential re-
action model and the reaction mechanism function was
Fn–Bna–Fn. Compared with optimized multireaction mech-
anism of [Ni(PMBP-PNH)(Py)] (Fig. 12), the correction co-
efficient of the second step was not good. The third step
adopted the A → B→ C reaction model and the mecha-
nism function was F1–Bna. Single-step and multi-step re-
action models were used to fit the fourth stage of the de-
composition, unfortunately, a high quality of fit has not
achieved.
Fig. 7. A plot of Ea and log A as a function of α for the second step of [Ni(PMBP-PNH)(Py)3] based on the OFW model-free method using TG results. The
error limits specified by bars.

G.-C. Xu et al. / Thermochimica Acta 429 (2005) 31–42
37
Fig. 8. Fit of the second step of the TG curve of [Ni(PMBP-PNH)(Py)3]. Signs measured, (—) calculated.
3
.2.2. Thermal kinetic TG-analysis of [Ni(PMBP-PNH)Py]
The stages of removal of pyridine molecule and Ph NO2
were taken from the OFW model-free analyses. The multire-
action mechanisms were tested to fit the curves.
group of PMBP-PNH were analyzed by the multivariate non-
linear regression analysis. The start values for the parameters
It is clear in Fig. 11 that the activation energy as-
−
1
sumes a value of 210 kJ mol
at the beginning of the
Fig. 9. A plot of Ea and log A as a function of α for the third step of [Ni(PMBP-PNH)(Py)3] based on the OFW model-free method using TG results. The error
limits specified by bars.

3
8
G.-C. Xu et al. / Thermochimica Acta 429 (2005) 31–42
Fig. 10. Fit of the third step of the TG curve of [Ni(PMBP-PNH)(Py)3]. Signs measured, (—) calculated.
decomposition and with increasing mass loss, drops
model was used to fit it. The results were shown in
Fig. 12.
−
1
to a value of 68 kJ mol . At the end, the value as-
−
1
cends to about 240 kJ mol . This dependence of the
activation energy is an indication that the overall reac-
tion contains three steps. Hence three-step mechanism
Fig. 13 shows that the activation energy assumes a value
−
1
of 235 kJ mol
at the beginning of reaction and at the
−1
end it drops to a value of 130 kJ mol . This indicates
Fig. 11. Dependence of Ea and log A vs. α for the first step of [Ni(PMBP-PNH)(Py)] based on the OFW method.

G.-C. Xu et al. / Thermochimica Acta 429 (2005) 31–42
39
Fig. 12. Fit of the first step of the TG curve of [Ni(PMBP-PNH)(Py)]. Signs measured, (—) calculated.
that the decomposition reaction contains at least two steps.
Presumably, the F1–Bna model was used to fit it, the results
were satisfied (Fig. 14).
The optimized mechanism function of first step was
A → B → C → D sequential reaction model, the mechanism
function was Fn–Bna–Fn, relevant Ea were 174.99, 70.99
and 112.14 kJ mol 1, and log A were 13.72, 3.88 and
−
−
1
8.44 s . The second step adopted A → B → C reaction
model and the reaction mechanism function was F1–Bna.
We tried to use single-step and multi-step mechanism model
to fit the third stage of decomposition reaction, but the results
were unsatisfied.
Fig. 13. Dependence of Ea and log A vs. α for the second step of [Ni(PMBP-PNH)(Py)] based on the OFW method.

4
0
G.-C. Xu et al. / Thermochimica Acta 429 (2005) 31–42
Fig. 14. Fit of the second step of the TG curve of [Ni(PMBP-PNH)(Py)]. Signs measured, (—) calculated.
−
1
3
.2.3. Thermal kinetic TG-analysis of
the decomposition. Ea has a value about 460 kJ mol
in the rage of 0.02 < α < 0.32, with the increasing α, it
[Cu(PMBP-PNH)Py]
−
1
TG kinetics of the overall steps of [Cu(PMBP-PNH)Py]
drops to 125 kJ mol . This indicates that the decompo-
sition reaction contains two steps. So the Fn–Fn reac-
tion model was used to fit it, the results were shown in
Fig. 16.
decomposition were fitted.
Fig. 15 shows the variation of Ea and log A as a func-
tion of α from the OFW analysis for the first step of
Fig. 15. A plot of Ea and log A as a function of α for the first step of [Cu(PMBP-PNH)(Py)] based on the OFW method using TG results.

G.-C. Xu et al. / Thermochimica Acta 429 (2005) 31–42
41
Fig. 16. The first step of the [Cu(PMBP-PNBH)Py] decomposition was the best fit to mechanism function. Signs measured, (—) calculated.
Fig. 17 shows the dependence of activation energy and
of pre-exponential versus degree of reaction, the incon-
stant activation energy is serious indications of the pres-
ence of a multi-step process. Therefore, we tried to use
multireaction mechanisms to fit. The results were satisfied
The results were shown in Figs. 16 and 18, respectively.
The first step adopted A → B → C reaction model, and the
optimized mechanism function of this step was Fn–Fn, rel-
−
1
−1
evant Ea were 467kJ mol and 102 kJ mol . The second
step also adopted A → B → C sequential reaction, and the
reaction mechanism function was Fn–Fn.
(Fig. 18).
Fig. 17. A plot of Ea and log A as a function of α for the second step of [Cu(PMBP-PNH)(Py)] based on the OFW model-free method using TG results.

4
2
G.-C. Xu et al. / Thermochimica Acta 429 (2005) 31–42
Fig. 18. The second step of the [Cu(PMBP-PNBH)Py] decomposition was the best fit to mechanism function. Signs measured, (—) calculated.
Acknowledgement
[13] M.F. Iskander, L. Sayed, A.F.M. Hefny, S.E. Zayan, J. Inorg. Nucl.
Chem. 38 (1976) 2209.
[
[
14] G.H. Havanur, V.B. Mahale, Indian J. Chem. 26A (1987) 1063.
15] H. Adams, D.E. Fenton, G. Minardi, E. Mura, M. Angelo, Inorg.
Chem. Commun. 3 (2000) 4.
This work was supported by the National Natural Science
Foundation of China (No. 20262005, 20366005).
[16] X.C. Tang, D.Z. Jia, K.B. Yu, X.G. Zhang, X. Xia, Z.Y. Zhou, J.
Photochem. Photobiol. A: Chem. 134 (2000) 23.
References
[17] L. Liu, D.Z. Jia, Y.M. Qiao, Y.L. Ji, K.B. Yu, J. Chem. Crystallogr.
32 (2002) 255.
[
1] N. Raman, A. Kulandaisamy, A. Shunmugasundaram, K. Jeyasubra-
manian, Transition Met. Chem. 26 (2001) 131.
[18] L. Liu, D.Z. Jia, Y.L. Ji, K.B. Yu, J. Photochem. Photobiol. A: Chem.
154 (2003) 117.
[
[
2] T. Yoshikuni, J. Mol. Catal. A-Chem. 148 (1999) 285.
3] B.A. Uzoukwu, P.U. Adiukwu, S.S. Al-Juaid, P.B. Hitchcock, J.D.
Smith, Inorg. Chim. Acta 250 (1996) 173.
[19] L. Liu, D.Z. Jia, Y.L. Ji, Synth. React. Inorg. Met. Org. Chem. 32
(2002) 739.
[20] L. Liu, D.Z. Jia, Y.M. Qiao, K.B. Yu, Chin. J. Chem. 20 (2002)
286.
[21] Y.L. Ji, L. Liu, D.Z. Jia, Y.M. Qiao, K.B. Yu, J. Chem. Crystallogr.
32 (2002) 505.
[
[
4] Z.Y. Yang, R.D. Yang, F.S. Li, K.B. Yu, Polyhedron 19 (2000) 2599.
5] W.F. Yang, S.G. Yuan, Y.B. Xu, Y.H. Xiao, K.M. Fang, J. Radioanal.
Nucl. Chem. 256 (2003) 149.
[
[
6] A.K. El-Sawaf, D.X. West, Transition Met. Chem. 23 (1998) 417.
7] N. Kalarani, S. Sangeetha, P. Kamalakannan, D. Venkappayya, Russ.
J. Coord. Chem. 29 (2003) 845.
[22] L. Zhang, L. Liu, D.Z. Jia, K.B. Yu, Struct. Chem. 15 (2004)
327.
[23] Y.L. Ji, L. Liu, D.Z. Jia, K.B. Yu, Chin. J. Struct. Chem. 21 (2002)
553.
[24] D. Dollimore, P. Tong, K.S. Alexander, Thermochim. Acta 282–283
(1996) 13.
[8] C. Pettinari, F. Marchetti, C. Santini, R. Pettinari, A. Drozdov, S.
Troyanov, G.A. attiston, R. Gerbasi, Inorg. Chim. Acta 315 (2001)
88.
[
9] F. Marchetti, C. Rettinar, R. Pettinari, A. Cingolani, D. Leonesi, A.
Lorenzotti, Polyhedron 18 (1999) 3041.
[25] J. Opfermann, J. Therm. Anal. Calorim. 60 (2000) 641.
[26] J. Li, F.X. Zhang, Y.W. Ren, Y.Q. Hun, Y.F. Nan, Thermochim. Acta
406 (2003) 77.
[
10] O.N. Kataeva, A.T. Gubaidullin, I.A. Litvinov, O.A. Lodochnikova,
L.R. Islamov, A.I. Movchan, G.A. Chmutova, J. Mol. Struct. 610
[27] H.L. Friddman, J. Polym. Sci. 6 (1965) 183.
[28] T. Ozawa, Bull. Chem. Soc. Jpn. 38 (1965) 1881.
[29] J.H. Flynn, L.A. Wall, J. Polym. Sci. 4 (1966) 323.
[30] S. Vyazovkin, Thermochim. Acta 211 (1992) 181.
[31] S. Vyazovkin, Int. Rev. Phys. Chem. 19 (2000) 45.
(2002) 175.
[
[
11] Y. Akama, A. Tong, Microchem. J. 53 (1996) 34.
12] Y. Akama, A. Tong, N. Matsumoto, T. Ikeda, S. Tunaka, Vib. Spec-
trosc. 13 (1996) 113.