New energetic copper(II) complexes with pyrazolyl type ligands

Article abstract of DOI:10.1002/zaac.201000276

Nine Cu^II complexes (I-IX) containing the azide ion and bis-2,6-(pyrazol-1-yl)pyridine (pp), bis-2,6-(pyrazol-1-yl)pyridine (dmpp), and 2-(pyrazol-1-yl)-6-(3,5-dimethylpyrazol-1-yl)pyridine (mpp), which are derivatives of pyrazolylpyridine, were prepared in nonaqueous medium. These complexes were characterized by elemental analyses and IR spectroscopy. Crystals of one of these complexes [CumppClN₃ (VII)] were prepared in suitable size, and a molecular structure of this complex was obtained with X-ray diffraction method. Complexes were examined by thermogravimetry and differential scanning calorimetry methods. Thermal decomposition was observed in complexes including two azide groups similar to that seen in explosives. In the complexes containing one azide group, formation of the Cu^I complexes was observed after thermal decomposition of the azide group.

Full text of DOI:10.1002/zaac.201000276

ARTICLE
DOI: 10.1002/zaac.201000276
New Energetic Copper(II) Complexes With Pyrazolyl Type Ligands
[a]
[b]
[c]
[d]
[e]
Sevi Öz,* Ingrid Svoboda, Raif Kurtaran, Mecit Aksu, Musa Sari,
[f]
[f]
Melike Kunduraci, and Orhan Atakol
Keywords: Thermochemistry; Pyrazolyl complexes; Azido explosives; Energetic compounds; Copper
Abstract. Nine CuII complexes (I–IX) containing the azide ion and structure of this complex was obtained with X-ray diffraction method.
bis-2,6-(pyrazol-1-yl)pyridine (pp), bis-2,6-(pyrazol-1-yl)pyridine Complexes were examined by thermogravimetry and differential scan-
(
(
dmpp), and 2-(pyrazol-1-yl)-6-(3,5-dimethylpyrazol-1-yl)pyridine ning calorimetry methods. Thermal decomposition was observed in
mpp), which are derivatives of pyrazolylpyridine, were prepared in complexes including two azide groups similar to that seen in explo-
nonaqueous medium. These complexes were characterized by elemen- sives. In the complexes containing one azide group, formation of the
I
tal analyses and IR spectroscopy. Crystals of one of these complexes Cu complexes was observed after thermal decomposition of the azide
3
[CumppClN (VII)] were prepared in suitable size, and a molecular group.
Introduction
Bis-2,6-(3,5-dimethylpyrazol-1-yl)pyridine is an NNN-type
ligand known since 1980.[
1, 2]
It is frequently used in coordina-
II [3–5]
tion chemistry since it is a terpyridyl-like ligand. Cu ,
II [6, 7]
[8]
II [9]
[10, 11]
II
Co ,
gold, platinum, Ni , silver
and many Fe
[
12]
complexes with pyrazolylpyridine ligands were reported.
Figure 1. Open structure of the prepared ligands. X = Y = H (pp), X =
Y = CH (dmpp), X = CH , Y = H (mpp).
III
[13]
Moreover, there are also reports mentioning Ru complexes
3
3
and titanium complexes,[ with catalytic properties. In this
14]
study, bis-2,6-(pyrazol-1-yl)pyridine (dmpp) with symmetrical
structure
and
2-(pyrazol-1-yl)-6-(3,5-dimethylpyrazol-1-
yl)pyridine (mpp) with asymmetrical structure were used
as ligands. Figure 1 illustrates the open structure of these li-
gands.
1
:1 and 1:2 within the nonaqueous solution and the following
complexes were obtained:
CuppClN (I)
3
It was known from previous studies that complexes are
CuppNO N (II)
3
3
II
formed with Cu and these ligands depending on the anion in
Cupp(N ) (III)
3
2
the medium.[
4, 15, 16]
Accordingly, an azide ion was added to the
CudmppClN (IV)
3
environment so that mole ratio of the pyrazole ligand would be
CudmppNO N (V)
3
3
Cudmpp(N ) (VI)
3
2
CumppClN (VII)
3
*
Dr. S. Öz
CumppNO N (VIII)
Fax: +90-312-223-2395
E-Mail: sevioz@hotmail.com
3
3
Cumpp(N ) (IX)
3
2
[
[
[
[
[
[
a] Faculty of Science and Arts, Department of Chemistry
Elemental analyses and IR spectroscopy were used to deter-
mine the stoichiometry of these complexes.
Ahi Evran University
40200 Kırşehir, Turkey
b] Material Science, FB 11
CuCl ·2H O and Cu(NO ) ·3H O were used for the forma-
2
2
3 2
2
Technical University Darmstadt
tion of complexes. The reason for using Cu(NO ) ·3H O is the
63287 Darmstadt, Germany
3 2
2
c] Faculty of Science and Arts, Department of Chemistry
Balıkesir University
oxidizing property of the nitrate group. Alternative explosive
characteristics of the pyrazolyl complexes with AgNO pre-
3
10020 Balıkesir, Turkey
[10, 11]
pared in the previous studies were reported.
d] Faculty of Science and Arts, Department of Chemistry
Düzce University
These complexes contain azide, and are rich in nitrogen. Be-
cause of this reason, these complexes are thought to be ener-
getic complexes, and they were examined by thermogravi-
metry (TG) and differential scanning calorimetry (DSC). Only
single crystals of complex VII were obtained and the molecu-
lar structure was determined by X-ray diffraction studies.
14400 Düzce, Turkey
e] Faculty of Education
Gazi University
06100 Ankara, Turkey
f] Faculty of Science, Department of Chemistry
Ankara University
06100 Ankara, Turkey
Z. Anorg. Allg. Chem. 2011, 637, 257–262
© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
257

S. Öz et al.
ARTICLE
Table 1. Results of elemental analyses and selected IR data of prepared complexes.
Ligand Elemental Analyses
IR /cm–1
or
Complex
Calculated /%
Experimental /%
γ
CH(Ar)
γ
CH(Aliph)
γ
N3
C=N (Ring) C=C (Ring)
γ γ
C
H
N
Cl
Cu
C
H
N
Cl
Cu
pp
62.55 4.29
65.26 5.47
67.40 6.41
37.51 2.57
31.85 3.16
36.83 2.53
44.12 4.19
39.78 4.23
43.42 4.13
41.06 3.45
38.38 3.22
40.36 3.38
33.15
29.26
26.19
–
–
–
–
–
–
62.41 4.67
65.77 5.11
66.79 5.96
33.09
28.07
27.10
–
–
–
–
–
–
3171–3114
–
–
–
–
1605
1604
1601
1590
1582
1587
1589
1591
1590
1590
1593
1588
1591
1590
1589
mpp
dmpp
I
3163–3103 2931–2870
3165–3097 2933–2864
31.80 10.07 18.04 37.93 3.12
31.24 9.86
17.72 3134–3062
15.64 3109–3055
16.95 3147–3066
–
–
–
2058–2083 1622
II
30.38
42.93
–
–
15.32 30.56 3.27
17.71 36.65 3.04
15.56 43.86 4.22
14.03 38.84 4.49
15.31 42.90 4.35
16.71 40.59 4.10
15.62 38.12 3.73
16.43 40.41 3.55
28.19
41.76
–
–
2040
2054–2079 1611
1620
III
IV
27.43 8.68
25.69 7.47
14.83 3142–3062 2928–2869 2044–2058 1622
14.19 3134–3056 2926–2964 2052
15.08 3138–3064 2930
15.92 3130–3061 2930
15.23 3117–3059 2931
15.96 3145–3027 2933
V
27.82
37.12
–
–
26.54
36.41
–
–
1609
VI
2051–2077 1610
VII
VIII
IX
29.46 9.32
28.82 8.82
2054
2058
1616
1614
30.97
39.82
–
–
30.42
39.14
–
–
2081–2065 1620
Experimental Section
General
Eurovector 3018 C,H,N,S analyzer was used for elemental analyses
for C, H and N. Cl analyses were performed with AgNO gravimetri-
3
cally. Cu analyses however, were performed on GBC Avanta PM
Model AAS device. For Cu analyses, the sample (2–3 mg) was di-
3 2 2
gested in a solution containing HNO (1.0 mL 63 %) and H O
(
1.0 mL 30 %), diluted to 100 mL and directly fed into FAAS device.
IR spectra were recorded by Shimadzu Infinity Model device. Shi-
madzu DTG 60H and DSC60 devices were used for thermal analyses,
which were performed under nitrogen atmosphere with a heating rate
–
1
of 10 °C·min and within platinium pans.
X-ray Data Collection and Structure Refinement
The crystal and instrumental parameters used in the unit-cell determi-
nation and data collection are summarized in Table 1. Diffraction
measurements were made at room temperature with a Oxford Diffrac-
tion Xcalibur (TM) Single crystal X-ray Diffractometer with Sapphire
Figure 2. Ortep drawing of complex VII.
α
CCD Detector with Mo-K radiation (λ = 0.71073 Å), using ω-2θ scan
mode. Unit-cell dimensions were determined and refined by using the
angular settings of 25 automatically centered reflections in the 2.46 ≤
θ ≤ 26.37 ranges. The structure was solved by the direct methods using
2
SHELXS-97 and refined by full-matrix least-squares techniques on F
[17]
with SHELXL-97.
The empirical absorption corrections were ap-
[
18]
plied by the semi-empirical method by CrysAlis CCD software.
Non-hydrogen atoms were anisotropic and all hydrogen atom positions
were refined in an isotropic approximation in the riding model with
the Uiso(H) = 1.5 Ueq(C,H) for methyl groups and Uiso(H) = 1.2
[19]
U
iso(C,H) for other carbon atoms. An ORTEP drawing of the com-
plex with 40 % probability displacement thermal ellipsoids, atom-la-
beling scheme and packaging of the molecules in the unit cell are
shown in Figure 2 and Figure 3, respectively.
Crystallographic data (excluding structure factors) for the structure in this
paper have been deposited with the Cambridge Crystallographic Data
Centre CCDC, 12 Union Road, Cambridge CB21EZ. Copies of the data
can be obtained on quoting the depository number CCDC-745491 (VII)
(
Fax: +44-1223-336-033; E-Mail: deposit@ccdc.cam.ac.uk or
www://www.ccdc.cam.ac.uk.
Figure 3. Packing of the atoms in the unit cell.
2
58
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© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2011, 257–262

New Energetic Copper(II) Complexes With Pyrazolyl Type Ligands
Table 2. Crystal and experimental data for complex VII.
Preparation of the Ligands
Preparation was made according to pp, dmpp, and mpp literature.[1]
a /Å
b /Å
c /Å
α /°
12.7075(5)
14.6951(9)
Preparation of pp: Pyrazol (6.8 g, 0.1 mol) was solved in diglyme
16.2662(9)
(
150 mL) at room temperature. To this solution, newly-cut metallic so-
90
dium (3.9 g, 0.1 mol) was added under nitrogen and reflux, and the
β /°
90
solution was stirred for 3–4 hours to dissolve the potassium. Subse- γ /°
quently, solid 2,6-dichloropyridine (7.4 g, 0.05 mol) was added to this V /Å
90
3
3037.5(3)
Z
8
solution, and was dissolved by heating. Temperature of the solution
was raised to 110–120 °C and the solution was stirred for about 12
hours. Formation of solid NaCl was observed. After this period, the
cooled solution was poured onto water-ice mixture (500 mL), and NaCl
was dissolved by agitating. The colorless precipitate was filtered and
dried in air.
Cell measurement temperature
Crystal dimensions /mm
302(2)
0.22 × 0.22 × 0.03
1.663
–3
Density (diffrn) d /g·cm
F(000)
1544
μ
1.626
T /K
302(2)
radiation
Mo-K
a
Preparation of dmpp: Dmpp was prepared from 3,5-dimethylpyrazole
λ /Å
0.71073
18976
0.999
(
0.1 mol) and 2,6-dichloropyridine (0.05 mol) according to the proce-
Reflns number
dure for preparation of pp.
θ
min
max
Preparation of mpp: This ligand was prepared in two steps.
θ
h
k
0.999
min – hmax
–15,15
–18,15
–20,16
3105
Step 1: Pyrazole (3.4 g, 0.05 mol) was dissolved in diglyme (150 mL)
together with newly-cut metallic sodium (1.95 g, 0.05 mol). This solu-
– k
min
max
l
min – lmax
tion was allowed to react with 2,6-dichloropyridine at a temperature of reflns number total
Reflns number gt
1299
1
10 °C for 6 hours. This mixture was poured onto ice water (300 mL).
Reflns threshold expression
>2σ(I)
0.1268
0.0384
0.1031
0.881
Afterwards, the colorless precipitate was filtered and air-dried.
R
R
all
Step 2: 3.5-Dimethylpyrazole (4.8 g, 0.05 mol) was dissolved in di-
glyme (100 mL) at room temperature. To this solution, newly-cut me-
tallic sodium (1.95 g, 0.05 mol) was added under nitrogen and reflux,
and the solution was stirred for 3–4 hours to dissolve the sodium. The
substance (9.02 g, 0.05 mol) formed in step 1, was added to the solution
and the solution was stirred for about 24 hours at 120–130 °C. At the
end of this period, the mixture was poured into ice water (300 mL).
The colorless precipitate was filtered and air-dried.
wR
goodness of fit
–3
δ
δ
max /e·Å
min /e·Å
0.492
–0.377
–3
Table 3. Selected bond lengths /Å and angles /° around the coordination
sphere for complex VII.
N1–N2
1.358(4)
Preparation of the Complexes
N1–Cu1
2.057(3)
CuppCl(N
3
3
) (I), CudmppCl(N ) (IV), and CumppCl(N
3
) (VII): pp, N3–Cu1
1.973(3)
dmpp, or mpp (0.01 mol) was dissolved in MeCN:MeOH (1:1) (50 mL) N4–N5
1.396(4)
N5–Cu1
2.049(3)
mixture by heating. To this solution, a solution of CuCl
mol) within hot MeOH (20 mL) and aqueous solution of NaN
mol) in hot water (10 mL) were added, and the resulting solution was
allowed to settle for 24 hours. The brown precipitate was filtered and
air-dried.
2
·2H
2
O (0.01
(0.01
N6–N7
1.046(6)
3
N6–Cu1
1.937(4)
N7–N8
1.249(7)
Cl1–Cu1
2.4797(13)
113.2(3)
N4–N5 Cu1
N7–N6 Cu1
N6–N7–N8
N6–Cu1–N3
N6–Cu1–N5
N3–Cu1–N5
N6–Cu1–N1
N3–Cu1–N1
N5–Cu1–N1
N6–Cu1–Cl1
N3–Cu1–Cl1
N5–Cu1–Cl1
N1–Cu1–Cl1
123.4(5)
Cupp(NO
VIII): According to the procedure above, organic ligand (0.01 mol),
Cu(NO ·3H O (0.01 mol), and NaN (0.01 mol) were used to prepare
complexes.
3 3 3 3 3 3
)(N ) (II), Cudmpp(NO )(N ) (V), and Cumpp(NO )(N )
174.6(7)
(
159.17(18)
98.17(17)
77.12(14)
100.47(16)
78.37(14)
152.70(13)
102.65(16)
98.07(10)
96.66(10)
98.50(10)
3
)
2
2
3
Cupp(N
ing to the procedure above, organic ligand (0.01 mol), CuCl
0.01 mol) and NaN (0.02 mol) were used to prepare complexes.
3
)
2
(III), Cudmpp(N
3
)
2
(VI), and Cumpp(N
3
)
2
(IX): Accord-
2
·2H O
2
(
3
Results and Discussion
Results of the elemental analyses and some important IR data
for the ligands and complexes prepared are given in Table 1.
The molecular structure of complex VII obtained by X-ray dif-
Results of the elemental analyses and molecular model indi-
II
fraction studies is given in Figure 2, data collection and crystal cate that the Cu ion/ligand ratio is 1:1 for all complexes. The
data are given in Table 2, and important bond lengths and crystal packaging diagram of complex VII is shown in Fig-
bonding angles around the coordination sphere are given in Ta- ure 3. It can be seen from Figure 2 and Figure 3 that the coor-
II
ble 3.
dination arrangement around the pentacoordinate Cu ion is a
Z. Anorg. Allg. Chem. 2011, 257–262
© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
259

S. Öz et al.
ARTICLE
distorted square pyramid of three nitrogen atoms from the li-
gand, one chlorine atom, and one nitrogen atom from azide.
Since not for all complexes molecular structures could be ob-
tained by single crystal X-ray diffraction, it would not be very
accurate to propose the same coordination for all. However,
five-membered coordination is one of the coordination forms
II
encountered most frequently for Cu[ ions, particularly for
20]
square-pyramidal coordination sphere. The molecular struc-
tures of pentacoordinate transition metal complexes show an
extensive range from regular trigonal bipyramidal to regular
square pyramidal. The structural index parameter, τ = (β–α/60),
was evaluated by the two large angles in the pentacoordinate
arrangement, where τ = 0.0 for a regular square pyramidal, τ =
[
21]
1
.0 for a trigonal bipyramidal arrangement (α < β).
The
II
coordination arrangement around Cu is slightly distorted from Figure 5. TG curve of Cudmpp(NO )(N )·H O. ––– TG curve, ········
3
3
2
regular square pyramidal, as ascertained by the observed τ DTA curve.
value of 0.10 [α = 152.70(13)° and β = 159.17(14)°]. Coordina-
tion seems to be square pyramidal, a chlorine atom and three
nitrogen atoms of the pyrazole and pyridyl ligand constitute the
complexes can be seen in Table 4. Thermal breaking of the
crystalline water seen in complexes II and V is exothermic, as
expected. All the complexes give the first thermal decomposi-
tion reactions at around 200 °C. This reaction can be explained
basal plane of the square pyramid, and the azide nitrogen atom
II
occupies the apical position (Figure 2). The Cu –N(azide) dis-
II
II
tance is slightly shorter than the Cu –N(pyrazole) and Cu –
N(pyridyl) distances. The average Cu–N bond lengths
based on the data in the previous literature. The first thermal
[
2.004(3) Å] are similar to those in other trans-Schiff base
[25]
reaction is the breaking of azide groups.
Complexes I, VI,
[22, 23]
II
complexes.
The Cu –Cl distances of 2.4798(13) Å are in
II
and IX contain two azide groups per Cu ion, and the mass
losses for all the three complexes is over 90 % in the first ther-
mal reaction (Figure 6), exothermal heat measured with DSC
II
[24]
well agreement with the reported Cu –Cl distances. The co-
ordination arrangement is characterized by an N1–Cu–N5 axial
angle 152.70(13)°, and N3–Cu–Cl and N3–Cu–N6 equatorial
angles range from 98.07(10) to 159.17(14)°. The two rings con-
sisting of (Cu, N1, N2, C4, N3) and (Cu, N5, N4, C8, N3) are
planar. The dihedral angles between the planes of two rings
are 6.96(16)°. The copper atom lies –0.0578(16) and
–1
exceeds 400 kJ·mol (Figure 7). The order of the decomposi-
tion temperatures is as follows:
Cupp(N ) (III) > Cudmpp(N ) (VI) > Cumpp(N ) (IX)
3
2
3 2
3 2
Mass losses in the first thermal decomposition reaction of
complexes I, II, IV, and VII, which include one chlorine atom,
range between 82 and 94 %. Ligands of CuppClN3 and
–
0.0458(14) Å out of the (Cu, N1, N2, C4, N3) and (Cu, N5,
N4, C8, N3) planes, respectively.
CudmppClN are symmetrical. Mass losses in these complexes
3
TG results showed that complexes II and V contain crystal-
line water, (Figure 4 and Figure 5).
are between 82 and 94 %, and the mass loss in the CumppClN3
complex of the asymmetrical ligand is about 91 %. There are
not any anomalies in these thermal decompositions. Azide ions
constitute 10 % of the total mass. However, the mass loss rises
to 90 % level in the decomposition. Probably, all the energy of
the azide group is distributed within the whole complex and
this causes the complex to decompose as an energetic molecule
as a whole. Order of the temperatures measured by DSC is:
CudmppClN (IV) > CumppClN (VII) > CuppClN (I).
3
3
3
Mass losses in the first thermal reaction in the complexes
containing nitrate ions are about 82 % for CuppNO N ·2H O
3
3
2
(
II), and 30 % for CudmppNO N ·H O (V). Mass loss for
3 3 2
CumppNO N (VIII), however, is about 91 %. In this group,
3
3
order of the amount of exothermal temperatures is:
CudmppNO N ·H O (V) CuppNO N ·2H O (II)
>
>
3
3
2
3
3
2
CumppNO N (VIII).
3
3
What is abnormal here is the 30 % mass loss observed in the
O. ––– TG curve, ········ first thermal decomposition of the CudmppNO ·H O (IV)
Figure 4. TG curve of Cupp(NO
3
)(N
3
)·2H
2
3
N
3
2
DTA curve.
complex. As can be seen in the TG curve of this complex, there
is a two step exothermic decomposition between 220–260 °C.
It is understood by examining the TG curves that complex II The experimentally found mass ratio of the azide group is
contains two mol of crystalline water, and complex V contains 29.60 %, on the other hand the theoretically expected value is
one mol of crystalline water. Thermoanalytical data of the nine 9.28 %. It is more likely than not that this two step decomposi-
2
60
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© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2011, 257–262

New Energetic Copper(II) Complexes With Pyrazolyl Type Ligands
Table 4. Thermoanalytical data of the complexes.
Complex First thermal reaction –
removal of crystalline water
Second thermal reaction –
decomposition of azide ions
Third thermal reaction –
decomposition of residue
Temperature Calculated
Experimental Temperature
Calculated
Experimental
Temperature
range /°C
–
Experimental mass Measured energy by
range /°C
–
mass loss /% mass loss /%
range /°C
mass loss /% mass loss /%
loss /%
–
DSC /kJ·mol–1
I
–
–
213–222
DTG: 219
223–254
11.93
10.12
82.50 ± 2.65
81.90 ± 1.86
133.35 ± 1.16
II
43–74
8.68
8.50
255–306
Combining with
first reaction
327.88 ± 12.11
7
–
8–110
Total
–
DTG: 248
191–205
DTG:269
–
III
IV
V
–
23.44
10.28
9.28
94.50 ± 2.68
84.80 ± 1.22
29.60 ± 1.44
–
459.52 ± 16.45
221.94 ± 10.77
346.71 ± 12.07
DTG:202
204–213
–
–
–
–
–
DTG:209
220–260
60–76
3.97
3.72
414–478
47.15 ± 1.24
DTG:68
DTG: 234–251
Two steps
193–207
VI
–
–
–
–
–
–
–
–
–
–
–
–
20.25
11.04
10.33
21.71
95.84 ± 1.38
91.25 ± 1.78
91.66 ± 4.70
92.22 ± 3.18
–
–
–
–
–
–
–
–
439.90 ± 14.96
157.60 ± 7.24
240.64 ± 6.87
411.28 ± 27.48
DTG:205
199–208
VII
VIII
IX
DTG:206
195–209
DTG: 204
214–224
DTG: 220
tion accounts for the thermal decomposition of the azide group
together with its distributing its energy to the whole molecule
causing some of the molecules exothermally decompose as
whole. But not all of the molecules decomposed since the azide
ion leaves one electron during the decomposition:
–
–
N3 → 3/2N + e
2
2
+
+
This electron is capable of turning Cu ion into Cu and so,
I
CudmppNO may be formed. There are examples of such Cu
3
[4, 26]
complexes in the literature.
It is thought that a second
thermal decomposition occurs with the oxidizing effect of the
nitrate in CuppNO N3 (II) and CumppNO N3 (VIII) com-
3
3
plexes following the breaking of the azide group. However,
there is a temperature difference of 100 °C between the two
reactions of the CudmppNO N (V) complex. This difference
3
3
was thought to be an experimental error, but then the experi-
ment was repeated several times and the same result was en-
sured. However, a strong exothermal decomposition is also ob-
served in this complex at around 400 °C (Figure 3). This
decomposition is because of the oxidizing effect of the nitrate
group. On the other hand, this cannot be seen in pp and mpp
complexes, which decompose at about 200 °C with a mass loss
of about 84–91 %, similar to those having one chlorine atom
and one azide group. Probably, the energy arising from the exo-
thermal decomposition of the azide is transferred to the mole-
cule in these complexes, which leads to the decomposition of
the whole molecule. Why the decomposition of the
CudmppNO N (V) complex doesn't resemble the decomposi-
Figure 6. TG curves of Cupp(N
dmpp(N -----.
3
)
2
3 2
–––, Cu mpp(N ) ········, Cu
3 2
)
3
3
tions of the CuppNO N (II) and CumppNO N (VIII) com-
3
3
3
3
plexes? This question can be answered as the ligand is more
electron donating. The reason for this electron donating behav-
ior is the activation of the pyrazole rings by the four methyl
I
groups. The more stable the Cu dmppNO complex (the forma-
3
tion of which we assume) is, the more complex is left behind,
and the carbonaceous remains decompose a second time with
an intense exothermal reaction at around 400 °C. The methyl
groups are electron donating and for this reason, the
Figure 7. DSC curves of Cupp(N
dmpp(N -----.
3
)
2 3 2
–––, Cu mpp(N ) ········, Cu
3
)
2
CudmppNO complex, which is formed while the azide group
3
Z. Anorg. Allg. Chem. 2011, 257–262
© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
261

S. Öz et al.
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3
3
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All decompositions of the complexes with two azide groups
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organic material exothermally and rapidly like explosive mate-
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Received: July 8, 2010
Published Online: October 22, 2010
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62
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© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2011, 257–262