Nickel(II) complexes prepared from NNN type ligands and pseudohalogens : SSSynthesis, structure and thermal decomposition

Article abstract of DOI:10.1007/s10973-007-7709-4

Six nickel(II) complexes, using azide and thiocyanate ions, have been synthesized from bis-2,6(pyrazol-1-yl)pyridine (pp) and some methyl derivatives, 2-(3,5-dimethyl(pyrazol-1-yl)-6-(pyrazol-1-yl)pyridine (app) and bis-2,6(3,5-dimethyl(pyrazol-1-yl) pyridine (dmpp) in non-aqueous media. The complex structures were analyzed using elemental analysis, IR spectroscopy and thermogravimetry. Appropriate crystals of complex, containing azide [Nipp(N ₃)₂]?MeOH (I) and thiocyanate [Nidmpp(SCN) ₂?MeOH] (VI) were prepared and the molecular structures determined using X-ray diffraction. Complex I was seen to be dinuclear as stated in literature, space group P2₁/n, monoclinic, a=10.503, b=10.681, c=13.291 A, β=106.56° and Z=2 whereas complex VI was found to be mononuclear, space group P2₁/n, monoclinic, a=8.646, b=12.614, c=20.697 A, β=97.18° and Z=2. The Ni(II) coordination in both complexes were octahedral. Thermogravimetric studies showed azide containing structures to resemble the characteristics of explosive materials. Coordinative MeOH were seen to leave the structure in thiocyanate containing complexes, followed by irregular degradation above 300°C.

Full text of DOI:10.1007/s10973-007-7709-4

Journal of Thermal Analysis and Calorimetry, Vol. 92 (2008) 2, 617–624
NICKEL(II) COMPLEXES PREPARED FROM NNN TYPE LIGANDS AND
*
PSEUDOHALOGENS
Synthesis, structure and thermal decomposition
1
F. Nazli DÏn¸er Kaya , Ingrid Svoboda , Orhan Atakol , ÜmÏt Ergun , Adnan Kenar , Musa
2
3**
3
3
4
Sari and Kaan C. Emregül
3
1
Mersin University, Faculty of Pharmacy, Department of Analytical Chemistry, Mersin, Turkey
2
Strukturforschung, FB Materialwissenschaft, Technische Hochschule, Darmstadt Petersenstrasse 23, D-64287 Darmstadt,
Germany
3
Ankara University, Science Faculty, Department of Chemistry, TandoÈan 06100 Ankara, Turkey
Gazi University, Faculty of Education, Beêevler Ankara, Turkey
4
Six nickel(II) complexes, using azide and thiocyanate ions, have been synthesized from bis-2,6(pyrazol-1-yl)pyridine (pp) and
some methyl derivatives, 2-(3,5-dimethyl(pyrazol-1-yl)-6-(pyrazol-1-yl)pyridine (app) and bis-2,6(3,5-dimethyl(pyrazol-1-yl)
pyridine (dmpp) in non-aqueous media. The complex structures were analyzed using elemental analysis, IR spectroscopy and
thermogravimetry. Appropriate crystals of complex, containing azide [Nipp(N
Nidmpp(SCN) ·MeOH] (VI) were prepared and the molecular structures determined using X-ray diffraction. Complex I was seen
to be dinuclear as stated in literature, space group P2
/n, monoclinic, a=10.503, b=10.681, c=13.291 , b=106.56° and Z=2 whereas
complex VI was found to be mononuclear, space group P2
/n, monoclinic, a=8.646, b=12.614, c=20.697 , b=97.18° and Z=2. The
3 2
) ]·MeOH (I) and thiocyanate
[
2
1
1
Ni(II) coordination in both complexes were octahedral. Thermogravimetric studies showed azide containing structures to resemble
the characteristics of explosive materials. Coordinative MeOH were seen to leave the structure in thiocyanate containing com-
plexes, followed by irregular degradation above 300°C.
Keywords: azide, crystal structure, nickel(II) complexes, synthesis, thermal analysis, thiocyanate
Introduction
(pyrazol-1-yl)-6-(pyrazol-1-yl)pyridine (app) and
bis-2,6(3,5-dimethyl(pyrazol-1-yl) pyridine (dmpp)
were synthesized with the intention of forming
polynuclear nickel(II) complexes using azide and
thiocyanate ions. X-ray studies revealed dinuclear
complexes to form with azide ions and mono nuclear
complexes to form with thiocyanate ions. Figure 1
gives the formulas of the ligands pp, app and dmpp.
Thermal analysis, especially thermogravimetry
is an exceptionally effective method in determination
of complex stoichiometry. The mass of the
coordinatively bonded solvent molecules give very
Bis-2,6(3,5-dimethyl(pyrazol-1-yl) pyridine (dmpp) is a
terpyridyl type tridendate ligand synthesized at the be-
ginning of the 1990’s [1]. Due to the presence of 5 nitro-
gen donor atoms side by side in the three aromatic rings
dmpp and similar molecules are denoted as strong lig-
ands. Also the planar structure of the three donor atoms
increase this effect. There are many similar studies and
structures dealing with this subject. The structures of
iron(II), copper(II) and cobalt(II) complexes of dmpp
[2–4] and dinuclear structures of Ni(II) [5] have been re-
ported in literature. There are also many studies dealing
with the catalytic effect of some pyrazolyl pyridine
complexes [6–11].
It has been established since 1986 that azide and
thiocyanate ions form m-bridges of end–end (1,1) and
end–on (1.3) types [12, 13]. There are many examples
in literature dealing with the 1,1 and 1,3 bridges
formed by azide and thiocyanate ions [14–19].
In this this study bis-2,6(pyrazol-1-yl)pyridine
Fig. 1 The formulas of the ligands pp, app and dmpp
(
pp) and some methyl derivatives, 2-(3,5-dimethyl-
th
In dedication to the 66 birthday of Prof. Dr. h.c. Hartmut Fuess
*
*
*
Author for correspondence: atakol@science.ankara.edu.tr
1
388–6150/$20.00
2008 Akadémiai Kiadó, Budapest
Akadémiai Kiadó, Budapest, Hungary
Springer, Dordrecht, The Netherlands
©

NAZLI DN†ER KAYA et al.
beneficial results for the complex stoichiometry. The
was filtered and dried. The dry crystals were
recrystallized in a MeOH:H O (1:1) mixture.
final mass of the residues is also very effective for
stoichiometric determination. For this reason, TG and
DTA methods were employed alongside elemental
analysis and IR spectroscopy.
2
dmpp
Bis-2,6(3,5-dimethyl(pyrazol-1-yl) pyridine, dmpp
9.6 g, 0.1 mol) was reacted with 2.4 g (0.104 mol) of
metallic sodium for 2 h in 100 mL of diglym. The
unreacted sodium particles were separated and
,6-dichloropyridine (7.4 g, 0.05 mol) was added to
(
Experimental
Materials
2
the solution and stirred for 2 days at 110–130°C. This
mixture was poured over 600 mL of iced water and
the precipitate was filtered and recrystallized in a
Nickel(II) chloride hexahydrate (Aldrich), sodium
azide (Sigma) and potassium thiocyanate (Sigma)
were used without further purification. All other
chemicals were of AR grade and used as received.
Caution. Although our samples were stable dur-
ing handling, metal azido complexes are potentially
explosive; only a small amount of material should be
prepared and it should be handled with care.
MeOH:H O (1:1) mixture.
2
Complex synthesis
Azide containing complexes: [Nipp(N
3
)
2
]
2
·MeOH (I),
Niapp(N ) ] (II) and [Nidmpp(N ) ] ·2MeOH (III)
3 2 2 3 2 2
[
The ligand of pp, app or dmpp (0.003 mol) is dis-
solved in 70 mL of MeCN and heated up to 45°C. To
this, nickel(II) chloride hexahydrate (0.003 mol,
Ligand synthesis
pp
0
.714 g) dissolved in 20 mL of methanol and sodium
Pyrazole (6.8 g, 0.1 mol) was dissolved in 100 mL of
diethylene glycol dimethyl ether (diglym) at 50°C.
Metallic Na (2.4 g, 0.104 mol) was added in small
fragments and the solution was stirred for 2 h result-
ing in the formation of sodium pyrazolate. The
unreacted sodium fragments were separated and
azide (0.006 mol, 0.390 g) dissolved in 10 mL of wa-
ter was added. The medium temperature should not
exceed 45°C, otherwise the crystals formed are very
small. The solution was left to stand for 12 h and the
resulting crystals are filtered and left to dry under at-
mospheric conditions. Elemental analysis results and
some important IR data are given in Table 1.
2
,6-dichloropyridine (7.4 g, 0.05 mol) was added to
the solution. The solution was stirred for two days in a
temperature range of 110–130°C. The resulting mix-
ture was poured into 600 mL of water-ice mixture and
the resulting precipitate was filtered and dried under
atmosphere conditions. The dry precipitate was crys-
Thiocyanate containing complexes:
[Nipp(SCN)
2
·MeOH] (IV), [Niapp(SCN)
·MeOH] (VI)
·MeOH]
2
(
V), [Nidmpp(SCN)
2
tallized in a MeOH:H
2
O (1:2) mixture.
The ligand of pp, app or dmpp (0.004 mol) was dis-
solved in 70 mL of MeCN and heated. To this was
added the solutions of nickel(II) chloride hexahydrate
app
(
0.004 mol, 0.955 g) dissolved in 20 mL hot methanol
and potassium thiocyanate (0.004 mol, 0.776 g) dis-
solved in 15 hot water. The mixture was left to stand for
days and the resulting crystals were filtered and left to
Pyrazole (6.8 g, 0.1 mol) was dissolved in 100 mL
diglym at 50°C and metallic Na (2.4 g, 0.104 mol) was
added in small fragment and the solution was stirred for
2
2
h resulting in the formation of sodium pyrazolate. The
unreacted Na pieces were separated and
,6-dichloropyridine (14.8 g, 0.1 mol) was added to the
dry under atmospheric conditions. Elemental analysis
results and some important IR data are given in Table 1.
2
solution. The mixture was stirred for two days at 60°C
on a water bath. The mixture was then poured onto 600
mL of an ice–water mixture and the resulting precipitate
filtered and dried. The precipitate was identified as
Measurement techniques
Elemental analysis was performed on
a
Eurovector 3018 C,H,N,S analyzer instrument.
Nickel analysis was done gravimetrically using
dimethylglyoxime. IR spectrums were obtained on a
Mattson FTIR 1000 instrument using the KBr disk
technique.
2
pyrazol-1-yl-6- chloropyridine. An equimolar amount
of 3,5-dimethylpyrazole was dissolved in diglym and re-
acted with 2.4 of metallic sodium.
-pyrazol-1-yl-6=chloro–pyridine was added to this so-
g
2
lution and stirred for two days in the temperature range
of 110–130°C. The mixture was then poured onto 600
mL of water-ice mixture and the resulting precipitate
TG-DTA curves were obtained using
a
Shimadzu TG-60H instrument. Aluminium pans were
used for curves obtained between room temperature and
618
J. Therm. Anal. Cal., 92, 2008

NNN TYPE LIGANDS AND PSEUDOHALOGENS
J. Therm. Anal. Cal., 92, 2008
619

NAZLI DN†ER KAYA et al.
4
50°C, whereas platinum pans were used for curves ob-
tained between room temperature and 750°C. The
curves were obtained under nitrogen atmosphere with a
in the WinGX package [22] and refined using
SHELXL97 [21].
For complex I, all non-hydrogen atoms were re-
fined with anisotropic thermal displacement parameters.
All the hydrogen atoms were placed geometrically ide-
alized positions and constrained to ride on their parent
atoms with distances in the range 0.89–0.97  and with
U (H)=1.2U (C). For complex VI, the C18 atom is
3
flow rate of 100 cm min . The heating rate was
–1
–1
10°C min for the curves obtained between room tem-
–1
perature and C, and 5, 10, 20, 30°C min for those ob-
tained between room temperature and 450°C.
DSC curves were obtained
Shimadzu DSC-60 instrument between room temper-
on
a
iso
eq
disordered. The disorder of atoms C18a and C18b were
refined, with occupancies of 0.60(2) and 0.40(2), re-
spectively. All non-hydrogen atoms were refined with
anisotropic thermal displacement parameters. Disor-
dered atom hydrogens were placed geometrically ideal-
ized positions and constrained to ride on their parent at-
oms with distances in the 0.98  and with
–
ature and 450°C with a heating rate of 10°C min un-
1
der nitrogen atmosphere with a flow rate of
–
1
3
0 mL min .
X-ray data were collected on an Oxford Diffrac-
tion Xcalibur (TM) Single Crystal X-ray
Diffractometer [20] with MoK
radiation using w/2q
a
scan mode low-temperature facilities. Unit cell pa-
rameters were refined from the setting angles of 25
centered reflections in the range of (I) 4.14£q£26.36
and (II) 2.87£q£28.11. Three standard reflections for
every 120 min during data collection showed no sig-
nificant intensity variations. The structures were
solved by a combination of direct methods and Fou-
rier techniques and refined by full-matrix least
squares using the solution program SHELXS97 [21]
Uiso(H)=1.5Ueq(C). Other hydrogen atoms were placed
in calculated positions.
Results and discussion
Azide and thiocyanate ions are known for their incli-
nation to form two types of m-bridges: 1,1 and 1,3
[10]. The crystal structures of only two of the six syn-
Table 2 Crystallographic and experimental data for complexes I and VI
Complex I
Complex VI
2 2
NiO S
Formula
C
22
H
22
N22Ni
2
O
2
C
18
H
23
N
7
Formula mass
744.00
100(2)
0.71073
1002.48
100(2)
Temperature/K
Wavelength/
0.71073
Crystal system, space group
monoclinic, P2
10.503(1)
10.681(1)
13.291(2)
106.56(1)
1429.2(3)
2
1
/n
monoclinic, P2
8.646(10)
12.614(10)
20.697(2)
97.18(10)
2239.5(4)
2
1
/n
a/
b/
c/
b/°
3
Volume/
Z
–
3
Calculated density/Mg m
1.729
1.487
–
1
Absorption coefficient/mm
F(000)
1.386
1.081
760
1030
Crystal size/mm
0.30×0.30×0.10
0.35×0.24×0.10
56.22
2q
max/°
52.72
Index range
–13£h£12, –13£k£13, –14£l£16
–7£h£11, –15£k£16, –26£l£26
Number of reflections used
Number of parameters
2921 (I³ 2s (I))
250
3683 (I³ 2s (I))
305
R
R
R
int
0.037
0.0707
0.0337
0.0623
w
0.0828
0.1679
Goodness of fit
0.958
1.055
–3
Dr min, Dr max/e 
–0.511, 0.485
–0.435, 0.682
620
J. Therm. Anal. Cal., 92, 2008

NNN TYPE LIGANDS AND PSEUDOHALOGENS
Table 3 Selected bond lengths () and angles (°) of the
dinuclear Ni complex [Nipp(N ·MeOH (I)
3 2 2
) ]
Ni
N1
N3
N5
N6
N9
N2
N2
N5
N7
N8
N10
N11
2.112(2)
2.023(2)
2.132(2)
2.054(2)
2.101(3)
1.373(3)
1.386(4)
1.369(3)
1.208(3)
1.148(3)
1.035(3)
1.255(4)
Ni
Ni
Ni
Ni
N1
N1
N4
N6
N7
N9
N10
Fig. 2 The molecular structure and atomic labeling scheme of
compound I. Displacement ellipsoids are drawn at the
0% probability level. Unlabelled atoms are related to
5
labeled atoms by –x, –y, 1–z
N2
N4
N7
N8
N10
N9
N3
N3
N6
N3
N6
N9
N3
N6
N9
N1
N5
N6
N7
N9
N10
Ni
Ni
112.13(15)
Ni
111.62(15)
128.64(18)
176.9(3)
120.1(2)
178.6(3)
167.65(9)
95.36(10)
96.81(10)
76.84(8)
105.25(8)
89.96(9)
76.52(8)
100.97(8)
91.64(9)
Ni
N6
Ni
N11
N6
N9
N9
N1
N1
N1
N5
N5
N5
Ni
Ni
Fig. 3 The molecular structure and atomic labeling scheme of
compound VI. Displacement ellipsoids are drawn at the
Ni
Ni
40% probability level
Ni
thesized complexes could be enlightened, of which
one is dinuclear and the other mononuclear. Appro-
priate crystals for X-ray analysis could not be ob-
tained with the other four. On the other hand,
Ni
Ni
Ni
[
Nidmpp(N ) ] ·2MeOH (III), has previously been re-
3 2 2
ported to be dinuclear in structure [5].
The
[Nipp(N
sphere. The Ni–N lengths are between 2.132 and
.032 . These coordination bond lengths are found
to be about 0.1  longer with respect to the O , N
and N O coordination spheres. However, although
Ni(II)
ion
in
complex
coordination
6
I
ORTEP drawing [23] of molecular structures
and atomic labeling scheme of the compounds I and
VI are shown in Figs 2 and 3. Crystallographic and
experimental data for complexes I and VI are given in
Table 2 and selected bond lengths and angles are
given in Tables 3 and 4.
(
3
)
2
]
2
·MeOH) is in the N
2
O
2 4
6
3
3
nitrogen is a hard ligand, due to its high electron do-
nating capability it can give electrons to the Ni(II) ion
even from this distance resulting in longer bond
lengths. The bond lengths observed in complex I are
almost the same as those obtained for complex III, as
given in literature [5]. The N6 and N3 atoms within
the octahedral structure of complex I are in an axial
position. On the other hand, N1, N5, N9 and N6’ form
the basal plane of the octahedron as the N3–Ni–N6
angle is largest in the octahedral structure with a
value of 167.65°.
The figures show the Ni(II) ion to be in an octa-
hedral coordination sphere in complexes I and VI.
Complex III, previously reported in literature, has a
similar coordination structure with complex I. The
Ni(II) ions are seen to be coordinated by the the nitro-
gen donors of the ligand and two nitrogen of the azide
ion in complex I. In addition, end – on coordination of
one azide ion to the other Ni(II) ion, leads to the for-
mation of m-bridges and dinuclear structures.
J. Therm. Anal. Cal., 92, 2008
621

NAZLI DN†ER KAYA et al.
Table 4 Selected bond lengths () and angles (°) of the
mononuclear Ni complex [Nidmpp(SCN)
VI)
2
MeOH]
(
Ni
Ni
Ni
Ni
Ni
Ni
N1
N1
N4
S1
S2
N1
N3
N5
N6
N7
O1
N2
N2
N5
C12
C13
2.115(3)
2.038(3)
2.104(3)
2.009(3)
2.041(3)
2.113(3)
1.386(4)
1.386(4)
1.388(4)
1.633(4)
1.638(4)
N2
N4
N6
N6
N3
N6
N3
N7
N6
N3
N7
N5
N3
N7
O1
N1
N5
Ni
Ni
Ni
Ni
Ni
Ni
Ni
Ni
Ni
Ni
Ni
Ni
Ni
Ni
111.7(2)
2
Fig. 4 TG curves of the [Nipp(SCN) MeOH] (IV),
[
2 2
Niapp(SCN) MeOH] (V) and [Nidmpp(SCN) ·MeOH]
Ni
112.58(19)
175.27(11)
91.13(12)
93.48(11)
104.22(12)
76.67(11)
91.90(11)
89.30(12)
86.13(10)
177.82(11)
85.92(11)
76.91(12)
91.75(12)
90.26(11)
(
VI) complexes
N3
N7
N7
N5
N5
N5
O1
O1
O1
O1
N1
N1
N1
both thiocyanate groups don’t form bridges. The
N6–N7–N8 and N9–N10–N11 angles are quite close
to one another with values of 176.86 and 178.62° re-
spectively. The N9–N10 and N10–N11 distances are
1
.035 and 1.255 , respectively, whereas the N6–N7
and N7–N8 distances are 1.208 and 1.148  respec-
tively meaning the N–N distances on the m-bridge are
closer. This situation can be explained on the basis of
the azide ion resonance boundary formulas.
N=N=N« N–Nº N
a
b
The bonds between the nitrogen atoms are dou-
ble bonds in form (a) and thus their lengths should be
close to each other. As a result form (a) is more appro-
priate a structure for a m-bridge. On the other hand as
no m-bridges are formed at N9–N10–N11 form (b) is
also a possibility. Thus, as one of the bonds ap-
proaches a triple bond and gets shorter the other is a
single bond which should be longer. This can also be
observed from the IR spectrums of complex I which
Complex VI ([Nidmpp(SCN) ·MeOH]), is
2
mononuclear in structure as the thiocyanate ions have
not formed a bridge. The nickel(II) ion is coordinated
to the hard ends of the nitrogen atoms and the sixth
coordination corner is occupied by a solvent molecule
(
MeOH). The coordination sphere of the complex is
O and the bond lengths are between 2.006 and
.116 , with a mean bond length of 2.069 . The
N
5
–1
gives twonN3 vibration bands at 2117 and 2195 cm .
2
The nickel ions in both complexes have been co-
ordinated by the nitrogen atoms of the azide and
thiocyanate ions. As Ni(II) is a borderline acid coordi-
nation through the soft-end of the thiocyanate ions is
not preferred, resulting in coordination through the
hard-end [24]. There are examples of 1,3-m-bridge co-
ordination for Ni(II) with thiocyanate ions [25]. Ac-
cording to this literature dimerization can be expected
for thiocyanate containing the folowing complexes
over bridges.
presence of an oxygen atom in the coordination
sphere increases the coordination bond lengths as ox-
ygen is a more hard donor with comparison to nitro-
gen. The methanol oxygen and O–Ni–N7 are in axial
position whereas N6, N1, N3 and N5 compose the
basal plane. The N7–Ni–O1 angle is close to
1
80°with a value of 177.72°.
Another important result obtained from the
X-ray data is the state of the azide and thiocyanate
groups. In complex I one of the azide groups forms a
bridge (N6–N7–N8), whereas the other does not
(
N9–N10–N11). On the other hand in complex VI
622
J. Therm. Anal. Cal., 92, 2008

NNN TYPE LIGANDS AND PSEUDOHALOGENS
Table 5 Thermoanalytical data
First thermal reaction
MeOH or water loss
Second thermal reaction
thermal decomposition
Complex
Temperature
range/°C
Expected mass/
%
Found mass/
%
Temperature
Found mass loss/
%
range/°C
4
8–94
199–202
[
[
[
[
[
[
Nipp(N
3
)
2
]
2
·MeOH
4.84
–
4.65
–
95.53
98.22
86.82
46.84
50.49
58.74
DTA peak: 74.29
DTA peak: 200.6
207–213
3 2 2
Niapp(N ) ]
–
DTA peak: 209.6
7
6–134
226–267
Nidmpp(N
3
)
2
]
2
·2MeOH
7.24
7.65
7.17
6.75
6.80
6.23
6.93
6.17
DTA peak: 137.7
DTA peak: 242.5
8
1–191
303–435
Nipp(SCN)
2
MeOH]
DTA peak: 138
DTA peak: 345–356
7
3–164
314–448
2
Niapp(SCN) MeOH]
DTA peak: 144
DTA peak: 343–358
7
5–158
325–459
2
Nidmpp(SCN) MeOH]
DTA peak: 144
DTA peak: 376
Thermal analysis at this point is a very important tool.
Figure shows the TG curves of the
Nipp(SCN) MeOH], [Niapp(SCN) MeOH] and
Nidmpp(SCN) MeOH] complexes. All three com-
studies. Table 5 gives the thermoanalytical data and
Fig. shows the DTA curves of the
[Nipp(SCN) MeOH], [Niapp(SCN) MeOH] and
4
5
[
2
2
2
2
[
[Nidmpp(SCN) MeOH] complexes. The decomposi-
2
2
plexes are seen to give similar curves. The 6% mass
loss seen between 70–150°C, is probably due to the
loss of the coordinative MeOH group in the struc-
ture.This is very high temperature proves that metha-
nol is coordinated at Ni(II).
tion process is a two-step endothermic reaction. Dur-
ing this process the ligand undergoes decomposition
together with carbonization. The difference in the
mass loss is probably due to the formation of carbon-
ized residue. The Ni(II) oxide amounts are very close
to the expected values (Ni(II) was converted to nickel
oxide and all the carbonized residue was removed by
flowing oxygen into the oven at 700°C).
The essential mass loss is observed between
3
00–380°C; 46% for [Nipp(SCN)
Niapp(SCN) MeOH] and
Nidmpp(SCN) MeOH]. Although these mass losses
2
MeOH], 47% for
[
58% for
2
[
The
curves
of
[Nipp(N ) ] ·MeOH,
3 2 2
2
can be correlated to the large organic groups in the
ligands, the values obtained are smaller than ex-
pected. In literature Pd(II) and Ni(II) complexes pre-
[Niapp(N ) ] and [Nidmpp(N ) ] ·2MeOH are as ex-
3 2 2 3 2 2
pected (Fig. 6). As the azide ion is an explosive com-
pound, all complexes containing azides are also of ex-
–
–
pared with pyrazol type ligands and SCN and N3
ions, have been reported recently [26–28]. Similar
comments are given for thermogravimetry in these
Fig. 6 TG curves of [Nipp(N ) ·MeOH (I), [Niapp(N
3
2
]
2
3 2 2
) ]
Fig. 5 DTA curves of the [Nipp(SCN)
Niapp(SCN) MeOH] (V) and [Nidmpp(SCN)
VI) complexes
2
MeOH] (IV),
(
3 2 2
II) and [Nidmpp(N ) ] ·2MeOH complexes (III)
[
2
2
MeOH]
(
J. Therm. Anal. Cal., 92, 2008
623

NAZLI DN†ER KAYA et al.
plosive character and the curves resemble those of ex-
plosive materials. These complexes are seen to de-
compose exothermically without leaving any residue;
between 198–200°C for [Nipp(N ) ] · MeOH, be-
10 V. J. Catalano, R. Kurtaran, R. A. Heck, A. Öhman and
M. G. Hill, Inorg. Chim. Acta, 286 (1999) 181.
1 H. Grove, M. Julve, F. Lloret, P. E. Kruger,
K. W. Thörnroos and J. Sletten, Inorg. Chim. Acta,
1
3
2 2
325 (2001) 115.
tween 205–211°C for [Niapp(N
35–245°C for [Nidmpp(N
3
)
2
]
2
and between
1
1
2 M. F. Charlot, O. Kahn, M. Chaillet and C. Larriev,
J. Am. Chem. Soc., 108 (1986) 2574.
2
3
)
2
]
2
·2MeOH. The effect
of the number of methylene groups on the decomposi-
tion temperature is quite evident from the results.
Curves and elemental analysis results showed
3 R. Cortes, J. I. Larramendi, L. Lezama, T. Rojo,
K. Urtiaga and M. I. Arriorta, Dalton Trans., 2723 (1992).
14 J. Ribas, A. Escuer, M. Monfort, R. Vicente, R. Cortes,
L. Lezama and T. Rojo, Coord. Chem. Rev.,
93–195 (1999) 027.
[
Nipp(N ) ] ·MeOH and [Nidmpp(N ) ] ·2MeOH to
3 2 2 3 2 2
1
contain 1 and 2 mol of MeOH, respectively.
1
1
1
5 A. Escuer, R. Vicente, F. A. Mautner and M. A. Goher,
Inorg. Chem., 36 (1997) 1233.
6 K. J. Reddy, M. V. Rajasekharan and J. P. Tuchaques,
Inorg. Chem., 37 (1998) 5978.
Supplementary materials
7 H. Nunez, E. Eseriva, J. S. Carrib, A. Sancho,
J. G. Lozano and L. Soto, Inorg. Chim. Acta,
Crystallographic data for the structural analysis have been de-
posited with the Cambridge Crystallographic Data Center,
CCDC 606869 (I) and CCDC 606870 (VI) Copies of this in-
formation can be obtained free of charge from the Director,
CCDC, 12 Union Road, Cambridge, CB2, 1EZ, UK (fax
324 (2001) 117.
1
1
2
8 M. Julve, M. Verdaugher, G. de Munno, J. Antonio Real
and G. Bruno, Inorg. Chem., 32 (1993) 795.
9 C. Diaz, J. Ribas, N. Sanz, X. Solans and M. F. Bardia,
Inorg. Chim. Acta, 286 (1999) 169.
+
44-1223-336-033; e-mail: deposit@ccdc.cam.ac.uk or
http://www.ccdc.cam.ac.uk).
0 Oxford Diffraction (2002) CrysAlis CCD and CrysAlis
RED. Version 1. 170. 14. Oxford Diffraction, Oxfordshire,
England.
Acknowledgements
2
1 G. M. Sheldrick, SHELXS97 and SHEXL97. Program for
Crystal Structure Solution and Refinement. University of
Gottingen, Germany 1997.
Professor Orhan Atakol is A DAAD grantee and would like to
thank Prof. Dr. HARTMUT FUESS for providing laboratory fa-
cilities. The authors also thank the Ankara University Scientific
Research Fund (Project No: 20030705083) for their support.
22 L. J. Farrugia, WinGX. Program for Crystallography
Package, J. Appl. Cryst., 32 (1999) 837.
23 A. L. Spek, Platon. Program for Crystal Molecular
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2
4 D. F. Shriver and P. W. Atkins, Inorganic Chemistry,
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