3D azido-bridged cobalt(II) complexes with diazines as coligands

Article abstract of DOI:10.1016/j.ica.2011.05.021

Two new three-dimensional azido-bridged Co(II) compounds with formula [Co(N₃)₂(2,5-Me₂pyz)]_n (1) and [Co(N₃)₂(2-ampym)]_n (2) have been structurally and magnetically characterized

Full text of DOI:10.1016/j.ica.2011.05.021

Inorganica Chimica Acta 376 (2011) 23–27
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Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
3D azido-bridged cobalt(II) complexes with diazines as coligands
Franz A. Mautner , Beate Sodin , Ramon Vicente b
a,
⇑
a
a
Institut für Physikalische und Theoretische Chemie, Technische Universität Graz, Rechbauerstr. 12, A-8010 Graz, Austria
Departament de Quimica Inorganica and Institut de Nanotecnologia, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona, Spain
b
a r t i c l e i n f o
a b s t r a c t
Article history:
Two new three-dimensional azido-bridged Co(II) compounds with formula [Co(N ) (2,5-Me pyz)] (1)
3
2
2
n
Received 28 February 2011
Received in revised form 12 May 2011
Accepted 20 May 2011
and [Co(N
3
)
2
(2-ampym)]
n
(2) have been structurally and magnetically characterized. 2,5-Me
2
pyz and
2-ampym are 2,5-dimethylpyrazine and 2-aminopyrimidine, respectively. Compound 1 crystallizes in
the monoclinic system with space group P2 /c and compound 2 in the orthorhombic system with space
group Pnma. In 1 and 2 each cobalt atom is linked to the four nearest-neighbors by end-to-end (EE) azido
bridges, forming square layers. These layers are further connected to 3D networks by the N,N -bridging
ligands 2,5-dimethylpyrazine or 2-aminopyrimidine. The magnetic properties of 1 and 2 are reported.
1
Available online 30 May 2011
0
Keywords:
Azido complexes
Cobalt(II)
The plots of
v
M
or
v
M
T for 1 and 2 show antiferromagnetic coupling.
Ó 2011 Elsevier B.V. All rights reserved.
Synthesis
Crystal structure
Magnetic properties
1
. Introduction
In recent years a great number of 1D to 3D polynuclear deriva-
and other potentially bridging ligands as 1,3- or 1,4-diazines
14,15]. Taking into account other spin carriers like Co(II), the re-
ported 1D to 3D [Co(N (L) ] compounds are scarce [15–32],
[
3
)
2
2
tives from paramagnetic 3d ions have been prepared with the aim
to obtain molecular magnets with high critical temperatures. From
the synthetic point of view these polynuclear compounds have
been usually built by mixing the paramagnetic spin carriers with
suitable bridging and terminal ligands. Between the potential 3d
spin carriers the Mn(II) has been extensively employed combined
with three-atom azido bridging ligand. With the above mentioned
strategy, a great number of compounds with general formula
although the number has quickly increased mainly after the publi-
cation of the double end-on (EO) azido bridged single-chain mag-
0
net (SCM) [Co(2,2 -bithiazoline)(N
3
)
2
] [18]. The low number of
fully characterized [Co(N
3
)
2
(L)
2
] compounds is not surprising due
to synthetic problems: in the case of the Mn(II) derivatives, by slow
evaporation of methanol or water/methanol solutions of Mn(II)
salts, R-pyridine monodentate or bidentate aromatic N-donor
ligands and sodium azide, it is possible to obtain well formed sin-
gle crystals suitable for X-ray structural determination. In case of
the Co(II) salts, the same procedure usually generates a microcrys-
talline precipitate in few seconds.
The combination of the anisotropic Co(II) cation with the coor-
dination versatility and the consequent different superexchange
coupling pathways of the azido bridging ligand, has produced
several interesting compounds from the magnetic and structural
[
Mn(N
3
)
2
(L)
2
] have been reported. L are usually R-pyridine mono-
one bidentate aromatic N-donor ligand.
dentate ligands or (L)
2
These compounds show all range of dimensionalities: from cluster
to 3D systems [1–13]. The azido bridging ligand shows also the
capability to coordinate in different modes, mainly in the
end-to-end, EE) or 1,1 (end-on, EO) modes, which can be present
simultaneously in the same [Mn(N (L) ] compound. The different
l
1,3
(
l
3
)
2
2
dimensionalities plus the different coordination modes generate a
great number of topologies. Taking into account that the EE coordi-
nation mode typically promotes antiferromagnetic, AF, interac-
tions and the EO coordination mode promotes ferromagnetic, F,
interactions, the great diversity of dimensionalities and topologies
points of view like the compound [Co(N
meso- ,b-bi(4-pyridyl)glycol) showing a Kagomé layer [19] or
the weak ferromagnet [Co( (4-acpy) (4-acpy = 4-acetyl-
pyridine) [24,25]. A unique 3D Co(II)–azido sublattice has been
found in the ferromagnet [Co (N (hmt)(H O)] (hmt = hexameth-
3 2
) (bpg)](DMF)4/3 (bpg =
a
l
1,3-N
3
)
2
2 n
]
2
3
)
4
2
n
found in the [Mn(N
diversity in their magnetic behavior.
Focusing our attention on the synthesis of 3D compounds, one
synthetic strategy is based in mixing Mn(II) salts with the azido
3
)
2
(L)
2
] compounds has as consequence a great
ylenetetramine) [28]. Very recently, new 1D systems exhibiting
ferrimagnetic [29] or single-chain magnetic behavior [30,31] have
been described.
In this paper, we report two new three-dimensional azido-
bridged Co(II) compounds with formula [Co(N
(1) and [Co(N (2-ampym)] (2), 2,5-Me pyz and 2-ampym are
2,5-dimethylpyrazine and 2-aminopyrimidine, respectively, which
3 2 2 n
) (2,5-Me pyz)]
⇑
Corresponding author. Tel.: +43 316 873 8234; fax: +43 316 873 8225.
E-mail address: mautner@ptc.tu-graz.ac.at (F.A. Mautner).
3
)
2
n
2
0
020-1693/$ - see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2011.05.021

2
4
F.A. Mautner et al. / Inorganica Chimica Acta 376 (2011) 23–27
are built from the above described strategy to mix Co(II) salts, azi-
do ligand and other potentially bridging ligands as 1,3- or 1,4-dia-
zines, along with their magnetic properties.
respectively. Crystallographic data and some features of the struc-
ture refinements are summarized in Table 1. The collected data
were corrected for absorption by using SADABS [35] based upon Laue
symmetry by using equivalent reflections. The structures were
solved by direct methods and refined with the full-matrix least-
2
. Experimental
squares technique by using the SHELXTL/PC program package [36].
All non-hydrogen atoms were refined anisotropically, whereas all
the H atoms were placed in geometrically idealized positions and
constrained to ride on their parent atoms.
2
.1. General
Cobalt(II) chloride hexahydrate, sodium azide, 2-aminopyrimi-
dine and 2,5-dimethylpyrazine (Aldrich) were used as obtained.
Aqueous hydrazoic acid is obtained with a modified Kipp’s gener-
3. Results and discussion
ator by decomposition of NaN
quent transfer of HN into H O with aid of an inert-gas stream [33].
Diluted HN in the synthesis of the complexes is used to avoid an-
3 2 4 2
in H SO /H O (1:3 v:v) and subse-
3.1. Crystal structures
3
2
3
ꢀ
2ꢀ
ionic impurities, like OH (hydrolysis) or CO
air).
3
(CO
2
uptake from
3 2 2 n
3.1.1. Description of the structure of [Co(N ) (2,5-Me pyz)] (1)
The three-dimensional neutral cobalt–azido compound 1 can be
described as square layers with only EE azido bridges. N,N -bridg-
0
Caution! Azide compounds and hydrazoic acid (HN
3
) are poten-
tially explosive! Only small amount of material should be pre-
pared, and it should be handled with care.
ing 2,5-dimethylpyrazine ligands further connect the 2D Co–azido-
sublattice to form a 3D network structure. A perspective view of 1
together with the atom numbering scheme is presented in Fig. 1a.
The Co(1) is located at center of inversion and is coordinated by six
nitrogen atoms with a slightly elongated octahedral geometry. Two
N atoms in trans-position are part of two 2,5-dimethylpyrazine li-
gands. The remaining equatorial N atoms belong to four azido
groups linked to four different cobalt atoms in an EE bridging mode
generating two-dimensional Co(N ) layers extended parallel to
3 2
the bc-plane of the monoclinic unit cell (Fig. 1b and c). The Co–
N(azido) bond distances are 2.108(2) and 2.141(2) Å, whereas the
Co–N(2,5-Me pyz) is 2.224(2) Å. The Co(1)–N(11)–N(12), Co(1)–
2
3 2 2 n
2.2. [Co(N ) (2,5-Me pyz)] (1)
CoCl
.03 mmol), and NaN
.00 mL aqueous hydrazoic acid at room temperature. After 3 days
2
ꢁ6H
2
O (0.480 g, 2.02 mmol), 2,5-dimethylpyrazine (0.220 g,
2
5
3
(0.293 g, 4.50 mmol) were dissolved in
dark red crystals of 1 were separated. Yield: 0.146 g (28.6%). Calc.
for C CoN (251.13): C, 28.7; H, 3.2; Co, 23.5; N, 44.6. Found: C,
8.6; H, 3.3; Co, 23.7; N, 44.4%. IR (KBr, cm ) 3409 (w), 2079 (vs)
), 1494 (m), 1451 (m), 1381 (w), 1326 (m), 1156 (m), 1071
m), 1032 (w), 979 (w), 895 (w), 467 (m).
6
H
8
8
ꢀ1
2
mas (N
3
N(13)–N(12C) and N(11)–N(12)–N(13F) bond angles are 139.6(2)°,
(
0
1
22.7(2)° and 177.9(3)°, respectively. The Co–NNN–Co torsion an-
gles are ±100.2(4)° and the dihedral angle between
3
l1,3-N -bridged
3 2 n
2.3. [Co(N ) (2-ampym)] (2)
CoN (azido)-planes is 13.4°. The Co azido layers are further linked
4
along the a-axis by the ring N atoms of the 2,5-dimethylpyrazine
ligands thus forming the 3D network. The Co(1)ꢁ ꢁ ꢁCo(1C) intralayer
distance is 5.6932(13) Å. The Co(1)ꢁ ꢁ ꢁCo(1A) interlayer separation
is 7.2360(16) Å.
CoCl
.82 mmol), and NaN
6.0 mL aqueous hydrazoic acid by heating up to 90 °C. Upon slow
2
ꢁ6H
2
O (0.490 g, 2.07 mmol), 2-aminopyrimidine (0.270 g,
2
2
3
(0.293 g, 4.50 mmol) were dissolved in
cooling to 4 °C red crystals of 2 were separated after one week.
Yield: 0.375 g (77.2%). Calc. for C CoN (238.10): C, 20.2; H,
.1; Co, 24.8; N, 52.9. Found: C, 20.0; H, 1.9; Co, 24.9; N, 53.2%.
H
4 5
9
3 2 n
3.1.2. Description of the structure of [Co(N ) (2-ampym)] (2)
2
ꢀ1
Complex 2 crystallizes in space group Pnma of the orthorhombic
crystal system. The atom numbering scheme is presented in Fig. 2a.
As in complex 1, a three-dimensional neutral 3D network is formed
IR (KBr, cm ) 3471 (m), 3418 (w), 3372 (m), 2082 (vs)
3
mas (N ),
1
637 (s), 1579 (s), 1487 (s), 1461 (m), 1357 (m), 1241 (w), 1201
(
(
m), 1101 (w), 995 (w), 791 (m), 662 (w), 637 (w), 615 (w), 532
w), 475 (m).
Table 1
Crystal data and structure refinement for compounds 1 and 2.
2.4. Spectral and magnetic measurements
Compound
1
2
Infrared spectra were recorded (4000–400 cmꢀ1) with a Perkin–
Empirical formula
Formula weight
T (K)
Crystal system
Space group
a (Å)
C
6
H
8
CoN
8
C
4 5 9
H CoN
Elmer 1600 Series FT-IR spectrophotometer as KBr pellets. Mag-
netic susceptibility measurements under several magnetic fields
in the temperature range 2–300 K and magnetization measure-
ments in the field range of 0–5 T were performed with a Quantum
Design MPMS-XL SQUID magnetometer at the Magnetochemistry
Service of the University of Barcelona. All measurements were per-
formed on polycrystalline samples. Pascal’s constants were used to
estimate the diamagnetic corrections, which were subtracted from
the experimental susceptibilities to give the corrected molar mag-
netic susceptibilities.
251.13
100(2)
monoclinic
P2 /c
7.2360(14)
6.9775(14)
8.998(2)
107.52(3)
433.2(2)
2
238.10
100(2)
orthorhombic
Pnma
7.0878(14)
12.883(3)
8.905(2)
90
813.1(3)
4
1
b (Å)
c (Å)
b (°)3
V (Å )
Z
F(0 0 0)
254
476
Crystal size (mm)
0.30 ꢂ 0.20 ꢂ 0.10
0.30 ꢂ 0.22 ꢂ 0.15
ꢀ
3
Dcalc (g cm
)
1.925
1.945
l
(Mo K
a
) (mmꢀ1)
1.958
2888
2.084
5956
2
.5. X-ray crystallography
Collected data
Independent reflections (Rint
Parameters
)
880 (0.0324)
71
860 (0.0259)
74
The single-crystal diffraction studies of both complexes were
performed with a Bruker APEX II CCD diffractometer equipped
with graphite-monochromated Mo K radiation (k = 0.71073 Å)
by using the -scan technique at 100(2) K. The SMART and SAINT soft-
ware packages [34] were used for data collection and integration,
R
1
[I > 2
wR (all data)
Goodness-of-fit (GOF) on F
r
(I)]
0.0345
0.0815
1.092
0.463/ꢀ0.467
0.0269
0.0632
1.206
0.276/ꢀ0.311
a
2
2
x
ꢀ
3
Residual extrema (e Å
)

F.A. Mautner et al. / Inorganica Chimica Acta 376 (2011) 23–27
25
Fig. 1. (a) Perspective view of 1 showing the atom-numbering scheme. Ellipsoid are at the 50% propability level. Symmetry codes: (A) ꢀx + 2, ꢀy + 2, ꢀz; (B) ꢀx + 1, ꢀy + 2, ꢀz;
C) ꢀx + 1, y + 1/2, ꢀz + 1/2; (D) x, ꢀy + 3/2, z ꢀ 1/2; (E) x, ꢀy + 5/2, z ꢀ 1/2; (F) ꢀx + 1, y ꢀ 1/2, ꢀz + 1/2. (b) Packing view of 1 along [0 1 0]. (c) Packing view of 1 along [1 0 0].
(
0
ꢀ3
3
ꢀ1
by connecting square layers with only EE azido bridges via N,N -
bridging 2-aminopyrimidine ligands. Each Co(II) metal ion, located
at a center of inversion, is coordinated octahedrally by six N atoms
of which two are part of the 2-aminopyrimidine ligands and the
other four belong to azide groups. The Co–N(azido) bond lengths
are 2.120(2) and 2.128(2) Å, whereas the axial Co–N(2-ampym)
is 2.200(2) Å. The Co(1)–N(11)–N(12), Co(1)–N(13)–N(12B) and
N(11)–N(12)–N(13C) bond angles are 121.48(12)°, 132.06(12)°
rive at minimum values of 28 ꢂ 10 cm mol at 8 K for 1 and
ꢀ3 3 ꢀ1
16 ꢂ 10 cm mol
at 12 K for 2. At 2 K the
v
M
values are
30 ꢂ 10 and 17 ꢂ 10 cm mol for 1 and 2, respectively. The
sharp maxima in the versus T plots for 1 and 2 can indicate
3D antiferromagnetic ordering below the temperature of these
maxima. For 1 and 2 the T room temperature values decrease
ꢀ3
ꢀ3
3
ꢀ1
v
M
v
M
continuously upon lowering the temperature with a change of
slope around 20 K for 1 and 45 K for 2, Fig. 4. The magnetic suscep-
tibility in the range 30–300 K for 1 and 50–300 K for 2 obeys the
0
and 177.9(2)°, respectively. The Co–NNN–Co torsion angles are
±
116.4(2)°. The dihedral angle between
do)-planes within the Co-azide layer is 18.2°, whereas the dihedral
angle between CoN (azido)-planes of Co(1) and Co(1D) is 45.9°.
l
1,3-N
3
-bridged CoN
4
(azi-
Curie–Weiss law (
v
M
= C/(T ꢀ h)) with C = 3.35 and h = ꢀ69.3 K
for 1 and C = 3.63 and h = ꢀ86.7 K for 2. The C values of 3.35 and
3.63 correspond to g values of 2.67 and 2.78 for 1 and 2, respec-
tively. The negative Weiss constants for 1 and 2 in the respective
high temperature ranges indicate antiferromagnetic coupling in
4
The Co azido layers are further linked along the b-axis by the ring
N atoms of the 2-aminopyrimidine ligands thus forming the 3D
network (Fig. 2b and c). The Co(1)ꢁ ꢁ ꢁCo(1C) intralayer distance is
both compounds between Co(II) ions bridged by EE azido and
0
5
.6907(13) Å. The Co(1)ꢁ ꢁ ꢁCo(1A) interlayer separation is 6.4415
N,N -diazine ligands. The Néel temperature, T
N
, for complexes 1
(
15) Å. The aromatic rings of the 2-aminopyrimidine molecules
and 2 was determined by the in phase of zero field ac magnetic
0
form dihedral angles of 42.3°, in contrast to [Co(N (pym)] [15],
3
)
2
n
susceptibility
v
(T) which has maxima of 19.5 and 42.5 K for 1
where the pyrimidine rings have a coplanar arrangement. The ami-
no groups form hydrogen bonds of type N–Hꢁ ꢁ ꢁN to azide nitrogen
atoms [N(2)ꢁ ꢁ ꢁN(11) = 3.018(2) Å, and N(2)–N(13) = 3.091(2) Å].
and 2, respectively under Hac = 4 Oe and frequency of 957 Hz. For
1, the magnetization at 2 K increases upon increasing the applied
field with a change of slope around 2.5 T to a value of 0.33 Nb at
2
+
5
T, far from the saturation value of the Co ion, which suggest a
strong 3D antiferromagnetic ordering. For 2, the magnetization at
K increases upon increasing the applied field to a value of
0.13 Nb at 5 T without change of slope, far also from the saturation
3.2. Magnetic properties
2
The magnetic properties of 1 and 2, in the form of
M
v versus T
2
+
are presented for the value of the applied magnetic field of 5000 G
value of the Co ion suggesting also a strong 3D antiferromagnetic
ordering.
ꢀ
3
(
9
Fig. 3). The room temperature
v
M
values of 9.17 ꢂ 10
and
ꢀ3
3
ꢀ1
.32 ꢂ 10 cm mol for 1 and 2, respectively increase upon low-
In Table 2 are shown some structural and magnetic data for the
reported 2D or 3D azido–Co(II) compounds built from 2D (4,4)
ering the temperature in a similar manner, reaching sharp maxima
ꢀ3
3
ꢀ1
ꢀ3
3
ꢀ1
of 45 ꢂ 10 cm mol at 20 K for 1 and of 27 ꢂ 10 cm mol at
Co(
l
1,3-N
3
)
2
layers. The compounds 1–4 order antiferromagneti-
in the range 7.8–42 K whereas the compounds 5–
4
5 K for 2. After the maxima, the values decrease quickly, to ar-
v
M
cally below T
N

2
6
F.A. Mautner et al. / Inorganica Chimica Acta 376 (2011) 23–27
Fig. 2. (a) Perspective view of 2 showing the atom-numbering scheme. Ellipsoid are at the 50% propability level. Symmetry codes: (A) ꢀx, ꢀy + 1, ꢀz; (B) ꢀx ꢀ 1/2, ꢀy + 1,
z ꢀ 1/2; (C) ꢀx ꢀ 1/2, ꢀy + 1, z + 1/2; (D) x, ꢀy + 3/2, z. (b) Packing view of 2 along [1 0 0]. (c) Packing view of 2 along [0 1 0].
Fig. 4. Plot of
Me pyz)] (1) (open dots) and [Co(N
under external magnetic field of 5000 G.
M 3 2
v T vs. T in the 300–2 K range of temperature for [Co(N ) (2,5-
Fig. 3. Plot of
v
M
vs. T in the 300–2 K range of temperature for [Co(N
3
)
2
(2,5-
2
n
3
)
2
(2-ampym)]
n
(2) (black dots) measured
Me pyz)] (1) (open dots) and [Co(N
2
n
3 2
)
(2-ampym)] (2) (black dots) measured
n
under external magnetic field of 5000 G. The solid line shows the best fit in the
high-temperature region as Curie–Weiss law (see text).
0
pling between the 2D (4,4) Co(
diazine bridging ligands. In compound 4 the 2D (4,4) Co(
layers are bridged through the 1,4-bis(tetrazole-1-yl)ethane (endi)
ligand. In this case the 3D AF ordering below T = 7.8 K is more dif-
ficult to explain because the endi ligand is a (CH linker. Gao et al.
l
1,3-N
3
)
2
layers through the N,N -
8
are weak ferromagnets below T
into account the (CH linker in the formally 3D compound 7, 5–
can be considered from the magnetic point of view as spin-
canted layers ferromagnetically ordered below T through dipolar
C
in the range 10–23 K. Taking
3 2
l1,3-N )
2 4
)
8
N
C
2 2
)
interactions [26]. The Coꢁ ꢁ ꢁCo interlayer distances in 5–8 are in
explain the absence of the spin canting in 4 for its unique triclinic
crystal system [26]. The Coꢁ ꢁ ꢁCo interlayer distances in 1–4 are in
the range 6.0–8.7 Å.
the range 10.6–15.2 Å. For compounds 1–3 the 3D AF ordering be-
N
low T in the range 19.5–42.5 K can be explained from the AF cou-

F.A. Mautner et al. / Inorganica Chimica Acta 376 (2011) 23–27
27
Table 2
Some structural and magnetic data for compounds with Co(II) azide (4,4) square layers.
Compounda
1
2
3
4
5
6
7
8
Dimension
3D
2.224
2.108
3D
3D
2.165
2.123
2.125
125.6
124.1
5.739, 5.599
5.978
108.5, 133.4
68.8
3D
2D
2D
3D
2D
b
Co–N
L
(Å)
2.200
2.120
2.128
132.1
121.5
5.6907
6.4415
116.4
18.2
2.144, 2.125
2.140, 2.118
2.136, 2.095
123.6, 136.7
140.1, 145.1
5.746
8.68
107.9, 75.2
81.7
2.172
2.125
2.133
149.2
128.2
5.848
11.73
84.9
2.185
2.113
2.142
150.0
121.1
5.932
13.60
131.0
55.5
2.127
2.100
2.158
145.7
119.0
5.794
10.633
122.5
62.1
2.136, 2.139
2.099, 2.103
2.161, 2.158
146.1, 146.2
120.1, 120.3
5.845, 5.842
15.18, 15.172
124.1, 123.7
61.1, 61.2
58.9
3
Co–N(N ) (Å)
2
.141
139.6
22.7
Co–N–N (°)
1
Coꢁ ꢁ ꢁCo (Å) (intra-layer)
Coꢁ ꢁ ꢁCo (Å) (inter-layer)
5.6932
7.2360
100.2
13.4
s
d (°)
Co–N–N–Co (°)
c
83.3
62.3
N
L
–Coꢁ ꢁ ꢁCo–N
L
(°)
5.7
8.9
55.2/50.0
75.0
50.0
–
T
C
or T (K)
N
T
N
= 19.5
T
N
= 42.5
T
N
= 41
T
N
= 7.8
T
C
= 11.2
T
C
= 10
T
C
= 23
C
T = 22.1
Magn. behavior below T
C
or T
N
AF
AF
AF
AF
weak F
weak F
3.25/ꢀ54.1
[19]
weak F
3.36/ꢀ59.3
[27]
weak F
C (cm3 mol K)/h (K)
ꢀ1
d
3.35/ꢀ69.3
3.63/ꢀ86.7
3.38/ꢀ104
3.62/ꢀ48.5
3.55/ꢀ45.4
3.04 (3.40)/ꢀ48.2 (ꢀ54.2)
Reference
this work
this work
[15]
[26]
[24,25]
[26,27]
a
Compound 3: [Co(N
3
)
2
(pym)]
n
(pym = pyrimidine); compound 4: [Co(N
(bpg)] (bgp = meso- ,b-bi(4-pyridyl)glycol); compound 7: [Co(N
(btze = 1,4-(tetrazole-1-yl)ethane).
coordinated N atom of organic ligand L.
Dihedral angle between neighboring [CoN
3
)
2
(endi)]
n
(endi = 1,2-(tetrazole-1-yl)ethane); compound 5: [Co(N
3 2 n
) (4-acpy)] (4-acpy = 4-ace-
tylpyridine); compound 6: [Co(N
)
3 2
n
a
)
3 2
(btzb)] (btzb = 1,4-(tetrazole-1-yl)butane); compound 8:
n
[
3 2 n
Co(N ) (btze)]
b
N
L
c
4
] planes defined by azido N atoms.
Corresponding parameters from Curie–Weiss law (
= C/(T ꢀ h)).
d
v
M
[
[
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4
. Conclusion
9
Here we have presented two new 3D azido–Co(II) compounds
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and similar structural motif: Co(
l
1,3-N
3
)
2
square layers connected
pyz)] (1) and [Co(N (2-
(2). Compounds 1 and 2 show 3D antiferromagnetic
coupling below T = 19.5 and 42.5 K, respectively. From the point
of view of possible useful magnetic properties to be applied in de-
vices, it is important to have high T values in compounds built
from M( square layers. For this reason the synthetic strat-
0
via N,N -diazine ligands: [Co(N
3
)
2
(Me
2
n
3 2
)
[
ampym)]
n
N
4
[
C
(
l1,3-N
3
)
2
egy to bind antiferromagnetically the spin canted 2D M(
planes through N,N -diazine ligands should be avoided.
l
1,3-N
3
)
2
[
[
0
[
[
17] C.-S. Hong, J.-E. Koo, S.-K. Son, Y.-S. Lee, Y.-S. Kim, Y. Do, Chem. Eur. J. 7 (2001)
Acknowledgments
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243.
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25 (2003) 13976.
1
This research was supported by the Spanish MICINN (Grant
CTQ2009-07264), the Generalitat de Catalunya (Grant
[
[
19] X.-Y. Wang, L. Wang, Z.-M. Wang, S. Gao, J. Am. Chem. Soc. 128 (2006) 674.
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(2006) 2776;
2
009SGR1454) and SIDA (Grant No. 348-2002-6879). FAM thanks
(
7
b) K.C. Mondal, O. Sengupta, M. Nethaji, P.S. Mukherjee, Dalton Trans. (2008)
67.
Dr. J. Baumgartner (TU-Graz) for support.
[
[
21] T. Liu, Y. Zhang, Z. Wang, S. Gao, Inorg. Chem. 45 (2006) 2782.
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Appendix A. Supplementary material
9054.
[
[
[
[
23] X.-T. Wang, Z.-M. Wang, S. Gao, Inorg. Chem. 46 (2007) 10452.
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26] R.-Y. Li, X.-Y. Wang, T. Liu, H.-B. Xu, F. Zhao, Z.-M. Wang, S. Gao, Inorg. Chem.
47 (2008) 8134.
Selected bond parameters for 1 (Table S1) and 2 (Table S2). AC
susceptibility data of 1 (Figure S1) and of 2 (Figure S2) at an ac
magnetic field of 4 Oe with a frequency of 957 Hz. CCDC 714909
and 714910 contain the supplementary crystallographic data for
[
[
27] E.-Q. Gao, P.-P. Liu, Y.-Q. Wang, Q. Yue, Q.-L. Wang, Chem. Eur. J. 15 (2009)
1217.
1
and 2. These data can be obtained free of charge from The
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6280;
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
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(
b) R.-Y. Li, Z.-M. Wang, S. Gao, CrystEngComm 11 (2009) 2096.
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[
(
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(
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