Syntheses and crystal structures of two novel Cu(II) and Co(II) complexes with 3-methyl-4-(p-bromophenyl)-5-(2-pyridyl)-1,2,4-triazole

Article abstract of DOI:10.1007/s11224-009-9569-y

A new ligand, 3-methyl-4-(p-bromophenyl)-5-(2-pyridyl)-1,2,4-triazole (L) and its complexes, trans-[CuL₂(ClO₄)₂] (1) and cis-[CoL₂(H₂O)₂](ClO₄)₂·H₂O·CH₃OH (2), have been synthesized and characterized by UV, IR, electrospray ionization mass spectrum, elemental analyses, and single-crystal X-ray diffraction methods. In the structure, two L ligands are stabilized by intermolecular π···π interactions between the triazole rings. In the complexes, each L ligand adopts a chelating bidentate mode through N atom of pyridyl group and one N atom of the triazole. Both complexes have a similar distorted octahedral [MN₄O₂] core (M = Cu²⁺ and Co²⁺) with two ClO₄^- ions in the trans position in 1 but two H₂O molecules in the cis arrangement in 2. Springer Science+Business Media, LLC 2009.

Full text of DOI:10.1007/s11224-009-9569-y

Struct Chem (2010) 21:237–244
DOI 10.1007/s11224-009-9569-y
ORIGINAL RESEARCH
Syntheses and crystal structures of two novel Cu(II) and Co(II)
complexes with 3-methyl-4-(p-bromophenyl)-5-(2-pyridyl)-1,2,4-
triazole
•
Wei Lu Dun-Ru Zhu Yan Xu Hui-Min Cheng
•
•
•
•
Jian Zhao Xuan Shen
Received: 26 October 2009 / Accepted: 27 November 2009 / Published online: 6 December 2009
Ó Springer Science+Business Media, LLC 2009
Abstract A new ligand, 3-methyl-4-(p-bromophenyl)-5-
(2-pyridyl)-1,2,4-triazole (L) and its complexes, trans-
[CuL2(ClO4)2] (1) and cis-[CoL2(H2O)2](ClO4)2ꢀH2Oꢀ
CH3OH (2), have been synthesized and characterized by
UV, IR, electrospray ionization mass spectrum, elemental
analyses, and single-crystal X-ray diffraction methods. In
the structure, two L ligands are stabilized by intermolec-
ular pꢀꢀꢀp interactions between the triazole rings. In the
complexes, each L ligand adopts a chelating bidentate
mode through N atom of pyridyl group and one N atom of
the triazole. Both complexes have a similar distorted
octahedral [MN4O2] core (M = Cu2? and Co2?) with two
interesting magnetic properties [4–7], especially, some
iron(II)–triazole complexes have spin-crossover properties
which can be used in molecular electronics [8], as infor-
mation storage [9] and switching materials [10]. Recently,
some 4-substituted 3,5-di(2-pyridyl)-1,2,4-triazoles and
their metal complexes have been prepared by us and other
groups [11–18]. However, complexes with asymmetrically
3,5-di-substituted 1,2,4-triazole have been little studied so
far [19–26]. Herein, we report the syntheses of a new 1,2,4-
triazole ligand, 3-methyl-4-(p-bromophenyl)-5-(2-pyridyl)-
1,2,4-triazole (L) and its complexes, trans-[CuL2(ClO4)2]
(1) and cis-[CoL2(H2O)2](ClO4)2ꢀH2OꢀCH3OH (2). Their
single crystal structures and spectral properties have
systematically been investigated.
-
ClO4 ions in the trans position in 1 but two H2O mole-
cules in the cis arrangement in 2.
Keywords Syntheses ꢀ Triazole ꢀ Crystal structures ꢀ
Copper(II) complex ꢀ Cobalt(II) complex
Experimental
General
Introduction
All chemicals used were of analytical grade. Solvents were
purified by conventional methods. Melting point was
determined using an X4 digital microscopic melting point
apparatus, and was uncorrected. Elemental analyses (C, H,
N) were carried out with a Thermo Finnigan Flash 1112A
elemental analyzer. IR spectra were recorded on a Nicolet
Avatar 380 FT-IR instrument with KBr pellets in the range
4000–400 cm-1. UV–Vis spectra were recorded on a Per-
kin–Elmer Lambda 35 spectrometer at room temperature in
Over the past few decades, 1,2,4-triazole derivatives have
attracted much attention, mainly because of the fact that
these molecules can act as flexible bridging ligands and
spacers between transition metal ions [1–3]. Some com-
plexes containing substituted 1,2,4-triazole ligands show
1
acetonitrile solution. The H-NMR spectra were measured
W. Lu ꢀ D.-R. Zhu (&) ꢀ Y. Xu ꢀ H.-M. Cheng ꢀ J. Zhao ꢀ
X. Shen
College of Chemistry and Chemical Engineering, State Key
Laboratory of Materials-Oriented Chemical Engineering,
Nanjing University of Technology, Nanjing 210009,
People’s Republic of China
with a Bruker AM 500 spectrometer at ambient tempera-
ture in CDCl3 using TMS as internal reference. Electro-
spray ionization mass spectrum (ESI-MS) was recorded
with an LCQ ADVANTAGE MAX mass spectrometer,
with MeOH on the mobile phase; the flowrate of the mobile
e-mail: zhudr@njut.edu.cn
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Struct Chem (2010) 21:237–244
phase was 0.2 cm3 min-1. The spray voltage, the capillary
voltage, and the capillary temperature were 4 kV, 40 V,
and 260 °C, respectively.
X-ray data collection and structure determination
The well-shaped single crystals of L, 1, and 2 were selected
for X-ray diffraction study. The unit cell parameters and
intensity data were collected at 293(2) K on a Bruker
SMART CCD diffractometer with a detector distance of
5 cm and frame exposure time of 10 s using a graphite-
Synthesis of L
The ligand, 3-methyl-4-(p-bromophenyl)-5-(2-pyridyl)-
1,2,4-triazole (L) was synthesized by the reaction of 4,40-
dibromophenylphosphazoanilide (2.251 g, 6.05 mmol) and
N-acetyl-N0-(2-pyridoyl)hydrazine (0.985 g, 5.50 mmol) in
o-dichlorobenzene at 180–190 °C for 3 h [27], yield
0.946 g (54.6%), m.p. 183–185 °C. Colorless single crys-
tals suitable for X-ray analysis were obtained from acetone
upon slow evaporation at room temperature. Elemental
analyses: found (%): C, 53.47; H, 3.66; N, 17.69.
C14H11BrN4 Calcd. (%): C, 53.35; H, 3.52; N, 17.78. UV
(nm): k = 226, 281.7. IR (cm-1): m = 3049.5 m, 3003.6
m, 2921.3 w, 1589.7 m, 1526.2 m, 1491.2 s, 1070 m, 998.4
˚
monochromated MoKa (k = 0.71073 A) radiation. The
structures were all solved by direct methods and refined on
F2 by full-matrix least squares procedures using SHELXTL
software [28]. All non-hydrogen atoms were anisotropi-
cally refined. Atoms N1, N5, C1, C16, and C17 of the
pyridyl rings in the L ligand were found to be disordered
over two positions (N1, N1A; N5, N5A; C1, C1A; C16,
C16A; and C17, C17A) and fixed at 0.5. Atoms O7, O8,
-
O9, and O10 of one ClO4 anion in 2 were also highly
disordered, with an occupancy of 0.540(5) for O7, O8, O9,
and O10 and 0.460(5) for O7A, O8A, O9A, and O10A,
respectively. All H atoms of organic ligand were generated
geometrically and allowed to ride on their respective parent
atoms, but not refined. Crystallographic data are summa-
rized in Table 1. The selected bond lengths and angles for
L, 1, and 2 are listed in Table 2.
1
m. H-NMR d: 2.37 (3H, s), 7.11–7.13 (2H, d), 7.22–7.24
(1H, t), 7.62–7.24 (2H, d), 7.76–7.80 (1H, t), 8.17–8.18
(1H, d), 8.30–8.31 (1H, d).
Synthesis of trans-[CuL2(ClO4)2] (1)
To a solution of L (0.189 g, 0.60 mmol), in boiling EtOH
Results and discussion
(10 cm3),
a
solution of Cu(NO3)2ꢀ3H2O (0.073 g,
0.30 mmol) in EtOH (5 cm3) was added. The mixture was
filtered into an EtOH solution containing NaClO4ꢀH2O
(0.084 g, 0.60 mmol). The blue crystalline solid that
formed was isolated, washed with H2O, and dried in vacuo
to yield 0.209 g (85.9%) of the complex. Blue single
crystals suitable for X-ray analysis were obtained from a
methanol solution. Elemental analyses: found (%): C,
37.49; H, 2.56; N, 12.39. C28H22Br2Cl2CuN8O8 Calcd.
(%): C, 37.67; H, 2.48; N, 12.55. UV (nm): k = 227,
289.8. IR (cm-1): m = 3084.4 w, 2913.1 w, 1614.3 m,
1549.1 m, 1501.1 s, 1112.4–1091.8 s, 1024.6 m, 929.1 m,
624.1 s. ESI-MS: m/z = 792.05, 504.85, 348.53.
Syntheses
The asymmetrically 3,5-di-substituted 1,2,4-triazole (L)
reacts with M2? (M = Cu and Co) ion and NaClO4 in
molar ratio 2:1:2 to form two neutral monomeric hexaco-
ordinate complexes, trans-[CuL2(ClO4)2] (1) and cis-
[CoL2(H2O)2](ClO4)2ꢀH2OꢀCH3OH (2), which are stable in
air. Yields for complexes 1 and 2 are 85.9 and 81.2%,
respectively. The elemental analyses were satisfactory and
indicate that each complex contains one metal ion, two
triazole ligands, and two ClO4- anions except 2 with three
water molecules and one methanol molecule.
Synthesis of cis-[CoL2(H2O)2](ClO4)2ꢀH2OꢀCH3OH (2)
Crystal structure of L
Complex 2 was prepared in 81.2% yield by a procedure
similar to complex 1 but using CoCl2ꢀ6H2O instead of
Cu(NO3)2ꢀ3H2O. The pale orange single crystals suitable
for X-ray diffraction were obtained by evaporation from
a methanol solution. Elemental analyses: found (%): C,
35.57; H, 3.43; N, 11.61. C29H32Br2Cl2CoN8O12 Calcd.
(%): C, 35.75; H, 3.31; N, 11.50. UV (nm): k = 226,
282. IR (cm-1): m = 3405.8 s, 3080.8 w, 2917.4 w,
1607.7 m, 1539.9 m, 1495.4 s, 1144.6–1089.6 s, 1021.4
m, 927.3 m, 636.8 s. ESI-MS: m/z = 787.93, 503.26,
365.42, 344.93.
The molecular structure of L with the atom-numbering
scheme is shown in Fig. 1. In the structure, the central
1,2,4-triazole ring is surrounded by a pyridyl group, a
methyl group, and a p-bromophenyl ring. Meanwhile, the
triazole ring of each ligand is superimposed by a forming
pꢀꢀꢀp stack with that of one adjacent ligand. The separation
˚
of the parallel triazole ring from adjacent one is 3.593 A,
whereas the stacking distance between the two triazole ring
˚
centroids is 3.628 A. It is noticeable that some atoms of the
pyridyl group are highly disordered, the occupancy factors
for N1, N5, C1, C16, and C17 are all fixed as 0.50. Bond
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Struct Chem (2010) 21:237–244
239
Table 1 Crystal data and
structure refinement for L, 1,
and 2
Compounds
L
1
2
Empirical formula
Formula weight
Crystal system
Space group
C14H11BrN4
315.18
Monoclinic
P21/m
C28H22Br2Cl2CuN8O8 C29H32Br2Cl2CoN8O12
892.80
Monoclinic
P21/n
974.28
Orthorhombic
P212121
˚
a (A)
11.258(2)
7.1854(14)
17.322(4)
90
7.8413(16)
14.723(3)
14.396(3)
90
9.3232(19)
17.115(3)
25.365(5)
90
˚
b (A)
˚
c (A)
a (°)
b (°)
c (°)
108.59(3)
90
99.94(3)
90
90
90
3
˚
V (A )
1328.1(5)
4
1637.0(6)
2
4047.4(14)
4
Z
Dc
l (mm-1
1.576
1.811
1.599
)
3.086
3.334
2.596
F (000)
632
886
1956
Crystal size (mm)
h range
0.12 9 0.14 9 0.32 0.10 9 0.12 9 0.20
0.12 9 0.13 9 0.24
3.21–25.00
31125
3.09–25.00
11150
2.98–25.00
13668
Reflections collected
Independent reflections
2545 [Rint = 0.067] 2877 [Rint = 0.166]
7106 [Rint = 0.186]
3343
Reflections observed [I [ 2r(I)] 1861
1502
Data/restraints/parameters
Goodness-of-fit on F2
R/wR [I [ 2r(I)]
2545/18/232
2877/0/223
1.016
7106/160/537
0.989
1.269
0.0872/0.2412
0.1169/0.2514
0.81, -0.97
0.0694/0.1099
0.1633/0.1332
0.47, -0.53
0.0843/0.1461
0.2007/0.1779
0.43, -0.49
R/wR (all data)
-3
)
˚
Max., min. Dq (eA
Table 2 Selected bond
˚
L
1
2
distances (A) and angles (°) for
L, 1, and 2
N1–C1
1.402(17)
1.455(16)
1.383(17)
1.383(19)
1.380(18)
1.462(16)
1.903(11)
110.6(12)
110.9(11)
123.0(11)
104.4(11)
106.3(10)
118.9(11)
Cu1–N1
Cu1–N2
N2–N3
2.066(5)
Co1–N1
2.163(5)
2.120(5)
2.145(5)
2.132(5)
2.034(4)
2.076(4)
1.862(7)
N1–C5
1.971(5)
1.371(7)
Co1–N2
N2–N3
Co1–N5
N6–N7
Co1–N6
N5–C17
Cu1–O4
2.565(6)
Co1–O1 W
Co1–O2 W
Br1–C12
N5–C19
Br1–C12
N4–C6–N2
N4–C7–N3
N4–C7–C8
C7–N4–C6
C7–N3–N2
N1–C5–C6
Br1–C12
1.912(7)
90.0(2)
81.4(2)
79.8(2)
100.2(2)
180.0
O4–Cu1–N1
O4–Cu1–N2
N1–Cu1–N2
N1–Cu1–N2A
O4–Cu1–O4A
N1–Cu1–N1A
N2–Cu1–N2A
O1 W–Co1–O2 W
O1 W–Co1–N1
N1–Co1–N2
95.04(19)
89.17(19)
75.25(19)
76.36(19)
167.83(19)
166.65(19)
176.98(19)
N5–Co1–N6
O1 W–Co1–N5
O2 W–Co1–N1
N2–Co1–N6
180.0
180.0
Crystal structure of 1
lengths and angles in L are comparable with those reported
for the related structures [16, 27]. The dihedral angle
between the triazole ring and the p-bromophenyl ring is
90.0(1)°.
A projection of the structure of 1 is presented in Fig. 2a
together with the atomic labeling system. The complex
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Struct Chem (2010) 21:237–244
Crystal structure of 2
Figure 2b presents the structure of 2 with its atom numbering
system. The crystal structure consists of a [CoL2(H2O)2]2?
-
cation, two ClO4 anions, one lattice water molecule, and
one methanol molecule. Similar to 1, the cobalt atom in 2 is
also coordinated by four nitrogen atoms from two L ligands
and two oxygen atoms from two H2O molecules to form a
distorted octahedral geometry. However, two coordinated
water molecules in 2 are in a cis arrangement, which has not
been observed in the complexes with asymmetrically 3,5-
di-substituted 1,2,4-triazole [19–23]. This feature is also
different from that found in a mononuclear cobalt(II) com-
plex with symmetrically 3,5-di-substituted 1,2,4-triazole,
[Co(MBPT)2(H2O)2](ClO4)2ꢀ4H2O [30] [MBPT = 4-
(p-methylphenyl)-3,5-bis(2-pyridyl)-1,2,4-triazole] where
two coordinated water molecules are in a trans oriented. The
˚
Co–O(2W) distance is 0.042 A longer than Co–O(1W) one,
whereas the Co–N bond lengths are in the ranges from
˚
2.120(5) to 2.163(5) A. Although the Co–Npy bond lengths
˚
[2.163(5) and 2.145(5) A] are longer than the Co–Ntrz bond
˚
lengths [2.120(5) and 2.132(5) A], the difference is smaller
than those observed in [Co(MBPT)2(H2O)2](ClO4)2ꢀ4H2O.
The coordination mode of L ligand in 2 is similar to that
found in 1, however, the geometric parameters are quite
Fig. 1 Projection of the structure of L with the atomic labeling
system. Hydrogen atoms are omitted for clarity
˚
different. The bond lengths [N1–C5, 1.319(8) A; N2–N3,
˚
1.403(7) A; N2–C6, 1.297(7) A] of L in 2 are different from
˚
crystallizes in the monoclinic space group P21/n and there
is an inversion center at the copper(II) atom. The copper
atom is surrounded by four nitrogen atoms from two L
ligands in the equatorial plane and two oxygen atoms from
˚
those [N1–C5, 1.368(8) A; N2–N3, 1.371(7) A; N2–C6,
˚
˚
1.310(8) A] found in 1. These differences are caused mainly
by the cations (Cu2? and Co2? ions), maybe it can be con-
sidered as a ‘‘cation effect.’’ The triazole ring with N2 atom
makes dihedral angles of 6.1(2)° and 75.2(2)° with the
N1-containing pyridyl ring and Br1-containing phenyl ring,
respectively, whereas the triazole ring with N6 atom makes
dihedral angles of 5.7(2)° and 66.3(2)° with the N5-con-
taining pyridyl ring and Br2-containing phenyl ring,
respectively. One ClO4- anion is highly disordered (54:46)
and is connected to the coordinated water by O–HꢀꢀꢀO
hydrogen bonding. In addition, there are six kinds of inter-
molecular hydrogen bond interactions in 2: (1) between
coordinated water molecules and lattice water [O1W–
H1WBꢀꢀꢀO3W and O2W–H2WBꢀꢀꢀO3W]; (2) between
coordinated water molecules and methanol [O1W–
H1WAꢀꢀꢀO11]; (3) between lattice water and uncoordinated
nitrogen atom of the triazole [O3W–H3WAꢀꢀꢀN3 and O3W–
-
two ClO4 ions in the axial positions to form a distorted
octahedral geometry. Each L ligand coordinates to copper
atom through N1 atom of the pyridyl ring and N2 atom of
the triazole, which is similar to the coordination modes in
the related complexes [19–26]. The Cu–N bond lengths are
within the normal ranges observed for octahedral complex
[19]. However, the Cu–N bond to the triazole nitrogen is
˚
0.095 A shorter than that to the pyridyl nitrogen. The same
feature has been observed in the similar complexes
˚
[19–23]. The Cu–O distance is 2.565(6) A, indicating the
-
involvement of two ClO4 ions in the coordination [29],
which is different from that found in a homologous cop-
per(II) complex, [CuL02](ClO4)2 [21] [L0 = 3-ethyl-4-
(p-methylphenyl)-5-(2-pyridyl)-1,2,4-triazole] where the
-
ClO4 ions are uncoordinated. The ligand L in 1 is non-
-
planar. The triazole ring makes dihedral angles of 11.5(2)°
and 66.3(2)° with the pyridyl ring and p-bromophenyl ring,
respectively. The crystal structure is further stabilized by
weak intermolecular C–HꢀꢀꢀN [C1–H1AꢀꢀꢀN3 = 143° and
H3WBꢀꢀꢀN7]; (4) between lattice water and ClO4 anion
-
[O3W–H3WAꢀꢀꢀO9]; (5) between methanol and ClO4
anion [O11–H11BꢀꢀꢀO8]; (6) between hydrogen atoms of the
-
pyridyl ring and ClO4 anion [C3–H3AꢀꢀꢀO8; C16–
˚
C1ꢀꢀꢀN3 = 3.134(9) A] and C–HꢀꢀꢀO [C4–H4AꢀꢀꢀO4 =
H16AꢀꢀꢀO4; C17–H17AꢀꢀꢀO4 and C17–H17AꢀꢀꢀO5]
(Table 4). These extensive hydrogen bonds assemble the
cation unit, anions, lattice water molecule, and methanol
molecule into a three-dimensional structure (Fig. 4).
˚
132° and C4ꢀꢀꢀO4 = 3.222(9) A; C8–H8AꢀꢀꢀO3 = 155°
˚
and C8ꢀꢀꢀO3 = 3.425(10) A] hydrogen bonds (Fig. 3 and
Table 3).
123

Struct Chem (2010) 21:237–244
241
Fig. 2 Projection of the
structures of 1 (a) and 2 (b) with
the atomic labeling system.
Hydrogen atoms, lattice water,
methanol, and anions for 2 are
omitted for clarity
Fig. 3 The crystal packing of 1
viewed along the a-axis
showing the hydrogen bonding
Spectral characterization
higher band is shifted by about 15 wavenumbers [31]. So,
in the spectrum of the complex 1 (or 2), a band at 1614.3
(or 1607.7) (m) and 1549.1 (or 1539.9) cm-1 (m) can be
assigned to the coordinated pyridyl ring, respectively. This
means that in 1 and 2, each L ligand uses one pyridyl
The IR spectrum of free L shows two medium bands at
1589.7 and 1526.2 cm-1, attributable to the pyridyl ring
vibrations. Upon pyridine coordination to a metal the
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Struct Chem (2010) 21:237–244
be assigned as the IR-allowed m mode, IR-forbidden m
mode and the non-degenerate ClO3 symmetrical bending
frequency, respectively [32]. The medium and broad band
centered at 3405.8 cm-1 for 2 is mainly attributed to H–O–
H stretching vibrations of the water molecules, suggesting
the existence of hydrogen bonding interactions [33]. While
the absence of similar high-frequency absorption for 1
suggests that there is no water molecule within the struc-
ture. These features are in agreement with the results of
X-ray analyses. In addition, the stretching vibrations of
C(Ph)–Br bond at 1070, 1024.6, and 1021.4 cm-1 are
attributed to L, 1, and 2, respectively.
Table 3 The hydrogen bonding geometry of 1
˚
˚
˚
D–HꢀꢀꢀA
D–H (A) HꢀꢀꢀA (A) DꢀꢀꢀA (A) D–HꢀꢀꢀA (°)
C1–H1AꢀꢀꢀN3a 0.93
C4–H4AꢀꢀꢀO4b 0.93
C8–H8AꢀꢀꢀO3c 0.96
2.34
2.53
2.53
3.134(9)
3.222(9)
143
132
3.425(10) 155
Symmetry codes: (a) -x, -y, -z; (b) -1 ? x, y, z; (c) ‘ - x,
-1/2 ? y, 1/2 - z
Table 4 The hydrogen bonding geometry of 2
˚
˚
˚
D–HꢀꢀꢀA
D–H (A) HꢀꢀꢀA (A) DꢀꢀꢀA (A) D–HꢀꢀꢀA (°)
O1W–H1WBꢀꢀꢀO3Wa 0.82
O1W–H1WAꢀꢀꢀO11 0.82
O2W–H2WBꢀꢀꢀO3 W 0.82
O2W–H2WAꢀꢀꢀO10a 0.81
2.00
1.95
2.10
2.35
2.21
2.12
2.60
2.56
2.45
2.43
2.58
2.59
2.720(7) 145
2.649(9) 142
2.705(7) 131
2.987(12) 136
2.871(7) 137
2.837(7) 146
3.168(11) 127
3.353(14) 156
3.228(15) 141
3.178(10) 138
3.268(10) 131
3.464(11) 157
In the UV–Vis spectrum of the complex 1 (or 2) in
acetonitrile solution, two intense bands at 227 (or 226) and
289.8 (or 282) nm are attributed to the L p–p* and n–p*
transitions in contrast to those (226 and 281.7 nm) in the
free L–acetonitrile solution.
O3W–H3WBꢀꢀꢀN7b
O3W–H3WAꢀꢀꢀN3
O3W–H3WAꢀꢀꢀO9
O11–H11BꢀꢀꢀO8
C3–H3AꢀꢀꢀO8c
0.82
0.83
0.83
0.85
0.93
0.93
0.93
0.93
The structures of complexes 1 and 2 in solution were
also studied by ESI-MS [34–36]. Figure 5a displays the
positive ESI-MS of 1 in methanol solution. Three main
peaks were observed. The base peak at m/z 792.05 is
[CuL2(ClO4)]? ion and that at m/z 504.85 is [CuL3]2?. The
peak at m/z 348.53 is [CuL2]2?. Figure 5b displays the
positive ESI-MS of 2 in methanol solution. Four main
peaks were also observed. The peak at m/z 787.93 is
[CoL2(ClO4)]?. The base peak at m/z 503.26 is [CoL
(MeOH)(ClO4)]?, which is one [CoL(ClO4)]? structure
unit containing a solvent molecule in it. The peaks at m/z
344.93 and 365.40 are [CoL2]2? and [L(H2O)(MeOH)]?,
respectively. Compared to that of [Co(bpy)3(ClO4)3] [35],
the spectrum of the complex 2 in solution showed no sign
of the presence of Co(III) complex. It clearly indicates that
C16–H16AꢀꢀꢀO4d
C17–H17AꢀꢀꢀO4
C17–H17AꢀꢀꢀO5
Symmetry codes: (a) 1/2 ? x, -5/2 - y, -z; (b) -1/2 ? x, -5/2
- y, -z; (c) -1 - x, 1/2 ? y, ‘ - z; (d) -1/2 ? x, -3/2 - y, -z
nitrogen and one triazole nitrogen for chelate binding. In
the complex 1 (or 2), the bands due to the ionic perchlorate
groups are around 1112.4–1091.8 (or 1144.6–1089.6) (s),
929.1 (or 927.3) (w), 624.1 (or 636.8) cm-1 (s), which can
Fig. 4 The crystal packing of 2
viewed along the a-axis
showing the hydrogen bonding
123

Struct Chem (2010) 21:237–244
243
792.05
100
(a)
95
90
85
80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
793.90
348.53
346.89
728.19
795.80
790.35
350.63
732.38
420.39
504.85
503.77
726.36
796.80
797.76
798.74
418.33
379.61
774.17
695.65
691.48
422.30
450
507.11
520.98 571.17
307.87
300
650.43
650
856.76
850
210.78
200
135.31 167.57
100 150
287.46
250
0
50
350
400
500
550
600
700
750
800
900
m/z
503.26
100
95
90
85
80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
(b)
501.83
787.93
365.40
789.89
364.64
344.93
786.24
505.26
790.90
791.84
367.13
724.23
368.17
369.98
344.02
325.68
770.17
506.70
514.84
722.27
792.83
462.92
450
227.88 248.99
200 250
631.30
650
710.40
122.18 156.16
100 150
573.55
600
793.81 852.39
0
300
350
400
500
550
700
750
800 850
900
m/z
Fig. 5 Positive ion ESI-MS of 1 (a) and 2 (b) in methanol solution
123

244
Struct Chem (2010) 21:237–244
7. Klingele MH, Boyd PDW, Moubaraki B, Murray KS, Brooker S
(2005) Eur J Inorg Chem 910
8. Krober J, Codjovi E, Kahn O, Groliere F, Jay C (1993) J Am
Chem Soc 115:9810
9. Kahn O, Martinez CJ (1998) Science 279:44
10. Zhu D, Xu Y, Yu Z, Guo Z, Sang H, Liu T, You X (2002) Chem
Mater 14:838
11. Klingele MH, Brooker S (2003) Coord Chem Rev 241:119
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there is no chemical reduction/oxidation reaction in the
solution and that the complex 2 is also stable in methanol
solution. In addition, it should be mentioned that the for-
mation of the different aggregates in the ESI-MS spectra of
1 and 2 can be influenced by the concentration of the
complexes [37].
Conclusion
14. Zhu DR, Wang ZX, Song J, Li YZ, Lan DY (2005) Chin J Inorg
Chem 21:128
Two new copper(II) and cobalt(II) complexes with
3-methyl-4-(p-bromophenyl)-5-(2-pyridyl)-1,2,4-triazole
(L) and its complexes trans-[CuL2(ClO4)2] (1) and cis-
[CoL2(H2O)2](ClO4)2ꢀH2OꢀCH3OH (2) have been synthe-
sized, and their molecular structures determined by X-ray
analyses, IR, and ESI-MS. Structural analyses indicate that
both 1 and 2 have a similar pseudo-octahedral [MN4O2]
core with two ClO4- ions in the trans position in 1 but two
H2O molecules in the cis arrangement in 2.
15. Zhou J, Yang J, Qi L, Shen X, Zhu D, Xu Y, Song Y (2007)
Transit Met Chem 32:711
16. Qi L, Zhu DR, Xie DJ, Wu YF, Shen X (2008) Chin J Inorg
Chem 24:868
17. Yang J, Bao WW, Ren XM, Xu Y, Shen X, Zhu DR (2009)
J Coord Chem 62:1809
18. Matouzenko GS, Bousseksou A, Borshch SA, Perrin M, Zein S,
Salmon L, Molnar G, Lecocq S (2004) Inorg Chem 43:227
19. Zhou AY, Wang ZX, Lan Y, Yuan LT, Liu CY (2006) Acta
Crystallogr E62:m591
20. Zhou BG, Wang ZX, Qiu XY, Liu CY (2006) Acta Crystallogr
E62:m3176
21. Wu P, Wang Z, Zhou B, Huang L (2007) Acta Crystallogr
E63:m3060
22. Wang Z, Lan Y, Wu P, Huang L (2008) Acta Crystallogr
E64:m593
Supplementary material
CCDC 751207, 751208, 751209 for compounds L, 1, and 2
contain the supplementary crystallographic data for this
article. These data can be obtained free of charge from
www.ccdc.cam.ac.uk/conts/retrieving.html or from the
Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; Fax: ?44-1223-336033; e-mail:
deposit@ccdc.cam.ac.uk.
23. Wang ZX, Gong XN, Qu ZR, Wu PF, Zhang XM (2009) Chin J
Inorg Chem 25:567
24. Wang Z, Gong I, Liu C, Zhang X (2009) Acta Crystallogr
E65:m157
25. Wang Z, Liu C, Zhang X, Gong X (2009) Acta Crystallogr
E65:m22
26. Wang ZX, Xu HJ, Gong XN, Wu PF (2009) Chin J Inorg Chem
25:906
27. Xie DJ, Lu W, Wang ZX, Zhu DR (2009) Acta Crystallogr
E65:o1177
Acknowledgment This study was funded by the National Nature
Science Foundation of China (Nos. 20771059, 20771050, and
20971068) and the Natural Science Foundation of Jiangsu Province
(BK2008371).
28. Sheldrick GM (1997) SHELXTL, structure determination soft-
ware programs, Version 5.10. Bruker Analytical X-ray Systems
Inc., Wisconsin
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(2007) Struct Chem 18:237
30. Zhu DR, Song Y, Xu Y, Zhang Y, Fun HK, You XZ (2000)
Polyhedron 19:2019
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