Synthesis, crystal structure, magnetic property and thermal studies of [Ni(CH3COO)2·(NH2CH2Ph) 4]

Article abstract of DOI:10.1016/j.saa.2011.08.044

[Ni(CH₃COO)₂·(NH₂CH ₂Ph)₄] complex was synthesized using benzylamine and nickel acetate. The molecular structure of this complex was obtained by single crystal X-ray diffraction and characterized by e

Full text of DOI:10.1016/j.saa.2011.08.044

Spectrochimica Acta Part A 83 (2011) 344–347
Contents lists available at SciVerse ScienceDirect
Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
journal homepage: www.elsevier.com/locate/saa
Synthesis, crystal structure, magnetic property and thermal studies of
[Ni(CH3COO)2·(NH2CH2Ph)4]
Zhiqiang Guoa, Chenzhong Yaob, Yali Panc, Hongbo Tonga, Xuehong Weia,∗
a Institute of Applied Chemistry, Shanxi University, Taiyuan 030006, PR China
b Department of Applied Chemistry, Yuncheng University, Yuncheng 044000, PR China
c Shanxi Border Inspection and Quarantine Bureau, Taiyuan 030024, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 11 May 2011
Received in revised form 12 August 2011
Accepted 24 August 2011
[Ni(CH3COO)2·(NH2CH2Ph)4] complex was synthesized using benzylamine and nickel acetate. The molec-
ular structure of this complex was obtained by single crystal X-ray diffraction and characterized by
elemental analysis, IR spectrometry and thermal analysis. The complex crystallized in the mono-
˚
˚
˚
clinic space group P2(1)/n with cell parameters a = 11.234(4) A, b = 6.459(2) A, c = 22.647(8) A, ˛ = 90.00,
◦
3
˚
ˇ = 91.149(4) , ꢀ = 90.00, V = 1642.8(10) A , Z = 2. The structure has been solved by direct methods
and refined to R1 = 0.0876 for 6377 observed reflections I > 2ꢁ(I). Magnetic studies for complex show
the data over the whole temperature range 5–300 K are well fitted to the Curie–Weiss law with
C = 1.03 cm3 K mol−1 and ꢂ = −1.38 K. This fitting indicates antiferromagnetic interaction between the Ni
ions and the metal center exhibits distorted octahedral coordination geometries. The thermal analysis
was carried out to understand the thermal stability of the title complex.
Keywords:
Nickel metal complex
Crystal structure
Magnetic properties
© 2011 Elsevier B.V. All rights reserved.
1. Introduction
2. Experimental
2.1. Materials and measurements
The design and synthesis of new mononuclear and multinuclear
metal complexes have become one of the most active areas in the
material chemistry field, where metal complexes exhibiting versa-
tile optical and electrical properties and magnetic behaviors, such
as single molecule magnets (SMM), have attracted special attention
over the past decade [1–4]. In order to gain a better understanding
of the correlation between structure and magnetism, increasing
attention has been paid to the construction of two dimensional (2D)
or three-dimensional (3D) magnetic systems [5–7].
Nowadays, except for nuclear magnetic resonance, electron spin
resonance and Mossbauer spectroscopy, the magnetic susceptibil-
ity measurements are also often-used way to study the structure
and magnetism of transition metal complexes. In this paper, we
report the synthesis, structures, thermal analysis and magnetic
property of [Ni(CH3COO)2·(NH2CH2Ph)4], which was characterized
by elemental analysis, IR spectrometry and single crystal X-ray
diffraction. The single-crystal X-ray analysis reveals that it crystal-
lizes in the monoclinic space group P2(1)/n. Magnetic studies for
complex show the data over the whole temperature range 5–300 K
are well fitted to the Curie–Weiss law with C = 1.03 cm3 K mol−1
and ꢂ = −1.38 K. This fitting indicates antiferromagnetic interaction
between the Ni ions.
The reagents and chemicals
for
preparation
of
[Ni(CH3COO)2·(NH2CH2Ph)4] were used as received unless
noted otherwise. Acetonitrile, ethyl acetate and petroleum ether
were purchased from Beijing Chemical Plant and treated according
to standard methods used before. Elemental analyses were carried
out using a Vario EL-III analyzer (Germany). Melting points are
determined on a STUART SMP10 melting point apparatus and
uncorrected. The IR spectra were determined on a FTIR8400S IR
spectrophotometer (SHIMADZU) by dispersing samples in KBr
disks. Magnetic measurements were carried out on supercon-
ducting quantum interference device (SQUID, QUANTUM DESIGN,
MPMS XL-7) for researching the magnetic behaviors at 5–300 K.
Thermal analysis was carried out between 35 ◦C and 900 ◦C in
nitrogen atmosphere using NETZSCH STA 449F3 instrument. Single
X-ray diffraction data of the compound was collected at 293 K
on a Bruker SMART APEX diffractometer/CCD area detector using
˚
monochromated Mo K␣ radiation, ꢃ = 0.71073 A.
2.2. Synthesis of [Ni(CH3COO)2·(NH2CH2Ph)4]
To a stirred solution of Ni(CH3COO)2·4H2O (0.249 g, 1 mmol) in
dry acetonitrile (50 ml) was added dropwise a acetonitrile solu-
tion of benzylamine (15 ml, 4 mmol) at room temperature under an
argon atmosphere. Then the reaction mixture was stirred at 80 ◦C
∗
Corresponding author. Tel.: +86 351 7010722; fax: +86 351 7011688.
E-mail address: guozhiqiang7988@yahoo.com.cn (X. Wei).
1386-1425/$ – see front matter © 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.saa.2011.08.044

Z. Guo et al. / Spectrochimica Acta Part A 83 (2011) 344–347
345
for 3 h, the resulting clear light blue solution was cooled to room
temperature, filtrated and concentrated to the point of crystalliza-
tion. Upon standing for several days at ambient temperature this
provided blue prismatic samples of complexes suitable for X-ray
structure determination. The yield is 91%, m.p. 102–105 ◦C. Analy-
ses: calculated: C, 63.49; H, 6.99; N, 9.25. Found: C, 63.37; H, 7.04; N,
9.27. IR (KBr, cm−1): 3367.5, 3286.5, 3182.3, 3002.9, 2939.3, 1951.8,
1816.8, 1622.0, 1556.5, 1548.7, 1496.7, 1456.3, 1409.9, 1344.3,
1305.7, 1190.0, 1163.0, 1153.4, 1074.3, 1016.4, 954.7, 891.1, 734.8,
698.2, 667.3, 619.1, 603.7 and 484.1.
2.3. X-ray structure determination
Single X-ray diffraction data of the compound was in viscous
hydrocarbon oil on glass fibres at 293 K on a Bruker SMART APEX
diffractometer/CCD area detector using monochromated Mo K␣
˚
radiation, ꢃ = 0.71073 A. A total of N reflections were collected by
Fig. 1. ORTEP diagram of compound C32H42N4NiO4 with thermal ellipsoids at 50%
using ␻ scan mode. Corrections were applied for Lorentz and polar-
ization effects as well as absorption using multi-scans (SADABS)
[8]. The structure was solved by direct method (SHELXS-97) [9].
Then the remaining non-hydrogen atoms were obtained from the
successive difference Fourier map. All non-H atoms were refined
with anisotropic displacement parameters, while the H atoms
were constrained to parent sites, using a riding mode (SHELXTL).
Details of the crystal parameters, data collection, and refine-
ments are summarized in Table 1. The molecular structure of
the compound is displayed in Fig. 1. The crystallographic data of
[Ni(CH3COO)2·(NH2CH2Ph)4] was deposited with the Cambridge
Crystallographic Data Centre as supplementary publication No.
CCDC823430.
probability (H not shown for clarity).
to the out-of-plane C–H bending vibrations of benzene ring. There
is also a strong band at 1163.0 cm−1, which is assigned to C–N
stretching vibrations. The strong bands located at 1556.5 cm−1
and l409.9 cm−1 are assigned to the stretching asymmetric ꢄas
(COO−) and the symmetric vibration ꢄs (COO−) of carboxylate
anion, respectively. Through observe the ꢅꢆ (COO−) between the
asymmetric ꢄas (COO−) and the symmetric ꢄs (COO−) bands, some
important information about the different binding modes of the
acetate groups coordinate to the metal atoms could be provided
[10,11]. The difference between ꢄas (COO−) and ꢄs (COO−) is about
146.6 cm−1, suggesting that these information are consistent with
the results of X-ray structure.
3. Results and discussion
3.2. Description of crystal structures
3.1. Infrared spectra
The molecular structure of the crystalline complex
[Ni(CH3COO)2·(NH2CH2Ph)4] is shown in Fig. 1. It crystallized
in the monoclinic space group P2(1)/n with cell parame-
The IR spectra of the [Ni(CH3COO)2·(NH2CH2Ph)4] show char-
acteristic absorption bands at 3367.5 cm−1, 3286.5 cm−1 due to
the ꢄ (–NH2) stretching vibrations. The bands at 1458.7 cm−1
,
˚
˚
˚
1496.6 cm−1 and 1456.2 cm−1 are assigned to C–C skeletal vibra-
tion modes and the bands at 743.8 cm−1 and 698.2 cm−1 attributed
ters a = 11.234(4) A, b = 6.459(2) A, c = 22.647(8) A, ˛ = 90.00,
◦
3
˚
ˇ = 91.149(4) , ꢀ = 90.00, V = 1642.8(10) A and Z = 2. The central
Ni (II) ion in complex is coordinated by four nitrogen atoms of
the benzylamine occupying the equatorial plane and two oxygen
atoms of two carboxylate anions situated at the axial sites, hence
adopting a slightly distorted octahedral coordination sphere.
Table 1
Summary of crystallographic for C17H24O6.
Empirical formula
Crystal color
C32H42N4NiO4
Blue
˚
The bond lengths of Ni–N1 and Ni–N2 are 2.◦141(3) A and
˚
2.158(4) A, the bond angle of N1–Ni–N2 is 89.15(14) . At the axial
Formula weight
Temperature
Wavelength
605.41
293(2) K
0.71073 A
sites, the Ni (II) ion is with two carboxylate anion through oxygen
atom in trans positions. The bond angle of N1–Ni–N2 is divided
equally by two carboxylate anions, and the bond length of O1–Ni is
˚
Crystal system
Space group
Unit cell dimensions
Monoclinic
P2(1)/n
˚
◦
˚ ˚
a = 11.234(4) A, ˛ = 90 , b = 6.459(2) A,
2.079(3) A. Summary of selected bond lengths and angles is given
◦
◦
˚
ˇ = 91.149(4) , c = 22.647(8) A, ␥ = 90
1642.8(10) A
in Tables 2 and 3, respectively.
3
˚
Volume
Z
2
3.3. Magnetic properties of [Ni(CH3COO)2·(NH2CH2Ph)4]
Calculated density
Absorption coefficient
F(0 0 0)
1.224 Mg/m3
0.630 mm−1
644
The magnetic properties of the sample have also been investi-
gated through the measurement of their magnetic susceptibilities
over the temperature range of 5–300 K. Temperature dependence
of magnetic susceptibility (ꢇM) and the effective magnetic moment
(ꢈeff) vs. T plots are shown in Fig. 2 at 500 Oe. At 300 K, the ꢈeff value
of the complex (2.95 B.M.) is slightly larger than the spin-only value
of Ni (II) metal ion (2.828 B.M. (ꢈSD = [4S(S + 1)]1/2, S = 1)). With the
temperature decreasing to 50 K, the ꢈeff value can be reached to
2.90 B.M. However, when the temperature is lower than 50 K, there
is a rapid decrease for the ꢈeff value. The ꢈeff vs. T data reveal
anti-ferromagnetic interactions exist between the Ni (II) ions. The
curve of ꢇM vs. T obeys the Curie–Weiss law. According to the
Crystal size
Theta range for data collection
Limiting indices
0.30 mm × 0.20 mm × 0.20 mm
1.80–25.01◦
−13 ≤ h ≤ 12, −7 ≤ k ≤ 7, −13 ≤ l ≤ 26
6377/2854 [R(int) = 0.0263]
98.5%
Reflections collected/unique
Completeness to theta = 25.01
Absorption correction
Max. and min. transmission
Refinement method
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I > 2ꢁ(I)]
R indices (all data)
Largest diff. peak and hole
Semi-empirical from equivalents
0.8844 and 0.8336
Full-matrix least-squares on F2
2962/0/214
1.255
R1 = 0.0876, wR2 = 0.2734
R1 = 0.0983, wR2 = 0.2887
−3
˚
3.006 and −0.394 e A

346
Z. Guo et al. / Spectrochimica Acta Part A 83 (2011) 344–347
Table 2
2
˚
Bond lengths (A) for C32H42N4NiO4.
100
Atoms
Length
Atoms
Length
0
Ni–O(1)
2.079(3)
2.079(3)
2.141(3)
2.141(3)
2.158(4)
2.158(4)
1.473(6)
1.478(6)
1.246(5)
1.231(6)
1.531(6)
1.379(8)
1.403(8)
C(3)–C(4)
C(4)–C(5)
C(5)–C(6)
C(6)–C(7)
1.343(8)
1.413(9)
1.330(9)
1.375(9)
1.495(8)
1.381(8)
1.399(8)
1.393(9)
1.389(10)
1.365(10)
1.404(10)
1.581(7)
80
60
40
20
0
Ni–O(1ꢀ)
Ni–N(1ꢀ)
Ni–N(1)
-75.55 %
-2
-4
-6
-8
Ni–N(2)
C(8)–C(9)
Ni–N(2ꢀ)
N(1)–C(1)
N(2)–C(8)
O(1)–C(15)
O(2)–C(15)
C(1)–C(2)
C(2)–C(3)
C(2)–C(7)
C(9)–C(14)
C(9)–C(10)
C(10)–C(11)
C(11)–C(12)
C(12)–C(13)
C(13)–C(14)
C(15)–C(16)
-17.05 %
0
200
400
600
800
Table 3
Angles (◦) for C32H42N4NiO4.
Temperature /ºC
Fig. 3. TG and DSC curves of [Ni(CH3COO)2·(NH2CH2Ph)4].
Atoms
Angles
Atoms
Angles
O(1)–Ni–O(1ꢀ)
O(1)–Ni–N(1ꢀ)
O(1ꢀ)–Ni–N(1ꢀ)
O(1)–Ni–N(1)
O(1ꢀ)–Ni–N(1)
N(1ꢀ)–Ni–N(1)
O(1)–Ni–N(2)
O(1ꢀ)–Ni–N(2)
N(1ꢀ)–Ni–N(2)
N(1)–Ni–N(2)
O(1)–Ni–N(2ꢀ)
O(1ꢀ)–Ni–N(2ꢀ)
N(1ꢀ)–Ni–N(2ꢀ)
N(1)–Ni–N(2ꢀ)
N(2)–Ni–N(2ꢀ)
C(1)–N(1)–Ni
C(8)–N(2)–Ni
C(12)–C(13)–C(14)
O(2)–C(15)–O(1)
O(1)–C(15)–C(16)
180.0(2)
C(15)–O(1)–Ni
133.2(3)
113.3(4)
117.9(5)
121.2(5)
120.8(5)
122.7(6)
119.0(6)
118.5(6)
123.4(6)
118.3(6)
115.6(4)
118.0(5)
121.9(5)
120.0(5)
121.1(6)
120.3(6)
118.8(6)
120.4(6)
115.1(5)
3.4. Thermal analysis
85.71(13)
94.29(13)
94.29(13)
85.71(13)
180.0(3)
88.78(14)
91.22(14)
90.65(14)
89.35(14)
91.22(14)
88.78(14)
89.35(14)
90.65(14)
180.00(19)
119.9(3)
N(1)–C(1)–C(2)
C(3)–C(2)–C(7)
C(3)–C(2)–C(1)
C(7)–C(2)–C(1)
C(4)–C(3)–C(2)
C(3)–C(4)–C(5)
C(6)–C(5)–C(4)
C(5)–C(6)–C(7)
C(6)–C(7)–C(2)
N(2)–C(8)–C(9)
C(14)–C(9)–C(10)
C(14)–C(9)–C(8)
C(10)–C(9)–C(8)
C(11)–C(10)–C(9)
C(12)–C(11)–C(10)
C(13)–C(12)–C(11)
C(9)–C(14)–C(13)
O(2)–C(15)–C(16)
Thermogravimetric and differential scanning calorimetry of
[Ni(CH3COO)2·(NH2CH2Ph)4] crystals were carried out between
35 ◦C and 900 ◦C in nitrogen atmosphere at a heating rate of
10 ◦C/min using NETZSCH STA 449F3 instrument. The TG and
DSC curves of [Ni(CH3COO)2·(NH2CH2Ph)4] complex show that
these decomposition occurred in the temperature range 81–285 ◦C
with a net weight loss of 75.55%, the percentage weight loss
was consistent with material decomposition and elimination of
the four (NH2CH2Ph) species and residual acetonitrile solvent.
The final weight loss of 17.05% ending at 562 ◦C, is attributed
to alongside rupture of the chelate bond, in other words, two
remaining tightly bound fragments of (CH3COO−) were com-
pletely decomposed. Thus from thermal analyses, it is seen that
the complex crystal can be utilized for applications up to 100 ◦C
(Fig. 3).
118.0(3)
121.5(6)
126.4(4)
118.5(5)
following equation: ꢇM = C/(T − ꢂ). Curie constant of the compound
is 1.03 cm3 K mol−1, and Weiss constant (ꢂ) is −1.38 K. This phe-
nomenon is in agreement with the presence of one Ni (II) metal
ions (S = 1, g = 2, C = 1 cm3 K mol−1). Decreasing the temperature,
ꢇM continuously increases to reach 0.165 cm3/mol at 5 K indicat-
ing dominant anti-ferromagnetic interactions between Ni (II) ions
and the presence of a single ground state. Moreover, the magnetic
properties of the present complex may indicate the Ni2+ is in a
moderate-intensity octahedral ligand field.
4. Conclusions
In summary, we have thus described a simple and efficient
synthetic method for [Ni(CH3COO)2·(NH2CH2Ph)4]. The crystal
structure indicates that it adopts a slightly distorted octahedral
coordination sphere. The central Ni (II) ion in complex is coordi-
nated by four nitrogen atoms of the benzylamine occupying the
equatorial plane and two oxygen atoms of two carboxylate anions
situated at the axial sites. Magnetic studies for complex show that
there is antiferromagnetic interaction between the Ni (II) ions. And
the thermal analyses indicate that it is thermally stable up to 100 ◦C.
0.18
0.16
0.14
0.12
0.10
0.08
0.06
0.04
0.02
0.00
3.0
2.9
2.8
2.7
2.6
2.5
Acknowledgements
Financial support from the National Natural Science Foundation
of China (No. 20572065), the Natural Science Foundation of Shanxi
Province (Nos. 2011021011-1, 2008011021 and 2008012013-2)
and the Key Laboratory Foundation of Shanxi Province are grate-
fully acknowledged.
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