Synthesis and crystal structure of polymeric thiocyanato-bridged copper(II) complex with 4-nitro-2-[(2-piperidin-1ylethylimino)methyl] phenolate

Article abstract of DOI:10.1134/S1070328411120013

A polymeric thiocyanato-bridged Schiff base copper(II) complex [Cu(L)(NCS)] _n, where L is 4-nitro-2-[(2-piperidin-1-ylethylimino)methyl] phenolate, has been synthesized and structurally characterized by elemental analysis, infrared spectra, and single crystal X-ray diffraction. The complex crystallizes in the monoclinic space group P2₁ with a = 8.527(5), b = 10.296(6), c = 9.697(6) A, β = 103.77(2)°, V = 826.8(8) A³, Z = 2. In the complex, the Cu atom is in a square pyramidal coordination with one O and two N donor atoms of the Schiff base ligand and with one thiocyanate N atom, defining the basal plane, and with one symmetry related thiocyanate S atom occupying the apical position. The thiocyanate ligand links the Cu atoms through the end-to-end bridging mode.

Full text of DOI:10.1134/S1070328411120013

ISSN 1070ꢀ3284, Russian Journal of Coordination Chemistry, 2012, Vol. 38, No. 1, pp. 71–75. © Pleiades Publishing, Ltd., 2012.
Synthesis and Crystal Structure of Polymeric ThiocyanatoꢀBridged
Copper(II) Complex with 4ꢀNitroꢀ2ꢀ[(2ꢀpiperidinꢀ1ꢀ
ylethylimino)methyl] Phenolate1
Z. X. Hanga, *, X. W. Wangb, and B. Dongc
a College of Biological and Chemical Engineering, Anhui Polytechnic University, Wuhu 241000, P.R. China
b Department of Biological and Enviromental Engineering, Hefei University, Hefei 230022, P.R. China
c College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, P.R. China
*eꢀmail: hangzhx@163.com
Received January 27, 2011
Abstract
4ꢀnitroꢀ2ꢀ[(2ꢀpiperidinꢀ1ꢀylethylimino)methyl]phenolate, has been synthesized and structurally characterꢀ
ized by elemental analysis, infrared spectra, and single crystal Xꢀray diffraction. The complex crystallizes in
the monoclinic space group 21 with = 8.527(5), = 10.296(6), = 9.697(6) = 103.77(2)
826.8(8) Å3
= 2. In the complex, the Cu atom is in a square pyramidal coordination with one O and two N
—A polymeric thiocyanatoꢀbridged Schiff base copper(II) complex [Cu(L)(NCS)]n, where L is
P
a
b
c
Å,
β
°, V =
,
Z
donor atoms of the Schiff base ligand and with one thiocyanate N atom, defining the basal plane, and with
one symmetry related thiocyanate S atom occupying the apical position. The thiocyanate ligand links the Cu
atoms through the endꢀtoꢀend bridging mode.
DOI: 10.1134/S1070328411120013
1
INTRODUCTION
without further purification. C, H, and N elemental
analyses were performed on a VarioꢀELꢀIII analyzer.
Copper was determined by titration with EDTA. The
infrared spectra were recorded on a PerkinElmer 2000
spectrophotometer with KBr pellets in the region
4000–400 cm–1.
Metal complexes with Schiff base ligands composed
of salicylaldehyde and its derivatives with primary
amines have received much attention for many years
[1–4]. Schiff base copper(II) complexes have been exꢀ
tensively investigated for their magnetic and biological
properties [5–8]. Thiocyanate anions are widely used as
bridging groups for the preparation of polynuclear copꢀ
per(II) complexes with Schiff bases [9–11]. In this paꢀ
per, a novel endꢀtoꢀend thiocyanatoꢀbridged polymeric
Synthesis of [Cu(L)(NCS)]n. 5ꢀNitrosalicylaldeꢀ
hyde (0.167 g, 1 mmol) and 1ꢀ(2ꢀaminoethyl)piperiꢀ
dine (0.128 g, 1 mmol) were mixed and stirred in methꢀ
anol (50 ml) at room temperature for 30 min to give an
orange solution. To the solution was added with stirring
a methanol solution (30 ml) of ammonium thiocyanate
(0.076 g, 1 mmol) and copper acetate monohydrate
(0.199 g, 1 mmol). The final mixture was further stirred
at room temperature for 30 min to give a deep blue soꢀ
lution. The resulting solution was allowed to stand at
room temperature without further disturbing for a week
to give blue blockꢀshaped single crystals. The crystals
were isolated by filtration, washed three times with
methanol, and dried in air. The yield was 82%.
copper(II) complex [Cu(L)(NCS)]n (I) derived from
the Schiff base ligand 4ꢀnitroꢀ2ꢀ[(2ꢀpiperidinꢀ1ꢀylethꢀ
ylimino)methyl]phenol (HL) has been synthesized and
structurally characterized.
O2N
N
N
OH
(HL)
For C15H18CuN4O3S
anal. calcd., %: C, 45.3; H, 4.6; N, 14.1; Cu, 16.0.
Found, %:
C, 45.1; H, 4.7; N, 14.1; Cu, 16.2.
EXPERIMENTAL
Materials and measurements. All chemicals were
available commercially as AR grade and were used
Crystal structure determination. The suitable single
crystal of the complex was mounted on a glass fiber for
data collection performed on a Bruker SMART
1
The article is published in the original.
71

72
HANG et al.
Table 1. Crystallographic data and structure refinement paꢀ Table 2. Selected bond lengths (Å) and bond angles (deg)*
rameters of
I
Bond
d, Å
Bond
d, Å
Parameter
Value
Fw
397.93
Cu(1)–N(1)
Cu(1)–N(3)
1.937(8) Cu(1)–N(2)
1.932(10) Cu(1)–O(3)
2.806(3)
2.111(8)
1.956(7)
Crystal shape/color
Crystal siz, mm
Crystal system
Space group
Block/blue
0.32
Monoclinic
21
×
0.27
×
0.27
Cu(1)–S(1A)
P
Angle
ω
, deg
Angle
ω
, deg
a
, Å
, Å
, Å
, deg
8.527(5)
10.296(6)
9.697(6)
103.77(2)
826.8(8)
2
b
N(3)Cu(1)N(1) 164.9(3) N(3)Cu(1)O(3)
90.4(3)
93.6(3)
c
N(1)Cu(1)O(3)
N(1)Cu(1)N(2)
91.3(3) N(3)Cu(1)N(2)
β
V
Z
μ
, Å3
84.4(3) O(3)Cu(1)N(2) 175.7(3)
N(3)Cu(1)S(1
A
)
95.1(3) N(1)Cu(1)S(1
A
)
)
100.0(2)
97.2(2)
(MoK
), cm–1
1.469
α
Tmin
/Tmax
0.6508/0.6925
3921
O(3)Cu(1)S(1
A)
84.0(2) N(2)Cu(1)S(1
A
Measured reflections
Unique reflections
* Symmetry code for (A): 2 – x, –1/2 + y, 2 – z.
2683
Observed reflections
Parameters/restraints
Goodness of fit on F2
1910
1000 CCD area diffractometer equipped with a graphꢀ
iteꢀmonochromatic Mo radiation ( = 0.71073 ) at
K
λ
Å
α
217/1
298 K. The unit cell dimensions were obtained with the
leastꢀsquares refinements, and the structures were
solved by direct methods using the SHELXTLꢀ97 proꢀ
gram [12]. The final refinement was performed by fullꢀ
matrix leastꢀsquares methods with anisotropic thermal
0.977
R1
,
,
wR2
(
I
≥
2
σ
(
I
))*
0.0705, 0.1630
0.0939, 0.1791
parameters for the nonꢀhydrogen atoms on F
2. Hydroꢀ
gen atoms were placed in calculated positions and conꢀ
strained to ride on their parent atoms. Multiscan abꢀ
sorption correction was applied by using the SADABS
program [13]. The crystallographic data and experiꢀ
mental details for structural analysis of the complex are
R1
wR2 (all data)*
Fo2 − Fc2) /
∑
w
2
*
R
=
∑
||F
| – |
F
||/
∑
|
F
|, wR = [
∑
w(
(
Fo2) ]
2 1/2
.
1
o
c
o
2
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 38
No. 1
2012

SYNTHESIS AND CRYSTAL STRUCTURE OF POLYMERIC
73
Cu(1
A)
O(1)
N(4)
C(6)
S(1
A
)
C(9)
C(5)
C(7)
N(1)
C(8)
C(10)
C(1)
C(2)
O(2)
C(11)
C(4)
N(2)
C(14)
C(12)
C(3)
Cu(1)
N(3)
C(15)
O(3)
C(13)
S(1)
Fig. 1. Molecule of complex
level. Atoms labeled with the suffix (
I
, showing the atomꢀnumbering scheme. Displacement ellipsoids are drawn at the 30% probability
) or unlabeled are at the symmetry position 2 – , –1/2 + , 2 –
A
x
y
z.
summarized in Table 1. Selected bond lengths and anꢀ
gles are given in Table 2.
Supplementary material has been deposited
with the Cambridge Crystallographic Data Centre
(no. 794038; deposit@ccdc.cam.ac.uk or http://
www.ccdc. cam.ac.uk).
The asymmetric unit of the complex is shown in
Fig. 1. The complex is an endꢀtoꢀend thiocyanatoꢀ
bridged polymeric copper(II) complex. The Cu atom
is in a square pyramidal coordination with one O and
two N donor atoms of the Schiff base ligand and with
one thiocyanate N atom, defining the basal plane, and
with one symmetry related thiocyanate S atom, occuꢀ
pying the apical position. The deviation of the Cu atꢀ
om from the leastꢀsquares plane defined by the four
RESULTS AND DISCUSSION
The reaction of HL, ammonium thiocyanate, and
copper acetate in methanol gave a novel endꢀtoꢀend
thiocyanatoꢀbridged polymeric copper(II) complex.
The elemental analyses are in accordance with the forꢀ
mula proposed by the Xꢀray singleꢀcrystal structure
determination.
basal donor atoms is 0.135(2)
⎯
Å. The Cu–N and
Cu O bond lengths are within normal values and are
comparable to those observed in other copper(II)
complexes with Schiff bases [16–18]. The bond length
of Cu–S is much longer than those of the Cu–O and
Cu–N, yet it is also comparable with the values in the
The Schiff base HL shows a weak and broad band at
ν
3413 cm–1 corresponding to
(OH) of the phenolic endꢀtoꢀend thiocyanatoꢀbridged copper(II) complexꢀ
group, which is absent in the copper(II) complex. The
strong and sharp band at 1643 cm–1 for HL is assigned
es [9, 11, 19]. The significant distortion of the square
pyramid is revealed by the bond angles between the
to
ν
(C=N), which is shifted to lower frequencies apical and basal donor atoms, ranging from 84.0(2)
° to
100.0(2) . The bridging NCS groups in the
(1621 cm–1) in the spectrum of the complex. The inꢀ
°
tense band indicative of the thiocyanate group is at complex are nearly linear and show bent coordination
2108 cm–1. The spectrum of the complex also shows
modes with the copper atoms (N(3)–C(15)–
S(1)/Cu(1)–N(3)–C(15)/Cu(1)–S(1)i–C(15)i
/167.9(9) /99.3(3) ).
some new bands in the 470–430 cm–1 regions, which reꢀ
=
flect the formation of Cu–O and Cu–N bonds [14, 15]. 178.3(10)
°
°
°
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 38
No. 1
2012

74
HANG et al.
x
z
0
y
Fig. 2. Molecular packing of complex
I
viewed along the x axis.
In the crystal structure, the [CuL] units are linked
by the endꢀtoꢀend thiocyanate ligands, forming polyꢀ
ACKNOWLEDGMENTS
The authors acknowledge the Natural Science Founꢀ
dation on the Anhui Higher Education Institutions of
meric chains running along the
Fig. 2.
y axis, as shown in
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 38
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2012

SYNTHESIS AND CRYSTAL STRUCTURE OF POLYMERIC
75
9. You, Z.ꢀL. Z. Anorg. Allg. Chem., 2006, vol. 632, p. 669.
China (grant no. K12011A038), the Sience and Technolꢀ
ogy project of Wuhu (grant no. 2011Agriculture5), and
the Teaching project of Anhuic Province (grant
no. 20100725).
10. Banerjee, S., Drew, M.G.B., Lu, C.ꢀZ., et al., Eur. J.
Inorg. Chem., 2005, p. 2376.
11. Hong, Z., Transition Met. Chem., 2008, vol. 33, p. 797.
12. Sheldrick, G.M., SHELXTLꢀ97
Crystal Structure Solution, G ttingen (Germany): Univ.
of G ttingen, 1997.
13. Sheldrick, G.M., SADABS
sorption (and Other) Correction, G
Univ. of G ttingen, 1997.
, Program for XꢀRay
ö
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