Synthesis and crystal structures of copper(II) complexes derived from 5-methoxy-2-[(2-morpholin-4-ylethylimino)methyl]phenolate and (2-Morpholin-4-ylethyl)-(1-pyridin-2-ylethylidene)amine

Article abstract of DOI:10.1007/s10870-011-0033-7

A pair of copper(II) complexes, [CuL¹(ONO₂)(OH ₂)] 1 and [CuBrL²N₃] 2, where L¹ is 5-methoxy-2-[(2-morpholin-4-ylethylimino)methyl]phenolate, and L² is (2-morpholin-4-ylethyl)-(1

Full text of DOI:10.1007/s10870-011-0033-7

J Chem Crystallogr (2011) 41:1002–1006
DOI 10.1007/s10870-011-0033-7
ORIGINAL PAPER
Synthesis and Crystal Structures of Copper(II) Complexes
Derived from 5-Methoxy-2-[(2-morpholin-4-ylethylimino)
methyl]phenolate and (2-Morpholin-4-ylethyl)-(1-pyridin-
2-ylethylidene)amine
•
Zhi-Xi Hang Bo Dong Xing-Wen Wang
•
Received: 1 July 2010 / Accepted: 11 February 2011 / Published online: 22 February 2011
Ó Springer Science+Business Media, LLC 2011
Abstract A pair of copper(II) complexes, [CuL1(ONO2)
(OH2)] 1 and [CuBrL2N3] 2, where L1 is 5-methoxy-
2-[(2-morpholin-4-ylethylimino)methyl]phenolate, and L2 is
(2-morpholin-4-ylethyl)-(1-pyridin-2-ylethylidene)amine,
have been synthesized and characterized by elemental
analysis, IR spectra and single crystal X-ray diffraction.
Complex 1 crystallizes in the monoclinic space group
of Schiff bases and their metal complexes have been
widely investigated [7–11]. Recent research indicates that
in the presence of metal ions, the phenolic-containing
compounds are believed to damage the cytoplasmic
membrane, and show potential antimicrobial activity
[12, 13]. 5-Methoxy-2-[(2-morpholin-4-ylethylimino)methyl]
phenolate (HL1) and (2-morpholin-4-ylethyl)-(1-pyridin-
2-ylethylidene)amine (L2) (Scheme 1) are two new Schiff
bases, the metal complexes with them have never been
reported so far. In order to construct new Schiff base
complexes and understand the coordination mode of the
Schiff bases, in this article, two new copper(II) complexes,
[CuL1(ONO2)(OH2)] 1 and [CuBrL2N3] 2, have been
synthesized and characterized by elemental analysis, IR
spectra and single crystal X-ray diffraction.
˚
P21/c, with a = 10.496(2), b = 19.113(3), c = 8.586(2) A,
b = 105.186(10)°. Complex 2 crystallizes in the mono-
clinic space group C2/c, with a = 16.606(3), b = 7.357(2),
˚
c = 26.043(5) A, b = 94.996(2)°. The Cu atom in each
complex is five-coordinate in a square pyramidal geometry.
Keywords Synthesis Á Crystal structure Á Schiff base Á
Copper
Introduction
Experimental
Schiff bases derived from the condensation of aldehydes
with organic amines are a kind of versatile ligands in
coordination chemistry due to their easy synthesis and wide
applications [1–6]. The biological and catalytic properties
Materials and Measurements
All chemicals were available commercially as AR grade
and were used without further purification. C, H, and N
elemental analyses were performed on a Vario-EL-III
analyser. The IR spectra were recorded on a Perkin Elmer
2000 spectrophotometer with KBr pellets in the region
Z.-X. Hang (&)
College of Biological and Chemical Engineering, Anhui
Polytechnic University, Wuhu 241000,
People’s Republic of China
4000–400 cm-1
.
Caution Sodium azide is potentially explosive, only
small quantity should be used and handled with great care.
e-mail: hangzhx@163.com
B. Dong
College of Chemical Engineering, Nanjing Forestry University,
Nanjing 210037, People’s Republic of China
Synthesis of HL1
4-Methoxysalicylaldehyde (1.0 mmol, 152.2 mg) and
2-morpholin-4-ylethylamine (1.0 mmol, 130.2 mg) were
mixed in 50 mL methanol and then stirred and refluxed for
X.-W. Wang
Department of Biological and Environmental Engineering, Hefei
University, Hefei 230022, People’s Republic of China
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J Chem Crystallogr (2011) 41:1002–1006
1003
SMART 1000 CCD area diffractometer equipped with a
˚
O
N
O
N
graphite-monochromatic MoKa radiation (k = 0.71073 A)
N
N
at 298 K. The unit cell dimensions were obtained with the
least-squares refinements and the structures were solved by
direct methods using SHELXTL-97 program [14]. The
final refinement was performed by full-matrix least-squares
methods with anisotropic thermal parameters for the non-
hydrogen atoms on F2. The water H atoms in 1 are located
in a difference Fourier map and refined isotropically, with
O–H and HÁÁÁH distances restrained to 0.85(1) and
N
O
OH
HL1
L2
Scheme 1 The Schiff bases HL1 and L2
30 min. The solvent was removed by distillation to give
yellow product. Yield: 97%.
˚
Elemental analysis calcd. for C14H20N2O3 (%): C 63.6,
H 7.6, N 10.6; Found: C 63.5, H 7.6, N 10.7.
1.37(2) A, respectively. Other H atoms were placed in
calculated positions and constrained to ride on their parent
atoms. Multi-scan absorption correction was applied by
using the SADABS program [15]. The crystallographic
data and experimental details for structural analysis of the
complexes are summarized in Table 1. Selected bond
lengths and angles are given in Table 2. Hydrogen bonds
are listed in Table 3.
Synthesis of L2
2-Acetylpyridine (1.0 mmol, 121.1 mg) and 2-morpholin-
4-ylethylamine (1.0 mmol, 130.2 mg) were mixed in
50 mL methanol and then stirred and refluxed for 30 min.
The solvent was removed by distillation to give yellow
product. Yield: 99%.
Elemental analysis calcd. for C13H19N3O (%): C 66.9, H
8.2, N 18.0; Found: C 67.1, H 8.3, N 17.8.
Synthesis of [CuL1(ONO2)(OH2)] (1)
Table 1 Crystal data and structure refinement parameters
Complex
1
2
A methanol solution (10 mL) of copper(II) nitrate trihy-
drate (0.1 mmol, 24.2 mg) was added to the methanol
solution (10 mL) of HL1 (0.1 mmol, 26.4 mg), and
refluxed for 1 h. The resulting clear blue solution was
allowed to evaporate slowly in air at room temperature for
a week, affording deep blue single crystals which were
collected by filtration, washed with methanol and dried in
air. Yield: 54% (based on HL1).
CCDC no.
776832
776833
Formula
C
14H21CuN3O7
C13H19BrCuN6O
418.79
FW
406.88
Crystal shape/colour
Crystal size (mm3)
Crystal system
Space group
Block/blue
Block/blue
0.20 9 0.18 9 0.18 0.27 9 0.23 9 0.23
Monoclinic
P21/c
Monoclinic
C2/c
Elemental analysis calcd. for C14H21CuN3O7 (%): C
41.3, H 5.2, N 10.3; Found: C 40.9, H 5.4, N 10.5.
˚
a (A)
10.4962(17)
19.113(3)
8.5865(15)
105.186(10)
1662.4(5)
4
16.606(3)
7.3574(14)
26.043(5)
94.996(2)
3169.8(10)
8
˚
b (A)
˚
c (A)
Synthesis of [CuBrL2N3] (2)
b(°)
3
˚
V (A )
A methanol solution (10 mL) of copper(II) bromide
(0.1 mmol, 22.3 mg) was added to the methanol solution
(10 mL) of L2 (0.1 mmol, 23.3 mg) and sodium azide
(0.1 mmol, 6.5 mg), and refluxed for 1 h. The resulting
clear blue solution was allowed to evaporate slowly in air
at room temperature for a few days, affording deep blue
single crystals which were collected by filtration, washed
with methanol and dried in air. Yield: 37% (based on L2).
Elemental analysis calcd. for C13H19BrCuN6O (%): C
37.3, H 4.6, N 20.1; Found: C 37.5, H 4.6, N 19.9.
Z
˚
k (MoKa) (A)
0.71073
298(2)
0.71073
298(2)
s (K)
l (MoKa) (cm-1
)
1.357
3.910
Tmin
Tmax
0.773
0.418
0.792
0.467
Measured reflections
Unique reflections
Observed reflections
Parameters/restraints
9830
10639
3599
3422
2708
2661
233/3
200/0
Goodness of fit on F2 1.066
1.079
Crystal Structure Determination
R1, wR2 [I C 2r(I)]a
R1, wR2 (all data)a
0.0382, 0.0817
0.0343, 0.0724
0.0574, 0.0894
P
0.0520, 0.0791
P
The suitable single crystals of the complexes were mounted
on glass fibers for data collection performed on a Bruker
P
P
a
R1 = ||Fo|-|Fc||/ |Fo|, wR2 = [ w(Fo2-Fc2)2/ w(Fo2)2]1/2
123

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J Chem Crystallogr (2011) 41:1002–1006
˚
m(–OH) of the phenolic group and the water molecule. The
strong and sharp bands at 1,645 for HL1 and 1,641 for L2
are assigned to the m(C=N), which are shifted to lower
frequencies in the spectra of the complexes, 1,617 cm-1
for 1 and 1,613 cm-1 for 2. For 1, the bands indicative of
the nitrate group are at 1,450 and 1,317 cm-1. For 2, the
Table 2 Selected bond lengths (A) and bond angles (°)
1
Cu1–O1
1.9082(17)
2.0010(19)
2.355(2)
93.41(8)
171.95(8)
85.02(9)
94.53(8)
83.06(7)
Cu1–N1
Cu1–N2
1.928(2)
2.065(2)
Cu1–O7
Cu1–O4
O1–Cu1–N1
N1–Cu1–O7
N1–Cu1–N2
O1–Cu1–O4
O7–Cu1–O4
O1–Cu1–O7
O1–Cu1–N2
O7–Cu1–N2
N1–Cu1–O4
N2–Cu1–O4
88.01(7)
172.84(8)
92.59(8)
104.70(8)
92.63(8)
intense band indicative of the azide group is at 2,064 cm-1
.
The spectra of the complexes also show some new bands in
the 470–430 cm-1 regions, which reflect the formation of
Cu–O and Cu–N bonds [16, 17].
2
Structure Description of 1
Cu1–N1
2.058(3)
Cu1–N2
Cu1–N4
1.966(2)
1.968(3)
Cu1–N3
2.093(2)
The molecular structure of complex 1 is shown in Fig. 1.
The Cu atom in the complex is five-coordinated by the
phenolate O, imine N, and amine N atoms of L1 and by two
O atoms, respectively from a nitrate anion and a water
molecule, forming a square pyramidal geometry. All the
bond lengths and angles are comparable to those observed
in other copper(II) complexes with square pyramidal
coordination [18–20]. The coordination around the Cu
atom displays somewhat distortion. The Cu atom deviates
from the least-squares plane defined by the four basal
Cu1–Br1
2.6506(6)
164.79(11)
94.76(11)
99.58(11)
95.76(7)
N2–Cu1–N4
N4–Cu1–N1
N4–Cu1–N3
N2–Cu1–Br1
N1–Cu1–Br1–
N2–Cu1–N1
N2–Cu1–N3
N1–Cu1–N3
N4–Cu1–Br1
N3–Cu1–Br1
78.59(10)
81.55(10)
152.35(10)
99.07(8)
102.66(7)
98.29(7)
˚
Table 3 Hydrogen-bond geometry (A, °)
D–HÁÁÁA
D–H
HÁÁÁA
DÁÁÁA
D–HÁÁÁA
˚
donor atoms by 0.128(2) A. The N1–Cu1–N2 bond angle is
1
deviate from the value for an ideal square pyramidal
geometry by 5.0(1)°, which is caused by the strain created
by the five-membered chelate ring Cu1–N1–C8–C9–N2.
In the crystal structure, molecules are linked through
intermolecular O–HÁÁÁO hydrogen bonds among the nitrate
anions, water molecules and the phenolate O atoms,
forming dimers, as shown by Fig. 2.
O7–H7AÁÁÁO1a
O7–H7BÁÁÁO6a
O7–H7BÁÁÁO4a
O7–H7BÁÁÁN3a
2
0.845(10) 1.902(15) 2.717(3) 161(3)
0.843(10) 2.22(2)
0.843(10) 2.36(2)
0.843(10) 2.65(2)
2.969(4) 148(3)
3.026(3) 136(3)
3.394(3) 149(3)
C4–H4ÁÁÁBr1b
0.93
0.97
2.83
2.91
2.51
2.58
3.722(3) 162(3)
3.790(3) 151(3)
3.358(3) 145(3)
3.258(3) 127(3)
C8–H8BÁÁÁBr1c
C10–H10BÁÁÁO1d 0.97
Structure Description of 2
C13–H13AÁÁÁN5
0.97
Symmetry transformations used to generate equivalent atoms
a
-x, -y, 2 – z
The molecular structure of complex 2 is shown in Fig. 3.
The Cu atom in the complex is five-coordinated by the
three N atoms of L2, and by one Br atom and one N atom of
an azide group, forming a square pyramidal geometry. All
the bond lengths and angles are comparable to those
observed in 1 and other copper(II) complexes with square
pyramidal coordination [21–23]. The coordination around
the Cu atom displays somewhat distortion. The Cu atom
deviates from the least-squares plane defined by the four
b
1/2 - x, 1/2 - y, -z
c
x, -1 ? y, z
d
-x, y, 1/2 - z
Results and Discussion
The two new Schiff bases have been synthesized by con-
densation reaction of 4-methoxysalicylaldehyde/2-acet-
ylpyridine and 2-morpholin-4-ylethylamine in methanol
(Scheme 2); the two copper complexes were easily prepared
by using 1:1 ratio of Schiff base ligand and metal salts.
˚
basal donor atoms by 0.318(2) A. The N1–Cu1–N2 and
N2–Cu1–N3 bond angles are deviate from the values for an
ideal square pyramidal geometry by 11.4(1) and 8.4(1)°,
respectively, which are caused by the strain created by the
five-membered chelate rings Cu1–N1–C5–C6–N2 and
Cu1–N2–C8–C9–N3.
IR Spectra
In the crystal structure, molecules are linked through
intermolecular C–HÁÁÁBr and C–HÁÁÁO hydrogen bonds,
forming a three-dimensional network, as shown by Fig. 4.
The Schiff base HL1 and the complex 1 show weak and
broad band at about 3,400 cm-1 corresponding to the
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J Chem Crystallogr (2011) 41:1002–1006
1005
Scheme 2 a Synthesis of HL1.
b Synthesis of L2. c Synthesis of
1. d Synthesis of 2
O
(a)
N
N
methanol
methanol
O
O
N
+
H2N
O
OH
O
OH
(b)
O
N
O
N
O
N
+
H2N
N
N
(c)
N
O
N
methanol
N
N
N
Cu(NO3)2
+
Cu
OH2
O
N
O
O2N
(d)
N
O
N
methanol
N
N
N
CuBr2
N3
+
Cu
N3
+
O
N
Br
Fig. 1 The molecule of 1, showing the atom-numbering scheme.
Displacement ellipsoids are drawn at the 30% probability level
In both complexes, the conformation of the morpholine
rings is chair. The square pyramidal coordination of the Cu
atoms can be proved by the s parameter, an index of the
degree of trigonality [24]. The s values calculated for the
complexes 1 and 2 are 0.015 and 0.207, respectively.
Supplementary Material
Fig. 2 The molecular packing of 1. Intermolecular hydrogen bonds
are shown as dashed lines
Crystallographic data for the structural analyses have been
deposited with the Cambridge Crystallographic Data
Centre as supplementary publication Nos. CCDC 776832
and 776833. Copies of this data can be obtained free
of charge via www.ccdc.cam.ac.uk/data_request/cif, by
emailing data_request@ccdc.cam.ac.uk, or by contacting.
The Cambridge Crystallographic Data Centre, 12 Union
Road, Cambridge CB2 1EZ, UK; Fax: ?44-1223-336033.
123

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J Chem Crystallogr (2011) 41:1002–1006
References
1. Biswas M, Pilet G, Tercero J, El Fallah MS, Mitra S (2009) Inorg
Chim Acta 362:2915
2. Rao PV, Rao CP, Wegelius EK, Rissanen K (2003) J Chem
Crystallogr 33:139
3. Pal S, Pal S (2000) J Chem Crystallogr 30:329
4. Alyea EC, Dee TD, Ferguson G (1985) J Chem Crystallogr 15:29
5. Borisova NE, Reshetova MD, Ustynyuk YA (2007) Chem Rev
107:46
6. Che CM, Huang JS (2003) Coord Chem Rev 242:97
7. Sonmez M, Celebi M, Berber I (2010) Eur J Med Chem 45:1935
8. Mohamed GG, Omar MM, Ibrahim AA (2009) Eur J Med Chem
44:4801
9. Bagihalli GB, Badami PS, Patil SA (2009) J Enzyme Inhib Med
Chem 24:381
10. Drozdzak R, Allaert B, Ledoux N, Dragutan I, Dragutan V,
Verpoort F (2005) Coord Chem Rev 249:3055
11. Gupta KC, Sutar AK (2008) Coord Chem Rev 252:1420
12. Loginova NV, Kovalchuk TV, Zheldakova RA, Chernyavskaya
AA, Osipovich NP, Glushonok GK, Polozov HI, Sorokin VL,
Shadyro OI (2006) Cent Eur J Chem 4:440
Fig. 3 The molecule of 2, showing the atom-numbering scheme.
Displacement ellipsoids are drawn at the 30% probability level. H
atoms have been omitted for clarity
13. Yamashita N, Tanemura H, Kawanishi S (1999) Mutat Res
425:107
14. Sheldrick GM (1997) SHELXTL-97, program for X-ray crystal
¨
structure solution. University of Gottingen, Germany
15. Sheldrick GM (1997) SADABS, Siemens area detector absorp-
¨
tion (and other) correction. University of Gottingen, Germany
16. Rajasekar M, Sreedaran S, Prabu R, Narayanan V, Jegadeesh R,
Raaman N, Rahiman AK (2010) J Coord Chem 63:136
17. EI-Metwally NM, Gabr IM, Shallaby AM, EI-Asmy AA (2005) J
Coord Chem 58:1145
18. Dieng M, Thiam I, Gaye M, Sall AS, Barry AH (2006) Acta
Chim Slov 53:417
19. Arnold PJ, Davies SC, Durrant MC, Griffiths DV, Hughes DL,
Sharpe PC (2003) Inorg Chim Acta 348:143
20. Fontecha JB, Goetz S, McKee V (2002) Angew Chem Int Ed
Engl 41:4553
21. Nakao Y, Yamazaki M, Suzuki S, Mori W, Nakahara A, Mat-
sumoto K, Ooi S (1983) Inorg Chim Acta 74:159
22. Matsumoto K, Ooi S, Nakatsuka K, Mori W, Suzuki S, Nakahara
A, Nakao Y (1985) J Chem Soc Dalton Trans 10:2095
23. Rojo T, Larramendi JIR, Duran I, Mesa JL, Via J, Arriortua MI
(1990) Polyhedron 9:2693
Fig. 4 The molecular packing of 2, viewed along the c axis.
Intermolecular hydrogen bonds are shown as dashed lines
Acknowledgments The author acknowledges the Pivot Construc-
tion Subject of the Applied Chemistry, and the Teaching Group of the
Courses Construction on Engineering Course Chemistry for financial
support.
24. Addison AW, Rao TN, Reedijk J, van Rijn J, Verschoor GC
(1984) J Chem Soc Dalton Trans 7:1349
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