Synthesis, characterization and crystal structure of a mononuclear zinc(II) complex derived from 2-[(2-propylaminoethylimino)methyl]phenol

Article abstract of DOI:10.1007/s10870-010-9696-8

A new zinc(II) complex, [Zn(C₁₂H₁₈N ₂O)Cl₂]. CH₃CN, derived from the Schiff base ligand 2-[(2-propylaminoethylimino) methyl]phenol, has been synthesized and characterized by elemental analysis, IR spectra, and X-ray crystallography. The complex crystallizes in the orthorhombic space group Pbcn with unit cell dimensions a = 26.387(9) A, b = 7.389(2) A, c = 18.731(6) A, V = 3,652(2) A³, Z = 8, R₁ = 0.0455 and wR ₂ = 0.1143. The asymmetric unit of the compound contains a mononuclear [Zn(C₁₂H₁₈N₂O)Cl₂] complex and an acetonitrile molecule linked together by an intermolecular N-H...N hydrogen bond. Crystal packing is stabilized by intermolecular N-H...O hydrogen bonds linking the molecules into chains along the b axis of the unit cell. Springer Science+Business Media, LLC 2010.

Full text of DOI:10.1007/s10870-010-9696-8

J Chem Crystallogr (2010) 40:561–563
DOI 10.1007/s10870-010-9696-8
ORIGINAL PAPER
Synthesis, Characterization and Crystal Structure
of a Mononuclear Zinc(II) Complex Derived
from 2-[(2-Propylaminoethylimino)methyl]phenol
•
•
•
Xiao-Fang Li Zhong-Lu You Peng Hou
Cheng-Lu Zhang
Received: 18 March 2008 / Accepted: 16 January 2010 / Published online: 30 January 2010
Ó Springer Science+Business Media, LLC 2010
Abstract A new zinc(II) complex, [Zn(C12H18N2O)Cl2]Á
CH3CN, derived from the Schiff base ligand 2-[(2-pro-
pylaminoethylimino)methyl]phenol, has been synthesized
and characterized by elemental analysis, IR spectra, and
X-ray crystallography. The complex crystallizes in the
orthorhombic space group Pbcn with unit cell dimensions
report the synthesis and structure of a new mononuclear
Schiff base zinc(II) complex derived from the Schiff base
ligand 2-[(2-propylaminoethylimino)methyl]phenol.
Experimental
˚
˚
a = 26.387(9) A, b = 7.389(2) A, c = 18.731(6) A,
˚
3
V = 3,652(2) A , Z = 8, R1 = 0.0455 and wR2 = 0.1143.
˚
Materials and Measurements
The asymmetric unit of the compound contains a mono-
nuclear [Zn(C12H18N2O)Cl2] complex and an acetonitrile
molecule linked together by an intermolecular N–HÁÁÁN
hydrogen bond. Crystal packing is stabilized by intermo-
lecular N–HÁÁÁO hydrogen bonds linking the molecules into
chains along the b axis of the unit cell.
All chemicals and reagents (AR grade) were commercially
available and used without further purification. N-propyle-
thane-1,2-diamine was purchased from Aldrich. C, H, and
N elemental analyses were performed on a Perkin–Elmer
240C elemental analyzer. The IR spectra were measured
with a Nicolet FT-IR 170-SX spectrophotometer. The
1HNMR spectra were recorded on a Bruker AVANCE
500 MHz spectrometer with tetramethylsilane as the
internal reference.
Keywords Schiff base Á Zinc(II) complex Á
Hydrogen bonds Á Coordination chemistry
Introduction
Synthesis of 2-[(2-Propylaminoethylimino)methyl]
phenol
Due to their biological activity, significance, and versatil-
ity in coordination modes, Schiff base compounds have
received wide attention [1–3]. Zinc is an important life
element, which acts as the active center of many enzymes
[4, 5]. In our investigations of aggregates of Schiff base
ligands with the zinc ion, we have recently reported the
structure of a new mononuclear zinc complex [6]. In
continuing our investigations of these compounds we now
The Schiff base ligand 2-[(2-propylaminoethylimino)
methyl]phenol was synthesized according to the procedure
described in Scheme 1. To a MeOH solution (10 mL) of
salicylaldehyde (1.0 mmol, 122.1 mg) was added a MeOH
solution (10 mL) of N-propylethane-1,2-diamine (1.0 mmol,
102.2 mg) with stirring. The mixture was stirred for 10 min
at room temperature to give a clear yellow solution. The
solvent was removed by distillation, yielding an orange oil.
Analysis calculated for C12H18N2O: C, 69.87; H, 8.80; N,
13.58%; found: C, 69.70; H, 8.93; N,13.72%. Selected IR
data (KBr, cm-1): 3380 (w), 3217 (w), 3072 (w), 2926 (m),
X.-F. Li Á Z.-L. You (&) Á P. Hou Á C.-L. Zhang
Department of Chemistry and Chemical Engineering,
Liaoning Normal University, Huanghe Road 850#,
116029 Dalian, People’s Republic of China
e-mail: youzhonglu@yahoo.com.cn
1
2851 (m), 1632 (s), 1497 (w), 1282 (s), 759 (s). HNMR
data (CDCl3, ppm): d = 8.07 (s, 1H), 7.40 (d, 1H), 7.13
123

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J Chem Crystallogr (2010) 40:561–563
(m, 1H), 6.81 (m, 1H), 6.72 (d, 1H), 4.32 (s, 1H), 3.73 (t,
2H), 2.88 (m, 2H), 2.53 (m, 2H), 1.87 (m, 1H), 1.46 (m,
2H), 0.98 (t, 3H).
Table 1 Crystal data and refinement parameters for the complex
CCDC deposit no.
Molecular formula
Molecular weight
Temperature (K)
Radiation k
662571
14H21Cl2N3OZn
C
383.61
298(2)
Synthesis of the Complex [Zn(C12H18N2O)Cl2]ÁCH3CN
˚
Mo Ka (0.71073 A)
Orthorhombic
Pbcn
A MeOH solution (5 mL) of ZnCl2 (0.1 mmol, 13.6 mg)
was added to a MeOH solution (10 mL) of 2-[(2-propyla-
minoethylimino)methyl]phenol (0.1 mmol, 20.6 mg) with
stirring. The mixture was stirred at room temperature for
10 min to give a great deal of white precipitate. To the
suspension was added with stirring an amount of 5 mL
MeCN, the precipitate was dissolved in the mixed solvents.
Upon keeping the final solution in air for a week, colorless
block-shaped crystals suitable for X-ray single crystal
analysis were formed at the bottom of the vessel on slow
evaporation of the solvents. Analysis calculated for
C14H21Cl2N3OZn: C, 43.83; H, 5.52; N, 10.95%; found: C,
43.65; H, 5.61; N, 11.04%. Selected IR data (KBr, cm-1):
3327 (w), 2925 (m), 2851 (m), 2237 (s), 1635 (s), 1582 (w),
1497 (w), 1450 (m), 1279 (s), 1118 (w), 757 (s).
Crystal system
Space group
˚
a/A
26.387(9)
7.389(2)
˚
b/A
˚
c/A
18.731(6)
3,652(2)
3
˚
V/A
Z
8
Dcalc (g cm-3
)
1.395
Crystal size (mm)
0.27 9 0.12 9 0.10
Colorless
1.639
Crystal colour
Absorption coefficient (mm-1
)
Absorption correction Tmin and Tmax 0.666 and 0.853
F(000)
1,584
Reflections collected/unique
Range/indices (h, k, l)
h limit (°)
No. of observed data, I [ 2r(I)
No. of variables
18,993/3,755 [Rint = 0.0618]
-25, 32; -8, 9; -23, 16
2.17–26.49
3,755
Crystal Structure Determination
191
Diffraction intensities for the complex were collected using a
Bruker SMART Apex II CCD area detector equipped with
No. of restraints
Goodness of fit on F2
0
˚
1.030
graphite-monochromated Mo-Ka radiation (k = 0.71073 A)
-3
)
˚
Largest diff. Peak and hole (e A
R1, wR2 [I C 2r(I)]a
R1, wR2 (all data)a
0.427 and -0.529
0.0455, 0.1143
0.0788, 0.1336
at 298(2) K. The crystal was enveloped with glue to avoid
the efflorescence. Absorption correction was applied by
SADABS [7]. The structure was solved by direct methods
and refined on F2 by full-matrix least-squares methods using
the SHELXTL package [8]. All of the non-hydrogen atoms
were refined anisotropically. H atoms were generated geo-
P
P
P
P
a
R1 = ||Fo| - |Fc||/ |Fo|, wR2 = [ w(Fo2 - Fc2)2/ w(Fo2)2]1/2
,
w = [r2(Fo)2 ? (0.0434(Fo2 ? 2Fc2)/3)2]-1
˚
metrically, with C–H distances of 0.93–0.97 A, N–H dis-
˚
tances of 0.90 A, and with Uiso(H) set to 1.2Ueq(C, N) and
˚
Table 2 Selected bond distances (A) and angles (°) for the complex
Bond distances
1.5Ueq(methyl C). The details of the crystallographic data
are summarized in Table 1. Selected bond lengths and
angles are summarized in Table 2. Hydrogen bonds are
listed in Table 3.
Zn1–O1
1.948(2)
Zn1–N1
Zn1–Cl2
2.023(3)
Zn1–Cl1
2.2207(12)
2.2312(13)
Bond angles
O1–Zn1–N1
N1–Zn1–Cl1
N1–Zn1–Cl2
95.55(12)
112.98(9)
111.06(9)
O1–Zn1–Cl1
O1–Zn1–Cl2
Cl1–Zn1–Cl2
111.05(8)
112.27(9)
112.79(5)
Results and Discussion
The [Zn(C12H18N2O)Cl2] complex is slightly soluble in
either MeOH or EtOH; however, it is soluble in a
solution of MeOH/MeCN (V:V = 2:1) or EtOH/MeCN
(V:V = 2:1).
Description of the Crystal Structure of the Complex
The single crystal X-ray structural analysis shows that the
complex consists of a mononuclear [Zn(C12H18N2O)Cl2]
Scheme 1 Synthesis of
2-[(2-propylaminoethylimino)
methyl]phenol
H
CHO
N
H
MeOH
N
N
+
H2N
OH
OH
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J Chem Crystallogr (2010) 40:561–563
563
zinc(II) complexes that we have recently reported [6]. The
bond angles of the atoms coordinated to the Zn atom range
from 95.55(12) to 112.98(9)°, which indicate a slightly
distorted tetrahedral geometry. Crystal packing is stabi-
lized by intermolecular N2–H2BÁÁÁN3 and N2–H2AÁÁÁO1
hydrogen bonds linking the molecules into chains along the
b axis of the unit cell (Fig. 2). The N1–C8–C9–N2–C10–
C11–C12 group in the complex adopts a zigzag pattern in
the packing diagram most likely to minimize steric effects.
Table 3 Geometrical parameters for hydrogen bonds
˚
˚
˚
Hydrogen bonds D–H (A) HÁÁÁA (A) DÁÁÁA (A) D–HÁÁÁA (°)
N2–H2AÁÁÁO1a
0.90
0.90
1.87
2.22
2.736(4)
3.024(5)
161
149
N2–H2BÁÁÁN3
a
x, - y, z
Conclusions
The present study shows that the Schiff base ligand
2-[(2-propylaminoethylimino)methyl]phenol coordinates
to the Zn atom through the phenolic O and imine N atoms.
The structure of the complex is stabilized by intermolecular
N–HÁÁÁN and N–HÁÁÁO hydrogen bonds. The mixed solvent
is a good choice to cultivate the single crystals of the
complex.
Fig. 1 Molecular structure of the asymmetric unit of the title
compound, showing the [Zn(C12H18N2O)Cl2] complex and a CH3CN
molecule. Dashed lines indicate intermolecular N–HÁÁÁN hydrogen
bonds
Supplementary Material
CCDC 662571 contains the supplementary crystallographic
data for this paper. These data can be obtained free of
charge at http://www.ccdccam.ac.uk/const/retrieving.html
or from the Cambridge Crystallographic Data Centre
(CCDC), 12 Union Road, Cambridge CB2 1EZ, UK; fax:
?44(0)1223-336033 or e-mail: deposit@ccdc.cam.ac.uk.
Acknowledgments This work was financially supported by the
Education Office of Liaoning Province (Project No. 2008T107).
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123