Crystal structure of dinuclear azide-bridged copper(II) complex [Cu 2((3,4-MeO-Ba)2En)2(μ1,1-N 3)2(N3)2]{(3,4-MeO-Ba) 2En=N,N′-Bis(3,4-dimethoxybenzylidene)-1,2-ethanediamine}

Article abstract of DOI:10.1134/S1070328411040063

New dinuclear copper(II)-azido complex [Cu₂((3,4-MeO-Ba) ₂En)₂(μ_1,1-N₃)₂(N ₃)₂] (I) ((3,4-MeO-Ba)₂En = N,N′-bis(3,4-dimethoxybenzylidene)-1,2-diaminoethane) has been synthesized and characterized by elemental analyses, FT-IR spectroscopy, and X-ray single-crystal diffraction. Complex I consists of a dinuclear unit that represents a new example of a copper(II)-azido compound and the Cu²⁺ ions are bridged by two azido ions in a double end-on fashion, consisting of two terminally bonded azido ligands. The Schiff base ligand (3,4-MeO-Ba) ₂En is chelated by two imino nitrogen atoms.

Full text of DOI:10.1134/S1070328411040063

ISSN 1070ꢀ3284, Russian Journal of Coordination Chemistry, 2011, Vol. 37, No. 5, pp. 394–398. © Pleiades Publishing, Ltd., 2011.
Crystal Structure of Dinuclear AzideꢀBridged Copper(II) Complex
[Cu2((3,4ꢀMeO–Ba)2En)2(µ1,1ꢀN3)2(N3)2]{(3,4ꢀMeO–Ba)2En =
N,N'ꢀBis(3,4ꢀDimethoxybenzylidene)ꢀ1,2ꢀEthanediamine}1
S. Jalali Akerdia, G. Grivania, H. StoeckliꢀEvansb, and A. D. Khalajic, *
a School of Chemistry, Damghan University, Damghan, P.O. Box 36715ꢀ364, Iran
b Institute of Physics, Laboratory Physical Chemistry, University of Neuch@atel, CHꢀ2009 Neuch@atel, Switzerland
c Department of Chemistry, Faculty of Science, Golestan University, Gorgan, Iran
*eꢀmail: alidkhalaji@yahoo.com; ad.khalqji@gu.ac.ir
Received July 13, 2010
Abstract
—
New dinuclear copper(II)ꢀazido complex [Cu2((3,4ꢀMeOꢀBa)2En)2(μ1,1ꢀN3)2(N3)2] (I) ((3,4ꢀMeOꢀ
Ba)2En = N,N'ꢀbis(3,4ꢀdimethoxybenzylidene)ꢀ1,2ꢀdiaminoethane) has been synthesized and characterized by
elemental analyses, FTꢀIR spectroscopy, and Xꢀray singleꢀcrystal diffraction. Complex
I consists of a dinuclear
unit that represents a new example of a copper(II)ꢀazido compound and the Cu2+ ions are bridged by two azido
ions in a double endꢀon fashion, consisting of two terminally bonded azido ligands. The Schiff base ligand (3,4ꢀ
MeOꢀBa)2En is chelated by two imino nitrogen atoms.
DOI: 10.1134/S1070328411040063
1
INTRODUCTION
EXPERIMENTAL
−
All reagents and solvents were purchased from Aldꢀ
rich and Merck and used without further purification.
The Schiff base ligand (3,4ꢀMeOꢀBa)2En was prepared
following the standard procedure [14]. The infrared
spectrum was recorded on a PerkinElmer FTꢀIR specꢀ
trophotometer as a KBr pellet. Elemental analyses
were carried out on a Heraeus CHN–OꢀRapid eleꢀ
mental analyzer. (Although we did not experience any
problem during the work, such compound as perchloꢀ
rateꢀ and azideꢀcontaining compounds, being potenꢀ
tially explosive should be used in small quantities and
handled with great care.)
Synthesis of complex I. A methanolic solution (5 ml)
of (3,4ꢀMeOꢀBa)2En (1 mmol) was added to a clear soluꢀ
tion of Cu(NO3)2 ⋅ 3H2O (1 mmol) dissolved in 20 ml of
methanol, which producted immediately a blue solution.
Then, 10 ml of acetone was added to this solution, and the
mixture was heated and stirred at room temperature for
1 h. The solution was allowed to stand at room temperaꢀ
ture, and a methanolic solution of NaN3 (0.8 mmol in
10 ml) was dropwise added to give a green solution. Green
The azido ion,
is one of the most interesting
N3,
bridging molecules in inorganic coordination comꢀ
pounds, because the azide ion can coordinate to tranꢀ
sition metal ions by different bridging modes, such as
μ
ꢀ(1,1) [1–3],
μ
ꢀ(1,3) [4, 5],
μ
ꢀ(1,1,1) [6], and ꢀ
μ
(1,1,3) [7]. The copper(II) complexes with Schiff base
ligands have attracted considerable attention in recent
years due to their various interesting properties like
molecular magnetism [2–7] and 1D assemblies [8].
Up to date, several dinuclear copper(II) compounds
have been reported. They are based on the azido ion
[2, 9, 10]. The dinuclear copper(II) complexes bridged
by the azide ion have rarely been reported [11].
As an additional contribution to the synthesis,
characterization, and crystal structures of copper(II)
complexes with Schiff base ligands and in the course of
our ongoing studies of these kinds of materials [12,
13], we describe here the synthesis and crystal strucꢀ
ture of the new dinuclear copper(II)ꢀazido complex
[Cu2((3,4ꢀMeOꢀBa)2En)2(μ1,1ꢀN3)2(N3)2] (I):
OMe
OMe
MeO
OMe
single crystals of Isuitable for Xꢀray analysis were obtained
after several days by the slow evaporation of solvents at
room temperature, then collected by filtration, and dried
in vacuo. The yield was 83%.
N
N3
Cu
N
N
N3
N3
Cu
N3
For C40H48N16O8Cu2
N
anal. calcd., %:
Found, %:
C, 47.66;
C, 47.71;
H, 4.80;
H, 4.83;
N, 22.23.
N, 22.26.
IR spectrum (
(C=N).
Xꢀray structure determination. Suitable crystals of
were obtained as thin green plates by slow evaporation of solꢀ
ν
, cm–1): 2062 and 2034 (N3), 1631 s
MeO
OMe
OMe
OMe
I
1
The article is published in the original.
394

CRYSTAL STRUCTURE OF DINUCLEAR AZIDEꢀBRIDGED COPPER(II) COMPLEX
395
Table 1. Crystallographic data and experimental details for
complex
vents at room temperature. The intensity data were collected
at 173 K (–100 C) on a Stoe Mark IIꢀImage Plate Diffracꢀ
tion System [15] equipped with a twoꢀcircle goniometer and
using Mo graphite monochromated radiation
I*
°
K
Parameter
Value
α
(
λ
= 0.71073
rotation scans were 0
= 90 , step Δω = 1.0
range 1.76 –52.59
Å
). The image plate distance was 130 mm,
ω
°
–180 at = 0 and 0 –54.0
°
°
θ
°
°
°
at
, exposures of 9 mins per image,
Formula weight
1008.02
θ
°
2
θ
°
°,
dmin max = 23.107–0.802
–
d
Å.
The structure was solved by direct methods using the
SHELXSꢀ97 program [16]. The refinement and all furꢀ
ther calculations were carried out using SHELXLꢀ97
[16]. The H atoms were included in calculated positions
and treated as riding atoms using SHELXL default paꢀ
rameters. The nonꢀH atoms were refined anisotropically
Crystal system, space group
Monoclinic, P21/n
a
, Å
, Å
8.2617(10)
9.7017(10)
27.828(3)
93.891(10)
2225.4(4)
2
b
using weighted fullꢀmatrix leastꢀsquares on F
2. A semiemꢀ
pirical (multiscan) absorption correction was applied usꢀ
ing the MULscanABS routine in PLATON [17]. The
c
, Å
crystal diffracted weakly beyond 40
R
°
in 2
θ
and, hence, the
int value is rather high. Crystallographic details of the data
β
, deg
Å3
collection and structure refinements are listed in Table 1.
Supplementary material has been deposited with the Camꢀ
bridge Crystallographic Data Centre (no.783985;
deposit@ccdc.cam.ac.ukorhttp://www.ccdc.cam.ac.uk).
V
,
Z
RESULTS AND DISCUSSION
μ, mm–1
1.03
3,4ꢀDimethoxybenzaldehyde and 1,2ꢀdiaminoetꢀ
hane reacted in a 2 : 1 molar ratio to form the bidentate
Schiff base ligand (3,4ꢀMeOꢀBa)2En [14].
Crystal size, mm3
0.40
×
0.12
×
0.03
The FTꢀIR spectra of I exhibit a strong absorption
band at 2062 and 2034 cm–1 confirming the terminal
Index ranges
h,
k
,
l
–10
–11
–33
≤
h
k
l
≤
10,
11,
33
−
≤
≤
and bridging coordination modes of the
ligand in
N3
≤
≤
this complex. Also, the strong band at 1631 cm–1 in
I
is
assignable to the
ligand.
ν(C=N) stretches of the Schiff base
Measured reflection
19262
The ORTEP plot of complex
Selected bond lengths and bond angles are listed in
Table 2. Complex is made up of oneꢀhalf [Cu((3,4ꢀ
I is shown in Fig. 1.
Independent reflection/parameters
4201/302
2147
I
MeOꢀBa)2En)(μ1,1ꢀN3)(N3)] moiety, while the other
half being symmetry related via the center of symmeꢀ
try. Each Cu ion is fiveꢀcoordinated with a distorted
squareꢀpyramidal geometry and is surrounded by four
nitrogen atoms (N(2), N(3), N(3)i and N(6)) in the
basal plane. The fifth coordination site of the square
pyramid is occupied by the one nitrogen atom N(1),
from the bidentate Schiff base ligand (3,4ꢀMeOꢀ
Ba)2En. The Cu2+ ions are bridging by two azido
Reflection with
I
> 2σ(I)
R
R
0.237
int
(
F2 > 2
σ(
F2))
0.088
wR
(
F2
)
0.146
ligands in an endꢀon fashion [2, 9]. The Cu(1)
⎯N(2),
Cu(1)–N(3), Cu(1)–N(3)i, and Cu(1)–N(6) inꢀplane
distances are 2.019(5), 2.024(5), 2.007(5), and Δρmax and Δρmin
,
e
Å–3
0.37 and –0.49
1.965(6) Å, respectively. One nitrogen atom N(1) from
the bidentate Schiffꢀbase ligand (3,4ꢀMeOꢀBa)2En
2
σ
F 2
+ (0.0334P) ], where P =
)
o
F 2 + 2Fc2 3.
2
occupied the axial position (Cu(1)ꢀN(1) 2.368(5) Å).
* w = 1/[
(
(
)
o
The geometry around the Cu2+ ion in
I
is distorted by
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 37
No. 5
2011

396
JALALI AKERDI et al.
Table 2. Selected bond distances and bond angles for I*
Bond
d
, Å
Bond
O(4)–C(16)
d, Å
Cu()–N(1)
2.368(5)
2.019(5)
2.024(5)
1.965(6)
2.007(5)
1.358(9)
1.404(9)
1.480(9)
1.238(9)
1.476(9)
1.281(10)
1.220(8)
1.142(9)
1.167(11)
1.176(11)
Cu(1)–N(2)
Cu(1)–N(3)
Cu(1)–N(6)
Cu(1)–N(3)i
O(1)–C(7)
O(1)–C(10)
O(2)–C(8)
O(2)–C(11)
O(3)–C(15)
O(3)–(19)
O(4)–C(20)
N(1)–C(1)
N(1)–C(12)
N(2)–C(2)
N(2)–(3)
1.354(10)
1.438(10)
1.370(8)
1.432(9)
1.363(10)
1.431(10)
N(3)–N(4)
N(4)–N(5)
N(6)–N(7)
N(7)–N(8)
Angle
ω, deg
Angle
ω, deg
N(1)Cu(1)N(2)
N(1)Cu(1)N(3)
N(1)Cu(1)N(6)
N(1)Cu(1)N(3)
N(2)Cu(1)N(3)
N(2)Cu(1)N(6)
81.8(2)
94.4(2)
C(2)N(2)C(3)
Cu(1)N(3)N(4)
Cu(1)N(3)Cu(1)i
Cu(1)iN(3)N(4)
N(3)N(4)N(5)
Cu(1)N(6)N(7)
N(6)N(7)N(8)
N(1)C(1)C(2)
N(2)C(2)C(1)
N(2)C(3)C(4)
O(1)C(7)C(6)
O(1)C(7)(8)
117.8(6)
126.1(4)
104.2(2)
127.5(4)
177.8(7)
127.2(6)
176.0(7)
108.6(5)
111.7(6)
127.2(6)
125.9(7)
116.1(6)
113.8(7)
125.4(7)
127.8(7)
124.4(6)
115.9(6)
114.7(7)
125.8(7)
94.2(2)
i
114.6(2)
91.9(2)
96.2(3)
N(2)Cu(1)N(3)i
N(3)Cu(1)N(6)
N(3)Cu(1)N(3)i
159.9(2)
168.9(2)
75.8(2)
i
N(3) Cu(1)N(6)
94.3(2)
C(7)O(1)C(10)
C(8)O(2)C(11)
C(15)O(3)(19)
C(16)O(4)C(20)
Cu(1)N(1)C(1)
Cu(1)N(1)C(12)
C(1)N(1)C(12)
Cu(1)N(2)C(2)
Cu(1)N(2)C(3)
116.7(6)
115.9(6)
117.4(6)
118.0(6)
99.6(4)
O(2)C(8)C(7)
O(2)C(8)C(9)
N(1)C(12)C(13)
O(3)C(15)C(14)
O(3)C(15)C(16)
O(4)C(16)C(15)
O(4)C(16)C(17)
143.3(5)
115.6(6)
110.9(4)
130.4(5)
Angle
ϕ, deg
Angle
ϕ, deg
N(1)–C(12)–C(13)–C(14)
N(1)–C(12)–C(13)–(18)
C(12)–N(1)–C(1)–C(2)
C(1)–N(1)–(12)–C(13)
178.5(7)
–6.7(12)
–123.4(7)
177.2(7)
N(2)–C(3)–(4)–C(5)
N(2)–C(3)–C(4)–(9)
C(2)–N(2)–C(3)–C(4)
C(3)–N(2)–C(2)–C(1)
–166.6(7)
15.0(12)
–178.8(7)
–131.9(7)
i
* Symmetry codes: –x + 1, –y, –z.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 37
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CRYSTAL STRUCTURE OF DINUCLEAR AZIDEꢀBRIDGED COPPER(II) COMPLEX
397
C(2)
C(1)
C(3)
N(2)
N(5)
C(5)
C(12)
N(1)
C(19)
C(20a)
O(4a)
C(6)
C(14)
C(11a)
C(13)
C(4)
O(2a)
N(3)
C(15)
N(4)
Cu(1)
C(17a)
O(1a)
O(3)
N(6)
N(7)
C(7)
C(9)
C(8a)
C(18)
N(8a)
N(8)
N(7a)
C(10)
C(10a)
C(8)
N(6a)
C(18a)
C(7a)
O(3a)
N(3a)
O(1)
C(16)
C(9a)
C(17)
C(15a)
Cu(1a)
O(4)
O(2)
C(13a)
C(4a)
N(4a)
C(14a)
C(11)
C(6a)
C(20)
C(19a)
C(12a)
N(1a)
C(1a)
N(5a)
C(5a)
N(2a)
C(3a)
C(2a)
Fig. 1. ORTEP drawing with the atom labeling scheme of I with displacement ellipsoid drawn at the 50% probability level.
the restricting bite of the chelate angle C(4)–C(5) are 177.2(7)
N(1)Cu(1)N(2) 81.8(2) . This angle is in a range of
82 –89 found for ethylenediamine chelate comꢀ
pounds and much less than 90 . The other NCu(1)N
°
, 178.5(7)
°, –178.8(7)°, and
°
⎯
166.6(7)°, indicating an almost planar configuration of
this moiety for the complexes studied here [18]. Selected
torsion angles are given in Table 2.
°
°
°
angles are also distorted from the squareꢀpyramidal
values (Table 2).
The geometry of hydrogen bonds in complex
I is
given in Table 3. Complex exhibits different intraꢀ
and intermolecular hydrogen bonding patterns built
up from nonclassical C–H···N hydrogen bonds in the
I
The Schiff base ligands (3,4ꢀMeOꢀBa)2En adopts a
Z,Zꢀconfiguration in this complex [18–20]. The value for the
dihedral angles C(1)–N(1)–C(12)–C(13), N(1)–C(12)–
C(13)–C(14), C(2)–N(2)–C(3)–C(4), and N(2)–C(2)– crystal structure (Fig. 2). The dinuclear units are
Table 3. Geometric parameters of hydrogen bond for structure I*
Distance,
H···A
Å
Contact D–H···A
Angle D–H···A, deg
D–H
D···A
C(1)–H(1
A
)···N(5)ii
0.98
0.97
0.97
0.94
2.58
2.62
2.61
2.51
3.495(9)
3.536(10)
3.137(10)
3.359(9)
155
158
114
150
C(11)–H(11A)···N(8)
C(11)–H(11
C
)···N(5)iii
C(18)–H(18)···N(4)i
i
ii
iii
* Symmetry codes: –x + 1, –y, –z; –x, –y, –z; x + 1, y, z.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 37
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398
JALALI AKERDI et al.
x
0
z
y
…
Fig. 2. Crystal packing viewed along the
y
axis of complex
I
. The CꢀH N interactions are shown as dotted lines.
8. Wen, H.ꢀR., Wang, C.ꢀF., Song, Y., et al., Inorg. Chem.,
2005, vol. 44, p. 9039.
linked by weak hydrogen bonds to form oneꢀdimenꢀ
sional chains along the axis.
y
9. Li, L., Liao, D., Jiang, Z., et al., Inorg. Chem., 2006,
vol. 45, p. 7665.
ACKNOWLEDGMENTS
10. Triki, S., GomezꢀGarcia, C.J., Ruiz, E., and Salaꢀ
Pala, J., Inorg. Chem., 2005, vol. 44, p. 5501.
We acknowledge the Golestan University for parꢀ
tial support of this work.
11. Koner, S., Saha, S., Mallah, T., and Okamoto, K.ꢀI.,
Inorg. Chem., 2004, vol. 43, p. 840.
12. Khalaji, A.D. and StoeckliꢀEvans, H., Polyhedron
2009, vol. 28, p. 3769.
,
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