Crystal structures of bis(AZIDO)bis(2-morpholin-4-ylethylamino)copper(II) and bis{2,4-dibromo-6-[(2-morpholin-4-ylethylimino)methyl] phenolato}copper(II)

Article abstract of DOI:10.1134/S0022476614010223

Two new copper(II) complexes [Cu(MEA)₂(N₃) ₂] (1) and [Cu(BMP)₂] (2), where MEA and BMP are 2-morpholin-4-ylethylamine and 2,4-dibromo-6-[(2-morpholin-4-ylethylimino) methyl]phenolate respectively, are prepared and characterized using elemental analysis, FT-IR spectroscopy, and X-ray single crystal diffraction. The crystal of 1 belongs to the triclinic system, space group P-1, with a = 6.661(2) A, b = 8.440(3) A, c = 8.913(3) A, α = 102.032(3)°, β = 107.899(2)°, γ = 98.242(3)°, V = 454.6(3) A³, Z = 1, D _c = 1.490 g/cm³, R ₁ = 0.0226, and wR ₂ = 0.0564. The crystal of 2 belongs to the monoclinic system, space group P2₁/c, with α = 7.0707(7) A, b = 15.438(1) A, c = 14.227(1) A, β = 96.659(2)°, V = 1542.5(3) A³, Z = 2, D _c = 1.821 g/cm ³, R ₁ = 0.0437, and wR ₂ = 0.1041. In each complex, the Cu atom is in a square planar coordination. The molecules of 1 are linked through intermolecular N-H.N and N-H.O hydrogen bonds to form layers parallel to the ab plane. The molecules of 2 are linked through intermolecular C-H.Br hydrogen bonds to form a 3D network.

Full text of DOI:10.1134/S0022476614010223

Journal of Structural Chemistry. Vol. 55, No. 1, pp. 134-138, 2014.
Original Russian Text © 2014 H.-Y. Liu.
CRYSTAL STRUCTURES OF Bis(AZIDO)bis(2-MORPHOLIN-
4-YLETHYLAMINO)COPPER(II) AND Bis{2,4-DIBROMO-
6-[(2-MORPHOLIN-4-YLETHYLIMINO)METHYL]
PHENOLATO}COPPER(II)
H.-Y. Liu
UDC 548.73:547.13:546.56
Two new copper(II) complexes [Cu(MEA)2(N3)2] (1) and [Cu(BMP)2] (2), where MEA and BMP are 2-
morpholin-4-ylethylamine and 2,4-dibromo-6-[(2-morpholin-4-ylethylimino)methyl]phenolate respectively,
are prepared and characterized using elemental analysis, FT-IR spectroscopy, and X-ray single crystal
diffraction. The crystal of 1 belongs to the triclinic system, space group P-1, with a = 6.661(2) Å,
b = 8.440(3) Å, c = 8.913(3) Å, ꢀ = 102.032(3)ꢁ, ꢂ = 107.899(2)ꢁ, ꢃ = 98.242(3)ꢁ, V = 454.6(3) Å3, Z = 1,
Dc = 1.490 g/cm3, R1 = 0.0226, and wR2 = 0.0564. The crystal of 2 belongs to the monoclinic system, space
group P21/c, with ꢀ = 7.0707(7) Å, b = 15.438(1) Å, c = 14.227(1) Å, ꢂ = 96.659(2)ꢁ, V = 1542.5(3) Å3,
Z = 2, Dc = 1.821 g/cm3, R1 = 0.0437, and wR2 = 0.1041. In each complex, the Cu atom is in a square planar
coordination. The molecules of 1 are linked through intermolecular N–H‰N and N–H‰O hydrogen bonds
to form layers parallel to the ab plane. The molecules of 2 are linked through intermolecular C–H‰Br
hydrogen bonds to form a 3D network.
DOI: 10.1134/S0022476614010223
Keywords: X-ray diffraction, copper complex, crystal structure, Schiff base, hydrogen bond.
1,2-Ethylenediamine and its derivatives are a kind of important starting material to synthesize multi-dentate Schiff
bases. The complexes derived from diamines and their Schiff base derivatives have attracted much attention in structural and
coordination chemistry [1-5]. Copper complexes have received considerable interest in the fields of medicinal chemistry for
their antibacterial, antitumor, and antifungal activities [6-8] and materials chemistry [9-11]. As an extension of the work on
such complexes, in this paper, two new copper(II) complexes [Cu(MEA)2(N3)2] 1 and [Cu(BMP)2] 2, where MEA and BMP
are 2-morpholin-4-ylethylamine and 2,4-dibromo-6-[(2-morpholin-4-ylethylimino)methyl]phenolate respectively, were
prepared and structurally characterized.
Experimental. Materials and physical measurements. 2-Morpholin-4-ylethylamine and 3,5-dibromosalicylaldehyde
were purchased from Lancaster Chemical Company Inc. Copper perchlorate was prepared by the reaction of Cu2(OH)2CO3
with perchloric acid in distilled water. All other chemicals were of analytical grade. Elemental analyses for C, H, and N were
performed using a Perkin-Elmer 240C elemental analyzer. Infrared spectra were recorded on a Nicolet 170SX FT-IR
spectrophotometer with KBr pellets in the 4000-400 cm–1 region. Molar conductance measurements were performed in a
DDS-11A conductivity meter.
School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan, P. R. China;
liuhuanyu03@163.com. The text was submitted by the authors in English. Zhurnal Strukturnoi Khimii, Vol. 55, No. 1,
pp. 139-143, January-February, 2014. Original article submitted August 7, 2012.
134
0022-4766/14/5501-0134 © 2014 by Pleiades Publishing, Ltd.

TABLE 1. Crystallographic Data and Details of Refinements for the Complexes
Parametrs
1
2
Empirical formula
Formula weight
C H CuN O
12 28 10
C H N NiO
16 16 2 2
2
408.0
Triclinic
P-1
327.0
Triclinic
P-1
Crystal system
Space group
Unit cell dimensions a, b, c, Å
α, β, γ, deg
6.661(2), 8.440(3), 8.913(3)
9.096(2), 11.351(2), 11.790(2)
102.032(3), 07.899(2), 98.242(3)
100.947(2), 93.050(2), 109.682(2)
3
V, Å
454.6(3)
1
1116.3(3)
3
Z
–3
1.490
1.459
D
, g⋅cm
calcd
F(000)
μ(MoK ), mm
215
510
–1
1.231
1.308
α
Collected/independent/observed reflections
θ range, deg
3732/1943/1865
2.49-27.00
0.0226/0.0564
0.0242/0.0571
1.054
9245/4768/3545
2.3-27.0
0.0388/0.0845
R /wR [I > 2σ(I )]
1 2
R /wR (all data)
1 2
2
GOOF on F
1.029
Synthesis of the [Cu(MEA) (N ) ] complex (1). 2-Morpholin-4-ylethylamine (0.130 g, 1 mmol), sodium azide
2 3 2
(0.065 g, 1 mmol), and copper perchlorate (0.370 g, 1 mmol) were mixed in methanol (20 ml). The mixture was stirred at
ambient temperature for 30 min to give a blue solution. Blue single crystals of 1 suitable for the X-ray analysis were obtained
several days later. The yield was 63%. Anal. Calcd. for C H CuN O : C, 35.3%; H, 6.9%; N, 34.3%. Found: C, 35.5%; H,
12 28
10
2
–1
6.9%; N, 34.4%. IR data (KBr; ν, cm ): 3287 (w), 3241 (w), 3159 (w), 2041 (vs), 1597 (m), 1459 (w), 1446 (w), 1331 (w),
1301 (w), 1271 (w), 1113 (s), 1068 (m), 1035 (w), 1011 (m), 982 (w), 925 (m), 882 (w), 854 (w), 771 (w), 610 (w), 537 (w),
442 (w), 347 (w).
Synthesis of the [Cu(BMP) ] complex (2). 2-Morpholin-4-ylethylamine (0.130 g, 1 mmol), 3,5-
2
dibromosalicylaldehyde (0.280 g, 1 mmol) were mixed in methanol (20 ml). The mixture was stirred for 30 min at ambient
temperature to give a yellow solution. To the above solution a methanolic solution (10 ml) of sodium azide (0.065 g, 1 mmol)
and copper perchlorate (0.370 g, 1 mmol) were added with stirring. The final mixture was further stirred at ambient temperature
for 30 min to give a blue solution. Blue single crystals of 2 suitable for the X-ray analysis were obtained several days later. The
yield was 45%. Anal. Calcd. for C H Br CuN O : C, 36.9%; H, 3.6%; N, 6.6%. Found: C, 36.8%; H, 3.5%; N, 6.7%. IR data
26 30
4
4
4
–1
(KBr; ν, cm ): 1613 (s), 1456 (m), 1401 (m), 1160 (w), 1110 (w), 856 (w), 777 (w), 707 (w), 586 (w), 530 (w), 445 (w).
X-ray data collection and structure determination. The crystal and instrumental parameters used in the unit cell
determination and data collection are summarized in Table 1. Diffraction measurements were made at 298(2) K on a Bruker
SMART APEX II X-ray diffractometer using graphite monochromated MoK radiation in ω scan mode. Unit cell dimensions
α
were determined and refined in the range 2.49 < θ < 27.00° for (1) and 1.95 < θ < 28.13° for (2). The SMART program [12]
was used for the data collection, indexing reflection and determination of lattice parameters, SAINT [12] was used for the
integration of the reflection intensity and scaling, and SADABS [13] was used for absorption correction. The structures were
2
solved by the direct method using SHELXS-97 and refined by full-matrix least-squares techniques on F with SHELXL-97
[14, 15]. All non-hydrogen atoms were refined with anisotropic displacement parameters. Hydrogen atoms were included in
their idealized positions and refined isotropically. Selected bond distances (Å) and angles (deg) for complexes are listed in
Table 2. Hydrogen bonding geometries are given in Table 3.
Results and discussion. Single crystals of the complexes are stable at ambient temperature and soluble in methanol,
–3
ethanol, and acetonitrile. The molar conductivity measurements of the complexes in DMSO at a concentration of 10 mol/l
135

TABLE 2. Selected Bond Lengths (Å) and Angles (deg) for the Complexes
1
2
Cu1–N1
2.015(1)
180
Cu1–O1
1.909(2)
180
N1–Cu1–N1A
N1–Cu1–N3
Cu1–N3
O1–Cu1–O1A
O1–Cu1–N1
Cu1–N1
86.9(1)
2.022(1)
93.1(1)
180
91.3(1)
1.996(3)
88.7(1)
180
N1–Cu1–N3A
N3–Cu1–N3A
O1–Cu1–N1A
N1–Cu1–N1A
TABLE 3. Hydrogen Bonding Geometry for the Complexes (Å, deg)
D–H⋯A
D–H
H⋯A
D⋯A
D–H⋯A
1
i
N1–H1B⋯N4
0.90
0.90
0.90
2.61
2.30
2.30
3.094(2)
3.052(2)
3.157(2)
115
140
159
ii
N1–H1B⋯O1
iii
N1–H1A⋯N5
2
i
C8–H8B⋯O1
0.97
0.07
0.97
2.31
2.86
2.56
2.808(2)
3.789(2)
3.381(2)
111
162
143
iv
C9–H9B⋯Br1
v
C12–H12A⋯O2
Symmetry codes: (i) 1–x, 1–y, 1–z; (ii) x, 1+y, z; (iii) –x, 1–y, 1–z; (iv) 1+x, 3/2–y, –1/2+z; (v) –x, 2–y, 1–z.
Fig. 1. ORTEP view of (1) with 30% thermal ellipsoids
and the atom numbering scheme. Atoms labeled with the
suffix A are at the symmetry position 1–x, 1–y, 1–z.
–1
suggest that the complexes are non-electrolyte, with conductance values of 45 Ω ⋅cm ⋅mol for 1 and 23 Ω ⋅cm ⋅mol for 2
2
–1
–1
2
–1
respectively [16].
Structure description of the complexes. The molecular structure of 1 is shown in Fig. 1. The complex possesses a
crystallographic inversion center symmetry with the Cu atom located at the inversion center. The Cu atom is coordinated by
two N atoms from two MEA ligands and two N atoms from two azide ligands, forming a square planar geometry. The Cu–N
bond lengths are comparable to those observed in similar copper(II) complexes [17, 18]. As expected, the morpholine rings
adopt a chair conformation to minimize the steric effects. In the crystal structure of 1, the molecules are linked through
intermolecular N–H⋯N and N–H⋯O hydrogen bonds to form layers parallel to the ab plane (Fig. 2).
136

Fig. 3. ORTEP view of (2) with 30% thermal ellipsoids
and the atom numbering scheme. Atoms labeled with the
suffix A are at the symmetry position 1–x, 1–y, 1–z.
Fig. 2. Molecular packing structure of (1). Hydrogen bonds are
drawn as dashed lines.
Fig. 4. Molecular packing structure of (2). Hydrogen bonds are
drawn as dashed lines.
137

The molecular structure of 2 is shown in Fig. 3. The complex possesses a crystallographic inversion center of
symmetry with the Cu atom located at the inversion center. The Cu atom is coordinated by two phenolate O and two imine N
atoms from two Schiff base ligands BMP, forming a square planar geometry. The Cu–N and Cu–O bond lengths are
comparable to those observed in similar copper(II) complexes with Schiff bases [19, 20]. As expected, the morpholine rings
adopt a chair conformation to minimize the steric effects. In the crystal structure of 2, molecules are linked through
intermolecular C–H⋯Br hydrogen bonds to form a 3D network (Fig. 4).
–1
IR spectra. The middle and sharp band at 3208 cm in the IR spectrum of 1 is assigned to the N–H vibrations. The
intense absorption in the IR spectrum of 1 is assigned to the stretching vibrations of the azide ligands. The strong absorption
–1
band at 1606 cm in the IR spectrum of 2 is attributed to the azomethine stretching frequencies of the Schiff base ligands.
Supplementary material. CCDC 895550 (1) and 895551 (2) contain the supplementary crystallographic data for
this paper. These data can be obtained free of charge through www.ccdc.cam.ac.uk/data_request/cif, or by e-mailing
data_request@ccdc.cam.ac.uk, or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge.
CB2 1EZ, UK. Fax: +44(0)1223-336033.
The work was supported by the Guangdong Pharmaceutical University Young Teachers’ Fund and the Ten Hundred
Thousand Project of the Bureau of Education of Guangdong Province, P. R. China.
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