Novel Mixed Complexes of Copper(II) and Ethylenediamine: Synthesis, Crystal Structure, and Catalytic Activity in the Cross-Coupling Reaction of 1-Phenyl-5H-tetrazole-5-thiol and Iodobenzene

Article abstract of DOI:10.1134/S1070363218030155

Two earlier unknown complexes, [Cu(en)₂(Hptt)]Br (Hptt = 1-phenyl-1H-terazole-5-thiol, en = ethylenediamine) and trans-[Cu(en)2(H2O)Br]Br, have been synthesized and characterized using X-ray diffraction analysis. In [Cu(en)₂(Hptt)]Br

Full text of DOI:10.1134/S1070363218030155

ISSN 1070-3632, Russian Journal of General Chemistry, 2018, Vol. 88, No. 3, pp. 495–499. © Pleiades Publishing, Ltd., 2018.
Original Russian Text © L.V. Myznikov, A.I. Fisher, U.N. Dmitrieva, T.V. Artamonova, Yu.E. Zevatskii, 2018, published in Zhurnal Obshchei Khimii, 2018,
Vol. 88, No. 3, pp. 468–472.
Novel Mixed Complexes of Copper(II) and Ethylenediamine:
Synthesis, Crystal Structure, and Catalytic Activity
in the Cross-Coupling Reaction
of 1-Phenyl-5H-tetrazole-5-thiol and Iodobenzene
a
b
a
a
a,c
L. V. Myznikov *, A. I. Fisher , U. N. Dmitrieva , T. V. Artamonova , and Yu. E. Zevatskii
a
St. Petersburg State University of Industrial Technologies and Design,
ul. Bol’shaya Morskaya 18, St. Petersburg, 191186 Russia
*
e-mail: myznikov_lv@mail.ru
b
St. Petersburg State Technological Institute (Technical University), St. Petersburg, Russia
c
V.I. Ulyanov (Lenin) St. Petersburg State Electrotechnical University “LETI,” St. Petersburg, Russia
Received October 19, 2017
Abstract—Two earlier unknown complexes, [Cu(en)
ethylenediamine) and trans-[Cu(en) (H O)Br]Br, have been synthesized and characterized using X-ray
diffraction analysis. In [Cu(en) (Hptt)]Br complex, the copper cation is bonded with the N atom of tetrazole
ring. Catalytic activity of the obtained complexes in cross-coupling reaction of 1-phenyl-5H-tetrazole-5-thiol
with iodobenzene is comparable to that of CuBr in the presence of 2 eq. of ethylenediamine.
2
(Hptt)]Br (Hptt = 1-phenyl-1H-terazole-5-thiol, en =
2
2
4
2
2
Keywords: copper, ethylenediamine, 1-phenyltetrazole-5-thiol, complex compound, X-ray diffraction analysis,
catalysis
DOI: 10.1134/S1070363218030155
Copper complex compounds, in particular, hetero-
ligand copper complexes with ethylenediamine and
various organic and inorganic ligands [1–3] are
attractive due to easiness of synthesis, catalytic
activity, and practical applications in medicine,
agriculture, microelectronics, and industry. The major
factor providing the diversity of such complexes is the
use of polyfunctional ligands with several sites forming
the coordination bonds. The formed complexes struc-
ture is determined by the synthesis conditions. Tetra-
zole-5-thiols substituted at position 1 can form com-
plex compounds involving nitrogen and sulfur
coordination sites; they have been widely used in the
synthesis of biologically active substances and
functional materials [4]. In most cases, these
compounds contain the metal–heteroatom coordination
bonds involving sulfur atoms or simultaneously sulfur
and nitrogen atoms [4, 5], the coordination exclusively
with nitrogen is much less common [6].
activity may aid in optimizing the conditions of copper-
catalyzed cross-coupling reactions of 1-substituted
tetrazole-5-thiols with aryl iodides, because such com-
plex compounds are formed during the reaction.
Based on our earlier studies on cross-coupling of
1
-substituted tetrazole-5-thiols with aryl iodides in the
presence of copper compounds [7, 8], we carried out
targeted synthesis of mixed copper and ethylenedi-
amine complexes at 85°С in the presence of copper(II)
bromide in anhydrous DMF and in the presence of
water.
The crystals of [Cu(en) (Hptt)]Br complex (Hptt =
2
1-phenyl-1H-tetrazole-5-thiol, en = ethylenediamine) 1
were obtained by slow evaporation of a solution of
copper(II) bromide, ethylenediamine, K CO , and
2 3
1-phenyl-1Н-tetrazole-5-thiol in anhydrous DMF at 85°С
under vacuum. In presence of traces of water 1-phenyl-
1H-tetrazole-5-thiol did not included in the inner
sphere and octahedral [Cu(en) (H O)Br]Br complex
2
2
2
Isolation of the mentioned complexes, their
characterization, and investigation of their catalytic
was formed. Complexes 1 and 2 were air-stable non-
hygroscopic crystalline substances, soluble in DMF.
4
95

4
96
MYZNIKOV et al.
Table 1. Crystallographic data and refinement parameters of the structures of compounds 1 and 2
Parameter
Formula
1
2
Parameter
F(000)
μ(CuK
1
2
C
11
H
21BrCuN
8
S
C
4
H
18Br
2
CuN
4
O
1784
5.832
72.49
708
–1
M
440.87
361.58
Monoclinic
P2 /n
α
), mm
10.288
67.48
7/–7
Crystal system
Space group
а, Å
Orthorhombic
Pbca
θ
max, deg
1
h
max/hmin
12/–10
17/–17
29/–26
9.9140(2)
14.2959(2)
23.8361(6)
6.4405(4)
15.4060(9)
12.0440(7)
kmax/kmin
18/–18
14/–9
2121
b, Å
lmax/lmin
c, Å
Number of independent 3345
Reflections
β, deg
90
98.003(6)
Number of reflections
3085
2043
118
2
0
2
0
with F
> 2σ(F
)
3
V, Å
3378.26(12)
1183.39(11)
Number of refined
199
parameters
2
0
2
0
T, K
100(2)
8
100(2)
4
R
1
/wR
2
[F
2
> 2σ(F
)]
0.0210/0.0533
1.066
0.0436/0.1175
1.066
Z
GOOF/F
3
3
d
calc, g/cm
1.734
2.030
Δρmax, e/Å
0.355
0.960
–3
Color and appearance Blue prisms
Blue prisms
Δρmin, e/Å
–0.371
–0.747
3
Crystal size, mm
0.23×0.17×0.12 0.24×0.18×0.10
2
+
The solubility of complex 2 was significantly higher.
The absorption band of ν(M–N) vibrations was
observed at 536 and 526 cm in the IR spectra of
In the complex cation of compound 1, Cu is
coordinated with two ethylenediamine (en) molecules
and one 1-phenyl-1H-tetrazole-5-thiol (Hptt ) anion in
–
1
–
complexes 1 and 2, respectively.
the square pyramid geometry (Fig. 1). The Cu–Nen
distances are in the range of 2.016–2.032 Å range, the
The structure of compounds 1 and 2 was deter-
mined using single-crystal X-ray diffraction analysis.
Compounds 1 and 2 exhibited orthorhombic and
monoclinic crystal systems, respectively (Table 1). All
asymmetric structural units contained a complex cation
–
and a Br anion.
Fig. 1. General view of a molecule of compound 1 in a
crystal. Nonhydrogen atoms are represented by thermal
ellipsoids (50% probability), H atoms are represented by
spheres with random radius; dashed line represents
intramolecular hydrogen bond.
Fig. 2. Molecular packing of compound 1 in a crystal. H-
bonds are shown with dashed lines. Hydrogen atoms are
not shown.
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NOVEL MIXED COMPLEXES OF COPPER(II) AND ETHYLENEDIAMINE
497
Fig. 3. General view of a molecule of compound 2 in a
Fig. 4. Molecular packing of compound 2 in a crystal. H-
bonds are shown with dashed lines. Hydrogen atoms are
not shown.
crystal. Nonhydrogen atoms are represented by thermal
ellipsoids (50% probability), H atoms are represented by
spheres with random radius.
Cu–N(Hptt) distance is equal to 2.306 Å. The intra-
molecular N–H···S hydrogen bond is formed by one
of the coordinated en molecules and a Hptt anion
Teller distortion affect the octahedral geometry. The
complex cations of compound 2 are bound with one
–
–
–
another and with Br anions via the N–HO, O–HBr ,
and N–HBr hydrogen bonds (N–O 3.169, O–Br 3.328–
(
N–S 3.315 Å).
3
.289, and N–Br 3.421–3.461 Å) (Fig. 4). The
The structure of complex 1 is stabilized by inter-
neighboring layers in the crystal structures of compounds
1
molecular N–H···π interactions between the NH group
of the en-ligand and the benzene ring of the Hptt-anion
of the neighbor complex cation (H–Cg 2.557 Å, Cg
being the centroid of carbon atoms of the benzene
ring); that leads to the formation of linear chain along
the b axis (Fig. 2).
and 2 are bound via weak Van der Waals interactions.
The catalytic activity of obtained complexes was
investigated using the cross-coupling of 1-phenyl-5H-
tetrazole-5-thiol with iodobenzene as the test reaction,
(Scheme 1) in comparison with CuBr in the presence
2
2
+
of 2 eq. of ethylenediamine. The data on the catalytic
activity are given in Table 2.
The complex cation of compound 2 consists of Cu
ion coordinated with two en molecules (as in
compound 1) an H O molecule, and Br anion, in
octahedral geometry (Fig. 3) [9]. The Cu–N(en)
distances are in the range of 1.999–2.036 Å, whereas
the Cu–O and Cu–Br distances are severely longer
–
According to the data in Table 2, yield of the
reaction products after 1.5 h of heating in the presence
of complex 2 were significantly higher than in the case
of complex 1; probably due to higher solubility of
complex 2 in the reaction medium. Catalytic activity of
2
(
2.718 and 2.948 Å, respectively). Tetragonal Jahn–
Scheme 1.
Table 2. Yields of product of cross-coupling of 1-phenyl-5Н-
tetrazole-5-thiol with iodobenzene after 1.5 h at 85°С
I
Catalyst
Complex 1
Complex 2
Yield, %
SH
+
35
61
39
55
59
N
N
N
N
CuBr
CuBr
CuBr
CuBr
2
2
2
2
–2NH
–2NH
–2NH
–2NH
2
2
2
2
CH
CH
CH
CH
2
2
2
2
CH
CH
CH
CH
2
2
2
2
NH
NH
NH
NH
2
2
2
2
–H
2
O
cat
S
–10H
2
O
а
43
N
N
a
N
2
The reaction was carried out in DMF–H O, 8 : 2 mixture.
N
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 88 No. 3 2018

4
98
MYZNIKOV et al.
complex 1 was comparable to that of the CuBr2–
NH CH CH NH system. The addition of water to the
of 1 g (56 mmol) of 1-phenyl-1H-tetrazole-5-thiol in
150 mL of DMF. The mixture was heated to 85°C,
slowly evaporated under vacuum until the onset of
crystallization, and slowly cooled to room temperature
under atmospheric pressure. The precipitate was
filtered off and dried. IR spectrum (KBr), ν, cm :
3321, 3294, 3219, 3164, 3108, 3090, 3077 (N–H),
2969. 2953, 2941, 2883 (C–H), 1595 (C=N), 1584,
1560, 1494, 1455, 1383, 1356, 1292, 1273, 1219,
1101, 1093, 1059 (N–N), 1043, 1014, 989, 919, 776,
2
2
2
2
2
CuBr –2NH CH CH NH system likely enhances the
2
2
2
2
2
solubility of copper complex compounds in the
reaction medium, and the product yield was
comparable to that obtained with the preliminarily
prepared complex 2. Further increase in the water
amount in the reaction medium decreased the
solubility of starting substances and reduced the yield
of the reaction product.
–
1
7
21, 696, 687, 571, 536 (Cu–N). Found: %: C 30.13;
In summary, complex compounds of 1-substituted
tetrazole-5-thiols with the copper–heteroatom coordina-
tion exclusively at the nitrogen atom were formed
under conditions of copper-catalyzed cross-coupling
reaction. 1-Substituted tetrazole-5-thiol fragment of the
formed complexes could be easily substituted with
water molecule.
H 4.99; N 25.33. C H BrCuN S. Calculated, %: C
2
11
21
8
9.97; H 4.80; N 25.42. 30.13; H 4.99; N 25.33.
[
Cu(en) (H O)Br]Br complex (2) was obtained
2
2
similarly from 1.25 g (56 mmol) of СuBr , 0.67 g
2
(
112 mmol) of ethylenediamine, 1.54 g (112 mmol) of
K CO , 150 mL of DMF, and 1 mL of H O. IR
2
3
2
–
1
spectrum (KBr), ν, cm : 3321, 3294, 3219, 3164,
108, 3090, 3077 (N–H), 2969. 2953, 2941, 2883
C–H), 1595 (C=N), 1584, 1560, 1494, 1455, 1383,
EXPERIMENTAL
3
(
1
1
The IR spectra were registered using a Shimadzu
FTIR-8400S spectrometer. Elemental analysis was
performed using a LECO CHNS-932 device. X-ray
diffraction data were collected with an Agilent
Technologies Supernova Atlas diffractometer at 100 K
356, 1292, 1273, 1219, 1101, 1093, 1059 (N–N),
043, 1014, 989, 919, 776, 721, 696, 687, 571, 536
(
Cu–N). Found %: C 13.17; H 5.15; N 15.64.
C H Br CuN O. Calculated, %: C 13.29; H 5.02; N
1
4
18
2
4
5.50.
using microfocused monochromatic CuK -radiation.
α
The structures were solved via the direct method and
refined under anisotropic approximation for nonhyd-
rogen atoms and under isotropic approximation for
hydrogen atoms, using the full-matrix least squares
method implemented in SHELXL-97 routine [10]
included in OLEX2 software package [11]. H atoms at
the C atoms were localized at the calculated positions
and refined via the rider model, U (H) = 1.2U (N)
Cross-coupling in the presence of complexes 1
and 2. 20 mol% of the complex compound was added
to a solution of 1.0 g (5.6 mmol) of 1-phenyl-1H-
tetrazole-5-thiol, 1.1 g (5.6 mmol) of iodobenzene, and
0.77 g (5.6 mmol) of dry K CO in 15 mL of
2
3
anhydrous DMF. The reaction mixture was stirred for
1.5 h at 85°С, cooled to 20°С, and poured into 50 mL
of water. The precipitate was filtered off and purified
using column chromatography (eluent: EtOAc–hexane,
2 : 8).
iso
eq
and N–H 0.90 Å for NH groups, U (H) = 1.2U (C)
2
iso
eq
and C–H 0.97 Å for CH groups, U (H) = 1.2U (C)
2
iso
eq
and C–H 0.93 Å for CH groups. H atoms of H O
2
Cross-coupling in the presence of CuBr and
molecules were localized using differential Fourier
series without refinement. The unit cell parameters
were determined and the intensities of diffraction
reflections were measured using CrysAlisPro software
package [12]. The absorption was accounted for
empirically using SCALE3 ABSPACK algorithm.
Crystallographic data and refinement parameters of
structures of compounds 1 and 2 were deposited at the
Cambridge Crystallographic Data Center (CCDC
2
ethylenediamine. 0.25 g (11.2 mmol) of CuBr and
2
0
.134 g (22.4 mmol) of ethylenediamine were added to
a solution of 1.00 g (5.6 mmol) of 1-phenyl-1H-
tetrazole-5-thiol, 1.14 g (5.6 mmol) of iodobenzene,
and 0.77 g of dry K CO (5.6 mmol) in 15 mL of
2
3
anhydrous DMF. The reaction mixture was stirred for
.5 h at 85°С, cooled to 20°С, and poured into 50 mL
of water. The precipitate was filtered off and purified
using column chromatography (eluent: EtOAc–hexane,
1
1
022459 and 1022460, respectively).
2
: 8).
[
Cu(en) (Hptt)]Br complex (1). 1.25 g (56 mmol)
2
of СuBr , 0.67 g (112 mmol) of ethylenediamine, and
Cross-coupling in the presence of water was carried
2
1
.54 g (112 mmol) of K CO were added to a solution
out similarly.
2
3
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NOVEL MIXED COMPLEXES OF COPPER(II) AND ETHYLENEDIAMINE
499
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