Synthesis and crystal structures of Zn(II)/Co(II) complexes with condensed heterocyclic based 1,2,4-triazole

Article abstract of DOI:10.1007/s10870-012-0317-6

Three Zn(II)/Co(II) coordination compounds with condensed heterocyclic based 1,2,4-triazole 8H-4, 7-diphenyl-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines (L¹), and 8H-4-phenyl-7-(pyridine-2-yl)-1,2,4-triazolo[3,4-b]-1,3, 4-thiadiazines (L²), Co(L¹)₂Cl₂ (1), Zn(L¹)₂Cl₂ (2). and Co(L²) ₂Cl₂ (3) were synthesized and structurally characterized by elemental analyses, IR spectroscopy and single-crystal X-ray diffraction. Complexes 1, 2 and 3 have mononuclear structure, the mononuclear structures of 1 and 2 were further assembled by the C-H...Cl and C-H...N weak interactions into an infinite 2-D supramolecular sheet. Springer Science+Business Media, LLC 2012.

Full text of DOI:10.1007/s10870-012-0317-6

J Chem Crystallogr (2012) 42:803–808
DOI 10.1007/s10870-012-0317-6
ORIGINAL PAPER
Synthesis and Crystal Structures of Zn(II)/Co(II) Complexes
with Condensed Heterocyclic Based 1,2,4-Triazole
•
•
•
Peng-Yuan Ma Jian-Bin Zhang Mei Bai
Duo-Zhi Wang
Received: 12 December 2011 / Accepted: 1 April 2012 / Published online: 21 April 2012
Ó Springer Science+Business Media, LLC 2012
Abstract Three Zn(II)/Co(II) coordination compounds
with condensed heterocyclic based 1,2,4-triazole 8H-4,
7-diphenyl-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines (L1), and
8H-4-phenyl-7-(pyridine-2-yl)-1,2,4-triazolo[3,4-b]-1,3,
4-thiadiazines (L2), Co(L1)2Cl2 (1), Zn(L1)2Cl2 (2). and
Co(L2)2Cl2 (3) were synthesized and structurally char-
acterized by elemental analyses, IR spectroscopy and
single-crystal X-ray diffraction. Complexes 1, 2 and 3
have mononuclear structure, the mononuclear structures
of 1 and 2 were further assembled by the C–H_Cl and
C–H_N weak interactions into an infinite 2-D supra-
molecular sheet.
due to efficient design strategies [3–5], but it is still diffi-
cult to prepare metal organic frameworks with predictable
topologies, and to predict the exact structures and com-
position of the coordination polymer, because the self-
assembly progress is highly influenced by several factors
such as the ligands’ nature, solvents, templates, counter-
anions, metal to ligand ratio, etc. Therefore, systematic
research on this topic is still important for understanding
the role of these factors in the formation of metal coordi-
nation frameworks [6–8].
Great efforts have been focused on ligands based on
azole heterocycle, which have both good coordination
ability and diverse coordination modes [9]. As the simple
small molecular ligands, triazole and its derivatives are
potential multitopic ligands in constructions of coordina-
tion complexes [10]. 1,2,4-Triazole and its derivatives are
very interesting ligands because they combine the coordi-
nation geometry of both pyrazoles and imidazoles with
regard to the arrangement of their three heteroatoms [11].
A large number of mononuclear [12], dinuclear [13], and
polynuclear [14] metal coordination compounds with 1,2,4-
triazole derivatives have been prepared and characterized
because of their interesting luminescence properties and
novel topologies [15]. However, there are still only rare
reports of ligands based on condensed heterocyclic based
1,2,4-triazole as building blocks for the construction of
coordination complexes.
Keywords Zn(II)/Co(II) complex Á Synthesis Á
Crystal structure
Introduction
The past decade has witnessed the explosive development
of metal organic frameworks (MOFs), because of not only
their intriguing varieties of molecular architectures and
topologies [1] but also their potential applications in fer-
roelectrics, nonlinear optics, porous materials, and cataly-
sis, etc. [2]. Recently remarkable progress has been made
in this new field of chemistry and materials science, largely
In this work, two ligands of condensed heterocyclic
based 1,2,4-triazole: (L1) and (L2) (Chart 1), have been
designed and synthesized. The reactions of these ligands
with the corresponding Zn(II)/Co(II) salts lead to the for-
mation of three new metal organic complexes with 0-D
structures. Those complexes were structurally character-
ized by elemental analyses, IR spectroscopy and single-
crystal X-ray diffraction. This paper reports on the results
P.-Y. Ma Á M. Bai Á D.-Z. Wang (&)
Xinjiang Laboratory of Advanced Functional Materials,
Chemistry and Chemical Engineering School of Xinjiang
University, Urumqi 830046, People’s Republic of China
e-mail: wangdz@xju.edu.cn
J.-B. Zhang
Physics and Chemistry Test Center of Xinjiang University,
Urumqi 830046, People’s Republic of China
123

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J Chem Crystallogr (2012) 42:803–808
pressure to give ligand L1, recrystallized from absolute
ethanol to give ligand L1 as white crystals (Chart 2).
N
N
N
N
S
S
N
N
1
Yield: *65 %. m.p. 210–212 °C. H NMR (CDCl3): d:
N
N
7.50 * 8.15(m, 10H, benzene), d: 4.05(s, 2H, thiadiazine);
Anal. Calcd for C16H12N4S: C, 65.73; H, 4.14; N, 19.16;
Found: C, 65.75; H, 4.12; N, 19.17. IR (cm21, KBr pellets):
3376w, 3192w, 3104w, 3059m, 3031m, 2998s, 2904m, 2800w,
2449w, 1960w, 1905w, 1813w, 1761w, 1714w, 1595w, 1568w,
1503w, 1460s, 1370s, 1302s, 1284m, 1233w, 1176w, 1157w,
1113w, 1073w, 1023w, 998w, 966w, 919w, 870w, 832w, 769m,
739w, 690s, 638w, 591w, 551w, 510w.
N
L1
L2
Chart 1 The structure of ligands L1 and L2
of an X-ray structural investigation of complexes Co(L1)2
Cl2 (1), Zn(L1)2Cl2 (2) and Co(L2)2Cl2 (3).
8H-4-Phenyl-7-(pyridine-2-yl)-1,2,4-triazolo[3,4-b]-1,3,
4-thiadiazines (L2)
Experimental Section
The intermediate of 3-phenyl-4-amino-5-sulfhydryl-1,2,4-
triazole (a) (5 mmol) and 2-bromo-1-(2-pyridyl)ethanone
(5 mmol) was added to absolute ethanol (30 mL), then was
refluxed for 4 h. Removing the the solvent under depress
pressure to give ligand L2, recrystallized from absolute
ethanol to give ligand L2 as white crystals. Yield: *60 %.
m.p: 208–210 °C. 1H NMR (CDCl3): d: 8.80 (dd, 1H,
6-pyridine), d: 8.30 (dd, 1H, 4-pyridine), d: 7.68–8.08 (m,
7H, 2,3-pyridine and benzene), d: 4.76(s, 2H, thiadiazine);
Anal. Calcd for C15H11N5S: C, 61.43; H, 3.75; N, 23.89;
Found: C, 61.45; H, 3.72; N, 23.90. IR (cm21, KBr pellets):
3308w, 3060w, 2997m, 2905m, 2793w, 2754w, 2660w, 2361s,
2008w, 1977w, 1725m, 1601m, 1569s, 1506s, 1486s, 1463s,
1437m, 1412s, 1391s, 1371m, 1328w, 1283w, 1253w, 1166w,
1092m, 1049w, 993w, 959w, 910w, 878m, 841w, 777s, 686s,
584s, 556w, 501w.
Materials and General Methods
Ethyl Benzoate, 85 % hydrazine hydrate, potassium
hydroxide, 2-acetylpyridine, acetophenone reagents used
for the syntheses were commercially available and
employed without further purification. The intermediate of
3-phenyl-4-amino-5-sulfhydryl-1,2,4-triazole (a) was pre-
pared according to reported procedures [16]. IR spectra
were measured on a Bruker Equinox 55 FT-IR spectrom-
eter with KBr Pellets in the range of 4,000–400 cm-1
.
Elemental analyses of C, H and N were performed on a
1
Thermo Flash EA 1112-NCHS-O analyzer. H NMR data
were collected using an INOVA-400 NMR spectrometer.
Chemical shifts are reported in d relative to TMS.
Synthesis of Ligand L1 and L2
Synthesis of Complexes 1–3
Co(L1)2Cl2 (1)
8H-4,7-Diphenyl-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines
(L1)
Complex 1 was prepared by dissolving CoCl2Á6H2O
(0.3 mmol) and L1 (0.3 mmol) in ethanol solution
(15 mL), then was refluxed for 3 h. After cooling and fil-
trated, Blue plate-shaped crystals were formed after several
days with the evaporation of the filtrate (ca. 30 % yield
The intermediate of 3-phenyl-4-amino-5-sulfhydryl-1,2,4-
triazole (a) (5 mmol) and 2-bromo-1-phenylethanone
(5 mmol) was added to absolute ethanol (30 mL), then was
refluxed for 4 h. Removing the solvent under depress
Chart 2 The route of synthesis of ligands L1 and L2
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J Chem Crystallogr (2012) 42:803–808
805
based on L1). Yield: 30 %. Anal. Calcd for C32H24Cl2
CoN8S2: C, 53.79; H, 3.39; N, 15.68. Found: C, 53.80; H,
3.41; N, 15.67. IR (cm21, KBr pellets): 3430w, 3058w,
2997w, 2917w, 2495w, 2262w, 1970w, 1896w, 1807w,
1763w, 1698w, 1593w, 1565w, 1530w, 1505s, 1479s, 1453s,
1437s, 1407m, 1384m, 1364m, 1315m, 1306m, 1276s, 1225m,
1182m, 1160w, 1124w, 1100w, 1073w, 993s, 915m, 833m,
806w, 786m, 768s, 758s, 742m, 689s, 641m, 597m, 557m,
510m, 475w, 432w.
days with the evaporation of the filtrate (ca. 30 % yield
based on L2). Yield: 25 %. Anal. Calcd for C30H22Cl2
N10S2Co: C, 50.29; H, 3.09; N, 19.55. Found: C, 50.35; H,
3.20; N, 19.67. IR (cm21, KBr pellets): 3058w, 2994m,
2913w, 2623w, 2248w, 2301w, 1994w, 1966w, 1891w,
1766w, 1700w, 1602m, 1565m, 1530w, 1453s, 1405m,
1365m, 1337s, 1312m, 1253m, 1225m, 1181m, 1155s, 1100m,
1072m, 1050m, 1020w, 923m, 840m, 801w, 770s, 751m,
694s, 652w, 622m, 599m, 565m, 512m, 472w, 442w.
Zn(L1)2Cl2 (2)
X-Ray Crystallography
Complex 2 was prepared by dissolving ZnCl2 (0.3 mmol)
and L1 (0.3 mmol) in ethanol solution (15 mL). Colorless
plate-shaped crystals were formed after several days with
the evaporation of the solvent (ca. 30 % yield based on L5).
Yield: 30 %. Anal. Calcd. for C32H24Cl2ZnN8S2: C, 53.30;
H, 3.35; N, 15.54. Found: C, 53.31; H, 3.33; N, 15.55. IR
(cm21, KBr pellets): 3441w, 3059w, 2915w, 1971w, 1896w,
1810w, 1763w, 1689w, 1590w, 1529w, 1476m, 1455s, 1411s,
1363m, 1308s, 1222w, 1184w, 1156w, 1124w, 1073w, 1045w,
994w, 918w, 830w, 786m, 760s, 737w, 689s, 639w, 600w,
555w, 510w, 474w, 432w.
X-ray single-crystal diffraction data for L and complex 1
were collected on a Bruker Smart 1000 CCD diffractom-
˚
eter at 293(2) K with Mo-Ka radiation (k = 0.71073 A) by
x-uscan mode. The program SAINT [17] was used for
integration of the diffraction profiles. Semi-empirical
absorption corrections were applied using SADABS pro-
gram. All the structures were solved by direct methods
using the SHELXS program of the SHELXTL package and
refined by full-matrix least-squares methods with SHELXL
[18]. Metal atoms in each complex were located from the
E-maps and other non-hydrogen atoms were located in
successive difference Fourier syntheses and refined with
anisotropic thermal parameters on F2. Hydrogen atoms of
carbon were included in calculated positions and refined
with fixed thermal parameters riding on their parent atoms.
Crystallographic data and experimental details for struc-
tural analyses are summarized in Table 1. The crystal data
file in CIF format was deposited on CCDC and reference
Co(L2)2Cl2 (3)
Complex 3 was prepared by dissolving CoCl2Á6H2O
(0.3 mmol) and L2 (0.3 mmol) in ethanol solution
(15 mL), then was refluxed for 3 h. After cooling and fil-
trated, Blue plate-shaped crystals were formed after several
Table 1 Crystal data and
structure refinement summary
for complexes 1–3
1
2
3
Formula
C32H24Cl2N8S2Co
C32H24Cl2N8S2Zn
696.96
C30H22Cl2N10S2Co
716.53
Formula wt
Crystal system
Space group
T/K
714.54
Monoclinic
P21/n
Monoclinic
P21/n
Monoclinic
P21/n
293(2)
293(2)
293(2)
˚
a/A
10.904(2)
17.993(4)
16.278(3)
90.00
10.898(2)
18.046(4)
16.313(3)
90.00
10.454(2)
17.949(4)
16.849(3)
90.00
˚
b/A
˚
c/A
a/°
b/°
c/°
104.05(3)
90.00
103.90(3)
90.00
102.19(3)
90.00
3
˚
V/A
3098.1(11)
4
3114.3(11)
4
3090.3(11)
4
Z
D/g cm-3
l/mm-1
F(000)
1.536
1.486
1.549
0.900
1.130
0.909
1460
1424
1460
Messured reflns
Obsd reflns
Ra/wRb
29844
29081
25832
a
R = R||Fo|-|Fc||/R|Fo|
Rw = [R[w(F2o-Fc2)2]/
7043
7067
6948
b
0.0530/0.2161
0.0386/0.1195
0.0645/0.1938
Rw(F2o)2]1/2
123

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J Chem Crystallogr (2012) 42:803–808
˚
Table 2 Selected bond distances (A) and angles (°) for complexes
1–3
numbers 857783–857785 (for complex 1–3, respectively).
This data can be obtained from the Cambridge Crystallo-
graphic Data Center, 12 Union Road, Cambridge CB2 1EZ,
UK; Fax: ?44-1223-336033; E-mail: deposit@ccdc.cam.
ac.uk.
Complex 1
Co(1)–N(5)
Co(1)–Cl(2)
2.027(3)
Co(1)–N(1)
2.035(3)
2.2256(12) Co(1)–Cl(1)
2.2313(12)
N(5)–Co(1)–N(1) 105.45(12) N(5)–Co(1)–Cl(2) 116.20(10)
N(1)–Co(1)–Cl(2) 102.93 (8)
N(1)–Co(1)–Cl(1) 115.14(9)
Complex 2
N(5)–Co(1)–Cl(1) 103.89(9)
Cl(2)–Co(1)–Cl(1) 113.38(5)
Results and Discussion
Syntheses and General Characterization
Zn(1)–N(5)
Zn(1)–Cl(2)
2.051(2)
Zn(1)–N(1)
Zn(1)–Cl(1)
2.048(2)
2.2363(8)
2.2315(9)
L1 and L2 was prepared in higher yield as white crystalline
solid by the reaction of 3-phenyl-4-amino-5-sulfhydryl-
1,2,4-triazole (a) with 2-bromo-1-phenylethanone and
2-bromo-1-(2-pyridyl)ethanone, respectively. The struc-
N(5)–Zn(1)–N(1) 104.79(9)
N(1)–Zn(1)–Cl(2) 104.76(7)
N(1)–Zn(1)–Cl(1) 114.47(7)
Complex 3
N(5)–Zn(1)–Cl(2) 113.92(7)
N(5)–Zn(1)–Cl(1) 103.24(6)
Cl(2)–Zn(1)–Cl(1) 115.44(4)
1
tures of L1 ~ L2 were determined by H NMR, IR, ele-
Co(1)–N(6)
Co(1)–Cl(1)
2.029(3)
Co(1)–N(1)
2.048(3)
mental analysis. The complexes 1–3 are air stable at room
temperature. The infrared spectra of 1 * 3 exhibits char-
acteristic absorptions for corresponding ligands with a
slight shift due to coordination. L1 and L2 and 1–3 all
exhibited absorptions corresponding to the framework
2.2583(13) Co(1)–Cl(2)
2.2563(12)
N(6)–Co(1)–N(1) 106.24(13) N(6)–Co(1)–Cl(1) 112.07(10)
N(1)–Co(1)–Cl(1) 102.55 (10) N(6)–Co(1)–Cl(2) 103.54(10)
N(1)–Co(1)–Cl(2) 113.63(10) Cl(1)–Co(1)–Cl(2) 118.44(5)
vibrations of aromatic rings at about 1,420–1,650 cm-1
.
distance of C(24)_N(2) and C(8)_N(6) are 3.468 and
˚
3.548 A, respectively, the angles of C(24)–H(24A)_N(2)
Crystal Structures
and C(8)–H(8b)_N(6) are 167.32 and 170.46°, respec-
tively. So the mononuclear structures was further assem-
bled by the C–H_Cl and C–H_N weak interactions into
an infinite 2-D supramolecular sheet (Fig. 1c).
Co(L1)2Cl2 (1) and Zn(L1)2Cl2 (2)
Structural analyses were carried out and similar cell
parameters of complexes 1 and 2 (Table 1). Compounds 1
and 2 have the general formula of M(L1)2Cl2 [M = Co (1),
M = Zn (2)]. In 1, the coordination environment of Co(II)
ion is also the same as Zn(II) that of ion in 2. Therefore, we
just describe structure of complex 1 later in this text in
detail relatively.
The mononuclear structure of complex 2 shows in
Fig. 2. The C–H_Cl and C–H_N weak interactions were
observed in 2, The distances of C(4)_Cl(1) and
˚
C(22)_Cl(2) are 3.504 and 3.782 A, respectively. The
distance of C(30)_N(2) and C(14)_N(6) are 3.562 and
˚
3.474 A, respectively, the angles of C(14)–H(14A)_N(6)
and C(30)–H(30A)_N(2) are 166.19 and 171.30°,
respectively. The mononuclear structures were further
assembled by the C–H_Cl and C–H_N weak interactions
into an infinite 2-D supramolecular sheet.
Complex 1 crystallizes in P21/n space group and the
selected bond distances and angles were listed in Table 2.
The X-ray diffraction analysis shows that 1 has a mono-
nuclear structure (see Fig. 1a). The Co(II) center features a
distorted tetrahedral geometry, and linked to two distinct
triazole N donors of two L1 ligands and two chlorine
atoms, the Co(1)–N(1) and Co(1)–N(5) bond distances are
Co(L2)2Cl2 (3)
˚
Complex 3 crystallizes in the monoclinic symmetry space
group P21/n. Crystallographic data and experimental
details for structural analyses were summarized in Table 1,
the selected bond distances and angles were listed in
Table 2. The X-ray diffraction analysis shows 3 has a
mononuclear structure (Fig. 3) with the center Co(II) ion
four-coordinated by two N atoms from two distinct triazole
N donors of two L2 ligands and two chlorine atoms. Thus,
Co(II) center lies in a distorted tetrahedral environment. L2
ligand acts as a typical monodentate ligand coordinating to
the Co(II) ion with the Co–N bond distances 2.029(3)–
2.035(3) and 2.027(3) A, respectively, which are in the
normal range [19]. Two L1 ligands all adopt monodentate
coordination mode.
It should be pointed out that the C–H_Cl weak inter-
actions were observed between adjacent mononuclear
structures. The distances of C(13)_Cl(1) and
˚
C(31)_Cl(2) are 3.765 and 3.504 A, respectively. There-
fore, mononuclear structures were further assembled by the
C–H_Cl weak interactions into an infinite 1-D supramo-
lecular chain (Fig. 1b). In addition, the C–H_N weak
interactions were observed between 1-D supramolecular
chains assembled by the C–H_Cl weak interactions. The
˚
2.048(3) A, the N–Co–N angle being 106.24(13)°. In
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J Chem Crystallogr (2012) 42:803–808
807
Fig. 3 View of the coordination environment of Co(II) ions in
3(H atoms omitted for clarity)
In summary, three new complexes with (L1) and (L2)
have been synthesized and structurally characterized. It is
interesting that Complex 1 and 2 have the similar structure
and general formula. The mononuclear structures of 1 and
2 were further assembled by the C–H_Cl and C–H_N
weak interactions into an infinite 2-D supramolecular sheet.
This result indicated that hydrogen-bonding interaction
play an important role in the formation of supramolecular
network structures.
Acknowledgment This work was financially supported by the
National Natural Science Funds of XinJiang, China (No. 2011211A009)
and supported by the Open Project Program of Xinjiang Laboratory of
Advanced Functional Materials, China (XJDX0902-2010-02).
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