Hydrothermal syntheses and structural characterization of four complexes with in situ formation of 1,2,3-triazole-4-carboxylate ligand

Article abstract of DOI:10.1016/j.molstruc.2009.03.020

Four new complexes constructed by 1,2,3-triazole-4-carboxylate and bipyridyl-like ligands, namely [Cu(ta)(bipy)·H₂O]_n (1), [Mn₂(ta)₂(bipy)₂(H₂O)₂·2H₂O]_n (2)

Full text of DOI:10.1016/j.molstruc.2009.03.020

Journal of Molecular Structure 928 (2009) 78–84
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Hydrothermal syntheses and structural characterization of four complexes
with in situ formation of 1,2,3-triazole-4-carboxylate ligand
a
b
a
Ze-Bao Zheng a, , Ren-Tao Wu , Ji-Kun Li , Yi-Feng Sun
*
a Department of Chemistry and Environmental Science, Taishan University, Yingbin Street, Taian, Shandong 271021, PR China
b Department of Materials and Chemical Engineering, Taishan University, Taian, Shandong 271021, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Four new complexes constructed by 1,2,3-triazole-4-carboxylate and bipyridyl-like ligands, namely
[Cu(ta)(bipy)ꢀH2O]n (1), [Mn2(ta)2(bipy)2(H2O)2ꢀ2H2O]n (2), [Zn(ta)(phen)2ꢀ5H2O]n (3), [Ni(ta)(phen)2ꢀ
8H2O]n (4), (ta = 1,2,3-triazole-4-carboxylate, bipy = 2,20-bipyridine, phen = 1,10-phen) were prepared
under hydrothermal conditions and characterized by IR, elemental analyses and single-crystal X-ray
analyses. Where the ta ligand is formed in situ by the decarboxylation of 1H-1,2,3-triazole-4,5-dicarbox-
ylic acid. In the complex 1, the Cu (II) ions are bridged by ta ligand into a one-dimensional zigzag chain
coordination polymer motif. Binuclear [Mn2(ta)2(bipy)2(H2O)2] units bridged by ta ligands are linked into
a two-dimensional layered structure via interdimeric hydrogen bonds within the structure of 2. Com-
pounds 3 and 4 are mononuclear complexes. Most interestingly, the crystal-lattice water molecules in
complexes 3 and 4 are connected via intermolecular OAHꢀꢀꢀO hydrogen bonds into 1D tapes and 2D
layers, respectively.
Received 12 February 2009
Received in revised form 11 March 2009
Accepted 12 March 2009
Available online 24 March 2009
Keywords:
1,2,3-Triazole-4-carboxylate
Hydrothermal synthesis
Coordination polymers
In situ decarboxylation
Ó 2009 Elsevier B.V. All rights reserved.
1. Introduction
or ammonia [17–18], cleavage and formation of disulfide bonds
[19–21] and many other hydro(solvo)thermal in situ ligand reac-
The synthesis and construction of metal–organic coordination
polymers have been rapidly developed in the recent decades
due to their interests in both structural diversities and potential
applications as functional materials [1], such as magnetism,
host–guest chemistry, catalysis, and functional porous materials
[2,3]. Some weak interactions, such as hydrogen-bonding and
tions have been successfully utilized to obtain new coordination
polymers. To the best of our knowledge, the coordination chemis-
try and structural properties of metal polymers containing ta li-
gands have been seldom documented to date [22]. In this
contribution, we report the preparation, X-ray crystal structures
and properties of four new coordination polymers: [Cu(ta)
(bipy)ꢀH2O]n (1), [Mn2(ta)2(bipy)2(H2O)2ꢀ2H2O]n (2), [Zn(ta)(phen)2
ꢀ5H2O]n (3), [Ni(ta)(phen)2ꢀ8H2O]n (4). The 1,2,3-triazole-4-carbox-
ylate is formed from the 1H-1,2,3-triazole-4,5-dicarboxylic acid
precursor via in situ decarboxylation under hydrothermal
conditions.
p–p stacking interactions, also greatly affect the structures of
coordination complexes [4]. Moreover, they may link low-dimen-
sional entities into high-dimensional supramolecular networks
[5].
More recently, hydro(solvo)thermal in situ ligand reactions have
provoked significant interest in not only the discovery of new or-
ganic reactions but also the exploration of uncommon metal–
organic frameworks (MOFs) that exhibit intriguing structural
diversity and/or promising properties for potential applications
[6–9]. Especially, some functional coordination polymers that are
inaccessible or not easily obtainable by routine synthetic methods
can also be obtained by hydro(solvo)thermal in situ ligand reac-
tions. Up to now, carbon–carbon bond formation [10–11], oxida-
tive hydroxylation of aromatic rings [12–13], decarboxylation of
aromatic carboxylates [14–15], hydrolysis of carboxylate esters
or organic nitriles [16], cycloaddition of organic nitriles with azide
2. Experimental
2.1. Materials and methods
All reagents and solvents employed were commercially avail-
able and used as received without further purification. H3tda was
synthesized according to the literature method [23].
Infrared-spectra were recorded on a Nicolet-460 spectropho-
tometer using KBr discs. Thermogravimetric analysis (TGA) was
carried out on a Delta Series TA-SDTQ600 in nitrogen atmosphere
from room temperature to 800 °C (heating rate = 10 °C minꢁ1
)
using aluminium crucibles. Elemental analyses were performed
with a PE-2400II apparatus.
* Corresponding author. Tel./fax: +86 538 6710865.
E-mail address: zhengzebao@163.com (Z.-B. Zheng).
0022-2860/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.molstruc.2009.03.020

Z.-B. Zheng et al. / Journal of Molecular Structure 928 (2009) 78–84
79
2.2. Syntheses
C27H27ZnN7O7: C, 51.72; H, 4.34; N, 15.63. Found: C, 51.68; H,
4.30; N, 15.67. IR (KBr, cmꢁ1): 3411 (s), 1589 (s), 1526 (m), 1444
(s), 1337 (m), 1255 (w), 799 (m), 747 (s).
[Cu(ta)(bipy)ꢀH2O]n (1):
A
mixture of Cu(CH3COO)2ꢀ2H2O
(0.109 g, 0.5 mmol), H3tda (0.078 g, 0.5 mmol) and 2,20-bipy
(0.082 g, 0.5 mmol) was dissolved in water (12 ml) and ethanol
(3 ml). The pH of the solution was adjusted to be about 6–7 with
0.2 mol Lꢁ1 aqueous NaOH, then the mixed solution was stirred
for 30 min at room temperature, transferred to and sealed in a
25 ml Teflon-lined stainless steel reactor, and then heated at
150 °C for 72 h. Upon cooling to room temperature, a blue solution
and a small amount of blue precipitate were obtained. The solution
was filtered and the filtrate was allowed to stand at room temper-
ature. After slow evaporation over three weeks, blue block single
crystals were obtained. Yield: 32% based on Cu. Anal. Calcd. for
C13H11CuN5O3: C, 44.76; H, 3.18; N, 20.07. Found: C, 44.71; H,
3.14; N, 20.14. IR (KBr, cmꢁ1): 3385 (s), 1588 (s), 1531 (m), 1424
(s), 1373 (m), 1285 (w), 871 (m), 722 (s).
[Mn2(ta)2(bipy)2(H2O)2ꢀ2H2O]n (2): The hydrothermal proce-
dure for the synthesis of complex 2 is similar to that for 1 except
that with the replacement of Cu(CH3COO)2ꢀ2H2O with MnCl2ꢀ4H2O
(0.099 g, 0.5 mmol), light yellow crystals were obtained. Yield: 35%
based on Mn. Anal. Calcd. for C26H26Co2N10O8: C, 43.58; H, 3.66; N,
19.54. Found: C, 43.52; H, 3.61; N, 19.60. IR (KBr, cmꢁ1): 3386 (s),
1598 (s), 1518 (m), 1429 (s), 1382 (m), 1193 (w), 809 (m), 773 (s).
[Zn(ta)(phen)2ꢀ5H2O]n (3): A mixture of Zn(CH3COO)2ꢀ2H2O
(0.110 g, 0.5 mmol), H3tda (0.078 g, 0.5 mmol) and phen (0.206 g,
1.0 mmol) was dissolved in water (12 ml) and ethanol (3 ml). The
pH of the solution was adjusted to be about 6–7 with 0.2 mol Lꢁ1
aqueous NaOH, then the mixed solution was stirred for 30 min at
room temperature, transferred to and sealed in a 25 ml Teflon-
lined stainless steel reactor, and then heated at 150 °C for 72 h.
Upon cooling to room temperature, a colorless solution and a small
amount of white precipitate were obtained. The solution was fil-
tered and the filtrate was allowed to stand at room temperature.
After slow evaporation over three days, colorless block single crys-
tals were obtained. Yield: 52% based on Zn. Anal. Calcd. for
[Ni(ta)(phen)2ꢀ8H2O]n (4): The hydrothermal procedure for the
synthesis of complex 4 is similar to that for 3 except that with
the replacement of Zn(CH3COO)2ꢀ2H2O with Ni(CH3COO)2ꢀ2H2O
(0.107 g, 0.5 mmol) light purple crystals were obtained. Yield:
35% based on Ni. Anal. Calcd. for C27H33NiN7O10: C, 47.98; H,
4.93; N, 14.51. Found: C, 47.92; H, 4.98; N, 14.46. IR (KBr, cmꢁ1):
3277(s), 1593(s), 1516 (m), 1419(s), 1357(m), 1226(w), 826 (m),
727 (s).
2.3. X-ray crystallography
X-ray diffraction measurements were carried out at 295 K with
graphite-monochromated Mo K
a radiation (k = 0.71073 Å) on a
Bruker APEX-II area-detector. A semiempirical absorption correc-
tion was applied to the data. The structure was solved by direct
methods using SHELXS-97 and refined against F2 by full matrix
least-squares using SHELXL-97 [24]. In the case of 4, the all-data
R-factors are not ideal, which may be attributed to the quality of
the crystal and to the high degree of hydration and thermal mo-
tion. Hydrogen atoms were placed in calculated positions. Crystal
data and experimental details of the structure determinations are
listed in Table 1. Selected bond lengths and angles for complexes
1–4 are summarized in Table 2.
3. Results and discussion
3.1. Syntheses
1H-1,2,3-Triazole-4,5-dicarboxylic acid and bipyridyl-like
mixed ligands were reacted in aqueous-ethanol medium with dif-
ferent metal salts (Cu(CH3COO)2ꢀ2H2O, Zn(CH3COO)2ꢀ2H2O,
Ni(CH3COO)2ꢀ2H2O, MnCl2ꢀ4H2O) at pH ranging from 6 to 7 in an
attempt to investigate the reactivity. Surprisingly, the results of
Table 1
Crystal, data collection and structure refinement parameters for complexes 1–4.
Complex
1
2
3
4
Empirical formula
Formula weight
Wavelength (Å)
Crystal system
Space group
a (Å)
C13H11CuN5O3
348.81
0.71073
Orthorhombic
Pbca
16.108(2)
9.363(1)
C26H26Mn2N10O8
716.45
C27H27Zn N7O7
626.93
0.71073
Monoclinic
P2(1)/c
10.530(8)
25.658(2)
10.698(8)
90
C27H33Ni N7O10
674.32
0.71073
Triclinic
0.71073
Triclinic
ꢀ
ꢀ
P1
P1
8.830(6)
9.454(7)
9.536(7)
98.657(1)
10.446(1)
11.104(1)
14.869(1)
81.703(2)
b (Å)
c (Å)
18.88(2)
90
a
(°)
b (°)
90
90
8
1.627
1416
1.554
101.115(1)
101.790(1)
1
1.587
366
107.676(1)
90
4
1.512
1296
72.757(2)
72.69(2)
2
1.429
706
0.683
c
(°)
Z
Dcalc (Mg mꢁ3
F (000)
)
l
(mmꢁ1
)
0.909
0.952
Crystal size (mm)
h range (°)
Index ranges
0.18 ꢂ 0.16 ꢂ 0.12
2.16–25.05
ꢁ19 6 h 6 19;
ꢁ9 6 k 6 11;
ꢁ22 6 l 6 14
13,097
0.15 ꢂ 0.12 ꢂ 0.10
2.22–25.04
ꢁ10 6 h 6 10;
ꢁ7 6 k 6 11;
ꢁ11 6 l 6 11
3996
0.18 ꢂ 0.16 ꢂ 0.12
1.59–25.05
ꢁ12 6 h 6 12;
ꢁ29 6 k 6 30;
ꢁ10 6 l 6 12
14,428
0.18 ꢂ 0.16 ꢂ 0.10
1.44–25.04
ꢁ12 6 h 6 10,
ꢁ13 6 k 6 11,
ꢁ16 6 l 6 17
7768
Reflections collected
Unique reflections
2517
2641
4875
5416
(Rint = 0.1401)
2517/0/199
1.038
(Rint = 0.0171)
2641/0/208
1.041
(Rint = 0.0488)
4875/0/379
1.039
(Rint = 0.0848)
5416/0/406
1.068
Data/restraints/parameters
Goodness of fit on F2
Final R indices [I > 2
R indices (all data)
r
(I)]
R1 = 0.0599, wR2 = 0.1421
R1 = 0.1347, wR2 = 0.1938
1.014/ꢁ0.356
R1 = 0.0322, wR2 = 0.0703
R1 = 0.0412, wR2 = 0.0751
0.234/ꢁ0.228
R1 = 0.0630, wR2 = 0.1468
R1 = 0.0971, wR2 = 0.1674
1.446/ꢁ0.647
R1 = 0.0944, wR2 = 0.1734
R1 = 0.2972, wR2 = 0.2428
0.517/ꢁ0.493
Largest difference in peak and
hole (e Åꢁ3
)

80
Z.-B. Zheng et al. / Journal of Molecular Structure 928 (2009) 78–84
Table 2
Selected bond lengths (Å) and angles (°) for complexes 1–4.
Compound 1
Cu(1)AN(3)#1
Cu(1)AN(4)
Cu(1)AO(1)#1
N(3)#1ACu(1)AN(4)
N(3)#1ACu(1)AO(1)#1
N(4)ACu(1)AO(1)#1
N(3)#1ACu(1)AN(5)
N(4)ACu(1)AN(5)
1.983(6)
2.009(6)
2.013(6)
166.5(2)
82.4(2)
92.0(2)
100.4(3)
81.0(2)
Cu(1)AN5
Cu(1)AN1
2.019(7)
2.174(6)
O(1)#1ACu(1)AN(5)
N(3)#1ACu(1)AN(1)
N(4)ACu(1)AN(1)
O(1)#1ACu(1)AN(1)
N(5)ACu(1)AN(1)
160.6(2)
94.3(2)
98.8(3)
100.7(2)
98.2(2)
Compound 2
Mn(1)AO(3)
Mn(1)AN(2)#2
Mn(1)AN(1)
2.147(2)
2.202(2)
2.220(2)
89.3(7)
93.7(7)
97.9(7)
97.3(7)
95.0(7)
163.1(7)
87.1(6)
171.3(6)
Mn(1)AN(5)
Mn(1)AO(1)
Mn(1)AN(4)
N(1)AMn(1)AO(1)
N(5)AMn(1)AO(1)
O(3)AMn(1)AN(4)
N(2)#2AMn(1)AN(4)
N(1)AMn(1)AN(4)
N(5)AMn(1)AN(4)
O(1)AMn(1)AN(4)
2.234(2)
2.242(2)
2.266(2)
74.4(6)
93.4(7)
168.9(7)
96.9(7)
94.5(7)
73.1(7)
87.9(7)
O(3)AMn(1)AN(2)#2
O(3)AMn(1)AN(1)
N(2)#2AMn(1)AN(1)
O(3)AMn(1)AN(5)
N(2)#2AMn(1)AN(5)
N(1)AMn(1)AN(5)
O(3)AMn(1)AO(1)
N(2)#2AMn(1)AO(1)
Compound 3
Zn(1)AN(1)
Zn(1)AN(7)
Zn(1)AN(4)
2.084(6)
2.130(4)
2.149(4)
98.8(2)
95.6(2)
164.1(2)
102.3(2)
93.4(2)
77.0(2)
160.6(2)
91.1(2)
Zn(1)AN(5)
Zn(1)AN(6)
Zn(1)AO(1)
N(5)AZn(1)AN(6)
N(1)AZn(1)AO(1)
N(7)AZn(1)AO(1)
N(4)AZn(1)AO(1)
N(5)AZn(1)AO(1)
N(6)AZn(1)AO(1)
N(7)AZn(1)AN(6)
2.174(4)
2.187(4)
2.241(5)
97.0(2)
77.6(3)
91.2(2)
98.4(2)
175.3(2)
83.4(2)
77.5(2)
Fig. 1. View of the metal coordination environment in 1 (H atoms and lattice water
are omitted for clarity).
N(1)AZn(1)AN(7)
N(1)AZn(1)AN(4)
N(7)AZn(1)AN(4)
N(1)AZn(1)AN(5)
N(7)AZn(1)AN(5)
N(4)AZn(1)AN(5)
N(1)AZn(1)AN(6)
N(4)AZn(1)AN(6)
other one by a ta ligand with the distance of 6.192(2) Å and forms
a 1D zigzag chain along the b-axis.
3.2.2. [Mn2(ta)2(bipy)2(H2O)2ꢀ2H2O]n
As shown in Fig. 3, two neighboring Mn(II) ions are bridged by
two 1,2,3-triazole-4-carboxylate groups, forming a binuclear struc-
ture with the distance between Mn1 and Mn1A being 0.4230 nm.
Each Mn(II) coordinates with two nitrogen atoms from one bipy
molecule, one oxygen atom and two nitrogen atoms from two ta
ligands and one oxygen atom from one water molecule, to give a
six-coordinate distorted octahedral structure, in which the equato-
rial plane is formed by N1, N4, N5 and O3 with a mean deviation of
0.0546 Å from the least-squares plane. The axial positions are
occupied by O1 and N2A with an O1AMn1AN2A angle of
171.3(6)°.
Compound 4
Ni(1)AN(1)
Ni(1)AN(5)
Ni(1)AN(4)
N(1)ANi(1)AN(5)
N(1)ANi(1)AN(4)
N(5)ANi(1)AN(4)
N(1)ANi(1)AN(6)
N(5)ANi(1)AN(6)
N(4)ANi(1)AN(6)
N(1)ANi(1)AN(7)
N(5)ANi(1)AN(7)
2.044(1)
2.088(8)
2.090(8)
101.0(5)
95.0(3)
79.6(4)
161.8(4)
96.2(3)
93.9(3)
92.6(3)
94.2(3)
Ni(1)AN(6)
Ni(1)AN(7)
Ni(1)AO(1)
N(4)ANi(1)AO(1)
N(6)ANi(1)AO(1)
N(7)ANi(1)AO(1)
N(4)ANi(1)AN(7)
N(6)ANi(1)AN(7)
N(1)ANi(1)AO(1)
N(5)ANi(1)AO(1)
2.090(8)
2.093(8)
2.121(8)
92.5(3)
85.6(3)
93.8(3)
171.0(3)
80.1(4)
78.2(5)
172.0(3)
In complex 2, the ligand exhibits a tridentate binding mode
(modes (b) in Scheme 1), differing from that in complex 1. In addi-
tion, the coordinated water molecules are connected with ta
groups through multiple strong hydrogen bonds (Table 3), which
generate a two-dimensional layered structure (Fig. 4).
Symmetry transformations used to generate equivalent atoms: #1 ꢁx + 1/2, y ꢁ 1/2,
z; #2 ꢁx, ꢁy + 2, ꢁz.
single-crystal structural analysis indicate that the metal atoms in
those complexes are coordinated by ta ligands, rather than the
deprotonated species of H3tda. This means that the in situ decar-
boxylation from H3tda to ta occurred under the hydrothermal
conditions.
3.2.3. [Zn (ta) (phen)2ꢀ5H2O]n (3) and [Ni(ta)(phen)2ꢀ8H2O]n (4)
The crystal analysis of complex 3 reveals that it is a mononu-
clear complex consisting of one Zn (II) ion, two phen molecules
and one 1,2,3-triazole-4-carboxylate anion. The Zn (II) center
exhibits a distorted octahedral surrounding (Fig. 5), in which the
equatorial plane is formed by two nitrogen atoms (N5, N6) from
two phen molecules and two atoms (N1, O1) from a ta anion with
a mean deviation of 0.0743 Å from the least-squares plane. The ax-
ial positions are occupied by two nitrogen atoms (N4, N7) from two
phen molecules with an N4AZn1AN7 angle of 164.14(16)°. The ta
ligand exhibits a bidentate binding mode (modes (c) in Scheme 1).
Interestingly, the five crystal-lattice water molecules and their
equivalents are interlinked by OAHꢀꢀꢀO hydrogen bonds into 1D
infinite tapes in the c direction (Fig. 6a). The geometric parameters
of the hydrogen bonds are summarized in Table 4. The average
OꢀꢀꢀO distance of 2.84 Å is longer than that of 2.78 Å estimated in
the tetramer of (D2O)4 [25], however, it is comparable to the corre-
sponding value of 2.85 Å in liquid water [26], and other examples
of 1D water tapes [27–28]. The water tapes consist of fused four-
3.2. Description of crystal structures
3.2.1. [Cu(ta)(bipy)ꢀH2O]n (1)
The coordination environment of the Cu(II) ion in complex 1 is
shown in Fig. 1. The Cu(II) ion is five coordinated, with one oxygen
atom from a ta ligand, two nitrogen atoms from one 2,20-bipy li-
gand and two nitrogen atoms from two ta ligands. The Cu(II) atom
exhibits a distorted square-pyramidal environment with the atoms
N4, N5, O1A, and N3A in the basal plane and N1 in the apical posi-
tion. The CuAN bond lengths are 1.983(6) to 2.174(6) Å, and the
CuAO bond length is 2.013(6) Å. The Cu1AN1 and Cu1AO1 bond
distances are comparable to those reported for Cu(H2tda)(H2O)4
[22]. In complex 1, every ta ligand adopts a tridentate mode
(Scheme 1a), as shown in Fig. 2, each Cu(II) atom is joined to an-

Z.-B. Zheng et al. / Journal of Molecular Structure 928 (2009) 78–84
81
O
O
O
O
M
O
M
O
M
N
N
M
N
N
N
N
N
N
N
M
(c)
(a)
(b)
Scheme 1. The coordination mode of ta.
Fig. 2. The 1D zigzag chain structure of 1 viewed along the b-axis.
Fig. 4. Perspective view of the 2D supramolecular layer of complex 2, the C atoms
of bipy ligands and H atoms are omitted for clarity.
Fig. 3. View of the metal coordination environment in 2 (H atoms and lattice water
are omitted for clarity).
Table 3
The hydrogen bonds in complex 2.
DAHꢀꢀꢀA
d(DAH)
d(HꢀꢀꢀA)
d(DꢀꢀꢀA)
\(DHA)
O3AH14ꢀꢀꢀO1#1
O3AH15ꢀꢀꢀO4#1
O4AH17ꢀꢀꢀO2#2
O4AH16ꢀꢀꢀO2
0.85
0.85
0.85
0.85
1.91
1.89
1.92
2.11
2.76
2.72
2.73
2.89
172.09
164.33
159.80
153.35
Symmetry transformations used to generate equivalent atoms: #1 ꢁx + 1, ꢁy + 2,
ꢁz; #2 ꢁx + 1, ꢁy + 1, ꢁz.
Fig. 5. Molecular structure of complex 3 with 30% probability ellipsoids, hydrogen
atoms are omitted for clarity.
and five-membered water rings, resulting in a water cluster nota-
tion as T4(2)5(2) according to Infantes’ classification [29]. The
tapes are linked by Zn(tac)(phen)2 units through OAHꢀꢀꢀO and
OAHꢀꢀꢀN hydrogen bonded to form a 2D supramolecular layer
(Fig. 6b).
The molecular structures of complexes 3 and 4 are similar (The
molecular structure of compound 4 is shown in Fig. 7). However,
the numbers of crystal-lattice water molecules in both complexes
are different, five water molecules for 3 and eight water molecules
for 4, respectively. In the formation of water cluster for compound
4 these results differ from those of compound 3.
Most interestingly, in 4 the water molecules formed two types
of water clusters (Fig. 8a): a 1D water tape consisting of fused four-
and ten-membered water rings formed by O6A, O7A, O8A, O9A,
O10A and their equivalents with the notation T4(2)10(2); hexamer
formed by O3A, O4A, O5A and their equivalents. The 1D tapes were
connected to the hexamers by hydrogen bonding into an unusual
2D layered notation as L4(4)6(2)10(6)20(10) according to Infantes’
classification [29] (Fig. 8a). The average OꢀꢀꢀO distance of 2.82 Å is

82
Z.-B. Zheng et al. / Journal of Molecular Structure 928 (2009) 78–84
Fig. 7. Molecular structure of complex 4 with 30% probability ellipsoids, hydrogen
atoms and lattice water are omitted for clarity.
Table 5
The hydrogen bonds in complex 4.
DAHꢀꢀꢀA
d(DAH)
d(HꢀꢀꢀA)
d(DꢀꢀꢀA)
\(DHA)
O3AH27ꢀꢀꢀO5
0.85
0.84
0.85
0.85
0.85
0.85
0.86
0.85
0.85
0.85
0.85
0.85
0.86
0.85
0.86
2.26
2.11
2.56
2.26
2.22
2.10
2.14
1.99
2.51
2.38
2.25
2.14
1.77
2.14
1.91
2.79
2.73
2.97
2.79
2.86
2.82
2.77
2.58
3.04
3.04
2.82
2.83
2.53
2.97
2.74
120.67
130.65
110.75
120.30
132.74
142.25
129.69
125.96
121.81
135.14
124.17
137.17
147.42
168.29
164.08
O4AH28ꢀꢀꢀO3#1
O4AH29ꢀꢀꢀO10
O5AH30ꢀꢀꢀO3
O5AH31ꢀꢀꢀO2#2
O6AH33ꢀꢀꢀO9#3
O7AH34ꢀꢀꢀO2#2
O7AH35ꢀꢀꢀO8
O7AH35ꢀꢀꢀO8#3
O8AH37ꢀꢀꢀO7#3
O9AH39ꢀꢀꢀO6#4
O9AH38ꢀꢀꢀO8
Fig. 6. (a) The 1D infinite chains formed by the crystal-lattice water molecules in
complex 3 via intermolecular OAHꢀꢀꢀO hydrogen bonds. (b) Perspective view of the
2D supramolecular layer of complex 3, the C atoms of phen and H atoms are
omitted for clarity.
O10AH41ꢀꢀꢀO7
O10AH40ꢀꢀꢀO4
O3AH3ꢀꢀꢀO5#5
Symmetry transformations used to generate equivalent atoms: #1 ꢁx + 1, ꢁy + 1,
ꢁz; #2 x + 1, y, z; #3 ꢁx + 1, ꢁy + 1, ꢁz + 1; #4 x, y + 1, z; #5 ꢁx + 1, ꢁy + 1, ꢁz.
Table 4
The hydrogen bonds in complex 3.
3.3. IR spectrum and thermal stability analysis
DAHꢀꢀꢀA
d(DAH)
d(HꢀꢀꢀA)
d(DꢀꢀꢀA)
\(DHA)
O3AH26ꢀꢀꢀO1
0.85
0.85
0.85
0.85
0.85
0.85
0.85
0.85
0.85
0.85
1.99
2.00
2.01
1.87
1.98
2.04
2.05
1.94
2.00
2.01
2.83
2.83
2.83
2.72
2.82
2.88
2.87
2.78
2.83
2.85
172.65
165.98
162.74
175.19
173.50
172.46
161.30
172.78
164.24
169.14
The absence of any strong bands around 1700 cmꢁ1 in the IR
spectrum of 1–4 indicates that 1,2,3-triazole-4-carboxylates have
been completely deprotonated in the form of ta anions. The sharp
bands in the region 1598–1588 cmꢁ1 in complexes 1–4 may be
attributed to the COO– asymmetric stretching modes, and the
bands at 1382–1337 cmꢁ1 are characteristic of the symmetric
O3AH27ꢀꢀꢀO6#1
O4AH29ꢀꢀꢀN3#2
O4AH28ꢀꢀꢀO2
O5AH30ꢀꢀꢀO4
O5AH31ꢀꢀꢀO3#3
O6AH33ꢀꢀꢀO7
O6AH32ꢀꢀꢀO4#3
O7AH34ꢀꢀꢀO5
stretching modes of COO–. The corresponding
215 for 1, 216 for 2, 252 for 3 and 236 for 4. The separation be-
tween asym(OCO) and sym(OCO) indicates the presence of mono-
D
(mas
ꢁ
ms) data are
O7AH35ꢀꢀꢀO3#4
m
m
Symmetry transformations used to generate equivalent atoms: #1 x, ꢁy + 1/2, z + 1/
2; #2 ꢁx + 1, ꢁy, ꢁz + 1; #3 x, ꢁy + 1/2, z ꢁ 1/2; #4 x, y, z ꢁ 1.
dentate coordination mode for the carboxylate group of ta anions
[31]. These conclusions are also supported by the results obtained
from X-ray diffraction measurements.
longer than that of 2.78 Å in the 2D (H2O)8 rings in [Cu(H-
mal)(4pds)]ꢀ6H2O [30], and very close to the corresponding value
of 2.84 Å in complex 3. The 2D water network is interpenetrated
with Ni(tac)(phen)2 units through OAHꢀꢀꢀO hydrogen bonds into
a 3D supramolecular network (Table 5 and Fig. 8b).
Thermogravimetric analysis (TGA) for compounds 1–4 was per-
formed under a flow of N2 gas (Fig. 9). For compound 1, its TG curve
shows two main steps of weight losses. The first step started at
40 °C and completed at 70 °C, which corresponds to the release
of one crystal-lattice water molecule. The observed weight loss of

Z.-B. Zheng et al. / Journal of Molecular Structure 928 (2009) 78–84
83
weight losses. The weight loss of 12.64% during the first and sec-
ond steps from 40 to 200 °C corresponds to the loss of two crys-
tal-lattice water molecules and two coordination water
molecules (calcd. 10.05%). The third step (360–420 °C) corresponds
to the release of bipy and ta ligands, giving MnO as the final
decomposition product which constitutes 22.56% (calcd. 21.48%).
Compound 3 loses lattice water in the range 35–100 °C with a
weight loss of 15.30% (calcd. 14.17%). The phen ligands are released
in 280–320 °C with a weight loss of 56.27% (calcd. 57.49%), result-
ing in the formation of an intermediate product [Zn(ta)]. This inter-
mediate species is further decomposed in 400–600 °C with the
formation of a final ZnO residue (found 11.59%, calcd. 12.98%).
Compound 4 loses lattice water (found 18.42%, calcd. 21.48%) from
35 to 80 °C. The phen ligand is released in 350–400 °C with a
weight loss of 52.16% (calcd. 53.45%). The intermediate product
[Ni(ta)] is further decomposed in 420–550 °C with the formation
of a possible final NiO residue (found 9.85%, calcd. 11.08%).
4. Conclusions
In summary, we have demonstrated that the in situ decarboxyl-
ation from 1H-1,2,3-triazole-4,5-dicarboxylic acid to 1,2,3-triazole-
4-carboxylate can occur under the hydrothermal conditions, and
four metal–organic compounds with 1D chains (1), 0D dimers (2)
and 0D monometer (3 and 4) structures. Most interestingly, the
crystal-lattice water molecules extend those complexes into 2D
(2 and 3) and 3D (4) structures by hydrogen bonds.
5. Supplementary material
Crystallographic data (excluding structure factors) for the struc-
ture analyses of complexes 1–4 have been deposited with the Cam-
bridge Crystallographic Data Center, CCDC No. 711696 1, 711697 2,
690417 3 and 685192 4. Copies of these information may be ob-
tained free of charge on application to the Director, CCDC, 12 Union
Road, Cambridge, CB2 1EZ, UK (fax: +44 1223 336033; e-mail: de-
posit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk).
Fig. 8. (a) Perspective view of the 2D supramolecular layer consisting of hydrogen
bonded water molecules in complex 4. (b) Perspective view of the 3D supramo-
lecular networks of complex 4, the C atoms of phen and H atoms are omitted for
clarity.
Acknowledgements
5.87% is close to the calculated value (5.16%). The final step (276–
310 °C) corresponds to the release of bipy and ta ligands, giving
copper oxides as the final decomposition product which consti-
tutes 23.46% (calcd. 22.80%). TG curve of 2 exhibits three steps of
We acknowledge the Postgraduate Foundation of Taishan Uni-
versity (No. Y05–2–02).
Fig. 9. TG curves of compounds 1–4.

84
Z.-B. Zheng et al. / Journal of Molecular Structure 928 (2009) 78–84
[13] C.M. Liu, D.Q. Zhang, D.B. Zhu, Cryst. Growth Des. 6 (2006) 524.
We thank Prof. Lourdes Infantes at Consejo Superior de Investi-
[14] S.T. Zheng, J. Zhang, G.Y. Yang, Angew. Chem. Int. Ed. 47 (2008) 3909.
[15] L.L. Johnston, K.A. Brown, D.P. Martin, R.L. LaDuca, J. Mol. Struct. 882 (2008) 80.
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[17] R.G. Xiong, X. Xue, H. Zhao, X.Z. You, B.F. Abrahams, Z.L. Xue, Angew. Chem. Int.
Ed. 41 (2002) 3800.
gaciones Cientificas (CSIC) for finding the classification symbol of
the 2D water layer in complex 4.
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