Two-dimensional and three-dimensional nickel(II) supramolecular complexes based on the new chelating ligand N-(4-carboxyphenyl)iminodiacetic acid: Hydrothermal synthesis and crystal structures

Article abstract of DOI:10.1016/j.molstruc.2004.07.024

Two new nickel (II) supramolecular complexes, [Ni(HCPIDA)(H ₂O)₃] (1) and [Ni₂(HCPIDA)₂(bpy) (H₂O)₄]·(H₂O)₂ (2) (H ₃CPIDA=N-(4-carboxyphenyl) iminodiacetic acid, bpy=4,4′- bipyridine) were synthesized through hydrothermal method. These supramolecular complexes have been structurally characterized by X-ray single crystal diffraction. The structure of 1 exhibits a new three-dimensional supramolecular framework with one-dimensional channels, formed by hydrogen bonding interactions. The structure of 2 shows a new two-dimensional joint-ladder like architecture constructed by hydrogen bonding and π-π staking interactions. The compounds 1 and 2 contain the zigzag-shape and ladder-shape supramolecular chains, respectively, which further extend into the three-dimensional and two-dimensional supramolecular network, respectively.

Full text of DOI:10.1016/j.molstruc.2004.07.024

Journal of Molecular Structure 707 (2004) 223–229
www.elsevier.com/locate/molstruc
Two-dimensional and three-dimensional nickel(II) supramolecular
complexes based on the new chelating ligand
N-(4-carboxyphenyl)iminodiacetic acid: hydrothermal synthesis
and crystal structures
a
Guoping Yong , Zhiyong Wang , Jiutong Chen
a,
b
*
aDepartment of Chemistry, University of Science and Technology of China, Jinzhai Road 96, Hefei Anhui 230026, China
bState Key Laboratory of Structural Chemistry, Chinese Academy of Science, Fuzhou Fujian 350002, China
Received 13 June 2004; revised 15 July 2004; accepted 20 July 2004
Available online 18 September 2004
Abstract
Two new nickel (II) supramolecular complexes, [Ni(HCPIDA)(H2O)3] (1) and [Ni2(HCPIDA)2(bpy)(H2O)4]$(H2O)2 (2) (H3CPIDAZ
N-(4-carboxyphenyl) iminodiacetic acid, bpyZ4,40-bipyridine) were synthesized through hydrothermal method. These supramolecular
complexes have been structurally characterized by X-ray single crystal diffraction. The structure of 1 exhibits a new three-dimensional
supramolecular framework with one-dimensional channels, formed by hydrogen bonding interactions. The structure of 2 shows a new two-
dimensional joint-ladder like architecture constructed by hydrogen bonding and p–p staking interactions. The compounds 1 and 2 contain
the zigzag-shape and ladder-shape supramolecular chains, respectively, which further extend into the three-dimensional and two-
dimensional supramolecular network, respectively.
q 2004 Elsevier B.V. All rights reserved.
Keywords: Hydrothermal synthesis; Crystal structure; Supramolecular network; Nickel(II) complex; N-(4-carboxyphenyl)iminodiacetic acid
1. Introduction
play an important role in the formation of these high
dimensional frameworks [12–20]. Doubtless, hydrogen
bond provides an ideal organizing force for supramolecular
networks, because its moderately directional intermolecular
interaction can effectively control short-range packing. In
the construction of new supramolecular networks based on
metal-containing complex, the polycarboxylate ligands are
of special interest [21–24], because they can be regarded not
only as hydrogen-bonding accepters but also as hydrogen-
bonding donors, depending upon the number of deproto-
nated carboxylate groups.
The rational design and synthesis of metal-directed
supramolecular framework have received much attention in
coordination chemistry because of their interesting molecu-
lar topologies and potential applications in catalysis, non-
linear optics, sensors, magnetism and molecular recognition
[1–5]. During the last decade, many high-dimensional
coordination complexes have been designed and prepared
through molecular self-assembly process [6–11]. The
construction of metal-organic supramolecular framework,
so far, can be achieved via three kinds of interactions, i.e.
coordinate covalent bonds, hydrogen bonds and p–p
staking interactions. It should be noted that weaker
intermolecular forces (hydrogen bond and p–p stacking)
In addition, recent practice has proved that hydrothermal
synthesis is an effective method for the construction of new
supramolecular complexes [18]. Although most of these
insoluble solids have been synthesized by controlled mixing
of suitable soluble molecular components, hydrothermal
conditions have demonstrated increasing success in provid-
ing alternative pathways to the preparation of crystalline
* Corresponding author. Tel.:C86-551-3603544; fax: C86-551-3631760.
E-mail address: zwang3@ustc.edu.cn (Z. Wang).
0022-2860/$ - see front matter q 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.molstruc.2004.07.024

224
G. Yong et al. / Journal of Molecular Structure 707 (2004) 223–229
supramolecular solids. Hydrothermal synthesis carried out
in superheated solvent systems provides ideal conditions for
the crystal growth owing to the enhanced transport ability of
the solvents [25].
in liquid N2, sealed under vacuum, and placed inside an
oven at 120 8C for 2 days (Scheme S1). Caution: the sealed
tube is potentially explosive and the volume of solvents
should be controlled. The green crystals of 1 and 2 were
collected and washed with ethanol. Yield: 65% for 1 and
21% for 2 based on Ni. FT-IR (KBr pellets, cmK1) for 1:
3444b, 3003w, 2923m, 1694s, 1580vs, 1451m, 1411vs,
1355w, 1325m, 1251s, 1196s, 1128m, 991w, 920w, 853m,
771w, 700m, 638w, 544w; for 2: 3392b, 3238b, 2934w,
1707s, 1591vs, 1515w, 1488w, 1405s, 1323m, 1289s,
1219m, 1197s, 1146m, 1122m, 1046w, 974w, 914w,
806m, 772m, 731w, 696w, 641m.
We focused on the synthesis of the polycarboxylate
ligands and prepared a new chelating ligand N-(4-carbox-
yphenyl)iminodiacetic acid (H3CPIDA). In this paper,
we report the two new supramolecular complexes,
[Ni(HCPIDA)(H2O)3] (1) and [Ni2(HCPIDA)2(bpy)
(H2O)4]$(H2O)2 (2). The compound 1 is a new three-
dimensional supramolecular network with one-dimensional
channels. The compound 2 exhibits a new two-dimensional
joint-ladder like supramolecular network.
2.3. X-ray crystallographic studies of 1 and 2
2. Experimental section
Single-crystal X-ray diffraction measurements of com-
plexes 1 and 2 were carried out with a Bruker Smart CCD
diffractometer at 293(2) K. The determination of unit
cell parameters and the data collections were performed
2.1. Materials and methods
All chemicals purchased were of reagent grade and used
without further purification. FTIR spectra were recorded in
the range 400–4000 cmK1 on a Bruker VECTOR-22 FT-IR
˚
with Mo Ka radiation (lZ0.71073 A). The structures
were solved by direct methods using SHELXS-97 [26] and
refined by full-matrix least-squares methods against F2
(SHELXL-97) [27]. All non-hydrogen atoms were refined
anisotropically. The C–H hydrogen atoms were added
theoretically and riding on the concerned atoms. The O–H
hydrogen atoms were located in successive difference
Fourier syntheses. Crystallographic data and experimental
details for structural analysis are summarized in Table 1.
Selected bond lengths and angles for 1 and 2 are listed in
Table 2.
1
spectrophotometer using KBr pellets. H NMR spectrum
was measured on a Avance AV400 NMR spectrometer at
room temperature. TG analysis were performed under air
with a heating rate of 10 8C minK1 using a Shimadzu TGA-
50H TG analyzer.
2.2. Synthesis
2.2.1. Preparation of N-(4-carboxyphenyl)iminodiacetic
acid (H3CPIDA)
A solution of KOH (33.6 g, 0.6 mol) in water (100 ml)
was added drop-wise to a solution of monochloroacetic acid
(28.4 g, 0.3 mol) in water (100 ml). To the resulting alkaline
solution, p-aminobenzoic acid (13.7 g, 0.1 mol) was slowly
added and the mixture was refluxed 30 h at 86 8C. Then the
reaction mixture was cooled to room temperature and
acidified with HCl (6 mol/l) until the desired white acid
precipitated (pH w2.5), which were collected by filtration,
washed with water and recrystallized in water (Scheme S1).
Yield: 32% based on p-aminobenzoic acid. FT-IR (KBr
pellet, cmK1): 3458b, 2919m, 1714m, 1612s, 1530m,
1462m, 1388s, 1278m, 1239m, 1192s, 975w, 772s, 693m,
Table 1
Crystal data and structure refinement for compounds 1 and 2
Compound
1
2
Formula
C11H15NiNO9
363.95
C32H30Ni2N4O18
876.02
Mr
Crystal system
Space group
Unit cell dimensions
˚
a (A)
˚
b (A)
Orthorhombic
Aba2
Monoclinic
P21/n
7.0064(18)
30.208(8)
12.604(3)
90.00
7.4820(15)
8.7950(18)
26.382(5)
96.11(3)
1726.2(6)
2
˚
c (A)
1
549w. H NMR (400 MHz, D2O, 25 8C): 7.84 (d, 2 H, m),
6.58 (d, 2 H, o), 4.23 (s, 4 H, CH2–COO).
b (8)
3
˚
V (A )
2667.8(12)
8
Z
T (K)
Dcalc (g cmK3
293(2)
293(2)
2.2.2. Hydrothermal synthesis of [Ni(HCPIDA)(H2O)3] (1)
and [Ni2(HCPIDA)2(bpy)(H2O)4]$(H2O)2 (2)
)
1.812
1.685
m (mmK1
)
1.505
1.181
Complexes 1 and 2 were synthesized hydrothermally in
the heavy-walled Pyrex tubes under autogenous pressure,
which contain Ni(NO3)2$6H2O, H3CPIDA, KOH and H2O
in a molar ratio of 2:2:1:556 for [Ni(HCPIDA)(H2O)3] 1;
Ni(NO3)2$6H2O, H3CPIDA, 4,40-bpy$2H2O, KOH, ethanol
and H2O in a molar ratio of 2:2:2:1:78:222 for [Ni2
(HCPIDA)2(bpy)(H2O)4]$(H2O)2 2. The tubes were frozen
F(000)
1504
900
Reflections collected
Independent reflections
Rint
3041
6626
1972
2275
0.0614
1414
0.0563
2046
Observed reflections
Final R1, wR2 [IO2s(I)]
Flack parameter
0.0523, 0.1194
K0.03 (4)
0.0911, 0.1729

G. Yong et al. / Journal of Molecular Structure 707 (2004) 223–229
225
from the above description, a HCPIDA2K ligand acts as
a tridentate ligand chelating a nickel atom. The positions
of oxygen atoms (O(1), O(3)) define the cis conformation
of the HCPIDA2K ligand. The bond angles around the
Ni atom at the equatorial plane defined by O(1), O(3),
O(7) and O(8) sum to 3608 within experimental error,
showing that they are coplanar. The bond lengths of Ni–N
and Ni–O are comparable with those of other nickel(II)
complexes [18,28].
Table 2
Selected bond lengths (A) and angles (8) for compounds 1 and 2
˚
1
2
Ni–O(1)
2.019 (7)
2.043 (6)
2.054 (8)
2.087 (8)
2.049 (7)
2.197 (8)
92.2 (3)
175.5 (3)
87.8 (3)
94.8 (3)
91.5 (3)
179.1 (3)
95.1 (3)
88.5 (3)
87.6 (3)
85.8 (3)
82.0 (3)
78.1 (3)
96.1 (3)
101.0 (3)
172.3 (3)
Ni(1)–O(1)
2.030 (6)
2.030 (6)
2.080 (8)
2.037 (7)
2.092 (8)
2.196 (7)
Ni–O(3)
Ni(1)–O(3)
Ni–O(7)
Ni(1)–O(7)
Ni–O(8)
Ni(1)–O(8)
Ni–O(9)
Ni(1)–N(1)
Ni–N
Ni(1)–N(2)
O(1)–Ni–O(3)
O(1)–Ni–O(7)
O(1)–Ni–O(8)
O(1)–Ni–O(9)
O(3)–Ni–O(7)
O(3)–Ni–O(8)
O(3)–Ni–O(9)
O(7)–Ni–O(8)
O(7)–Ni–O(9)
O(8)–Ni–O(9)
O(1)–Ni–N
O(3)–Ni–N
O(7)–Ni–N
O(8)–Ni–N
O(9)–Ni–N
O(1)–Ni(1)–O(3)
O(1)–Ni(1)–O(7)
O(1)–Ni(1)–O(8)
O(3)–Ni(1)–O(7)
O(3)–Ni(1)–O(8)
O(7)–Ni(1)–O(8)
O(1)–Ni(1)–N(1)
O(1)–Ni(1)–N(2)
O(3)–Ni(1)–N(1)
O(3)–Ni(1)–N(2)
O(7)–Ni(1)–N(1)
O(7)–Ni(1)–N(2)
O(8)–Ni(1)–N(1)
O(8)–Ni(1)–N(2)
N(1)–Ni(1)–N(2)
161.6 (2)
It is interesting that the basic building units
([Ni(HCPIDA)(H2O)3]) are connected into a one-dimen-
sional zigzag chain running parallel to the a direction via
extensive hydrogen bonds formed between the coordinated
water molecules and carboxylate oxygen atoms (See Fig. 2
and Fig. S1). The typical hydrogen bonds are O(7)/O(4) of
86.9 (3)
97.3 (3)
87.4 (3)
99.7 (3)
86.0 (3)
92.3 (3)
81.2 (2)
95.2 (3)
81.2 (2)
173.6 (3)
88.6 (3)
87.8 (3)
174.5 (3)
97.5 (3)
˚
˚
2.673 A and O(9)/O(3) of 2.784 A. It is notable that the
phenylcarboxylic groups of HCPIDA2K ligands are alter-
natively extended outwards at both sides of the chain
(Fig. S1). Each pair of adjacent phenylcarboxylic groups at
the same side forms one pitch of the chain, which is virtually
˚
oriented in a parallel fashion with a separation of 7.01 A
(equal to the length of a axis). The zigzag-shape chains are
further linked into a two-dimensional supramolecular
network in the ab plane through hydrogen bonding
interactions as shown in Fig. 2. The representative hydrogen
3. Results and discussion
˚
bonds are O(8)/O(5) (both 2.846 A). It is interesting that
3.1. Crystal structure of [Ni(HCPIDA)(H2O)3] (1)
all lateral phenylcarboxylic groups from neighboring chains
are intercalated in a zipper-like fashion, as shown in Fig. 2.
There are offset p–p staking interactions between the
intercalated phenylcarboxylic groups with the centroid
The single-crystal X-ray structural analysis shows that the
structure of compound 1 is a new three-dimensional
supramolecular framework in which the asymmetric unit
contains one Ni atom, one HCPIDA2K ligand and
three coordinated water molecules. The nickel (II) atom
˚
separation of 4.06 A. In addition, the two-dimensional
layers further assemble into three-dimensional framework
through hydrogen bonding interactions with O(2)/O(6)
˚
is coordinated by two oxygen atoms (Ni–O(1)Z2.019(7) A,
˚
˚
˚
of 2.653 A, O(2)/O(7) of 2.879 A and O(4)/O(9) of
Ni–O(3)Z2.043(6) A) and one nitrogen atom
2K
˚
2.783 A (Fig. S2). The most interesting feature of
˚
(Ni–NZ2.197(8) A) of one HCPIDA
ligand, and three
˚
compound 1 is that its three-dimensional supramolecular
framework consists of one-dimensional channels along
[100] direction (Fig. 3).
coordinated water molecules (Ni–O(7)Z2.054(8) A,
Ni–O(8)Z2.087(8) A, Ni–O(9)Z2.049(7) A), showing a
lightly distorted octahedral geometry (Fig. 1). As can be seen
˚
˚
3.2. Crystal structure of [Ni2(HCPIDA)2(bpy)(H2O)4]
$(H2O)2 (2)
The single-crystal X-ray structural analysis exhibits that
the structure of compound 2 is a unique two-dimensional
supramolecular network in which the asymmetric unit
contains 1 nickel atom, 1 HCPIDA2K ligand, 0.5 4,40-bpy
ligand, 2 coordinated water molecules and 1 uncoordinated
water molecule. The nickel (II) atom is coordinated by two
˚
oxygen atoms (Ni(1)–O(1)Z2.030(6) A, Ni(1)–O(3)Z
2K
˚
2.030(6) A) of HCPIDA
ligand, two nitrogen atoms
˚
˚
(Ni(1)–N(1)Z2.092(8) A, Ni(1)–N(2)Z2.196(7) A) of one
4,40-bipy ligand and one HCPIDA2K ligand, respectively,
and two coordinated water molecules (Ni(1)–O(7)Z
˚
˚
2.080(8) A, Ni(1)–O(8)Z2.037(7) A), showing a lightly
distorted octahedral geometry in which two cis confor-
mational oxygen atoms (O(1),O(3)) of HCPIDA2K ligand act
Fig. 1. ORTEP diagram of the coordination environment of the nickel atom
in 1; thermal ellipsoids are drawn at the 50% probability level; all hydrogen
atoms are omitted for clarity.

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G. Yong et al. / Journal of Molecular Structure 707 (2004) 223–229
Fig. 2. Two-dimensional supramolecular network in 1 as viewed down the c axis, showing the double hydrogen-bond-linked zigzag-shape chains, the dotted
lines represent hydrogen bonds.
as the apices (Fig. 4). In the asymmetric unit, the HCPIDA2K
ligand also acts as a tridentate ligand chelating a nickel atom.
Two asymmetric units then form a Z-shape dimmer which
contains two Ni atoms, two HCPIDA2K ligands, one 4,40-bpy
ligand and four coordinated water molecules. In the Z-shape
dimmer unit, two phenylcarboxylic groups are located above
and below the 4,40-bpy ring, respectively, which exhibit
strong intramolecular p–p staking interactions between 4,40-
bpy ring and HCPIDA2K aromatic rings with centroid/
like architecture (Fig. 5) [19], in which the Ni/Ni
˚
separation of two adjacent ladders is 5.785 A. It should be
noted that the uncoordinated water molecule (O(9)) links
the Z-shape [Ni2(HCPIDA)2(bpy)(H2O)4] units through
˚
multiple hydrogen bonds (O(9)/O(4)Z2.695 A, O(9)/
˚
˚
O(6)Z2.734 A, O(9)/O(8)Z2.790 A), which further
stabilize this two-dimensional supramolecular network.
3.3. IR spectroscopy
˚
centroid of 3.41 A. In addition, these aromatic p–p stakes
show offset or slipped packing rather than perfect face-to-
face array of atoms [29].
The IR spectrum of compound 1 shows characteristic
bands of carboxylate group at 1580 cmK1 for the antisym-
metric stretching and at 1411 cmK1 for symmetric stretch-
ing. The separation (D) between nasym (CO2) and nsym (CO2)
indicates the presence of monodentate (169 cmK1) coordi-
nation mode in compound 1 [30], which is consistent with
the crystal structure of 1. The presence of the characteristic
band at 1694 cmK1 in compound 1 indicates that the
deprotonation of H3CPIDA ligand is incomplete.
The absorption peak at 3444 cmK1 is assigned to nO–H of
the coordinated water molecules. The IR spectrum of
compound 2 exhibits that characteristic bands of carbox-
ylate group at 1591 cmK1 for the antisymmetric stretching
and at 1405 cmK1 for symmetric stretching. The separation
(D) between nasym (CO2) and nsym (CO2) indicates the
presence of monodentate (186 cmK1) coordination mode in
compound 2. The deprotonation of H3CPIDA ligand in
compound 2 is also incomplete, because there exists
A notable feature of the title compound 2 resides in the
formation of a new two-dimensional joint-ladder like
supramolecular network. As shown in Fig. 5, the coordi-
nated water molecules (O(8)) link the oxygen atoms (O(2))
of the carboxylate groups through double intermolecular
˚
hydrogen bonds (O(8)/O(2)Z2.676 A), giving a one-
dimensional ladder-shape structure along a direction (the
˚
neighboring Ni/Ni separation of 7.482 A), as shown in
Fig. S3. On the other hand, in the ladder-shape chain, there
are intermolecular aromatic p–p staking interactions
between slipped HCPIDA2K aromatic rings with cen-
˚
troid/centroid of 3.96 A. Furthermore, the coordinated
water molecules (O(7)) in one ladder link the oxygen atoms
of the carboxylate groups in the neighboring ladder through
˚
hydrogen bonds (O(7)/O(1)Z2.691 A, O(7)/O(4)Z
˚
2.712 A) to form the unique two-dimensional joint-ladder

G. Yong et al. / Journal of Molecular Structure 707 (2004) 223–229
227
Fig. 3. View of the three-dimensional supramolecular network of 1 along a axis, showing one-dimensional channels.
the characteristic band at 1707 cmK1. The two absorption
4. Conclusions
peaks at 3392 and 3238 cmK1 are assigned to nO–H of the
coordinated water molecules and uncoordinated water
molecules.
In this paper, two new two-dimensional and three-
dimensional supramolecular networks, constructed through
3.4. Thermal analysis
The TG curve of compound 1 exhibits the continuous
weight loss stages in the temperature range 185–450 8C
(Fig. S4a), corresponding to the release of the coordinated
water molecules and HCPIDA2K ligand. The remaining
weight of 19.75% corresponds to the percentage (20.52%)
of Ni and O components, indicating that the final product is
NiO. The whole weight loss (80.25%) is in agreement with
the calculated value (79.48%). Compound 2 also shows
the continuous weight loss stages in the temperature
range 142–505 8C (Fig. S4b), corresponding to the release
of the uncoordinated water molecules, coordinated water
molecules, and 4,40-bpy and HCPIDA2K ligands. The
remaining weight of 8.77% corresponds to the percentage
(8.53%) of Ni and O components, indicating that the final
product is NiO.
Fig. 4. Perspective view of the coordination environment of the nickel
atoms in compound 2, showing Z-shape dimmer; thermal ellipsoids are
drawn at the 50% probability level; all hydrogen atoms and uncoordinated
water molecules are omitted for clarity; Symmetry code: aZKx, Ky, Kz.

228
G. Yong et al. / Journal of Molecular Structure 707 (2004) 223–229
Fig. 5. View of two-dimensional joint-ladder like supramolecular network of 2 down the b axis, showing the double hydrogen-bond-linked ladder-shape chains,
the dotted lines represent hydrogen bonds.
hydrogen bonding and p–p stacking interactions, have been
synthesized and structurally characterized. The successful
synthesis of the new compounds 1 and 2 not only proves that
the strong capability of hydrothermal reaction in preparing
new supramolecular complexes but also shows that weaker
intermolecular interactions (hydrogen bonding and p–p
stacking interactions) contribute to the formation of higher-
dimensional supramolecular network.
Appendix. Supplementary material
Supplementary data associated with this article can be
found, in the online version, at doi:10.1016/j.molstruc.2004.
07.024
References
[1] J.M. Lehn, Angew. Chem. Int. Ed. Engl. 29 (1990) 1304.
[2] O.M. Yaghi, H. Li, C. Davis, D. Richardson, T.L. Groy, Acc. Chem.
Res. 31 (1998) 474.
5. Supplementary materials
[3] F. Wurthner, A. Sautter, Chem. Commun. 2000; 445.
[4] B. Moulton, M.J. Zaworotko, Chem. Rev. 101 (2001) 1629.
[5] G.R. Desiraju, Nature 412 (2001) 397.
Crystallographic data for the crystal structures reported
in this paper have been deposited with the Cambridge
Crystallographic Data Centre (CCDC nos 223189 for 1 and
227501 for 2). These materials can be obtained free of
charge via www.ccdc.cam.ac.uk/conts/retrieving.html (or
from the CCDC, 12 Union Road, Cambridge CB2 1EZ, UK;
fax:C44-1223-336033; e-mail: deposit@ccdc.cam.ac.uk).
[6] D. Cave, J.M. Gascon, A.D. Bond, S.J. Teat, P.T. Wood, Chem.
Commun. 2002; 1050.
[7] M.B. Zaman, M.D. Smith, H.C. zur Loye, Chem. Commun. 2001;
2256.
[8] R. Kitaura, K. Seki, G. Akiyama, S. Kitagawa, Angew. Chem. Int. Ed.
42 (2003) 428.
[9] R. Kitaura, K. Fujimoto, S. Noro, M. Kondo, S. Kitagawa, Angew.
Chem. Int. Ed. 41 (2002) 133.
[10] X.H. Bu, W. Chen, S.L. Lu, R.H. Zhang, D.Z. Liao, W.M. Bu,
M. Shionoya, F. Brisse, J. Ribas, Angew. Chem. Int. Ed. 40 (2001)
3201.
Acknowledgements
[11] B.Q. Ma, S. Gao, G. Su, G.X. Xu, Angew. Chem. Int. Ed. 40 (2001)
434.
The authors gratefully acknowledge the financial support
of the National Natural Science Foundation of China
(No. 50073021) and Foundation of Education Department
of Anhui Province (2002kj330ZD).
[12] U. Kortz, S.S. Hamzeh, N.A. Nasser, Chem. Eur. J. 9 (2003) 2945.
[13] S.R. Batten, B.F. Hoskins, R. Robson, New J. Chem. 22 (1998) 173.
[14] H. Li, M. Eddaoudi, M. O’Keeffe, O.M. Yaghi, Nature 402 (1999)
276.

G. Yong et al. / Journal of Molecular Structure 707 (2004) 223–229
229
[15] X.M. Zhang, M.L. Tong, M.L. Gong, X.M. Chen, Eur. J. Inorg. Chem.
2003; 138.
[24] F.A. Cotton, L.M. Daniels, C. Lin, C.A. Murillo, Chem. Commun.
1999; 841.
[16] X.M. Chen, G.F. Liu, Chem. Eur. J. 8 (2002) 4811.
[17] C.Y. Sun, X.J. Zheng, L.P. Jin, J. Mol. Struct. 646 (2003) 201.
[18] X.L. Wang, C. Qin, E.B. Wang, C.W. Hu, L. Xu, J. Mol. Struct. 692
(2004) 187.
[25] P.J. Hagrman, D. Hagrman, J. Zubieta, Angew. Chem. Int. Ed. 38
(1999) 2638.
[26] G.M. Sheldrick, SHELXS-97, Program for X-ray Crystal Structure
¨
Solution, Gottingen University, Germany, 1997.
[19] M. Du, X.H. Bu, J. Mol. Struct. 692 (2004) 195.
[20] J.C. Dai, S.M. Hu, X.T. Wu, Z.Y. Fu, W.X. Du, H.H. Zhang,
R.Q. Sun, New J. Chem. 27 (2003) 914.
[27] G.M. Sheldrick, SHELXL-97, Program for X-ray Crystal Structure
¨
Refinement, Gottingen University, Germany, 1997.
[28] M. Melnik, T. Sramko, M. Dunaj-Jurco, A. Sirota, C.E. Holloway,
Rev. Inorg. Chem. 15 (1995) 139.
[21] H.J. Choi, T.S. Lee, M.P. Suh, Angew. Chem. Int. Ed. 38 (1999)
1405.
[29] H.W. Park, S.M. Sung, K.S. Min, H. Bang, M.P. Suh, Eur. J. Inorg.
Chem. 2001; 2857.
[22] H. Li, C.E. Davis, T.L. Groy, D.G. Kelley, O.M. Yaghi, J. Am. Chem.
Soc. 120 (1998) 2186.
[30] K. Nakamoto, Infrared Spectra and Raman Spectra of Inorganic and
Coordination Compound, Wiley, New York, 1986.
[23] O.R. Evans, W.B. Lin, Inorg. Chem. 39 (2000) 2189.