2D Naphthalenedisulfonate-cadmiun coordination polymer with 2,4,5-tri(4-pyridyl)-imidazole as a co-ligand: Structure and catalytic property

Article abstract of DOI:10.1016/j.cclet.2013.11.045

A new 2D coordination polymer, [Cd(tpim)(1,5-nds)]_n (1), was constructed from 1,5-naphthalenedisulfonate (1,5-nds), 2,4,5-tri(4-pyridyl)- imidazole (tpim) and Cd(CH₃COO)₂·2H₂O, which can be subsequently used to

Full text of DOI:10.1016/j.cclet.2013.11.045

Chinese Chemical Letters 25 (2014) 243–246
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Chinese Chemical Letters
journal homepage: www.elsevier.com/locate/cclet
Original article
2D Naphthalenedisulfonate–cadmiun coordination polymer with
2,4,5-tri(4-pyridyl)-imidazole as a co-ligand: Structure and
catalytic property
Xing-Wei Wang a,b, Hui Guo b, Meng-Jie Liu a,b, Xin-Yi Wang a, , Dong-Sheng Deng
*
a,b,**
a Institute of Resources & Environment, Henan Polytechnic University, Jiaozuo 454150, China
b College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022, China
A R T I C L E I N F O
A B S T R A C T
Article history:
A new 2D coordination polymer, [Cd(tpim)(1,5-nds)]n (1), was constructed from 1,5-naphthalenedi-
sulfonate (1,5-nds), 2,4,5-tri(4-pyridyl)-imidazole (tpim) and Cd(CH3COO)2Á2H2O, which can be
subsequently used to promote the epoxide ring-opening reaction of epoxides and amines with
remarkable catalytic activity. In addition, the thermal and luminescent properties of 1 in the solid state
were also investigated.
Received 29 July 2013
Received in revised form 4 November 2013
Accepted 8 November 2013
Available online 27 November 2013
ß 2013 Xin-Yi Wang and Dong-Sheng Deng. Published by Elsevier B.V. on behalf of Chinese Chemical
Society. All rights reserved.
Keywords:
Crystal structure
Organosulfonate
Coordination polymer
Epoxide ring-opening
1. Introduction
Among the examples reported, arenedisulfonates have been
found to be some of the best candidates for the construction of
The rational design and construction of coordination polymers
(CPs) has recently attracted considerable interest, owing to their
potential application as functional materials in molecular magne-
tism, catalysis, fluorescent sensing, and gas sorption [1–4]. Although
CPs catalysis is a relatively new field, more and more related works
are being reported by many researchers [5]. Compared with
conventional homogeneous catalysts, the use of CPs as heteroge-
neous catalysts has many advantages, including separation and
recovery, disposal of spent catalysts, and so on [6,7].
So far, a lot of CPs, which are constructed out of cadmium (II)
and organic bridging units, including a variety of organocarbox-
ylate ligands, have been extensively documented [8]. However, in
comparison with other organic acid anions such as carbonates and
phosphonates, the coordination chemistry of organosulfonates is
relatively rare, probably for their weak coordinating ability,
despite similar structures [9]. Indeed, the efforts of many groups
have recently evidenced that the use of different amines alters the
size and nature of the organic regÀion. In the right chemical
environment of metal ions, the SO3 group can compete with
water molecules and coordinate to metal ions [10–12].
intriguing CPs with novel architectures because they have rigid
spacers and multiple potential binding sites, showing various
coordination modes ranging from
m1 to m6 [12,13]. Meanwhile, the
introduction of a second ligand possessing multifunctionality may
alter the structures and properties of these complexes [9–13]. The
tripodal ligand 2,4,5-tri(4-pyridyl)-imidazole (tpim) is an efficient
and versatile organic building unit for construction of coordination
architectures and has been widely used in the previous studies [14].
Inspired by these, in this paper, we employed 1,5-naphthalenedi-
sulfonates as bridging ligands and introduced 2,4,5-tri(4-pyridyl)-
imidazole as a co-ligand into the organosulfonate system. By this
strategy, we successfully synthesized one new Cd(II) arenedisulfo-
nate coordination polymer, [Cd(tpim)(1,5-nds)]n (1). Furthermore,
for its catalysis toward epoxide ring-opening reactions, the
luminescent and thermal properties have been determined.
2. Experimental
2.1. Materials and physical techniques
All reagents were commercially available and used as received.
The bridging ligand tpim was synthesized according to the
literature method [15]. Elemental analyses (C, H, N) were
performed by a PerkinElmer 240 elemental analyzer. IR spectrum
was recorded as KBr pellets on a Nicolet-6700 spectrometer in the
*
Corresponding author.
**
Corresponding author at: College of Chemistry and Chemical Engineering,
Luoyang Normal University, Luoyang 471022, China.
E-mail addresses: waxiyi@163.com (X.-Y. Wang), dengdongsheng168@sina.com
(D.-S. Deng).
1001-8417/$ – see front matter ß 2013 Xin-Yi Wang and Dong-Sheng Deng. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
http://dx.doi.org/10.1016/j.cclet.2013.11.045

244
X.-W. Wang et al. / Chinese Chemical Letters 25 (2014) 243–246
4000–400 cmÀ1 range. TG measurement was performed by
heating the crystalline sample from 25 8C to 850 8C at a rate of
10 8C/min in a N2 atmosphere on a SDTQ600 differential thermal
analyzer. Powder X-ray diffraction (PXRD) measurements were
Cd(II) ion, half 1,5-nds ligand, and one tpim co-ligand. As
illustrated in Fig. 1, each Cd(II) atom adopts a distorted octahedral
coordination sphere consisting of four pyridyl nitrogen atoms
from four individual tpim ligands and two oxygen atoms from two
individual sulfonates. The N3, N3A, N5B, and N5C comprise the
equatorial plane, and O3 and O3A are located in the axial
performed on a Bruker D8-ADVANCE X-ray diffractometer with Cu
˚
a radiation (l = 1.5418 A). The crystal structure determination
K
˚
was performed on a Bruker smart 1000 CCD diffractometer
positions. The Cd–N bond lengths are 2.333(2) and 2.366(2) A,
˚
equipped with graphite-monochromatized Mo
˚
K
a
radiation
respectively, and the Cd–O distance is 2.3335(18) A. They are
(
l
= 0.71073 A). 1H NMR spectra were recorded on a Varian
comparable to previously reported values [14]. As depicted in
Fig. 2, the 1,5-nds ligands bridge the Cd(II) atoms to form a 1D
polymeric chain. Each [Cd(1,5-nds)]n polymeric chain is further
linked by tpim ligands to construct a 2D sheet with 4(4).6(2)
topology (Fig. 3). The Cd. . .Cd distances separated by the sulfonate
groups of 1,5-nds and a pair of tpim are 12.188 (2) and 10.712
UNITY/NOVA 400 NMR spectra meter using CDCl3 as the solvent at
room temperature. Chemical shifts are given in
d relative to TMS.
The coupling constants J are given in Hz.
The synthesis and structural characterizations of polymer 1 are
described in the Supporting information. The crystallographic data
(Table S1) and other details on the refinement, bonds, lengths, and
angles (Table S2) are also provided in the Supporting information.
Crystallographic data for the structure reported in this paper have
been deposited with the Cambridge Crystallographic Data Center
as supplementary publication No.CCDC-947842.
˚
(4) A, respectively.
3.2. Thermogravimetric and X-ray power diffraction (XRPD) analyses
The thermogravimetric analysis (TGA) revealed that 1 was
stable up to 210 8C (Fig. 4). The TG curve of 1 exhibits three weight
loss stages. The first of 10.9% at 210–355 8C corresponds to partial
decomposition of organic ligands. The second and third weight
losses at 518–810 8C can be attributed to the decomposition of the
framework, forming CDO as a final product (observed 12.98%,
calcd. 13.0%). The pure polymer 1 was confirmed by powder X-ray
diffraction (PXRD) measurements in which diffraction peaks of
experimental data were in excellent agreement with the simulated
data from single-crystal X-ray data (Fig. S1 in Supporting
information).
2.2. Typical procedure for the ring-opening reactions of epoxides
The ring-opening reactions of the epoxides were carried out at
room temperature. In a typical aminolysis reaction, styrene oxide
(0.5 mmol) was treated with aniline (0.5 mmol) in the presence of
catalyst 1 (0.01 mmol). The reactions were monitored by thin layer
chromatography. After 4 h, the catalyst was filtered off, and the
filtrate was concentrated under reduced pressure. The crude
product was purified by flash column chromatography on silica gel
using a hexane/ethyl acetate mixture (10:1) as the eluent. The
products were isolated and analyzed by NMR techniques. The
recovered catalyst was washed with ethyl acetate, dried, and
reused without further purification or regeneration. Moreover, the
recovered catalysts were characterized by X-ray powder diffrac-
tion and showed identical results to those of the fresh samples.
3.3. Photoluminescent properties
Emission behavior of polymer 1, 1,5-nds, and tpim was studied
in solid state at room temperature (Fig. 5). Tpim and 1,5-nds
employed to synthesize polymer 1 exhibit good fluorescent
emission at 518 nm (lex = 494 nm) and 394 nm (lex = 345 nm),
respectively. Upon excitation at 380 nm, 1 displayed exhibits two
emission maxima at 411 and 456 nm. The observed blue-shifted
(62 nm) of polymer 1 may be assigned to an intraligand emission
state as reported for Cd(II) or other d10 metal complexes with N-
donor ligands [16]. The fluorescent intensity for 1 is much stronger
compared to the free ligands, possibly resulted from the
3. Results and discussion
3.1. Description of the structures of 1
The X-ray crystallographic analysis reveals that 1 is a 2D
coordination network. In the asymmetrical unit, there are half
Fig. 1. Coordination environment of Cd(II) in complex 1 with the ellipsoids drawn at the 30% probability level. Symmetry code: (A) Àx + 1/2, y, Àz + 1/2; (B) Àx + 1/2, y À 1,
Àz + 1/2; (C) x, y À 1, z.

X.-W. Wang et al. / Chinese Chemical Letters 25 (2014) 243–246
245
Fig. 2. View of 2D sheet in 1.
enhancement of rigidity of the ligand after the coordination effect
and the reduction of the loss of energy by radiation less decay [14].
3.4. Catalytic properties
CPs catalysts have recently gained prominence as a catalyst for
epoxide ring-opening reactions because these reactions provide
important synthetic tools for generating stereo-controlled fine
chemicals [17]. In the previous reports, two Cu-MOFs were
successful as heterogeneous catalysts for amino alcohol synthesis
[18]. In this paper, the CP 1 was examined as a heterogeneous
catalyst for the aminolysis reaction of epoxides under solvent-free
conditions. The results are summarized in Table 1. It is noted that
the CP 1 showed good catalytic properties (Table 1, entries 1–7).
The product yields are not very sensitive to reaction substrates in
the experiment.
Fig. 3. Schematic description of the 4-connected 2D network in 1.
1200
tpim
1000
800
600
400
200
0
1,5-nds
100
80
60
40
20
0
polymer 1
350 400 450 500 550 600 650 700 750 800 850 900
Wavelength (nm)
0
200
400
600
800
Temperature (oC)
Fig. 4. Thermogravimetric analysis (TGA) curve for 1.
Fig. 5. Emission spectra of polymer 1 and its constituting ligands.

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X.-W. Wang et al. / Chinese Chemical Letters 25 (2014) 243–246
Table 1
The ring-opening reactions of epoxides with amines catalyzed by 1a.
OH
NH
OH
NH
OH
NH
O
2 mol% catalyst
or
or
R
O
or
O
or
R
R
NH2
R
R = H, Cl, CH3
.
Entry
Epoxide
Amine
Aniline
Yieldb (%)
1
2
3
4
5
6
7
Styrene oxide
92, 90c, 88d
Styrene oxide
2-Chloroaniline
2-Methylaniline
Aniline
90
90
86
84
87
85
Styrene oxide
Cyclohexene oxide
Cyclohexene oxide
Cyclopentene oxide
Cyclopentene oxide
2-Chloroaniline
Aniline
2-Chloroaniline
a
Conditions: catalyst-2 mol%, 4 h stirring at room temperature.
Isolated yield.
b
c
Third run with reused catalyst.
d
Fourth run with reused catalyst.
Several control experiments were performed to confirm that
References
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In initial control reactions without CP 1, the reaction did not
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Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.cclet.2013.11.045.