Facile fabrication of Y4(1,2-BDC)6(H 2O)2·5H2O:Eu3+,Tb 3+ ultralong nanobelts and tunable luminescence properties

Article abstract of DOI:10.1039/c2ce25350j

Lanthanide-based coordination polymer yttrium 1,2-benzenebicarboxylate ultralong nanobelts have been successfully prepared through a simple and mild one-step approach on a large scale. Electron microscopy images show that the uniform nanobelts are about 100-150 nm in width, 20-40 nm in thickness and up to several hundreds of micrometers in length. The crystal structure of the obtained nanobelts belongs to the triclinic crystal system with space group P1. The exact chemical composition was obtained by X-ray powder diffraction (XRD), elemental analysis, thermal gravimetric analysis (TGA) and Fourier-transform infrared spectra (FT-IR). The ultralong nanobelts growth was explored by time-dependent experiments and a possible formation mechanism was proposed. The investigation of the luminescent properties reveals that the luminescence colors of yttrium 1,2-benzenebicarboxylate nanobelts co-doped with Tb³⁺ and Eu³⁺ ions under ultraviolet light can be tuned from green, through green-yellow and yellow, to red by changing the relative doping concentration of the activator ions. It is expected that the synthetic strategy can be used to prepare other nanoscale metal-organic frameworks.

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PAPER
Facile fabrication of Y4(1,2-BDC)6(H2O)2?5H2O:Eu3+,Tb3+ ultralong
nanobelts and tunable luminescence properties{
Hui Qiao,ab Yongchao Jia,ab Yuhua Zheng,ab Ning Guo,ab Qi Zhao,ab Wenzhen Lvab and Hongpeng You*a
Received 11th March 2012, Accepted 31st May 2012
DOI: 10.1039/c2ce25350j
Lanthanide-based coordination polymer yttrium 1,2-benzenebicarboxylate ultralong nanobelts have
been successfully prepared through a simple and mild one-step approach on a large scale. Electron
microscopy images show that the uniform nanobelts are about 100–150 nm in width, 20–40 nm in
thickness and up to several hundreds of micrometers in length. The crystal structure of the obtained
nanobelts belongs to the triclinic crystal system with space group P1. The exact chemical composition
was obtained by X-ray powder diffraction (XRD), elemental analysis, thermal gravimetric analysis
(TGA) and Fourier-transform infrared spectra (FT-IR). The ultralong nanobelts growth was
explored by time-dependent experiments and a possible formation mechanism was proposed. The
investigation of the luminescent properties reveals that the luminescence colors of yttrium
1,2-benzenebicarboxylate nanobelts co-doped with Tb3+ and Eu3+ ions under ultraviolet light can be
tuned from green, through green–yellow and yellow, to red by changing the relative doping
concentration of the activator ions. It is expected that the synthetic strategy can be used to prepare
other nanoscale metal–organic frameworks.
the product. Therefore, the facile, mild, low-cost, environmental
1. Introduction
and effective synthesis of NMOFs on a large scale is still a
Extensive metal–organic frameworks (MOFs) or coordination
challenge to material scientists. In addition, the selection of
polymers (CPs) have attracted considerable attention in recent
suitable ligands and metal ions is critical to successful prepara-
years due to their interesting structural properties and wide
tion of these molecular architectures. In particular, the use of
lanthanide ions has received special attention in recent years.19,20
potential applications in gas storage, catalysis, separations and
optical materials.1–6 Currently, the structural study of bulk-
Rare earth organic coordination compounds have great
scaled crystalline samples is a main fundamental interest in
potential to be used in luminescent devices, magnets, catalysts
metal–organic materials. Recently, an increased number of
and other functional materials due to their fantastic coordination
investigations have been focused on the design and construction
properties and special chemical characteristics resulting from the
of nano-scaled metal–organic frameworks (NMOFs), because
4f electronic shells of the lanthanide ions.21–23 Among the
they have potential uses in some fields, such as catalysis,
lanthanide ions, the Eu3+ and Tb3+ ions are two of the most
biosensing, biomedical imaging and anticancer drug delivery,
important luminescent activators, which have been considered as
since their physical and chemical properties may depend not only
attractive for use as visible luminescent materials because of their
on their chemical composition, but also on their structure,
strong red and green emissions. The aromatic polycarboxylates
morphology, phase, shape, size, distribution and spatial arrange-
are widely used in the construction of multifunctional MOFs
ment.7–10 Thus, various novel morphologies of NMOFs,
containing lanthanides due to their various coordinating modes
including spherical, cubic, belt-like, rod-like, tube-like, sheaf-
and stability to form metal–organic materials.24–26 Although the
like, broccoli-like and fan-like, hierarchical architectures etc11–14
synthesis and structure of bulk MOFs have been reported widely
have been constructed through the hydrothermal and solvother-
up to now, the preparation of related nanoscale rare earth
mal route, micro-emulsion method, ultrasonication method, and
materials has been seldom investigated. In the present paper,
so on.15–18 However, these methods either require large amounts
uniform and well-dispersed yttrium 1,2-benzenebicarboxylate
of energy or lead to environmental pollution and a high cost of
ultralong nanobelts were successfully prepared on a large scale
via direct precipitation in solution phase through choosing Y3+
aState Key Laboratory of Rare Earth Resource Utilization, Changchun
ions as the metal connectors and 1,2-benzenedicarboxylate (1,2-
H2BDC) as bridging ligands. Their structures, morphologies and
growth process were investigated in detail. Furthermore, the
luminescent properties of the samples were also studied. The
results indicate that tunable emission colors can be realized in
Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun,
130022, P. R. China
bGraduate School of the Chinese Academy of Sciences, Beijing, 100049,
P. R. China. E-mail: hpyou@ciac.jl.cn
{ Electronic supplementary information (ESI) available. See DOI:
10.1039/c2ce25350j
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these nanobelts by adjusting the co-doping concentrations of
Eu3+ and Tb3+ ions.
2. Experimental section
2.1 Materials
Ln(NO3)3 aqueous solutions were obtained through dissolving the
corresponding Ln2O3 (99.99%) (Ln = Y, Eu and Tb) in dilute
HNO3 solution at elevated temperature under agitation. Analytical
grade 1,2-benzenedicarboxylic acid (1,2-H2BDC), HNO3 and
absolute ethanol were purchased from Beijing Chemical Works
and used as received without further purification.
2.2 Preparation
In a typical synthesis of Y4(1,2-BDC)6(H2O)2?5H2O ultralong
nanobelts, 1 mmol of Y(NO3)3 aqueous solution was introduced
into 50 mL of an ethanol–water solution (v/v = 1 : 1) containing
1.5 mmol of 1,2-H2BDC under agitation at 80 uC. 0.6 mL of
ammonia was then added dropwise into the solution to form a
white precipitate. After reaction for 1 h, the precipitate was
collected by centrifugation and washed several times with
ethanol and water. The final products were dried in an oven at
60 uC. A similar process was employed to prepare Eu3+ and Tb3+
-doped Y4(1,2-BDC)6(H2O)2?5H2O nanobelts, except that a
certain amount of Y(NO3)3 was replaced by Eu(NO3)3 and
Tb(NO3)3 at the initial stage.
Fig. 1 XRD patterns of the samples: (a) a simulated XRD pattern using
the X-ray structure of reported [Er4(1,2-BDC)6(H2O)2]n single crystal, (b)
Y4(1,2-BDC)6(H2O)2?5H2O.
shift toward the smaller angle, indicating that the as-obtained
sample is isostructural with the structure of [Er4(1,2-
BDC)6(H2O)2]n and [Yb4(1,2-BDC)6(H2O)2]n.28 The spectral
shift of the diffraction peaks can be explained by the change of
ionic radii. When the Er3+ ions were replaced by the Y3+ ions
with a larger radius, the crystal lattice constants and d-spacing
increased and thus the diffraction angles decreased accordingly
following the Bragg equation. Additionally, no peaks of
impurities are observed from the activated ions doped yttrium
1,2-benzenebicarboxylate system (Fig. S1{), revealing that the
Eu3+ and Tb3+ ions have been effectively incorporated into the
host lattice.
2.3 Characterization
The X-ray powder diffraction (XRD) patterns were collected on
a D8 Focus (Bruker) diffractometer (continuous, 40 kV, 40 mA,
increment = 0.02u). The C, H and Y microanalyses were carried
out with a VarioEL (Elementar Analysensysteme GmbH) and
inductive coupled plasma (ICP) atomic emission spectrometric
analysis (POEMS, TJA), respectively. Thermogravimetric ana-
lyses (TGA) were performed with a thermal analysis instrument
(SDT2960, TA Instruments, New Castle, DE) at 10 uC min21 in
an air flow of 100 mL min21 from room temperature to 800 uC.
Fourier transform infrared spectroscopy (FT-IR) spectra were
recorded on a PerkinElmer 580B infrared spectrophotometer
from 4000–400 cm21; all samples were prepared as KBr pellets.
The size, morphology and composition of the samples were
determined using a scanning electron microscope (SEM, S-4800,
Hitachi) equipped with an energy dispersive X-ray spectrometer
(EDX, JEOL JXA-840). Excitation and emission spectra were
recorded on a Hitachi F-7000 spectrophotometer equipped with
a 150 W xenon lamp as the excitation source. All of the
measurements were performed at room temperature.
Elemental analysis gives the content of C, H and Y. The
obtained values are 39.50, 2.57 and 22.81%, respectively, which
basically agree with the theoretical values of C (39.31%), H
(2.59%) and Y (24.25%), supporting that the samples can be
formulated as Y4(1,2-BDC)6(H2O)2?5H2O. The thermal gravi-
metric analysis (TGA) curve (Fig. S2{) presents two major stages
of rapid weight loss, corresponding to the release of the seven
water molecules (8.68%) and the organic ligands (60.47%). The
results are consistent with the theoretical weight loss (8.62%,
60.57%) of the assumed structure Y4(1,2-BDC)6(H2O)2?5H2O.
These results further mean that the molecular formula of the
samples is Y4(1,2-BDC)6(H2O)2?5H2O.
According to the pervious report on the crystal structure of
bulk phase [Er4(1,2-BDC)6(H2O)2]n,27 the crystal structure of the
as-formed samples is triclinic with space group P1. The
asymmetric unit of the product (Fig. 2a) consists of four
crystallographically independent Y atoms, which are surrounded
by six, seven, eight and nine oxygen atoms belonging to the
carboxylate groups of six BDC anions and two coordinated
water molecules, respectively. Corresponding to the four
coordination environments, the geometry of each of the Y
atoms can be described as an octahedron (CN = 6), capped
trigonal prism (CN = 7), bicapped trigonal prism (CN = 8) and
capped square antiprism (CN = 9), respectively. The six
independent 1,2-BDC anions represent different connection
modes with the Y ions (Fig. 2b). One BDC adopts the
coordination mode (1) binding the Y ions, two adopt the
3. Results and discussion
3.1 Composition and crystal phase of the Y4(1,2-
BDC)6(H2O)2?5H2O ultralong nanobelts
The X-ray diffraction pattern of yttrium 1,2-benzenebicarbox-
ylate nanobelts shows that the sample is crystalline in spite of the
moderate reaction conditions (Fig. 1b). From Fig. 1, one can see
that all of the diffraction peaks can be well-indexed to the known
bulk phase of [Er4(1,2-BDC)6(H2O)2]n27 (Fig. 1a) except a minor
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3.2 Morphology characterization of the Y4(1,2-
BDC)6(H2O)2?5H2O nanobelts
The morphological and structural features of the Y4(1,2-
BDC)6(H2O)2?5H2O were investigated by scanning electron
microscopy (SEM). Typical images of the obtained products
are shown in Fig. 3 at different resolutions. From the lower-
magnified SEM images (Fig. 3a, b), one can see that the
precipitates contain a large quantity of uniform and well-
dispersed ultralong nanobelts with lengths up to hundreds of
micrometers. The high-magnified SEM images (Fig. 3c, d) reveal
that these nanobelts exhibit a smooth surface along their entire
length, and have widths of about 100–150 nm and thicknesses of
about 20–40 nm. The creasing or curling places imply that the
obtained nanobelts are flexible. The SEM images (Fig. S4a–e{)
of the Y4(1,2-BDC)6(H2O)2?5H2O:Eu3+,Tb3+ nanobelts with
different relative doping concentrations of the Eu3+ and Tb3+
ions show that the morphologies and sizes of the products are
similar to that of the yttrium 1,2-benzenebicarboxylate, indicat-
ing that activator ions (Eu3+/Tb3+) have little influence on the
morphology of the system. The EDX spectrum of Y4(1,2-
BDC)6(H2O)2?5H2O:2%Eu3+,8%Tb3+ nanobelts shows several
peaks corresponding to Y, C, O, Tb and Eu (Fig. S4f{),
confirming that active ions have been effectively incorporated
into the host lattice.
Fig. 2 The asymmetric coordination unit (a); coordination modes of
BDC ligand in the Y4(1,2-BDC)6(H2O)2?5H2O (b); the chain of
coordination polyhedra with connecting vertices (c); the 2D sheet-like
structure along the b axis (d). All of the figures were drawn using the CIF
file of the reported [Er4(1,2-BDC)6(H2O)2]n single crystal. The hydrogen
atoms were omitted for clarity. Y aqua (shown as polyhedra), O red, C
gray.
coordination mode (2) connecting the Y ions, while the other
three BDC adopt the coordination mode (3) binding the Y ions.
Each phthalate bridges two adjacent chains with two carboxylate
groups. As depicted in Fig. 2c, the four kinds of coordination
polyhedra connect into infinite chains by vertices connection
(shared oxygen atoms of two adjacent Y ions). The chains
composed of four repeated Y ions in the asymmetric unit are
further linked with each other via p–p stacking interactions to
form the wave-like 2-D layer network (Fig. 2d).
To understand the growth process of the nanobelts, we
investigated the evolutional morphology of the intermediates
obtained after different reaction times. Fig. 5 shows the SEM
images of the products formed at different reaction stages. After
a short reaction time of 0.5 min and 1 min, many nanorods were
obtained and were about 1–2 mm in length, 50 nm in width
(Fig. 4a, b). With an extension of the reaction time to 10 min, a
lot of nanobelts were formed and a few nanorods remained
(Fig. 4c), indicating that the formation and growth of the
nanobelts depended on the nanorods. When the time was
prolonged to 30 min, the products evolved into pure nanobelts
with uniform diameters and lengths of up to hundreds of
micrometers (Fig. 4d). On the basis of the above SEM results
and analysis, the possible conversion process may be as follows.
When the Y3+ ions and 1,2-BDC anions are mixed, the
amorphous nanorods are formed just after oversaturation.
Fig. S3{ shows the FT-IR spectrum of the as-obtained yttrium
1,2-benzenebicarboxylate. The characteristic bands at 1438–1419
and 1554–1518 cm21 can be attributed to the symmetric and
antisymmetric stretching vibration of the –COO groups of the
ionized ligand, confirming the presence of –COO groups.29 The
band at about 452 cm21 is the characteristic band of the Y–O
stretching vibration, revealing that the Y atoms have been
coordinated with the 1,2-BDC ligands successfully. The other
absorption at 3417 cm21 should be the –OH stretching vibration
of the water, revealing the presence of water in the yttrium 1,2-
benzenebicarboxylate.
Fig. 3 SEM images at different magnifications of the sample Y4(1,2-
BDC)6(H2O)2?5H2O.
Fig. 4 SEM images of the sample Y4(1,2-BDC)6(H2O)2?5H2O at
different growth stages: (a) 0.5 min, (b) 1 min, (c) 10 min, (d) 30 min.
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spectrum excited at 280 nm contains a group of peaks at about
580, 591, 616, 652 and 704 nm, which correspond to the
5D0A7FJ (J = 0–4) transitions of the Eu3+ ions, respectively
(Fig. 5d). The band around 330 nm can be assigned to the
characteristic emission from the 1,2-BDC organic ligand (Fig.
S5{). The most intense emission in the luminescent spectra
located at 616 nm for the Y4(1,2-BDC)6(H2O)2?4H2O:1%Eu3+ is
5
responsible for the brilliant-red emission. Among the D0A7FJ
5
(J = 0–4) transitions of the Eu3+ ions, the D0A7F2 transition
induced by the electric dipole moment is hypersensitive to the
surroundings, while the 5D0A7F1 transition allowed by the
magnetic dipole moment is almost independent of the environ-
ment.33 Thus, the strongest emission line at about 616 nm implies
that the Eu3+ ions locate in non-inversion symmetry sites in the
host. Meanwhile, the fluorescent lines of the Eu3+ ions at the
different symmetry sites exhibit different features. Therefore, the
Eu3+ ions can be used as a probe for the symmetry of the
surroundings of the Eu3+ ions in the host. When the Eu3+ ions
occupy the sites with C1 point symmetry, the fluorescent lines of
the Eu3+ ions should have 1 line for the 5D0A7F0 transition and
3 lines for the 5D0A7F1 transitions. A careful observation of the
emission spectrum finds that the fluorescent lines of the Eu3+
ions contain 1 line for the 5D0A7F0 transition and 3 lines for the
5D0A7F1 transitions. Therefore, the number of observed
fluorescent lines is in accordance with that of the Eu3+ ions at
the sites with C1 point symmetry, indicating that the Eu3+ ions
occupy the sites with C1 point symmetry. This result is in good
agreement with that of our structure analysis.
Fig. 5 Excitation and emission spectra of the Y4(1,2-BDC)6(H2O)2?
5H2O:1%Eu3+ nanobelts and Y4(1,2-BDC)6(H2O)2?5H2O:1%Tb3+ nanobelts.
Then, with the increase of reaction time, these nanorods grow
anisotropically to form crystalline ultralong nanobelts.
Therefore, it is believed that the crystals of Y4(1,2-
BDC)6(H2O)2?5H2O exhibit a 1D belt-like structure because of
coordination interactions. As depicted in Fig. 2c, the interesting
feature of the compound is the presence of 1D infinite chains by
coordinating interactions in the structure. This kind of structure
in combination with the high coordination number of the Y3+
ions favors the formation of the 1D belt-like structure, which
may also benefit the anisotropic nucleation and growth of the
Y4(1,2-BDC)6(H2O)2?5H2O.
In order to investigate the tunable photoluminescence proper-
ties of the Y4(1,2-BDC)6(H2O)2?5H2O nanobelts, we co-doped
the host lattice with different relative concentrations of the Tb3+
and Eu3+ ions (total dopant concentration: 10 mol%). Fig. 6
shows the emission spectra of the Y4(1,2-BDC)6(H2O)2?
5H2O:Eu3+,Tb3+ nanobelts under excitation at 280 nm. It can
be seen that the as-obtained purely Tb3+-doped sample showed
green emission under excitation with UV light. By co-doping the
host lattice with Eu3+ ions, the characteristic emission of the
Eu3+ ions could be observed besides the Tb3+ emission. As one
might expect, on increasing the relative concentration ratio of
3.3 Optical properties of the
Y4(1,2-BDC)6(H2O)2?5H2O:Eu3+,Tb3+ nanobelts
The luminescent properties of the Tb3+ and Eu3+ ions doped into
the Y4(1,2-BDC)6(H2O)2?5H2O samples were investigated. The
excitation spectrum of the Y4(1,2-BDC)6(H2O)2?5H2O:1%Tb3+
nanobelts consists of a strong broad band and some weak lines
(Fig. 5a). The intense band with a maximum at 280 nm can be
attributed to the overlap of the pAp* electron transition of the
1,2-BDC organic ligand30 and the absorption bands assigned to
the 4f8A4f75d1 transition of the Tb3+ ions.31 The other weak
lines are attributed to the characteristic f–f transitions of the
Tb3+ ions. The emission spectrum excited at 280 nm contains
four bands centered at 490, 549, 582 and 623 nm, which
correspond to the 5D4A7FJ (J = 6, 5, 4, 3) transitions,
respectively (Fig. 5b). Among these emission lines, the strongest
5
one is located at 549 nm due to the D4A7F5 transition of the
Tb3+ ions in the green region. Moreover, the weak band around
330 nm is assigned to the characteristic emission from the 1,2-
BDC organic ligands (Fig. S5{). Theses results indicate the
energy transfer from the yttrium 1,2-benzenebicarboxylate host
lattice to the Tb3+ ions.
The excitation spectrum of the Y4(1,2-BDC)6(H2O)2?5H2O:
1%Eu3+ nanobelts contains a strong absorption band centered at
280 nm and some weak lines, which can be assigned to the
overlap of the pAp* electron transition of the 1,2-BDC organic
Fig. 6 Emission spectra of the Tb3+ and Eu3+ co-doped Y4(1,2-
BDC)6(H2O)2?5H2O samples under excitation at 280 nm (total dopant
concentration: 10 mol%).
ligand30 and the charge-transfer band (Eu3+–O22 32
and the f–f
)
transitions of the Eu3+ ions, respectively (Fig. 5c). The emission
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Eu3+/Tb3+, the luminescence intensity of the Eu3+ ions gradually
increased, while that of Tb3+ decreased. Finally, the purely Eu3+
samples reveals that the Eu3+ ions occupy the sites with C1
symmetry. Furthermore, photoluminescence colors of the
Y4(1,2-BDC)6(H2O)2?5H2O samples co-doped with Eu3+ and
Tb3+ ions could be tuned from green, through green–yellow and
yellow, to red by simply adjusting the relative doping concentra-
tions of the activator ions. Moreover, the successful synthesis of
these ultralong nanobelts can provide a simple and convenient
route to prepare other nano-metal–organic materials with
different functional properties.
-
doped sample showed red emission. As a result, the photo-
luminescence color can be tuned from green, through green–
yellow and yellow, to red by simply adjusting the relative doping
concentrations of the Eu3+ and Tb3+ ions. This result was
confirmed by the corresponding CIE chromaticity diagram for
the emission spectra and the luminescence photograph under
254 nm light irradiation of the Eu3+- and Tb3+- co-doped Y4(1,2-
BDC)6(H2O)2?5H2O nanobelts (Fig. 7), indicating that the as-
obtained samples were capable of showing multicolor emissions
in the visible region under single-wavelength excitation and have
potential applications in fields such as light-display systems and
optoelectronic devices.
Acknowledgements
This work is financially supported by the Fund for Creative
Research Groups (Grant No. 20921002) and the National Basic
Research Program of China (973 Program, Grant Nos.
2007CB935502).
4. Conclusions
In summary, we successfully developed a simple, facile, low-cost
and effective one-step method for the fabrication of a coordina-
tion polymer of the Y4(1,2-BDC)6(H2O)2?5H2O ultralong
nanobelts on a large scale. The structure analysis proves that
Y4(1,2-BDC)6(H2O)2?5H2O nanobelts have a triclinic crystal
structure with space group P1. These uniform nanobelts have
widths of about 100–150 nm, thicknesses of 20–40 nm and
lengths of up to hundreds of micrometers. Time-dependent
experiments exhibit that the Y4(1,2-BDC)6(H2O)2?5H2O nano-
belts have already formed at an early stage, suggesting that the
formation of the nanobelts is mainly determined by the inherent
crystal structure. Under ultraviolet excitation, the doped Tb3+
and Eu3+ ions samples show green and red emissions,
respectively. The luminescent property of the Eu3+-doped
References
1 A. U. Czaja, N. Trukhan and U. Mu¨ller, Chem. Soc. Rev., 2009, 38,
1284–1293.
2 L. J. Murray, M. Dinca˘ and J. R. Long, Chem. Soc. Rev., 2009, 38,
1294–1314.
3 C. D. Wu, A. Hu, L. Zhang and W. Lin, J. Am. Chem. Soc., 2005,
127, 8940–8941.
4 Z. J. Zhang, S. C. Xiang and B. L. Chen, CrystEngComm, 2011, 13,
5983–5992.
5 M. D. Allendorf, C. A. Bauer, R. K. Bhakta and R. J. T. Houk,
Chem. Soc. Rev., 2009, 38, 1330–1352.
6 Y. Q. Xiao, Y. J. Cui, Q. Zheng, S. C. Xiang, G. D. Qian and B. L.
Chen, Chem. Commun., 2010, 46, 5503–5505.
7 D. M. Jiang, T. Mallat, F. Krumeich and A. Baiker, Catal. Commun.,
2011, 12, 602–605.
8 W. B. Lin, W. J. Rieter and K. M. L. Taylor, Angew. Chem., Int. Ed.,
2009, 48, 650–658.
9 K. B. Wang, Y. X. Yin, C. Y. Li, Z. R. Geng and Z. L. Wang,
CrystEngComm, 2011, 13, 6231–6236.
10 K. M. L. Taylor, W. J. Rieter and W. B. Lin, J. Am. Chem. Soc.,
2008, 130, 14358–14359.
11 Z. Ni and R. I. Masel, J. Am. Chem. Soc., 2006, 128, 12394–12395.
12 F. Ke, Y. P. Yuan, L. G. Qiu, Y. H. Shen, A. J. Xie, J. F. Zhu, X. Y.
Tian and L. D. Zhang, J. Mater. Chem., 2011, 21, 3843–3848.
13 Y. M. Jeon, J. Heo and C. A. Mirkin, J. Am. Chem. Soc., 2007, 129,
7480–7481.
14 K. Liu, Y. H. Zheng, G. Jia, M. Yang, Y. J. Huang and H. P. You,
CrystEngComm, 2011, 13, 452–458.
15 D. M. Jiang, A. D. Burrows and K. J. Edler, CrystEngComm, 2011,
13, 6916–6919.
16 S. Jung and M. Oh, Angew. Chem., Int. Ed., 2008, 47, 2049–2051.
17 W. Chen, Q. Peng and Y. D. Li, Adv. Mater., 2008, 20, 2747–2750.
18 S. M. Hu, H. L. Niu, L. G. Qiu, Y. P. Yuan, X. Jiang, A. J. Xie,
Y. H. Shen and J. F. Zhu, Inorg. Chem. Commun., 2012, 17, 147–150.
19 F. Ga´ndara, A. Andre´s, B. G. Lor, E. G. Puebla, M. Iglesias, M. A.
Monge, D. M. Proserpio and N. Snejko, Cryst. Growth Des., 2008, 8,
378–380.
20 X. J. Zhang, M. A. Ballem, M. Ahre´n, A. Suska, P. Bergman and K.
Uvdal, J. Am. Chem. Soc., 2010, 132, 10391–10397.
21 S. Q. Ma, X. S. Wang, D. Q. Yuan and H. C. Zhou, Angew. Chem.,
Int. Ed., 2008, 47, 4130–4133.
22 B. L. Chen, L. B. Wang, F. Zapata, G. D. Qian and E. B. Lobkovsky,
J. Am. Chem. Soc., 2008, 130, 6718–6719.
23 K. M. L. Taylor, J. D. Rocca, R. C. Huxford and W. B. Lin, Chem.
Commun., 2010, 46, 5832–5849.
24 N. L. Rosi, J. Kim, M. Eddaoudi, B. L. Chen, M. O’Keeffe and
O. M. Yaghi, J. Am. Chem. Soc., 2005, 127, 1504–1518.
25 X. P. Yang, R. A. Jones, J. H. Rivers and R. P. Lai, Dalton Trans.,
2007, 3963–3942.
26 K. Liu, H. P. You, Y. H. Zheng, G. Jia, Y. H. Song, Y. J. Huang, M.
Yang, J. J. Jia, N. Guo and H. J. Zhang, J. Mater. Chem., 2010, 20,
3272–3279.
Fig. 7 A CIE chromaticity diagram for the emission spectra (top) and
the luminescence photograph under 254 nm light irradiation (below) of
the Tb3+ and Eu3+ co-doped Y4(1,2-BDC)6(H2O)2?5H2O samples: (a)
10%Tb3+; (b) 1% Eu3+, 9%Tb3+; (c) 3% Eu3+, 7%Tb3+; (d) 6% Eu3+
4%Tb3+; (e) 8% Eu3+, 2%Tb3+; and (f) 10% Eu3+
,
.
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27 W. D. Song, J. B.Yan, H. Wang, J. L. Li, D. Y. Ma and S. W. Ng,
J. Coord. Chem., 2010, 63, 625–633.
28 Y. H. Wan, L. P. Jin, K. Z. Wang, L. P. Zhang, X. J. Zheng and S. Z.
Lu, New J. Chem., 2002, 26, 1590–1596.
29 F. Mohandes, F. Davar and M. S. Niasari, J. Magn. Magn. Mater.,
2010, 322, 872–877.
30 J. T. Sun, C. Chen and Z. B. Qin, J. Lumin., 1988, 40–41, 246–247.
31 W. Chen, R. Sammynaiken and Y. N. Huang, J. Appl. Phys., 2000,
88, 1421–1431.
32 G. Jia, H. P. You, Y. H. Zheng, K. Liu, N. Guo and H. J. Zhang,
CrystEngComm, 2010, 12, 2943–2948.
33 W. H. Zhu, Z. M. Wang and S. Gao, Inorg. Chem., 2007, 46, 1337–1342.
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