Encapsulation and sensitization of UV-vis and near infrared lanthanide hydrate emitters for dual- and bimodal-emissions in both air and aqueous media based on a porous heteroatom-rich Cd(II)-framework

Article abstract of DOI:10.1021/ic300665a

A porous heteroatom-rich Cd(II)-polymeric framework which is generated from an ethylene glycol ether-bridging dicarboxylate ligand L, 4,4′-bipy and Cd(II) ion is reported. It contains one-dimensional tubes (9-11 ?) which are able to trap cationic lanthanide hydrates such as Eu(H₂O) ₈³⁺, Tb(H₂O)₈³⁺, and Nd(H₂O)₈³⁺ under ambient conditions to generate Ln(H₂O)₈³⁺-loaded materials. In addition, the heteroatom-rich host material can effectively protect and sensitize the encapsulated Ln³⁺ emitters in their hydrate form in both air and aqueous media. Furthermore, the dual- and bimodal-emissions are successfully realized by intercalation of the different Ln³⁺-hydrates based on a guest-driven approach.

Full text of DOI:10.1021/ic300665a

Article
pubs.acs.org/IC
Encapsulation and Sensitization of UV−vis and Near Infrared
Lanthanide Hydrate Emitters for Dual- and Bimodal-Emissions in
Both Air and Aqueous Media Based on a Porous Heteroatom-Rich
Cd(II)-Framework
†
†
†
†
‡
‡
Yan-An Li, Shu-Kui Ren, Qi-Kui Liu, Jian-Ping Ma, Xueyuan Chen, Haomiao Zhu,
,
†
and Yu-Bin Dong*
†College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Engineering
Research Center of Pesticide and Medicine Intermediate Clean Production, Ministry of Education, Shandong Provincial Key
Laboratory of Clean Production of Fine Chemicals, Shandong Normal University, Jinan 250014, P.R. China
‡
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science,
Fuzhou, Fujian 350002, P.R. China
*
S Supporting Information
ABSTRACT: A porous heteroatom-rich Cd(II)-polymeric
framework which is generated from an ethylene glycol ether-
bridging dicarboxylate ligand L, 4,4′-bipy and Cd(II) ion is
reported. It contains one-dimensional tubes (9−11 Å) which
are able to trap cationic lanthanide hydrates such as
3+
3+
8
3+
8
Eu(H O)8 , Tb(H O) , and Nd(H O)
under ambient
conditions to generate Ln(H O) -loaded materials. In
2
2
2
3
+
2
8
addition, the heteroatom-rich host material can effectively
3
+
protect and sensitize the encapsulated Ln emitters in their
hydrate form in both air and aqueous media. Furthermore, the
dual- and bimodal-emissions are successfully realized by
3
+
intercalation of the different Ln -hydrates based on a guest-
driven approach.
INTRODUCTION
In this contribution, we present a neutral porous three-
dimensional Cd(II)-MOF which has a perfect pore size for
trapping lanthanide hydrates. The Cd(II)-MOF herein can
effectively protect and sensitize the Ln hydrate emitting in the
UV−vis and Near Infrared (NIR) ranges in both air and aqueous
media. Furthermore, the dual- and bimodal-emissions are
successfully realized based on the reversible heterolanthanide
cationic species encapsulation.
■
For access to the dual-emission and bimodal emission materials,
significant effort has been dedicated to the design and synthesis
of the heterolanthanide cocktails. However, the preparation of f-
f hybrids are very difficult because of the inherent disadvantage in
the synthesis of the organic ligands with specific recognizing sites
required by the different lanthanide cations.
3+
1
2
Metal−organic frameworks (MOFs), as a new class of porous
materials, provide a new chemical phase which consists of both
inorganic and organic components. In principle, their interior
microenvironment could be modified by simply changing the
functional organic spacers, metal nodes, and sometimes
counterions. Such advantages endow MOFs with a variety of
physicochemical properties. Most of the functionalities derive
from MOFs basically based on their ability to recognize specific
guest substrates through elusive host−guest interactions. Among
various MOFs, the porous heteroatom-rich MOFs with a
hydrophilic internal surface provide a novel platform to generate
new functionality, for example, trapping electrophilic species into
pores. With this in mind, we have initiated a synthetic program
for preparation of the porous heteroatom-rich MOFs, in which
the flexible open-chain polyether-bridged organic spacers are
RESULTS AND DISCUSSIONS
■
Synthesis and Characterization of Heteroatom-Rich
Cd(II)-MOF. Compound 1 ([Cd(4,4′-bipy)(H O)(L)]·(4,4′-
2
bipy)·11(H O)) was obtained as rod-like colorless crystals by the
2
combination of flexible ethylene glycol ether bridging bicarbox-
ylate ligand L and rigid 4,4′-bipyridine with Cd(OAc) under
hydrothermal conditions (Figure 1). The single-crystal analysis
revealed that 1 crystallizes in the tetragonal space group
P4(1)2(1)2 (Table 1). As shown in Figure 1, the Cd(II) nodes
extend along the crystallographic c axis through L to form a
single-stranded helix with a period of separation of 69.439 Å. It is
2
Received: March 30, 2012
3
chosen as the building blocks.
©
XXXX American Chemical Society
A
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Figure 1. (a) Synthesis of 1 and its Cd(II) coordination sphere. (b) Single helical L-Cd(II) chain.
Table 1. Crystal Data and Structure Refinement for 1
noteworthy that five such Cd(II)-L helical chains in 1 interwine
with each other to form a one-dimensional (1D) tube, in which
the shortest aromatic C···C distance between neighbor chains is
3.8 Å (Figure 2a). As shown in Figure 2a, each tube features a
distorted square-like channel and is surrounded by oxygen
atoms. The opposite O···O separations on the ethylene glycol
ether lie in a range of 9−12 Å, while the diagonal carboxylate
O···O distances are 10−11 Å. We find it noteworthy that all
chains within the tube have the same handedness (P-helix),
leading to an overall chiral structure. Furthermore, these 1D
tubes are cross-linked by 4,4′-bipy coligands to provide a novel
noninterpenetrating three-dimensional porous framework (Fig-
ure 2b). In addition, the packing of adjacent tubes along the
crystallographic c axis also leads to an open octagonal channel of
about 9 × 11 Å (Figure 2b). Interestingly, one uncoordinated
identification code
empirical formula
formula weight
1
C H Cd N O
25
6
2
74
2
6
1528.07
temperature
123(2) K
wavelength
0.71073 Å
crystal system, space group
unit cell dimensions
tetragonal, P4(1)2(1)2
a = 22.5663(14) Å
α = 90°
b = 22.5663(14) Å
β = 90°
c = 13.8877(18) Å
γ = 90°
3
volume
7072.1(11) Å
3
Z, calculated density
absorption coefficient
F(000)
4, 1.435 Mg/m
4
,4′-bipy per formula exists in the lattice. They are symmetrically
0.682 mm−
1
around the octagonal channels and face toward the center of the
channel with a N···N distance of ∼11 Å. Moreover, the
coordinated aquo oxygen atoms also face to the center of the
channels with a opposite O···O distance of ∼ 9 Å. As shown in
Figure 2b, both two types of channels are filled with water guest
molecules, which is further confirmed by thermogravimetric
analysis (TGA) (Supporting Information). The encapsulated
water molecules form two types of P-helical water chains within
these right-handed channels, respectively (Supporting Informa-
tion). The formation of P-type water-helices are clearly induced
by the P-helical channels. The average O···O distance within the
water chain in the distorted square-like channel is 2.684 Å, while
the average O···O separation of the water chain in an octagonal
channel is 2.605 Å. The average O···O distances herein are
3136
crystal size
0.45 × 0.13 × 0.13 mm
1.28 to 25.60 deg
−15 ≤ h ≤ 27
θ range for data collection
limiting indices
−
−
27 ≤ k ≤ 26
16 ≤ l ≤ 16
reflections collected/unique
completeness to θ = 25.60
absorption correction
37637/6668 [R(int) = 0.0403]
100.0%
semiempirical from equivalents
0.9166 and 0.7490
full-matrix least-squares on F2
max. and min. transmission
refinement method
data/restraints/parameters
6668/12/444
̂2
goodness-of-fit on F
1.106
final R indices [I > 2σ(I)]
R indices (all data)
R1 = 0.0378, wR2 = 0.0933
R1 = 0.0399, wR2 = 0.0945
4
significantly shorter than those of ice which might result from
the strong confined space effect.
B
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Figure 2. (a) Top and side views (shown in different colors for clarity) of five Cd(II)-L strands interwine with each other to generate 1D tube extended
along the crystallographic c axis. (b) Oxygen-rich 1D tubes are cross-linked by 4,4′-bipy to generate a noninterpenetrating three-dimensional framework.
As shown in the structure, there are two types of tubes in 1 which are filled with water guest molecules. The uncoordinated 4,4′-bipy are highlighted in
yellow-brown for clarity.
Figure 3. Solid-state emission spectra measured in air of (a) L and 1. (b) 1 immersed in an aqueous solution of Tb(ClO ) (2.0%) during 0.5−2.0 h (λ
4
3
ex
=
323 nm). (c) 1 immersed in an aqueous solution of Eu(ClO ) (2.0%) during 0.5−3.0 h (λ = 395 nm). (d) 1 immersed in an aqueous solution of
4
3
ex
Nd(ClO ) (2.0%) during 1.0−3.0 h (λ = 750 nm). The samples of 2 and 3 illuminated with 254 nm laboratory UV light are inserted.
4
3
ex
Encapsulation and Sensitization of Lanthanide Hy-
drate Emitters. It is worthy to note that 1 is luminescent. Upon
excitation at 340 nm, 1 emits strong blue light with an emission
maximum at 458 nm (Figure 3a), at which bilirubin is broken
C
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5
down. So 1 might have potential application in phototherapy to
5
treat newborn jaundice by destruction of bilirubin. Compared to
the ligand emission (483 nm), the emission intensity of 1 is
significantly enhanced, and the blue-shift luminescence of 1 is
believed to be based upon ligand-to-metal-charge-transfer
(LMCT). As shown above, the cavity sizes of two types of
hydrophilic channels are in the range of 9−11 Å, which are
3
+
perfect dimensions for trapping [Ln(H O) ] through hydro-
2
8
3
b,6
3+
gen bonding interactions. With this in mind, the Ln hydrate
adsorption experiments were carried out based on 1 (Scheme 1).
Scheme 1. Ln(III)-Hydrate Encapsulation Based on 1 in
Aqueous Solution
Figure 4. XRPD patterns of 1−4.
form a heterometallic host−guest system, furthermore, simulta-
neously sensitize their emissions to exhibit dual-emission. For
3
+
example, when 0.39Tb(H O) ⊂Cd(II)-MOF (2) was treated
2
8
with Eu(ClO ) (2.0%) in water for 10 min (Scheme 2), the
4
3
Scheme 2. Heterometallic Tb/Eu(III)-Hydrates
Encapsulation Based on 2 in Aqueous Solution
As expected, when 1 was immersed in an aqueous solution of
Tb(ClO4)3 (2.0%), the solid-state photoinduced-emission
3
+
monitoring indicates that the Tb(H O) was trapped (Scheme
2
8
3
+
1
). The maximal emission intensity of Tb was obtained after 2
h. Four typical lines of Tb emission were detected in the visible
spectrum (Figure 3b), corresponding to transitions from the D
state: D → F (487 nm), D → F (543 nm), D → F (583
3
+
5
4
5
7
5
7
5
7
4
6
4
5
4
4
5
7
nm), D → F (619 nm). The most prominent line was
4
3
3
+
observed at 543 nm. The ICP (Inductively Coupled Plasma)
measurement (Supporting Information) indicates that the doped
emission spectra (λ = 360 nm) indicated that both Tb(H O)
8
ex
2
3+
and Eu(H O)8 were incorporated to generate a heterolantha-
2
3+
3+
amount of Tb is up to 6.74% and afford 0.39Tb(H O) ⊂Cd-
nide cocktail (Figure 5). ICP analysis (Supporting Information)
indicates the absorbed amount of europium is up to 2.67%, while
the encapsulated amount of terbium is basically unchanged
2
8
3
+
(
II)-MOF (2). In a similar way, an Eu(H O) -loaded sample
2 8
was obatined by immersing 1 in a 2.0% aqueous solution of
3
+
3+
Eu(ClO ) for 1.5 h (Scheme 1). As shown in Figure 3c, the
(6.53%) to give rise to 0.37Tb(H O) /0.16Eu(H O) ⊂Cd-
4
3
2
8
2
8
3
+
5
7
emission bands of Eu arise from the D → F (J = 1, 2, 3, 4)
transitions of Eu . The corresponding emission bands are 589,
14, 650 and 698 nm, respectively. Among these transitions, D
F is the strongest. The ICP measurement (Supporting
2
Information) indicates that the doped amount of Eu is up to
.89% to afford 0.62Eu(H O) ⊂Cd(II)-MOF (3). As shown
(II)-MOF (5). No more changes for the luminescent intensities
have been observed in the emission spectrum after 2 h.
Compared to 5, the doped amount (based on ICP analysis,
Supporting Information) of europium further enhanced
0
J
3+
5
6
→
0
7
3
+
(9.05%), and the amount of terbium correspondingly reduced
3
+
3+
9
(4.12%), which suggests the formation of 0.28Tb(H O)
/
2
8
2
8
3
+
in Figure 3b−c, when the samples of 2 and 3 were excited with a
UV lamp (254 nm), the terbium and europium emitted their
distinctive colors which were readily observed with the naked
eye.
0.65Eu(H O) ⊂Cd(II)-MOF (6) at 2 h (Scheme 2). So the
2
8
incorporated terbium cationic species were partly replaced by the
incoming europium cationic species at 2 h. Reasonably, the
typical Eu3+ emission bands increased at the expense of Tb
emission as time went on, which was well demonstrated by their
emission spectra (Figure 5).
3+
Besides UV−vis emitters, the NIR-lanthanide emitter such as
3+
Nd can also be trapped by 1 (Scheme 1). For example, the
crystals of 1 were immersed in an aqueous solution of Nd(ClO4)3
3+
8
Notably, the encapsulated Ln(H O)
can be reversibly
displaced, and the Eu /Tb cocktail can also be obtained based
on 0.62Eu(H O) ⊂Cd(II)-MOF (3) (Scheme 3). For
example, treatment of 3 with Tb(ClO ) in aqueous solution
2
3+
3+
(
(
2.0%) at ambient temperature for 3 h, generating a Nd-
H O)8 -loaded sample. As shown in Figure 3d, emission bands
2
3+
3+
2
8
are observed at 876, 1057, and 1330 nm which are attributed to
4 3
the 4F3/2→ I9/2, F3/2→ I11/2, and F3/2→ I
4
4
4
4
4
transitions,
(2%) for 10 min, resulting in the formation of heterometallic
13/2
3
+
3+
respectively. The ICP measurement (Supporting Information)
host−guest system 0.32Eu(H O) /0.20Tb(H O) ⊂Cd-
2
8
2
8
3
+
indicates that the doped amount of Nd is up to 8.01%, which
MOF (7) (europium: 5.61%; terbium: 3.23%, based on ICP
analysis, Supporting Information). Compared to 5 and 6, the
codoped Cd(II)-MOF material of 7 displays the different relative
3
+
suggests the formation of 0.45Nd(H O) ⊂Cd(II)-MOF (4).
2
8
3
8
+
3+
The XRD patterns of the Eu(H O) , Tb(H O) , and
2
2
8
3+
3+
3+
Nd(H O)8 -loaded samples (2−4) confirm that the structure of
Eu /Tb emission intensities (Figure 5) caused by the different
encapsulated Eu /Tb molar ratios. The naked eye detectable
2
3+
3+
1
4
is maintained upon the lanthanide hydrates' adsorption (Figure
).
Guest-Driven Tunable Luminescent Properties. Tuna-
3
+
3+
colors of Tb(H O)8 /Eu(H O)8 ⊂Cd(II)-MOF samples
2
2
illuminated with 254 nm laboratory UV light objectively reflect
the changes of their emission spectra. As shown in Figure 5,
samples of 2−7 successively exhibit green, cyan, yellow, pink and
ble Luminescence within UV−vis Region in Air. Interestingly,
this heteroatom rich host is able to successively incorporate
different Ln3 cationic species into a single host framework to
+
3+
3+
red colors which are driven by the doped relative Eu /Tb
D
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Figure 5. Left: Solid-state emission spectra of 2, 3, 5, 6, and 7 (λ = 360 nm). The samples of 2, 3, 5, 6, and 7 illuminated with 254 nm laboratory UV
ex
light are inserted. Right: The corresponding XRPD patterns of 5−7 and as-synthesized of 1.
Figure 6, the typical Nd3+ emission bands in the NIR region
increased as the adsorption process going on. After 8 h, the
adsorption is finished depending on the emission spectral
Scheme 3. Heterometallic Eu/Tb(III)-Hydrates
Encapsulation Based on 3 in Aqueous Solution
3+
monitor. The slightly decreased emission from Tb which might
3+
be resulted from that the partial encapsulated Tb cations were
3+
replaced by Nd , which is further confirmed by ICP-LC. The
percentage. In principle, the stoichiometry of the codoped bis-
lanthanide in Cd(II)-MOF is not restricted, so the composition
of the cocktail can be easily tuned depending on the inherent bias
ICP analysis (Supporting Information) indicates that the residual
3
+
3+
Tb is 5.67% and corresponding adsorbed amount of Nd is up
3
+
3+
3
+
3+
to 5.54% to provide 0.31Tb(H
2
O)
8
/0.34Nd(H
2
O)
8
⊂Cd-
of the MOF antenna chromophore to sensitize Eu and Tb
3+
3+
MOF (8). So the adsorption of Tb and Nd by Cd(II)-MOF
did lead to the tunable emission between UV−vis and NIR
regions, that is, the bimodal-emission upon being excited at
different wavelengths. Again, the X-ray powder diffraction
emissions with comparable sensitivity. Such multiband emissions
from the heterolanthanide doped Cd(II)-MOFs might be a bar-
coded luminescent materials. The XRPD patterns on resulted
heterometallic materials of 5−7 are identical to that of 1, so the
framework is stable during the different lanthanide species
adsorption (Figure 5).
(
XRPD) monitoring confirms that the original structure remains
intact during the course of the reaction (Figure 6).
As shown above, lanthanide hydrate cationic species are
inserted into a neutral network of 1, so the corresponding anionic
species should be encapsulated for the charge compensation. The
X-ray photoelectron spectroscopy (XPS) observations of Cl 2p
peaks in 2−8 (Supporting Information) supported well the
Tunable Luminescence between UV−vis and NIR Regions
in Air. Besides UV−vis emitters, 1 can also the encapsulated both
UV−vis and NIR emitters such as terbium and neodymium. For
3
+
example, treatment of 0.39Tb(H O) ⊂Cd(II)-MOF (2) with
2
8
an aqueous solution of Nd(ClO ) (2.0%) resulted in the
4
3
−
coexistence of the ClO4 anion. To further confirm the
formation of UV−vis/NIR cocktail (Scheme 4). As shown in
encapsulated lanthanide species in 1 to be the hydrate form,
thermogravimetric analyses were carried out on the samples of
Scheme 4. Heterometallic Tb/Eu(III)-Hydrates
Encapsulation Based on 2 in Aqueous Solution
2
−8 (Supporting Information). TGA traces showed a gradual
weight-loss step (below 150 °C) of 12.9% for 2, (calcd. 13.3%),
1
5
7.3% for 3 (calcd. 16.4%), 12.1% for 4 (calcd. 11.9%), 11.2% for
(calcd. 10.1%), 18.7% for 6 (calcd. 18.5%), 10.5% for 7 (calcd.
3+
Figure 6. Left: Solid-state emission spectra of 2 immersed in a 2.0% aqueous solution of Nd at 2.0−8.0 h. As time went on, the emission intensities of
3
+
3+
Tb gradually decreased (λ = 323 nm), while the emission intensity of Nd correspondingly increased (λ = 750 nm). Right: Corresponding XRPD
ex
ex
patterns.
E
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Figure 7. Photoinduced emission spectra of 2−7 measured in air (I), moistened by water (II) and completely immersed in water (III). The samples of 2,
, 5, 6, and 7 in water illuminated with UV light (254 nm) are inserted.
3
9
.9%), and 14.7% for 8 (calcd. 14.5%), respectively, correspond-
to trap Eu3+ or Tb3+ and Eu /Tb hydrate species and,
furthermore, effectively sensitize their emissions in both air and
aqueous media under ambient conditions. In addition, the
luminescent cocktail emissions can be easily tuned within UV−
vis region and between UV−vis/NIR regions by adjusting the
ratios of the encapsulated lanthanide emitters. Such guest-driven
approach based on MOFs could be a viable approach to access to
the “cocktail” optical materials.
3+
3+
ing to escape of the water guest molecules. In addition, the IR
spectra performed on 2−8 also confirmed the existence of water
molecules (Supporting Information). It is well-known that the
hydration states of the lanthanide complexes have a very
significant effect on their metal-centered luminescent behaviors
resulted from the O-H vibrational quenching. The intense
emission of Ln(H O) herein reasonably indicates that the
7
3
+
2
8
strong coupling of O-H vibrations on the coordinated water
molecules is efficiently reduced within the heteroatom-rich
cavities by the interhost−guest O-H···O and O-H···N H-
EXPERIMENTAL SECTION
Materials and Methods. Cd(NO ) (Acros) was used as obtained
without further purification. Infrared (IR) samples were prepared as KBr
pellets, and spectra were obtained in the 400−4000 cm range using a
Perkin-Elmer 1600 FTIR spectrometer. Elemental analyses were
performed on a Perkin-Elmer Model 2400 analyzer. H NMR data
were collected using an AM-300 spectrometer. Chemical shifts are
reported in δ relative to TMS. All fluorescence measurements were
carried out on a Cary Eclipse Spectrofluorimeter (Varian, Australia)
equipped with a xenon lamp and quartz carrier at room temperature.
Thermogravimetric analyses were carried out using a TA Instrument
SDT 2960 simultaneous DTA-TGA under flowing nitrogen at a heating
rate of 10 °C/min. XRD pattern were obtained on a D8 ADVANCE X-
ray powder diffractometer with CuKa radiation (λ = 1.5405 Å). ICP-LC
was performed on IRIS Intrepid II XSP and NU AttoM.
■
3
2
6
bonding interactions. Besides our research group, some tunable
3
+
−1
luminescent MOFs based on reversible Ln encapsulation have
been reported very recently by others; the lanthanide species
loading therein, however, was carried out in DMF solution in
1
8
nonhydrate form. Lanthanide hydrate species loading in
aqueous solution based on porous heteroatom-rich MOFs
herein effectively expands the scope of guest-driven lanthanide
luminescent materials.
Luminescence in Water. To evaluate the protecting and
sensitizing ability of Cd(II)-MOF in an aqueous medium, the
3
+
luminescent properties of [Ln(H O) ] ⊂Cd(II)-MOF (2−4)
2
8
3
+
and [Ln/Ln′(H O) ] ⊂Cd(II)-MOF (5−7) were tested in
2
8
3
8
+
Synthesis of L. A mixture of corresponding polyether-bridged
water. When the Ln(H O) -loaded samples were moistened
2
3+
bisbenzaldehyde (1.62 g, 6 mmol), MeOH (20 mL), and H
mL) was stirred in a NaOH (40%, 15 mL) aqueous solution at 35 °C for
h. After neutralization by HCl, the product was obtained as white
2 2
O (30%, 6
and completely immersed in water, the corresponding Ln
emissions were clearly detected (Figure 7). Compared to their
luminescent spectra obtained in air, the corresponding emission
intensities measured in aqueous medium reduced to some extent,
which logically results from the water quenching by the loss of
lanthanide sensitization in part. Nevertheless, the Cd(II)-MOF
herein effectively protects and sensitizes the UV−vis and NIR
3
−1
solids (87%). IR (KBr pellet cm ): 2950 (m), 2885 (m), 2558 (m),
1
678 (), 1604 (s), 1579 (m), 1513 (m), 1481 (w), 1435 (s), 1300 (s),
1248 (s), 1166 (s), 1117 (w), 1046 (m), 944 (m), 857 (m), 843 (w), 769
1
(m), 692 (w), 645 (m), 628 (w). H NMR (300 MHz, DMSO-d , 25 °C,
6
TMS, ppm): 12.65 (s, 2H, -COOH), 7.91−7.88, 7.08−7.05 (d, d, 8H,
3+
-C H -), 4.41 (s, 4H, -OCH CH O-). Elemental analysis (%) calcd for
Ln emitters in aqueous solution.
6
4
2
2
C H O : C 63.57, H 4.63; Found: C 63.46, H 4.68.
16
14
6
Synthesis of 1. L (3.7 mg, 0.012 mmol), Cd(OAc) (7.5 mg, 0.033
2
CONCLUSIONS
■
mmol), 4,4′-bipyridine (2.9 mg, 0.018 mmol), and water (2 mL) were
sealed in a 5 mL glass tube. The mixture was heated at 150 °C for 2 days
under autogenous pressure. After the mixture was allowed to cool to
room temperature, colorless rod-like crystals were isolated from the tube
In summary, we have described a novel tunable luminescent
material based on a porous Cd(II)-MOF by reversible lanthanide
encapsulation. The porous heteroatom-rich Cd(II)-MOF is able
F
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in 36% yield. IR: 3442 (br), 2941 (w), 2882 (w), 2361 (w), 1604 (s),
Bu
R.; Bu
̈
nzli, J.-C. G. Inorg. Chem. 2009, 48, 5611. (k) Elhabiri, M.; Scopelliti,
1
1
547 (s), 1509 (w), 1413 (s), 1339 (w), 1303 (w), 1255 (s), 1219 (w),
171 (m), 1006 (m), 853 (w), 806 (m), 779 (m), 628 (m). Elemental
̈
nzli, J.-C. G.; Piguet, C. J. Am. Chem. Soc. 1999, 121, 10747.
(l) Bunzli, J.-C. G.; Piguet, C. Chem. Rev. 2002, 102, 1897.
̈
analysis(%) calcd for Cd H O C N : C 56.83, H 2.93, N 4.08;
(2) (a) Deng, H. X.; Doonan, C. J.; Furukawa, H.; Ferreira, R. B.;
Towne, J.; Knobler, C. B.; Wang, B.; Yaghi, O. M. Science 2010, 327, 846.
(b) Cui, Y.; Yue, Y.; Qian, G.; Chen, B. Chem. Rev. 2012, 112, 1126.
(c) Cohen, S. M. Chem. Rev. 2012, 112 (2), 970. (d) Li, J.-R.; Sculley, J.;
Zhou, H.-C. Chem. Rev. 2012, 112, 970. (e) Zhang, J.-P.; Zhang, Y,-B.;
Lin, J.-B.; Chen, X.-M. Chem. Rev. 2012, 112, 1001. (f) Wu, H.; Gong,
Q.; Olson, D. H.; Li, J. Chem. Rev. 2012, 112, 836. (g) Wang, C.; Zhang,
T.; Lin, W. Chem. Rev. 2012, 112, 1084. (h) Horcajada, P.; Gref, R.;
8
160 68 260 16
Found: C 56.77, H 2.85, N 4.32.
Typical Homo-Ln3+ Adsorption. 1 (25 mg) was immersed in a 2%
aqueous solution of Ln(ClO ) (Ln = Tb(III), Eu(III), and Nd(III)).
4
3
The resultant crystalline solids were collected and washed by water (5
mL × 3) and MeOH (5 mL × 2), Et O (5 mL × 1), and dried in air.
2
3
+
3+
3+
8
Typical Hetero-Ln /Ln′ Adsorption. Ln(H O) ⊂Cd(II)-
2
MOF (25 mg, Ln = Tb3 or Eu ) was immersed in a 2% aqueous
+
3+
3
+
3+
3+
solution of Ln′(ClO ) (Ln = Eu , Tb or Nd ). The resultant
́
Baati, T.; Allan, P. K.; Maurin, G.; Couvreur, P.; Ferey, G.; Morris, R. E.;
4
3
crystalline solids were collected and washed by water (5 mL × 3) and
Serre, C. Chem. Rev. 2012, 112, 1232. (i) Yoon, M.; Srirambalaji, R.;
Kim, K. Chem. Rev. 2012, 112, 1196. (j) Suh, M. P.; Park, H. J.; Park, H.
J.; Prasad, T. K.; Lim, D.-W. Chem. Rev. 2012, 112, 782. (k) Kreno, L. E.;
Leong, K.; Farha, O. K.; Allendorf, M.; Van Duyne, R. P.; Hupp, J. T.
Chem. Rev. 2012, 112, 1105. (l) Sumida, K.; Rogow, D. L.; Mason, J. A.;
McDonald, T. M.; Bloch, E. D.; Herm, Z. R.; Bae, T-H.; Long, J. R.
Chem. Rev. 2012, 112, 724.
MeOH (5 mL × 2), Et O (5 mL × 1), and dried in air.
2
Single-Crystal Analysis. C H Cd N O (1), M = 1528.07,
62
74
2
6
25
tetragonal, space group P4(1)2(1)2, a = 22.5663(14) Å, b =
3
2
1
2.5663(14) Å, c = 13.8877(18) Å, V = 7072.1(11) Å , Z = 4, D =
c
−3
−1
.435 g cm , μ(Mo ) = 0.682 mm , F(000) = 3136, θ = 25.60°;
reflections collected/unique: 37637/6668 [R(int) = 0.0403], R (I >
kα
max
1
2
σ(I)) = 0.0399, wR (I > 2σ(I)) = 0.0945. X-ray intensity data were
2
(3) (a) Dong, Y.-B.; Jiang, Y.-Y.; Li, J.; Ma, J.-P.; Liu, F.-L.; Tang, B.;
Huang, R.-Q.; Batten, S. R. J. Am. Chem. Soc. 2007, 129, 4520. (b) Jiang,
Y.-Y.; Ren, S.-K.; Ma, J.-P.; Liu, Q.-K.; Dong, Y.-B. Chem.Eur. J. 2009,
measured at 123 K on a Bruker SMART APEX CCD-based
diffractometer (Mo Kα radiation, λ = 0.71073 Å). The raw frame data
were integrated into SHELX-format reflection files and corrected for
1
5, 10742.
9
Lorentz and polarization effects using SAINT. Corrections for incident
(4) Ludwig, R. Angew. Chem., Int. Ed. 2001, 40, 1808.
9
and diffracted beam absorption effects were applied using SADABS.
(
(
5) Hendrik, J.; Vreman, R.; David, K. Pediatr. Res. 1998, 44, 804.
6) (a) Wang, P.; Ma, J.-P.; Dong, Y.-B.; Huang, R.-Q. J. Am. Chem. Soc.
None of the crystals showed evidence of crystal decay during data
collection. The structure was solved by a combination of direct methods
2
007, 129, 10620. (b) Dong, Y.-B.; Wang, P.; Ma, J.-P.; Zhao, X.-X.;
2
and difference Fourier syntheses and refined against F by the full-matrix
Tang, B.; Huang, R.-Q. J. Am. Chem. Soc. 2007, 129, 4872. (c) Wang, P.;
Ma, J.-P.; Dong, Y.-B. Chem.Eur. J. 2009, 15, 10432.
least-squares technique. Crystallographic data (excluding structure
factors) for the structure reported in this paper have been deposited with
the Cambridge Crystallographic Data Center as supplementary
publication no CCDC 857538. Copies of the data can be obtained
free of charge on application to CCDC, 12 Union Road, Cambridge
CB2 1EZ, U.K. (fax: (+44)1223-336-033; e-mail: deposit@ccdc.cam.ac.
uk).
(7) (a) Parker, D.; Dickins, R. S.; Puschmann, H.; Crossland, C.;
Howard, J. A. K. Chem, Rev. 2002, 102, 1977. (b) Wolbers, M. P. O.;
Veggel, F. C. J. M.; Snellink-Ruel, B. H. M.; Hofstraat, J. W.; Geurts, F. A.
J.; Reinhoudt, D. N. J. Am. Chem. Soc. 1997, 119, 138. (c) Chappell, L. L.;
Voss, D. A.; Horrocks, W. D.; Morrow, J. R. Inorg. Chem. 1998, 37, 3989.
̈
(
1
d) Wong, K.-L.; Law, G.-L.; Yang, Y.-Y.; Wong, W.-T. Adv. Mater. 2006,
8, 1051.
8) (a) An, J.; Shade, C. M.; Chengelis-Czegan, D. A.; Petoud, S.; Rosi,
ASSOCIATED CONTENT
Supporting Information
(
■
*
S
N. L. J. Am. Chem. Soc. 2011, 133, 1220. (b) Lan, Y.-Q.; Jiang, H.-L.; Li,
S.-L.; Xu, Q. Adv. Mater. 2011, 23, 5015.
Crystallographic data in CIF format. Further details are given in
Figures S1−S21. This material is available free of charge via the
Internet at http://pubs.acs.org.
(9) Sheldrick, G. M. SHELXTL, Version 5.12; Bruker Analytical X-ray
Systems, Inc.: Madison, WI, 1997.
AUTHOR INFORMATION
Corresponding Author
E-mail: yubindong@sdnu.edu.cn
■
*
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
This work was supported by NSFC (Nos. 91027003 and
1072118), 973 Program (No. 2012CB821705), “PCSIRT”,
■
2
Shangdong Natural Science Foundation (No. JQ200803), and
Taishan scholars’ construction project special fund.
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dx.doi.org/10.1021/ic300665a | Inorg. Chem. XXXX, XXX, XXX−XXX