Rare earth coordination polymers with zeolite topology constructed from 4-connected building units

Article abstract of DOI:10.1021/ic060116h

A series of rare earth coordination polymers, M(BTC)(DMF)(DMSO) (M = Tb (1), Ho (2), Er (3), Yb (4), Y(5)), with zeolite ABW topology have been synthesized under mild conditions. They exhibit the same three-dimensional (3D) architecture and crystallize in monoclinic symmetry space group P2 ₁/n. Their structures are built up from inorganic and organic 4-connected building units, whose vertex symbols are 4·4·6· 6·6·8. The building units link to each other to generate approximate 5 x 8 A² channels along the [100] direction. The luminescent and magnetic properties of these compounds are investigated, and the results reveal that they could be anticipated to be potential antiferromagnetic and fluorescent materials.

Full text of DOI:10.1021/ic060116h

Inorg. Chem. 2006, 45, 4065−4070
Rare Earth Coordination Polymers with Zeolite Topology Constructed
from 4-Connected Building Units
Xiaodan Guo, Guangshan Zhu,* Zhongyue Li, Yan Chen, Xiaotian Li, and Shilun Qiu*
State Key Laboratory of Inorganic Synthesis & PreparatiVe Chemistry, Jilin UniVersity,
Changchun 130012, China
Received January 19, 2006
A series of rare earth coordination polymers, M(BTC)(DMF)(DMSO) (M
) Tb (1), Ho (2), Er (3), Yb (4), Y(5)), with
zeolite ABW topology have been synthesized under mild conditions. They exhibit the same three-dimensional (3D)
architecture and crystallize in monoclinic symmetry space group P21/n. Their structures are built up from inorganic
and organic 4-connected building units, whose vertex symbols are 4
‚4‚6‚6‚6‚8. The building units link to each
other to generate approximate 5
×
8 Å2 channels along the [100] direction. The luminescent and magnetic properties
of these compounds are investigated, and the results reveal that they could be anticipated to be potential
antiferromagnetic and fluorescent materials.
Introduction
tetramine (hmt) ligand as the meta-organic tetrahedral
building block.4a The rare earth ions are always thought to
be unsuitable for four-connected nodes because they have a
higher coordination number and a more flexible coordination
geometry than traditional metals.5 However, the amazing
optical and magnetic properties of rare earth elements
encourage us to explore their coordination fashions.6 We find
that most rare earth ions of coordination polymers have
terminal coordinated molecules, which decrease their coor-
dination number linked with organic ligands, and disassocia-
tion or removal of the terminal coordinated molecules from
rare earth ions could make them become Lewis acid sites,
which may reveal their potential uses as sensors or catalysts
Inorganic-organic hybrid coordination polymers with
rigid and open frameworks have received intense attention
for their intriguing molecular topologies and great potential
applications as functional materials.1 Although many efforts
have been made to assemble designed and predictable
frameworks and properties, it is still regarded as an effective
and successful synthetic strategy to carefully choose func-
tional metal centers and expand the topological networks of
inorganic materials.2 The structures of many minerals, such
as diamond, quartz, rutile, perovskite, PtS, and feldspar, have
been artificially produced by replacing monatomic anions
(O2-, S2-) with polyatomic organic ligands as linkers and
utilizing the well-defined coordination geometries of metal
centers as nodes.3 Compared with these inorganic materials,
coordination polymers with zeolite topologies are still
unexplored.4 Recently, our group are engaged in assembling
novel frameworks with zeolite topologies through finding
suitable organic ligands and represent a novel three-
dimensional (3D) compound with the zeolite MTN topology
with 2522 Å3 cages via consideration of the hexamethylene-
(3) (a) Sun, J. Y.; Weng, L. H.; Zhou, Y. M.; Chen, J. X.; Chen, Z. X.;
Liu, Z. C.; Zhao, D. Y. Angew. Chem., Int. Ed. 2002, 41, 4471. (b)
Hoskins, B. F.; Robson, R. J. Am. Chem. Soc. 1990, 112, 1546. (c)
Gable, R. W.; Houskins, B. F.; Robson, R. J. Chem. Soc., Chem.
Commun. 1990, 762. (d) Chen, B.; Eddaoudi, M.; Reineke, T. M.;
Kampf, J. W.; O’Keeffe, M.; Yaghi, O. M. J. Am. Chem. Soc. 2000,
122, 11559. (d) Eddaoudi, M.; Kim, J.; O’Keeffe, M.; Yaghi, O. M.
J. Am. Chem. Soc. 2002, 124, 376. (f) Rosi, N. L.; Eddaoudi, M.;
Kim, J.; O’Keeffe, M.; Yaghi, O. M. Angew. Chem. 2002, 114, 294.
(4) (a) Fang, Q. R.; Zhu, G.; Xue, M.; Sun, J. Y.; Wei, Y.; Qiu, S.; Xu,
R. Angew. Chem., Int. Ed. 2005, 44, 2. (b) Tian, Y. Q.; Cai, C. X.; Ji,
Y.; You, X. Z.; Peng, S. M.; Lee, G. H. Angew. Chem., Int. Ed. 2002,
41, 1384. (c) Fe´rey, G.; Serre, C.; Mellot-Draznieks, C.; Millange,
F.; Surble´, S.; Dutour, J.; Margiolaki, I. Angew. Chem. 2004, 116,
6456.
(5) (a) Kiritsis, V.; Michaelides, A.; Skoulika, S.; Golhen, S.; Ouahab, L.
Inorg. Chem. 1998, 37, 3407. (b) Long, D. L.; Blake, A. J.; Champness,
N. R.; Schroder, M. Chem. Commun. 2000, 1369. (c) Long, D. L.;
Blake, A. J.; Champness, N. R.; Wilson, C.; Schroder, M. J. Am. Chem.
Soc. 2001, 123, 3401. (d) Wang, Z.; Jin, C. M.; Shao, T.; Li, Y. Z.;
Zhang, K. L.; Zhang, H. T.; You, X. Z. Inorg. Chem. Commun. 2002,
5, 642.
* To whom correspondence should be addressed. E-mail: sqiu@
mail.jlu.edu.cn (S. Q.); zhugs@mail.jlu.edu.cn. Fax: (+86) 431 5168331
(S. Q.).
(1) (a) Seo, J. S.; Whang, D.; Lee, H.; Jun, S. I.; Oh, J.; Jeon, Y. J.; Kim,
K. Nature 2000, 404, 982. (b) Chen, B.; Eddaoudi, M.; Hyde, S. T.;
O’Keeffe, M.; Yaghi, O. M. Science 2001, 291, 1021. (c) Sato, O.;
Iyoda, T.; Fujishima, A.; Hashimoto, K. Science 1996, 271, 49. (d)
Kahn, O.; Martinez, C. Science 1998, 279, 44.
(2) (a) O’Keefe, M.; Eddaoudi, M.; Li, H.; Reineke, T. M.; Yaghi, O. M.
J. Solid State Chem. 2000, 152, 3. (b) Kim, J.; Chen, B.; Reineke, T.
M.; Li, H.; Eddaoudi, M.; Moler, D. B.; O’Keeffe, M.; Yaghi, O. M.
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10.1021/ic060116h CCC: $33.50
Published on Web 04/22/2006
© 2006 American Chemical Society
Inorganic Chemistry, Vol. 45, No. 10, 2006 4065

Guo et al.
Table 1. Crystallographic Data for Complexes 1-5
1
2
3
4
5
empirical formula
fw
C14H16TbNO8S
517.2
C14H16HoNO8S
523.3
C14H16ErNO8S
525.6
C14H16YbNO8S
531.4
C14H16YNO8S
447.2
cryst syst
space group
a (Å)
b (Å)
c (Å)
â (deg)
V (Å3)
Z
monoclinic
P21/n
monoclinic
P21/n
monoclinic
P21/n
monoclinic
P21/n
monoclinic
P21/n
10.8724(11)
15.6218(17)
10.9924(11)
100.702(2)
1834.5(3)
4
10.844(2)
15.585(3)
10.961(2)
100.557(2)
1821.1(6)
4
10.8158(9)
15.5514(11)
10.9331(9)
100.557(2)
1807.8(3)
4
10.782(2)
15.510(3)
10.881(2)
100.26(3)
1790.4(6)
4
10.8388(12)
15.5918(18)
10.9421(13)
100.513(2)
1818.1(4)
4
T (K)
293(2)
293(2)
293(2)
293(2)
293(2)
λ (Å)
0.71073
1.873
4.008
0.0532
0.1001
0.71073
1.909
4.499
0.0418
0.0872
0.71073
1.931
4.797
0.0454
0.0787
0.71073
1.971
5.380
0.0239
0.0602
0.71073
1.634
3.362
0.0523
0.0876
F
calcd (g cm-3
)
µ (mm-1
)
Ra (I > 20σ(I))
b
Rw
2
2
2
a R ) ∑||Fo| - |Fc||/∑|Fo|. b Rw ) [∑w(Fo - Fc )/∑w(Fo )2]1/2
.
for organic transformations.7 The 1,3,5-benzenetricarbocylic
acid (H3BTC) possesses three carboxylic groups with
multifarious coordination modes and could be regarded as a
good candidate for an organic four-connected node (Figure
S1 in Supporting Information).8 In this paper, we reported a
series of 3D coordination polymers with ABW zeolite
topology, M(BTC)(DMF)(DMSO) (M ) Tb (1), Ho (2), Er
(3), Yb (4), Y(5)). Each metal center of these structures,
connected with four ligands (BTC), is regarded as an
inorganic four-connected node (T1), and a phenyl group of
a BTC ligand is considered to be an organic four-connected
node (T2) because of its linking with four metal centers.
These frameworks contain 5 × 8 Å2 channels viewed along
the [110] direction. The photoluminescent properties, mag-
netic properties, and thermal stabilities of these compounds
are investigated.
Synthesis of Tb(BTC)(DMF)(DMSO) (1). Tb(NO3)3‚nH2O (40
mg, 0.10 mmol) and H3BTC (10 mg, 0.05 mmol) was dissolved in
N,N′-dimethylformamide (DMF) (10 mL) and dimethylsulfoxide
(DMSO) (5 mL) at room temperature in a 50 mL beaker. The beaker
was sealed and left undisturbed at 60 °C for 7 days to give colorless
crystals. Yield: 72%. Anal. Calcd for C14H16TbNO8S (517.3): C,
32.51; H, 3.12; N, 2.71. Found: C, 33.48; H, 3.18; N, 2.77.
Synthesis of Ho(BTC)(DMF)(DMSO) (2). The procedure was
the same as that for 1 except that Tb(NO3)2‚nH2O was replaced by
Ho(NO3)3‚nH2O (40 mg, 0.1 mmol). Yield: 77%. Anal. Calcd
C14H16HoNO8S (523.3): C, 32.14; H, 3.08; N, 2.68. Found: C,
32.08; H, 3.06; N, 2.26.
Synthesis of Er(BTC)(DMF)(DMSO) (3). The procedure was
the same as that for 1 except that Tb(NO3)2‚nH2O was replaced by
Er(NO3)3‚nH2O (40 mg, 0.1 mmol). Yield: 75%. Anal. Calcd
C14H16ErNO8S (525.6): C, 31.99; H, 3.07; N, 2.66. Found: C,
31.88; H, 3.06; N, 2.66.
Synthesis of Yb(BTC)(DMF)(DMSO) (4). The procedure was
the same as that for 1 except that Tb(NO3)2‚nH2O was replaced by
Yb(NO3)3‚nH2O (40 mg, 0.1 mmol). Yield: 68%. Anal. Calcd
C14H16YbNO8S (531.4): C, 31.64; H, 3.03; N, 2.64. Found: C,
32.01; H, 3.06; N, 2.66.
Experimental Section
All chemicals purchased were of reagent grade or better and were
used without further purification. Rare earth nitrate salts (M(NO3)3‚
nH2O) were prepared by dissolving rare earth oxides with 6 M
HNO3, while adding H2O2 for Tb4O7; the mixtures were then
evaporated at 100 °C until the crystal film formed. Fluorescence
spectroscopy data were recorded on a LS55 luminescence spec-
trometer. The elemental analyses were carried out on a Perkin-
Elmer 240C elemental analyzer. The infrared (IR) spectra were
recorded (400-4000 cm-1 region) on a Nicolet Impact 410 FTIR
spectrometer using KBr pellets. TGA (thermal gravimetric analyses)
were performed under oxygen with a heating rate of 10 °C/min
using a Perkin-Elmer TGA 7 thermogravimetric analyzer.
Synthesis of Y(BTC)(DMF)(DMSO) (5). The procedure was
the same as that for 1 except that Tb(NO3)2‚nH2O was replaced by
Y(NO3)3‚nH2O (40 mg, 0.1 mmol). Yield: 58%. Anal. Calcd
C14H16YNO8S (447.2): C, 37.60; H, 3.61; N, 3.13. Found: C,
37.51; H, 3.66; N, 3.16.
X-ray Crystallographic Study. The intensity data were collected
on a Smart CCD diffractometer with graphite-monochromated Mo
KR (λ ) 0.71073 Å) radiation at room temperature in the ω-2θ
scan mode. An empirical absorption correction was applied to the
data using the SADABS program.9 The structures were solved by
direct methods. All non-hydrogen atoms were refined anisotropi-
cally. Hydrogen atoms were fixed at calculated positions and refined
by using a riding mode. All calculations were performed using the
SHELXTL program.10 The crystallographic data were summarized
in Table 1, and the selected bond lengths and bond angles of the
five complexes were listed in Table 2 and Table S1 in the
Supporting Information, respectively.
(6) (a) Liu, W. S.; Jiao, T. Q.; Li, Y. Z.; Liu, Q. Z.; Tan, M. Y.; Wang,
H.; Wang, L. F. J. Am. Chem. Soc. 2004, 126, 2280. (b) Ma, B. Q.;
Zhang, D. S.; Gao, S.; Jin, T. Z.; Yan, C. H.; Xu, G. X. Angew. Chem.,
Int. Ed. 2002, 39, 3644. (c) Serre, C.; Stock, N.; Bein, T.; Fe´rey, G.
Inorg. Chem. 2004, 43, 3159. (d) Mancino, G.; Ferguson, A. J.; Beeby,
A.; Long, N. J.; Jones, T. S. J. Am. Chem. Soc. 2005, 127, 524. (f)
Guo, X.; Zhu, G.; Fang, Q.; Xue, M.; Tian, G.; Sun, J.; Li, X.; Qiu,
S. Inorg. Chem. 2004, 44, 3850.
(7) (a) Reineke, T. M.; Eddaoudi, M.; Fehr, M.; Kelley, D.; Yaghi, O.
M. J. Am. Chem. Soc. 1999, 121, 1651. (b) Reineke, T. M.; Eddaoudi,
M.; O’Keeffe, M.; Yaghi, O. M. Angew. Chem., Int. Ed. 1999, 38,
2590.
(8) (a) Devic, T.; Serre, C.; Audebrand, N.; Marrot, J.; Ferey, G. J. Am.
Chem. Soc. 2005, 127, 12788. (b) Zhang, Z. H.; Shen, Z. L.; Okamura,
T.; Zhu, H. F.; Sun, W. Y.; Ueyama, N. Cryst. Growth Des. 2005, 5,
1191. (c) Zhang, Z. H.; Okamura, T.; Hasegawa, Y.; Kawaguchi, H.;
Kong, L. Y.; Sun, W. Y.; Ueyama, N. Inorg. Chem. 2005, 44, 6215.
(9) Sheldrick, G. M. SADABS, Program for Empirical Absorption
Correction for Area Detector Data; University of Go¨ttingen:
Go¨ttingen, Germany, 1996.
(10) Sheldrick, G. M. SHELXS 97, Program for Crystal Structure Refine-
ment; University of Go¨ttingen: Go¨ttingen, Germany, 1997.
4066 Inorganic Chemistry, Vol. 45, No. 10, 2006

Rare Earth Coordination Polymers with Zeolite Topology
Table 2. Selected Bond Lengths (Å) for Complexes 1-5
compound 1a
Tb(1)-O(1)
Tb(1)-O(3)
Tb(1)-O(5)
Tb(1)-O(7)
2.314(4)
2.426(5)
2.469(4)
2.350(5)
Tb(1)-O(2)
Tb(1)-O(4)
Tb(1)-O(6)#1
Tb(1)-O(8)
2.423(5)
2.422(4)
2.260(5)
2.386(5)
compound 2b
Ho(1)-O(1)
Ho(1)-O(3)#3
Ho(1)-O(5)#2
Ho(1)-O(7)
2.300(3)
2.444(3)
2.405(4)
2.334(4)
Ho(1)-O(2)#1
Ho(1)-O(4)#3
Ho(1)-O(6)#2
Ho(1)-O(8)
2.235(4)
2.398(3)
2.398(4)
2.365(4)
compound 3c
Er(1)-O(1)
2.279(5)
2.438(5)
2.393(5)
2.341(5)
Er(1)-O(2)#1
Er(1)-O(4)#3
Er(1)-O(6)#2
Er(1)-O(8)
2.222(5)
2.386(5)
2.385(5)
2.307(6)
Er(1)-O(3)#3
Er(1)-O(5)#2
Er(1)-O(7)
compound 4d
Yb(1)-O(1)
Yb(1)-O(3)
Yb(1)-O(5)
Yb(1)-O(7)
2.363(3)
2.367(3)
2.202(3)
2.290(3)
Yb(1)-O(2)
Yb(1)-O(4)
Yb(1)-O(6)
Yb(1)-O(8)
2.427(3)
2.375(3)
2.265(3)
2.330(3)
Figure 1. Coordination environments of metal center, M, in M(BTC)-
(DMF)(DMSO) (M ) Tb (1), Ho (2), Er (3), Yb (4), Y(5)) with
non-hydrogen atoms represented by thermal ellipsoids drawn at the 50%
probability level. Atoms labeled with additional A are symmetrically
equivalent to those atoms without such designation.
compound 5e
Y(1)-O(1)
2.292(2)
2.447(2)
2.398(3)
2.358(3)
Y(1)-O(2)#1
Y(1)-O(4)#2
Y(1)-O(6)#3
Y(1)-O(8)
2.230(3)
2.392(3)
2.396(3)
2.312(3)
Y(1)-O(3)#2
Y(1)-O(5)#3
Y(1)-O(7)
four BTC ligands through two chelating bidentate carboxylate
groups and two dimondentate carboxylate groups. It is not
unreasonable to regard it as an inorganic four-connected node
(T1) (Figure 2a). Since each BTC ligand coordinate with
four metal centers through carboxylate groups, it is more
clear to describe the structure when the phenyl group of the
BTC ligand are regarded as an organic four-connected node
(T2) (Figure 2b). As seen in Figure 2c, a zeolite ABW
topology is given if the couple of four-connected nodes, T1
and T2, are linked each other.12 The vertex symbols of both
T1 and T2 are 4‚4‚6‚6‚6‚8. As the structure of a zeolite
ABW, the framework of compounds also contain eight-
membered channels which are formed from four metal
centers and four phenyl groups linked by carboxylate groups.
Replacement of the four-connected centers of zeolite ABW,
Si and Al, with the rare metal ions and phenyl groups
replicates and expands the 3.4 × 3.8 Å2 eight-membered
channels to approximately 5 × 8 Å2. The channels of the
structure are viewed alone the [100] direction, as shown in
Figure 3.
According to a review by Yaghi’s group about the
building-block geometries of MOF crystals, there are 31
compounds with the topology of zeolite ABW (also named
as sra, Al in SrAl2) in the MOFs with tetrahedral building
blocks.13 After deeply exploring the structures, we find that
all of the building blocks are based on transitional metals,
but those based on rare earth metals are still unreported. For
the higher coordination number and more flexible coordina-
tion geometry of rare earth metals, it is difficult to control
the preparation process. A mild synthesis condition and a
suitable organic ligand are essential to construct the tetra-
hedral building units of ABW topology since a mild
temperature is helpful for the formation of lower coordination
a Symmetry transformations used to generate equivalent atoms: #1 -x
+ 2, -y, -z + 1. b Symmetry transformations used to generate equivalent
atoms: #1 -x + 2, -y, -z + 2; #2 x + 1/2, -y + 1/2, z + 1/2; #3 x +
1, y, z. c Symmetry transformations used to generate equivalent atoms: #1
-x + 1, -y, -z + 1; #2 x - 1/2, -y + 1/2, z - 1/2; #3 x - 1, y, z.
e Symmetry transformations used to generate equivalent atoms: #1 -x, -y,
-z + 1; #2 x - 1, y, z; #3 x - 1/2, -y + 1/2, z - 1/2.
Results and Discussion
Complexes 1-5 have been successfully synthesized under
mild conditions. Single-crystal X-ray diffraction, elemental
analysis, and TGA analysis studies performed on compounds
1-5 reveal that they are identical in structure with the
formula M(BTC)(DMF)(DMSO) (M ) Tb (1), Ho (2), Er
(3), Yb (4), or Y (5)).
Crystal Structure. X-ray diffraction studies performed
on these compounds reveal that each asymmetric unit
contains one eight-coordinated rare earth ion (M3+), one BTC
ligand, one coordinated DMF molecule, and one coordinated
DMSO molecule without any guest molecule. As shown in
Figure 1, each metal center (M3+) is coordinated with six
oxygen atoms (O1-O6) from four carboxylate groups of the
BTC ligands and two oxygen atoms (O7, O8) from a terminal
DMF molecule and a terminal DMSO molecule. The
carboxylic O-M, M-ODMF, and M-ODMSO bonds are in the
range of 2.222-2.469, 2.229-2.350, and 2.230-2.386 Å,
respectively, and all of them are comparable to those reported
for other rare earth metal coordination polymers.6f,11
To deeply understand the structures and how the topology
is a prototype for frameworks, it would be helpful to explore
the connection mode of the metal centers and organic ligands.
In the framework, each metal center (M3+) is connected with
(11) (a) Wan, Y.; Jin, L.; Wang, K.; Zhang, L.; Zheng, X.; Lu, S. New J.
Chem. 2002, 26, 1590. (b) Liu, C. B.; Sun, C. Y.; Jin, L. P.; Lu, S. Z.
New J. Chem. 2004, 28, 1019. (c) Sun, H. L.; Gao, S.; Ma, B. Q.;
Chang, F.; Fu, W. F. Micro. Meso. Mater. 2004, 73, 89.
(12) Atlas of Zeolite Framework Types, 5th ed.; Baerlocher, Ch., Meier,
W. M., Olson, D. H., Eds.; Elsevier: New York, 2001.
(13) Ockwig, N. W.; Delgado-Friedrichs, O.; O’Keeffe, M.; Yaghi, O. M.
Acc. Chem. Res. 2005, 38, 176.
Inorganic Chemistry, Vol. 45, No. 10, 2006 4067

Guo et al.
Figure 2. (a) Inorganic four-connected node containing one metal center connected with four BTC ligands and (b) an organic four-connected node presenting
one phenyl group linked with four mental centers which link to each other to produce (c) a zeolite ABW topology.
Figure 3. (a) Eight-membered channel consists of four metal centers and four phenyl groups linked through carboxylic groups, and (b) the framework of
the compound is viewed along [100] direction.
number rare earth ions and a suitable ligand makes the
formation of four-connected nodes possible. So compounds
1-5 are the first with zeolite ABW topology, and the
preparation process has been proven effectively to assemble
tetrahedral building units to obtain novel structures.
Photoluminescent Properties. The photoluminescent
spectra of compound 1 and free H3BTC are shown in Figure
4. Two emission groups for complex 1 in the range of 350-
450 (λex ) 235 nm) and 460-700 nm (λex ) 254 nm) are
observed. The emission ranging from 460 to 660 nm is
attributed to the terbium ion, corresponding to 5D4 f 7FJ (J
) 6, 5, 4, 3).14 Compound 1 exhibits three emission peaks,
one blue-shifted emission peak, one red-shifted emission
peak, and one main peak without shift compared with that
of free H3BTC. The main emission peak (387 nm) of
compound 1 and free H3BTC may be attributed to π* f
n.15 The blue-shifted emission band at 363 nm would be
assigned to the emission of the ligand-to-metal charge
Figure 4. Photoluminescence spectra of (a) Tb(BTC)(DMF)(DMSO)
excited at 235 nm, (b) Tb(BTC)(DMF)(DMSO) excited at 254 nm, and (c)
H3BTC excited at 235 nm.
(14) Zhao, B.; Chen, X. Y.; Cheng, P.; Liao, D. Z.; Yan, S. P.; Jiang, Z.
transfer (LMCT).16 The red-shifted emission peak at 423 nm
H. J. Am. Chem. Soc. 2004, 126, 15394.
(15) Thirumurugan, A.; Natarajan, S. Dalton Trans. 2004, 2923.
is probably related to the intraligand fluorescent emission:
4068 Inorganic Chemistry, Vol. 45, No. 10, 2006

Rare Earth Coordination Polymers with Zeolite Topology
Figure 6. PXRD patterns for Tb(BTC)(DMF)(DMSO): (a) a simulated
PXRD pattern calculated from single-crystal structure (black), (b) as-
synthesized (red), (c) after being heated at 150 °C (green), (d) after being
heated at 2000 °C (blue), and (e) after being heated at 250 °C (light blue).
Figure 5. øM vs T plot (black) and øMT vs T (blue) plots for Ho(BTC)-
(DMF)(DMSO).
similar red shifts have been observed before.17 The photo-
luminescent spectra of compounds 2, 3, 4, and 5 are
investigated and also show blue-emissions, as shown in
Figure S2 in Supporting Information. These compounds
could be anticipated as potential fluorescent materials.
Magnetic Properties. The magnetic properties of com-
pounds 2 and 3 are investigated from 4 K to room
temperature. For compound 2, the observed value of øMT
per [Ho] unit is 14.12 cm3 K mol-1 at room temperature,
which is close to the value of two noninteracting Ho3+ in
the dissociation of coordinated DMF and DMSO molecules
(calculated 29.23%). The decomposition of the compound
starts above 450 °C, and the remaining weight of 39.28%
corresponds to the percentage of the Tb and O components,
Tb4O7 (Figure S3 in Supporting Information). The powder
X-ray diffractions are performed for the as-synthesized
sample, and the samples heated at 150, 200, and 250 °C,
respectively (Figure 6). The PXRD patterns for samples
heated at 150 and 200 °C are similar to that of as-synthesized
sample, which indicates that such temperatures do not lead
to an obvious phase transformation. When the sample is
heated at 250 °C, the long-range order of the structure is
lost and a phase transformation is observed. So, the dis-
sociation of coordinated DMF and DMSO molecules leads
to the loss of structure and a phase transformation.
IR Spectrum. The compounds display similar IR spectra.
As shown in Figure S4 in Supporting Information, the
asymmetric and symmetric stretching vibrations of the
carboxylate groups have bands at 1538 and 1396 cm-1. The
bands at 1607, 3066, 851, 680, and 771 cm-1 are attributed
to the aromatic skeleton vibration of benzene ring, ν)C-H of
benzene, δ)C-H out of the face of benzene, and the
1,4-substitute of benzene ring, respectively. The bands at
1668 and 2929 cm-1 are from νCdO and the asymmetric
stretching vibration of the methyl group of the DMF
molecules. The lack of IR bands at 2657, 2545 (OCOOH-
H), and 1690 cm-1 (CCOOHd0) indicates the complete
deprotonation of H3BTC after the reaction. The broad band
centered at 3500 cm-1 is attributed to the H-bonded ν(OH)
groups mainly from adsorbed water.19
5
the I8 ground state.18 With a decrease in the temperature,
øMT decreases smoothly to a minimum of 10.10 cm3 K mol-1
at 4 K. The plot of øM-1 versus T over the whole temperature
range obeys the Curie-Weiss law [ø ) C/(T - θ)] with C
) 13.87 cm3 K mol-1 and θ ) -0.58 K. The decrease of
øMT and the negative value of θ indicate that the antiferro-
magnetic interaction between the Ho3+ ions dominates the
magnetic properties of complex 2 (Figure 5). The magnetic
behavior of compound 3 is represented in Figure S5 in the
Supporting Information and shows that øMT increases with
increasing temperature over the whole temperature range.
At room temperature, øMT is 11.07 cm3 K mol-1, which is
4
slightly lower than the value of Er3+ in the I15/2 ground
-1
state.17 The plot of øM versus T also obeys the Curie-
Weiss law [ø ) C/(T - θ)] with C ) 11.27 cm3 K mol-1
and θ ) -6.00 K. So compound 3 displays an antiferro-
magnetic interaction between the Er3+ ions.
Thermal Stability. The thermal stability of compound 1
has been studied using TGA and PXRD at different tem-
peratures. The TGA curve performed from 35 to 800 °C
shows no weight loss until 200 °C, which corresponds to
the crystallographic result without guest molecule. The first
weight loss of 28.58% from 200 to 300 °C is attributed to
Conclusions
A series of novel coordination polymers with zeolite ABW
topology, M(BTC)(DMF)(DMSO) (M ) Tb (1), Ho (2), Er
(3), Yb (4), Y(5)), have been synthesized first through
assembling both inorganic and organic building units. Each
metal center is regarded as an inorganic four-connected node,
for its connection with four BTC ligands. And the phenyl
(16) (a) Dai, J. C.; Wu, X. T.; Fu, Z. Y.; Cui, C. P.; Hu, S. M.; Du, W. X.;
Wu, L. M.; Zhang, H. H.; Sun, R. Q. Inorg. Chem. 2002, 41, 1391.
(b) Zhang, L. Y.; Liu, G. F.; Zheng, S. L.; Ye, B. H.; Zhang, X. M.;
Chen, X. M. Eur. J. Inorg. Chem. 2003, 2965.
(17) (a) Chen, W.; Wang, J. Y.; Chen, C.; Yue, Q.; Yuan, H. M.; Chen, J.
S.; Wang, S. N. Inorg. Chem. 2003, 42, 944. (b) Thirumurugan, A.;
Natarajan, S. Dalton Trans. 2004, 2923.
(18) (a) Benelli, C.; Gatteschi, D. Chem. ReV. 2002, 102, 2369. (b) Zheng,
X.; Wang, Z.; Gao, S.; Liao, F.; Yan, C.; Jin, L. Eur. J. Inorg. Chem.
2004, 2968.
(19) Fang, Q. R.; Shi, X.; Wu, G.; Tian, G.; Zhu. G. S.; Wang. R. W.;
Qiu, S. L. J. Solid State Chem. 2003, 176, 1.
Inorganic Chemistry, Vol. 45, No. 10, 2006 4069

Guo et al.
groups of BTC ligands are considered as organic four-
connected nodes because they are linked with four metal
centers. The building units link to each other to lead to a
three-dimensional framework with approximate 5 × 8 Å2
channels along the [100] direction. Compound 1 exhibits the
characteristic emission of terbium ions, and all of these
compounds show blue emissions. Compounds 2 and 3
display antiferromagnetic interactions. Thus, these com-
pounds could be anticipated as potential antiferromagnetic
and fluorescent materials.
Acknowledgment. This work was funded by the State
Basic Research Project (G2000077507) and the National
Nature Science Foundation of China (Grants 20571030,
20531030, 29873017, 20273026, and 20101004).
Supporting Information Available: CIF files, selected bond
lengths and angles, and emission spectra. This material is available
free of charge via the Internet at http://pubs.acs.org.
IC060116H
4070 Inorganic Chemistry, Vol. 45, No. 10, 2006