Synthesis, structure and property of one porous Zn(salen)-based metal-metallosalen framework

Article abstract of DOI:10.1007/s11426-013-5012-8

Chiral Schiff-base ligand L was synthesized through six steps in good overall yield from readily available 2-tert-butylphenol and was used to construct one chiral porous metal-metallosalen framework, [Zn ₅(μ₃-OH)₂(ZnL)

Full text of DOI:10.1007/s11426-013-5012-8

SCIENCE CHINA
Chemistry
December 20 3 Vol.56 No.12: 1–7
doi: 10.1007/s11426-013-5012-8
• ARTICLES •
doi: 10.1007/s11426-013-5012-8
Synthesis, structure and property of one porous Zn(salen)-based
metal-metallosalen framework
PENG YongWu1† ZHU ChengFeng1,2† & CUI Yong1*
,
1School of Chemistry and Chemical Technology and State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University,
Shanghai 200240, China
2School of Chemical Engineering, Hefei University of Technology, Hefei, Anhui 230009, China
Received August 8, 2013; accepted August 15, 2013
Chiral Schiff-base ligand L was synthesized through six steps in good overall yield from readily available 2-tert-butylphenol
and was used to construct one chiral porous metal-metallosalen framework, [Zn5(µ3-OH)2(ZnL)4(H2O)2]·18H2O (1, L = 5′,5″-
(1E, 1′E)-(1R, 2R)-cyclohexane-1,2-diylbis(azan-1-yl-1-ylidene)bis(methan-1-yl-1-ylidene)bis(3′-tert-butyl-4′-hydroxybiphenyl-
4-carboxylic acid), under mild reaction conditions. 1 was characterized by IR, TGA, CD, UV, PL, single-crystal and powder
X-ray crystallography. The structure of 1 displays a 3-fold interpenetrating 3D framework with 1D channel of 1.14 nm × 0.58
nm and imparts unique Zn(salen) units on the surface of the pore , in which (ZnL)2 dimer acts as multi-functionlized metal-
o
loligand. 1 is thermally robust with network decomposition temperature of 400 C and it also exhibits strong photolumines-
cence in the visible region.
Schiff-base, metal-metallosalen framework, photoluminescence
applied in asymmetric synthesis and separation, but less
1 Introduction
attention has been given to assemble salen or metallosalens
into crystalline infinite solids [16–21]. We have recently
utilized dicarboxyl-functionalized salen ligands to make
several 3D porous MOFs, which exhibit unique properties
on chemical sensor and asymmetric catalysis [22–23]. En-
couraged by the successful construction of the aforemen-
tioned functional porous metal-metallosalen frameworks
and to further extend our work in this field, herein we syn-
thesize a C2-symmetric salen ligand L and employ it to as-
semble with zinc ions to afford a porous metal-metallosalen
framework 1, and its structure, thermal stability and photo-
luminescence were studied.
Metal-organic frameworks (MOFs) are crystalline porous
hybrid solids composed of organic struts and inorganic
nodes, and have attracted growing interest because of their
intriguing architectures and topologies and promising ap-
plications in diverse areas such as gas storage, catalysis,
separation and chemical sensing [19]. Unlike traditional
inorganic materials, these materials feature structural diver-
sity and amenability to be designed with desired functional-
ities at the molecular level [10–13]. Carboxyl-based ligands
have been proved very useful building blocks to form po-
rous MOFs and numerous novel structures with fascinating
topologies and properties have been constructed with this
kind of ligands [14–15]. On the other hand, Salen ligands
and their metal complexes have been established as one of
the best known privileged ligands and have been widely
2 Experimental
2.1 Materials and apparatus
*Corresponding author (email: yongcui@sjtu.edu.cn)
† These authors contributed equally.
All of the chemicals are commercial available, and used
© Science China Press and Springer-Verlag Berlin Heidelberg 2013
chem.scichina.com www.springerlink.com

2
Peng YW, et al. Sci China Chem December (2013) Vol.56 No.12
without further purification. The IR (KBr pellet) spectra
were recorded (400–4000 cm–1 region) on a Nicolet Magna
750 FT-IR spectrometer. Thermogravimetric analyses (TGA)
were carried out in an N2 atmosphere with a heating rate of
10 °C min–1 on a STA449C integration thermal analyzer.
All UV-vis absorption spectra were recorded on a Lambda
20 UV-vis Spectrometer (Perkin Elmer, Inc., USA). The
fluorescence spectra were carried out on a LS 50B Lumi-
nescence Spectrometer (Perkin Elmer, Inc., USA). The CD
spectra were recorded on a J-800 spectropolarimeter (Jasco,
Japan).
2.3 Synthesis of ligand
The dicaxboxyl-functionalized Schiff-base ligand 5′,5″-(1E,
1′E)-(1R, 2R)-cyclohexane-1,2-diyl-bis(azan-1-yl-1-ylidene)
bis(methan-1-yl-1-ylidene)bis(3′-tert-butyl-4′-hydroxybiphe
nyl-4-carboxylic acid) (H4L) was prepared in six steps in an
overall 50% yield from 2-tert-butylphenol according to the
reported procedures (Scheme 1) [18, 25]. IR (KBr, cm–1):
3413 (w), 2942 (s), 2863 (m), 2669 (w), 2551 (w), 1684 (s),
1629 (s), 1607 (s), 1565(w), 1514 (w), 1469 (w), 1441 (s),
1422 (s), 1393 (m), 1361 (w), 1316 (m), 1292 (s), 1276 (s),
1254 (m), 1223 (w), 1176 (m), 1131 (w), 1101 (w), 1069
(w), 1039 (w), 1015 (w), 974 (w), 936 (w), 888 (w), 857
(m), 804 (w), 776 (m), 747 (w), 715 (w), 552 (w), 497 (w).
2.2 Crystallographic measurements and structure de-
termination
Single-crystal XRD data for the compound was collected on
a Bruker SMART Apex II CCD-based X-ray diffractometer
with Cu-Kα radiation (λ = 1.54178 Å) for 1 at 173(2) K. In
the range of 2.47  θ  68.36º, a total of 91529 reflections
2.4 Synthesis of complex 1
The ligand (0.0033 g, 0.005 mmol), Zn(NO3)2·6H2O
(0.0029 g, 0.010 mmol), DMF (0.3 mL), MeOH (0.1 mL)
and THF (0.1 mL) were added to a small vial that was
sealed and heated to 373 K for one day and then cooled to
room temperature. Yellow block-like crystals of 1 were
filtered, washed with DMF and MeOH, respectively, and
dried at room temperature. The yield based on the chiral
ligand is up to 69.0%. IR (KBr, cm–1): 3397 (w), 2938 (m),
2862 (m), 1663 (m), 1596(s), 1531 (s), 1462 (w), 1399 (s),
1385 (s), 1329 (m), 1277 (m), 1253 (m), 1230 (w), 1198 (w),
1183 (w), 1162 (s), 1084 (w), 1068 (m), 1036 (w), 1013 (w),
980 (w), 929 (w), 894 (w), 856 (m), 811 (w), 787 (m), 769
(m), 724 (w), 705 (w), 662 (w), 553 (w), 512 (m), 486 (w).
were collected and 52460 were independent with Rint
=
0.0484, of which 30905 were observed with I > 2(I). The
structure was solved by direct methods with SHELXS-97
and refined with SHELXL-97 [24]. All the non-hydrogen
atoms were refined by full-matrix techniques with aniso-
tropic displacement parameters. The hydrogen atoms were
geometrically fixed at calculated positions attached to their
parent atoms, and treated as riding atoms. The crystallo-
graphic data and other pertinent information of complex 1
are summarized in Table 1, and the selected bond lengths
and bond angles are given in Table 2.
3 Results and discussion
Table 1 Crystal data for the title compound
3.1 Synthesis and characterization
Complex
Empirical formula
Formula weight
1
C168H168N8O48Zn9
3655.43
The zinc (II) complex, 1, was synthesized under mild reac-
tion condition. Its bulk product was obtained by repeating
the experiment and the resulted crystals were collected by
filtration, washed several times with DMF and MeOH, and
dried under vacuum for 3 h. Phase purity of the bulk sample
was established by comparison of its observed and simulat-
ed powder X-ray diffraction patterns (PXRD) (Figure 1).
The thermal stability of 1 was investigated on crystalline
samples under a N2 atmosphere from 40 to 800 ºC. TGA
result of 1 shows that included guest molecules could be
readily released in the temperature range from 80 to 260 ºC
and the framework is stable up to ~400 ºC (Figure 2). Infra-
red spectrum of the complex 1 show that the carboxylate
groups are coordinated to Zn2+ ions, as evidenced by a shift
of the carboxylate stretching frequency from 1684 cm–1 in
the protonated salen precursor H4L to 1531 cm–1, which is
consistent with the structural results. The characteristic
peaks at 1399 and 1385 cm–1 may come from C=N vibration,
and the peaks at 2938 and 2862 cm–1 may be due
Radiation (CuKa) (Å)
1.54178
Crystal system ,Space group Monoclinic, C2
T (K)
a(Å)
b(Å)
c(Å)
100(2)
37.1058(19)
26.3491(12)
37.4578(18)
105.311(3)
35323(3)
4
 (º)
V(Å3)
Z
Dc (g/cm3)
0.0687
µ(CuK )(cm–1)
0.994
F(000)
7544
θ range for data collection (°)
Index ranges
2.47 to 68.36
–44 ≤ h ≤ 42,–30 ≤ k ≤ 31, –44 ≤ l ≤ 43
Reflections collected / unique 91529 /52460 (Rint = 0.0484)
Goodness-of-fit on F2
Completeness to theta
R, wR (I > 2σ(I))
1.097
96.7% (68.36 º)
R1 = 0.1106, wR2 = 0.2773
–0.05(3)
Flack parameter

Peng YW, et al. Sci China Chem December (2013) Vol.56 No.12
3
Table2 Selected bond lengths (Å) and bond angles (º)
Complex
Bond
1
Dist.
Bond
Zn(4)–O(17)
Dist.
Bond
Dist.
1.916(7)
1.948(6)
1.948(6)
1.911(9)
1.931(11)
1.996(7)
2.100(8)
2.147(14)
1.903(7)
1.950(7)
1.955(6)
1.973(9)
1.916(7)
(°)
Bond
Zn(10)–O(27)
Dist.
Zn(1)–O(10)
1.894(6)
1.907(7)
1.981(9)
1.998(8)
1.884(7)
1.894(8)
2.002(7)
2.041(8)
1.905(6)
1.911(7)
1.970(8)
1.989(8)
1.883(7)
(°)
1.893(6)
1.991(6)
1.992(8)
1.905(9)
1.950(7)
1.972(6)
2.114(1)
2.118(7)
1.907(9)
1.939(6)
1.943(7)
1.975(6)
1.916(7)
(°)
Zn(7)–O(15)#1
1.908(8)
1.908(8)
1.998(10)
1.998(10)
1.907(9)
1.931(11)
1.916(7)
1.905(9)
1.939(6)
1.972(6)
1.903(7)
Zn(1)–O(9)
Zn(4)–N(7)
Zn(7)–O(13)#3
Zn(10)–O(27)#4
Zn(10)–O(7)
Zn(1)–N(4)
Zn(4)–N(6)
Zn(7)–O(13)
Zn(1)–N(2)
Zn(5)–O(16)#1
Zn(8)–O(20)
Zn(10)–O(7)#4
O(6)–Zn(6)#3
O(8)–Zn(8)#4
O(15)–Zn(7)#5
O(16)–Zn(5)#6
O(21)–Zn(6)#5
O(22)–Zn(5)#5
O(25)–Zn(9)#4
Zn(2)–O(4)
Zn(5)–O(11)
Zn(8)–O(8)#4
Zn(2)–O(3)
Zn(5)–O(22)#2
Zn(8)–O(2)
Zn(2)–N(3)
Zn(5)–O(14)
Zn(8)–O(27)
Zn(2)–N(1)
Zn(5)–O(13)
Zn(8)–O(28)
Zn(3)–O(24)
Zn(6)–O(6)#3
Zn(9)–O(25)#4
Zn(3)–O(23)
Zn(6)–O(21)#2
Zn(9)–O(1)
Zn(3)–N(8)
Zn(6)–O(12)
Zn(9)–O(19)
Zn(3)–N(5)
Zn(6)–O(13)
Zn(9)–O(27)
Zn(4)–O(18)
Zn(7)–O(15)#2
Zn(7)–O(15)#1
Angle
Angle
Angle
Angle
(°)
O(10)–Zn(1)–O(9)
O(10)–Zn(1)–N(4)
O(9)–Zn(1)–N(4)
O(10)–Zn(1)–N(2)
O(9)–Zn(1)–N(2)
N(4)–Zn(1)–N(2)
O(4)–Zn(2)–O(3)
O(4)–Zn(2)–N(3)
O(3)–Zn(2)–N(3)
O(4)–Zn(2)–N(1)
O(3)–Zn(2)–N(1)
N(3)–Zn(2)–N(1)
O(24)–Zn(3)–O(23)
O(24)–Zn(3)–N(8)
O(23)–Zn(3)–N(8)
O(24)–Zn(3)–N(5)
O(23)–Zn(3)–N(5)
N(8)–Zn(3)–N(5)
116.2(3)
108.7(3)
98.8(3)
98.5(3)
110.2(4)
125.6(3)
117.0(3)
96.7(3)
111.0(4)
111.3(3)
97.6(3)
124.7(3)
119.0(3)
109.9(3)
98.1(3)
96.6(3)
110.6(3)
124.3(3)
O(18)–Zn(4)–O(17)
O(18)–Zn(4)–N(7)
O(17)–Zn(4)–N(7)
O(18)–Zn(4)–N(6)
O(17)–Zn(4)–N(6)
N(7)–Zn(4)–N(6)
O(16)#1–Zn(5)–O(11)
O(16)#1–Zn(5)–O(22)#2
O(11)–Zn(5)–O(22)#2
O(16)#1–Zn(5)–O(14)
O(11)–Zn(5)–O(14)
O(22)#2–Zn(5)–O(14)
O(16)#1–Zn(5)–O(13)
O(11)–Zn(5)–O(13)
O(22)#2–Zn(5)–O(13)
O(14)–Zn(5)–O(13)
O(6)#3–Zn(6)–O(21)#2
115.6(3)
97.4(3)
109.9(3)
110.9(3)
98.1(3)
126.0(3)
124.9(5)
110.6(5)
123.8(3)
85.4(5)
87.5(4)
88.8(4)
95.3(4)
91.1(3)
92.1(3)
178.6(4)
112.9(3)
O(21)#2–Zn(6)–O(12)
O(6)#3–Zn(6)–O(13)
O(21)#2–Zn(6)–O(13)
O(12)–Zn(6)–O(13)
O(15)#2–Zn(7)–O(15)#1
O(15)#2–Zn(7)–O(13)#3
O(15)#1–Zn(7)–O(13)#3
O(15)#2–Zn(7)–O(13)
O(15)#1–Zn(7)–O(13)
O(13)#3–Zn(7)–O(13)
O(20)–Zn(8)–O(8)#4
O(20)–Zn(8)–O(2)
O(8)#4–Zn(8)–O(2)
O(20)–Zn(8)–O(27)
O(8)#4–Zn(8)–O(27)
O(2)–Zn(8)–O(27)
O(20)–Zn(8)–O(28)
108.9(3)
124.4(4)
105.3(2)
100.0(3)
112.7(5)
108.4(4)
113.7(3)
113.7(3)
108.4(4)
99.5(4)
O(2)–Zn(8)–O(28)
88.7(5)
O(27)–Zn(8)–O(28)
O(25)#4–Zn(9)–O(1)
O(25)#4–Zn(9)–O(19)
O(1)–Zn(9)–O(19)
176.2(6)
105.5(3)
106.7(4)
122.8(3)
123.7(4)
101.5(3)
98.1(3)
O(25)#4–Zn(9)–O(27)
O(1)–Zn(9)–O(27)
O(19)–Zn(9)–O(27)
O(25)#4–Zn(9)–Zn(11)#4
O(27)–Zn(10)–O(27)#4
O(27)–Zn(10)–O(7)
O(27)#4–Zn(10)–O(7)
O(27)–Zn(10)–O(7)#4
O(27)#4–Zn(10)–O(7)#4
O(7)–Zn(10)–O(7)#4
O(8)#4–Zn(8)–O(28)
O(6)#3–Zn(6)–O(12)
79.9(3)
110.0(5)
106.3(4)
105.8(5)
105.8(5)
106.3(4)
122.2(9)
84.9(6)
153.0(6)
105.9(5)
98.4(5)
92.3(3)
97.7(4)
93.7(3)
84.1(5)
103.8(4)
Symmetry transformations used to generate equivalent atoms for 1: #1 –x–1/2, y–3/2, –z–1; #2 x+1/2, y–3/2, z+1; #3 –x, y, –z; #4 –x, y, –z–1; #5 x–1/2, y+3/2, z–1;
#6 –x–1/2, y+3/2, –z–1
Scheme 1 Synthesis of the ligand H4L and complex 1.

4
Peng YW, et al. Sci China Chem December (2013) Vol.56 No.12
lizes in chiral monoclinic space group C2 and the asymmet-
ric unit contains one formular unit. The basic building unit
of complex is composed of pentanuclear
1
a
[Zn5(µ3–OH)2(O2C)8] cluster and a dinuclear metallosalen
(ZnL)2. As shown in Figure 4, the pentanuclear
[Zn5(µ3–OH)2(O2C)8] unit is clustered by six bidentate and
two monodentate carboxylate groups of eight ZnL units. Of
the three independent Zn ions in the [Zn5(µ3–OH)2(O2C)8]
cluster, one (Zn7) is coordinated by two µ3–OH– anion and
two oxygen atoms from two bidentate carboxylate groups,
another (Zn6) is coordinated by one µ3–OH– anion and three
oxygen atoms from one monodentate carboxylate group and
two bidentate carboxylate groups, and the third (Zn5) is
coordinated by one µ3–OH– anion and one water molecule
and three oxygen atoms from three bidentate carboxylate
groups. Thus, the Zn6 and Zn7 ions adopt a distorted tetra-
hedral geometry with Zn–O bond lengths ranging from
1.907(9) to 1.975(6) Å, whereas the Zn5 adopts a trigonal
bipyramidal geometry with Zn–O bond lengths ranging
from 1.905(7) to 2.118(7) Å.
Figure 1 Experimental and simulated powder XRD patterns of 1.
In the two independent dimeric (ZnL)2 units (Zn1 and
Zn2, Zn3 and Zn4), each Zn center is coordinated in a dis-
torted tetrahedral geometry with two nitrogen atoms and
two oxygen atoms from two L ligands, which are tightly
intertwisted with each other (Figure 5). The Zn–N bond
lengths range from 1.970(8) Å to 2.041(8) Å and Zn–O
bond lengths range from 1.883(7) to 1.911(7) Å, respec-
tively, while the bond angles around Zn centers vary from
96.6(3) to 126.0(3)º. A careful examination of the crystal
structure of 1 reveals the ligand L in the dimer adopts a
unique conformation that significantly differs from the
common monomer ZnL or other ML motifs (Scheme 2) [22,
26–28]. The (ZnL)2 dimer acts as a multi-functionlized
metalloligand and binds to two [Zn5(µ3–OH)2(O2C)8] clus-
ters using its four carboxylate groups.
Figure 2 Thermal analysis curve of 1.
Each pentanuclear Zn5 cluster in 1 is thus linked by four
(ZnL)2 motifs and each (ZnL)2 unit is linked to two
[Zn5(µ3–OH)2(O2C)8] clusters to generate a chiral porous 3D
Figure 3 CD spectra of (R)/(S)-1.
to the stretching vibrations of methyl group. Solid-state cir-
cular dichroism (CD) spectra of 1 made from R and S enan-
tiomers of the H4L ligand are mirror images of each other,
which indicate their enantiomeric nature.
3.2 Structural description
A single-crystal X-ray diffraction study performed on 1
reveals a neutral 3D open metal-organic network. 1 crystal-
Figure 4 View of the pentanuclear [Zn5(µ3–OH)2(O2C)8] cluster.

Peng YW, et al. Sci China Chem December (2013) Vol.56 No.12
5
Figure 5 View of the structure of (ZnL)2 dimer.
Figure 7 A view of 3D porous structure of 1 along the a-axis.
Scheme 2 View of the coordination model of the different ZnL units.
framework (Figure 6). The single network possesses ~2.86
nm × 2.76 nm quadrangular channel along the a-axis and
~4.2 nm × 2.6 nm hexagonal channel along the c-axis (Fig-
ure 7 and 8). The overall structure of 1 contains three iden-
tical nets of [Zn5(µ3–OH)2(ZnL)4(H2O)2], which are mutu-
ally interpenetrated with each other to form a 3-fold inter-
penetrating 3D framework. The open channels in the single
network along a and c-axis are greatly reduced in the 3-fold
interpenetrated framework of 1 as the pores are nearly com-
pletely occupied by (ZnL)2 motifs from another two nets.
Despite this, there still exists a large 1D channel of 1.14 nm
× 0.58 nm along the b axis (Figure 9). Calculations using
the PLATON program indicate that 1 has 64.5% of total
volume available for guest inclusion [29].
Figure 8 A view of 3D porous structure of 1 along the c-axis.
Figure 9 The space-filling representations of a 1D channel of 1.14 nm ×
0.58 nm along the b-axis.
3.3 Photoluminescence property
The electronic spectrum of H4L is characterized by three 
→* transitions of phenyl and azomethine groups at 235,
263 and 318 nm, respectively. In addition, the band around
440 nm derives from the lowest absorption energy level of 
→* transiton. Upon the formation of 1, the two high en-
ergy bands around 263 and 318 nm show slight red shift (~7
nm), while the lowest energy band shows blue shift (~14
Figure 6 The building block in 1 (the Zn atoms are shown in polyhe-
dron).

6
Peng YW, et al. Sci China Chem December (2013) Vol.56 No.12
for the design of highly porous and robust metal-organic carboxylate
frameworks. Acc Chem Res, 2001, 34: 319–330
2
3
4
Qiu SL, Zhu GS. Molecular engineering for synthesizing novel
structures of metal-organic frameworks with multifunctional proper-
ties. Coord Chem Rev, 2009, 253: 2891–2911
Rosi NL, Eckert J, Eddaoudi M, Vodak DT, Kim J, O'Keeffe M,
Yaghi OM. Hydrogen storage in microporous metal-organic frame-
works. Science, 2003, 300: 1127–1129
Lee JY, Farha OK, Roberts J, Scheidt KA, Nguyen ST, Hupp JT.
Metal-organic framework materials as catalysts. Chem Soc Rev, 2009,
38: 1450–1459
5
6
Murray LJ, Dincă M, Long JR. Hydrogen storage in metal-organic
frameworks. Chem Soc Rev, 2009, 38: 1294–1314
Chen B, Xiang S, Qian, G. Metal-organic frameworks with functional
pores for recognition of small molecules. Acc Chem Res, 2010, 43:
1115–1124
Figure 10 UV-vis absorption spectra of 1 and H4L in the solid state.
7
8
9
Li JR, Kuppler RJ, Zhou HC. Selective gas adsorption and separation
in metal-organic frameworks. Chem Soc Rev, 2009, 38: 1477–1504
Allendorf MD, Bauer CA, Bhakta RK, Houk RJT. Luminescent met-
al-organic frameworks. Chem Soc Rev, 2009, 38: 1330–1352
Cui Y, Yue Y, Qian G, Chen B. Luminescent functional met-
al-organic frameworks. Chem Rev, 2011, 112: 1126–1162
10 Cao AM, Hu JS, Wan LJ. Morphology control and shape evolution in
3D hierarchical superstructures. Sci China Chem, 2012, 55: 2249–
2256
11 Ma L, Abney C, Lin W. Enantioselective catalysis with homochiral
metal-organic frameworks. Chem Soc Rev, 2009, 38: 1248–1256
12 Ma L, Falkowski JM, Abney C, Lin W. A series of isoreticular chiral
metal-organic frameworks as a tunable platform for asymmetric ca-
talysis. Nat Chem, 2010, 2: 838–846
13 Xuan W, Zhu C, Liu Y, Cui Y. Mesoporous metal-organic frame-
work materials. Chem Soc Rev, 2012, 41: 1677–1695
14 Furukawa H, Ko N, Go YB, Aratani N, Choi SB, Choi E, Yazaydin
AÖ, Snurr RQ, O’Keeffe M, Kim J, Yaghi OM. Ultrahigh porosity in
metal-organic frameworks. Science, 2010, 329: 424–428
Figure 11 Fluorescent emission spectra of 1 and H4L.
15 Zhao D, Timmons DJ, Yuan D, Zhou HC. Tuning the topology and
functionality of metal-organic frameworks by ligand design. Acc
Chem Res, 2010, 44: 123–133
16 Cho S-H, Ma B, Nguyen ST, Hupp JT. Albrecht-Schmitt TE. A met-
al-organic framework material that functions as an enantioselective
catalyst for olefin epoxidation. Chem Comm, 2006, 24: 2563–2565
17 Shultz AM, Sarjeant AA, Farha OK, Hupp JT, Nguyen ST.
Post-synthesis modification of a metal-organic framework to form
metallosalen-containing MOF materials. J Am Chem Soc, 2011, 133:
13252–13255
nm) (Figure 10). Upon excitation at 425 nm, 1 exhibits a
fluorescence emission with fluorescence quantum yield of
2.5% at 500 nm. And the fluorescence spectrum of 1 shows
that the emission peak is essentially the same as the sol-
id-state fluorescence signal of free ligand but with a blue
shift about 32 nm and thus can be assigned to the intralig-
and fluorescence emission (Figure 11).
18 Song F, Wang C, Falkowski JM, Ma L, Lin W. Isoreticular chiral
metal-organic frameworks for asymmetric alkene epoxidation: Tun-
ing catalytic activity by controlling framework catenation and vary-
ing open channel sizes. J Am Chem Soc, 2010, 132: 15390–15398
19 Yuan G, Zhu C, Liu Y, Cui Y. Nano- and microcrystals of a
Mn-based metal-oligomer framework showing size-dependent mag-
netic resonance behaviors. Chem Comm, 2011, 47: 3180–3182
20 Li G, Yu WB, N J, Liu TF, Liu Y, Sheng EH, Cui Y. Self-assembly
of a homochiral nanoscale metallacycle from a metallosalen complex
for enantioselective separation. Angew Chem Int Ed, 2008, 47:
1245–1249
4 Conclusions
In summary, we have synthesized one porous Zn(salen)-
based metal-metallosalen framework, 1, from a C2-
symmetric dicarboxyl-functionalized salen ligand. As ex-
pected, complex 1 exhibits a high thermal stability and good
photoluminescence in the visible region.
This work was supported by the National Natural Science Foundation of
China (21025103 and 21371119), the National Basic Research Program of
China (973 Program) (2014CB932102 and 2012CB8217), and Shanghai
Science and Technology Committee (10DJ1400100 and 12XD1406300).
21 Li G, Yu W, Cui Y. A homochiral nanotubular crystalline framework
of metallomacrocycles for enantioselective recognition and separa-
tion. J Am Chem Soc, 2008, 130: 4582–4583
22 Zhu C, Yuan G, Chen X, Yang Z, Cui Y. Chiral nanoporous met-
al-metallosalen frameworks for hydrolytic kinetic resolution of
epoxides. J Am Chem Soc, 2012, 134: 8058–8061
1
Eddaoudi M, David BM, Li HL, Chen BL, Reineke TM, O’Keeffe M,
Yaghi OM. Modular chemistry: Secondary building units as a basis
23 Zhu C, Xuan W, Cui Y. Luminescent microporous metal-metallo-

Peng YW, et al. Sci China Chem December (2013) Vol.56 No.12
7
coordination polymers. J Am Chem Soc, 2007, 129: 7480–7481
salen frameworks with the primitive cubic net. Dalton Trans, 2012,
41: 3928–3932
24 Sheldrick GM. SHELXTL Version 5.1 Software reference manual.
Madison, Wisconsin: Bruker AXS, Inc., 1997
27 Heo J, Jeon, YM, Mirkin CA. Reversible interconversion of homo-
chiral triangular macrocycles and helical coordination polymers. J
Am Chem Soc, 2007, 129: 7712–7713
28 Germain ME, Vargo TR, McClure BA, Rack JJ, Van Patten PG, Odoi
M, Knapp MJ. Quenching Mechanism of Zn(Salicylaldimine) by Ni-
troaromatics. Inorg Chem, 2008, 47: 6203–6211
25 Jeon YM, Heo J, Mirkin CA. Acid-functionalized dissymmetric salen
ligands and their manganese(III) complexes. Tetrahedron Lett, 2007,
48: 2591–2595
29 Spek AL. PLATON, Version 1.62. Utrecht, Nederland: University of
Utrecht, 1999
26 Jeon YM, Heo J, Mirkin CA. Dynamic interconversion of amorphous
microparticles and crystalline rods in salen-based homochiral infinite