Synthesis of Highly Stable Porous Metal-Iminodiacetic Acid Gels from A Novel IDA Compound

Article abstract of DOI:10.1002/cjoc.201600184

In this work, a novel and simple flexible aromatic multi-carboxylate compound N,N′-(4,4′-biphenylyl) iminodiacetic acid (BP-IDA) was synthesized, with which two new stable metal-IDA gels (denoted as MIG1 and MIG2) with three-dimensional network structures have been prepared successfully by employing Cr³⁺and Al³⁺as the metal ions, respectively. The rheological performance was investigated by means of dynamic rheology measurement. The morphology and microstructure were characterized by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction technique. Nitrogen sorption isotherm measurement suggests that the MIG1 aerogel has considerable porosity with the Brunauer-Emmett-Teller specific surface area up to 760 m²·g^?1. Owing to easy preparation, good stability, and three-dimensional network structure, the as-prepared metal-organic gels will possess potential applications in separation, catalysis, and drug delivery.

Full text of DOI:10.1002/cjoc.201600184

FULL PAPER
DOI: 10.1002/cjoc.201600184
Synthesis of Highly Stable Porous Metal-Iminodiacetic Acid
Gels from a Novel IDA Compound
Wenjing Chen,a,b Yanhong Jiang,a Xuesong Ding,*,b Chaoguo Yan,*,a and Baohang Han*,b
a College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, Jiangsu 225002, China
b CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience,
National Center for Nanoscience and Technology, Beijing 100190, China
In this work, a novel and simple flexible aromatic multi-carboxylate compound N,N'-(4,4'-biphenylyl) iminodi-
acetic acid (BP-IDA) was synthesized, with which two new stable metal-IDA gels (denoted as MIG1 and MIG2)
＋
＋
with three-dimensional network structures have been prepared successfully by employing Cr3 and Al3 as the
metal ions, respectively. The rheological performance was investigated by means of dynamic rheology measure-
ment. The morphology and microstructure were characterized by scanning electron microscopy, transmission elec-
tron microscopy, and X-ray diffraction technique. Nitrogen sorption isotherm measurement suggests that the MIG1
aerogel has considerable porosity with the Brunauer-Emmett-Teller specific surface area up to 760 m2•g1. Owing
to easy preparation, good stability, and three-dimensional network structure, the as-prepared metal-organic gels will
possess potential applications in separation, catalysis, and drug delivery.
Keywords iminodiacetic acid, chromium(III) ion, aluminum(III) ion, metal-IDA gels, porosity
Introduction
valent interactions, such as hydrogen bonding, van der
Waals force, and π-π interaction.[9,10] Compared with
MOFs, the metal-organic gels possess poor crystallini-
ties and unclear structures, however, they still have the
following advantages: (1) The reaction can proceed at a
low temperature, some materials can be obtained at
room temperature; (2) the reaction time is shorter and
solvent quantity is less; (3) reaction solvent is cheap and
with low toxicity, the reaction can proceed in ethanol,
water, N,N'-dimethylformamide (DMF), or the mixture
of them; (4) the easily obtained desired shapes of the
gels by utilizing various shapes of reaction containers
make them more suitable for industrialized and com-
mercial applications. Due to above points, metal-organic
gels have amounts of potential applications in cataly-
sis,[11] sensing,[12] anion recognition,[13] photophys-
ics,[14,15] vapor adsorption,[16] separation technologies,
electrochemical detection,[17] etc. Conformationally
flexible ligands with amide groups[18-20] have been often
employed to design metal-organic gels because the
formed networks are able to trap solvent molecules in
their crystal lattices. However, because the structures of
most ligands are complex with multi-step procedure, the
synthesis and functional researches of metal-organic
gels are still rarely reported up to date.
Metal-organic frameworks (MOFs), which consist of
metal ions or clusters coordinated to rigid organic lig-
ands to form periodic infinite network structures and
crystalline materials, have been springing up and widely
studied as a new type of porous materials in the past
decades.[1] Owing to their unique structures, MOFs can
be utilized in versatile applications such as adsorption,[2]
ion exchange, molecular recognition, catalytic, and op-
tical,[3] electrical, magnetic, chiral separation fields.[4]
MOFs are commonly in the form of powdery crystal. To
obtain a large size with a specific shape, the forming
process through adhesive generally results in the de-
crease of specific surface area and the blockage of
pores.[5] Therefore, it is still a huge challenge to process
MOFs[6] into optimal shape in the industry. In recent
years, supramolecular gels have attracted tremendous
attentions as a class of multifunctional materials.
Among them, the research on supramolecular gel con-
struction using the concept of coordination polymer and
introducing metal ions, called metal-organic gel, has
just begun and aroused people’s attention gradually due
to its potential applications in optical, electrical, and
catalysis fields.[7,8] The generation of metal-organic gels
with three-dimensional (3D) network structures is
mainly based on the coordination of metal ions and or-
ganic ligands, as well as some relatively weak non-co-
In this work, we design and synthesize a new flexi-
ble aromatic multi-carboxylate compound N,N'-(4,4'-
biphenylyl) iminodiacetic acid (BP-IDA) in two steps
*
E-mail: hanbh@nanoctr.cn; cgyan@yzu.edu.cn; dingxs@nanoctr.cn
Received March 29, 2016; accepted May 6, 2016; published online June 15, 2016.
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/cjoc.201600184 or from the author.
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Chen et al.
FULL PAPER
that is inspired by ethylene diamine tetraacetic acid
(EDTA). Besides the considerations mentioned above
about multi-carboxylate ligands, BP-IDA has its own
remarkable features. Firstly, conformationally flexible
ligands with auxiliary chemical interaction have often
been employed to design coordination polymers[21-23]
and metal-organic gels, and BP-IDA contains flexible
multi-carboxylate structures coincidentally. As a poly-
carboxylic acid, BP-IDA is similar to EDTA. The ni-
trogen atom and two carboxylate groups of the imino-
diacetate part can afford more abundant types of coor-
dination architectures to chelate metal ions strongly.[24,25]
Secondly, BP-IDA is more sensitive to chelate metal
ions with the flexible methylene groups,[26] they can
freely twist to meet the requirements of the coordination
geometries of metal atoms,[27,28] and may induce metal
clusters and link them into an extended framework with
various coordination modes.[29] Thirdly, the introduced
aromatic and carboxylate groups could offer additional
sites for π-π interaction and hydrogen bonding, respec-
tively. These non-covalent interactions further consoli-
date the structures of coordination polymers.[6,30] Above
all, BP-IDA with simple and flexible structure is very
suitable as a ligand to produce metal-organic gels. The-
se metal-organic gels are defined as metal-IDA gels
Scheme 1 Synthesis of compound 4-bpmb
N
CH3CH2OH
NH2NH2
N
CHO
N N
+
r.t.
N
Synthesis of N,N'-(4,4'-biphenylyl) diethyl iminodi-
acetate (BP-IDE)
Benzidine (1.84 g, 10.00 mmol), KI (7.97 g, 48.00
mmol), and K2HPO4 (8.30 g, 48.00 mmol) were added
into a dry 250 mL round bottom flask and dissolved in
120 mL anhydrous acetonitrile and ethyl bromoacetate
(4.86 mL, 44.00 mmol) under nitrogen atmosphere. The
reaction mixture was heated to 80 ℃ and refluxed for
40 h, and then cooled to room temperature. The residue
was removed by filtration, and the collected filtrate was
concentrated under vacuum to obtain an oily product.
The crude product was purified by silica chromatog-
raphy using ethyl acetate/petroleum ether (1/2) as eluant,
BP-IDE was obtained as gray solids in 63% yield
(Scheme 1). 1H NMR (400 MHz, CDCl3) δ: 7.39 (d, J＝
8.0 Hz, 4H, ArH), 6.65 (d, J＝8.0 Hz, 4H, ArH), 4.22
(dd, J＝8.0 Hz, 8H, CH2), 4.16 (s, 8H, CH2), 1.28 (t,
13
J＝8.0 Hz, 12H, CH3); C NMR (100 MHz, CDCl3) δ:
171.0, 146.6, 131.1, 127.3, 112.9, 61.1, 53.6, 14.3.
HRMS (ESI) calcd for C28H36N2NaO8 ([M＋Na]＋ )
551.2364, found 551.2373 (Figures S1－S3, Supporting
Information).
(MIGs). We prepared two new stable metal-IDA gels
＋
successfully from the bridging ligand and Cr3 and
＋
Al3 as the metal ions,[31] and these gels have lots of
potential applications owing to their 3D network struc-
ture, satisfactory strength, porosity, and stability.
Synthesis of N,N'-(4,4'-biphenylyl) iminodiacetic acid
(BP-IDA)
In a 100 mL round bottom flask, BP-IDE (2.64 g,
5.00 mmol) was dissolved in 50 mL ethanol, the reac-
tion mixture was heated to 78 ℃, aqueous NaOH solu-
tion (2.0 mol/L) was added slowly under heating until
pH＝8.0, the mixture was refluxed for 4 h. After cool-
ing to room temperature, ethanol was removed to get
brown solids. The sodium salt of BP-IDE was dissolved
in H2O (30 mL) and acidified with diluted HCl solution
until no further precipitate generated, finally the brown
product BP-IDA was obtained by filtration in 86% yield
(Scheme 1). 1H NMR (400 MHz, DMSO-d6) δ: 7.37 (d,
J＝8.0 Hz, 4H, ArH), 6.50 (d, J＝8.0 Hz, 4H, ArH),
4.03 (s, 8H, CH2); 13C NMR (100 MHz, DMSO-d6) δ:
174.0, 146.3, 129.2, 126.8, 112.0, 55.7. HRMS (ESI)
calcd for C20H19N2O8 ([MH]) 415.1147, found
415.1158 (Figures S4－S6, Supporting Information).
Experimental
Materials
Ethyl bromoacetate, potassium iodide, anhydrous
potassium hydrogen phosphate, acetonitrile, petroleum
ether, ethyl acetate, ethanol, sodium hydroxide, hydro-
chloric acid, hydrazine hydrate, tert-butanol, and
N,N'-dimethylformamide (DMF) were purchased from
Beijing Chemical Reagents Company and of analytical
grade. Benzidine, pyridine-4-carboxaldehyde, chromic
nitrate nonahydrate, and aluminum nitrate nonahydrate
were purchased from Sigma-Aldrich. N,N'-Bis-pyridin-
4-ylmethylene-hydrazine (4-bpmb) (Scheme 1),[15,32]
N,N'-(4,4'-biphenylyl) iminodiacetic acid (BP-IDA)
(Scheme 2)[33-35] were synthesized according to the re-
ported procedures.
Preparation of MIG1 aerogel
Synthesis of N,N'-bis-pyridin-4-ylmethylene-hydra-
zine (4-bpmb)
BP-IDA (0.042 g, 0.10 mmol), 4-bpmb (0.042 g,
0.20 mmol), and Cr(NO3)3•9H2O (0.120 g, 0.30 mmol)
in 2 mL DMF were sealed in a 10 mL Teflon-lined au-
toclave, then the suspension was subjected to ultrasonic
treatment until a clear mixture was got. The reaction
system was kept at 120 ℃ for 3 h, and then the MIG1
can be obtained (Figure 1). The blackgreen gel was
washed with DMF to remove unreacted starting materi-
als. Then, the wet gel was immersed in a large
Pyridine-4-ylmethylene-hydrazine (4.49 g, 40.00
mmol) was dissolved in 15 mL ethanol in a 25 mL
round bottom flask, and then hydrazine hydrate (1.03 g,
21.00 mmol) was added slowly with vigorous stirring.
After 15 min, the yellow precipitate appeared, 4-bpmb
was obtained by filtration in 70% yield. H NMR (400
MHz, CDCl3) δ: 8.76 (s, 4H, ArH), 8.57 (s, 2H, CH2),
7.70 (s, 4H, ArH) (Figure S7, Supporting Information).
1
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Synthesis of Highly Stable Porous Metal-Iminodiacetic Acid Gels from a Novel IDA Compound
Scheme 2 Synthesis of compound BP-IDA
COOEt
COOH
N
NH2
N
COOEt
COOH
H+
KI/K2HPO4
CH3CN
NaOH
EtOH
+
BrCH2COOEt
H2O
NH2
EtOOC
N
HOOC
N
COOEt
BP-IDE
COOH
BP-IDA
COOH
a
.
Cr(NO3)3 9H2O
MIG1
N
COOH
Solvothermal
4-bpmb
.
Al(NO3)3 9H2O
HOOC
N
MIG2
Solvothermal
COOH
Figure 1 Synthesis of metal-IDA gels (a) and photographic images of MIG1 (b) and MIG2 (c) gels in DMF.
amount of tert-butanol thoroughly to exchange DMF.
Finally the aerogel was obtained by freeze-drying under
vacuum (less than 20 Pa) for 24 h. The product is named
MIG1 aerogel. The preparation conditions were opti-
mized through varying feeding ratios, temperatures, and
concentrations, respectively (Tables S1－S4, Supporting
Information).
U.K.) using 300 W Al Kα radiation. Thermogravimetric
analysis (TGA) was performed on a Pyris Diamond
thermogravimetric/differential thermal analyzer (Perkin-
Elmer Instruments Co. Ltd., U.S.A.) by heating the
samples at 10 ℃•min1 to 800 ℃ under nitrogen at-
mosphere. Power X-ray diffraction (PXRD) patterns
were measured from 4° to 40° by a Philips X’Pert PRO
X-ray diffraction instrument (Philips, Netherlands). Ni-
trogen adsorption-desorption experimentation was con-
ducted using a 3Flex surface characterization analyzer
(Micromeritics, U.S.A.). The analysis was measured at
77 K, and the obtained nitrogen sorption isotherm was
assessed to give pore properties such as specific surface
area, pore size distribution, total pore volume, and so on.
The rheological properties were tested by a MARS2
rheometer (HAKKE, Thermo Scientific, Germany) with
25 mm diameter parallel-plate geometry at 25 ℃, the
gap distance between two plates was fixed to 2 mm and
the frequency sweep was in the range from 0.02 to 100
rad•s−1 at a fixed oscillatory strain of 1%.[36]
Preparation of MIG2 aerogel
The synthesis of MIG2 aerogel was similar to that of
MIG1 aerogel, except that Cr(NO3)3•9H2O was replaced
by Al(NO3)3•9H2O (Figure 1 and Table S5, Supporting
Information).
Instrumental characterization
1H NMR and 13C CP/MAS NMR spectra were col-
lected by a Bruker Advance III 400 NMR spectrometer
(Bruker, Germany). Infrared (IR) spectra were recorded
in KBr pellets with a Spectrum One Fourier transform
infrared (FT-IR) spectrometer (PerkinElmer Instruments
Co. Ltd., U.S.A.). The IR sample was prepared by dis-
persing the solid in KBr and compressing the mixtures
to form disks, and 16 scans were signal-averaged. Scan-
ning electron microscopy (SEM) observations were car-
ried out using a S-4800 microscope (Hitachi Ltd., Japan)
at an accelerating voltage of 6.0 kV. Transmission elec-
tron microscopy (TEM) observations were carried out
using a Tecnai G2 S-TWIN microscope (FEI, U.S.A.) at
an accelerating voltage of 200 kV. X-ray photoelectron
spectroscopy (XPS) data were acquired with an ESCA-
Lab220i-XL electron spectrometer (VG Scientific Ltd.,
Results and Discussion
IDA is well-known for a long time, which can coor-
dinate to metal ions as a common multidentate ligand.[37]
As a derivative of IDA, the obtained BP-IDA can also
chelate metal ions by two IDA groups. According to the
literature, although IDA has many coordination
modes,[17] once the auxiliary N-donor ligand is intro-
duced into the system, BP-IDA tends to form ideal tri-
dentate mode with metal atoms through IDA, N-donor,
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and solvent molecule.[18,21,38] In this work, gels were
fabricated through simple mixing of BP-IDA, auxiliary
ligand, and metal salt in DMF solution above 80 ℃. It
is rationalized that the mechanism underpinning the
construction of metal-organic gel hybrid progresses in
accordance with Figure 2, endorsed by theoretical in-
ference and experimental observations. Different from
most metal-organic gels,[39,40] the as-synthesized MIG1
and MIG2 are very stable when kept for more than sev-
eral months under ambient environment (room temper-
ature and pressure) without collapsing, and they can not
be dissolved under heating. Meanwhile, the state of
MIGs has no change to the external mechanical force
due to their high strength.
Several preparation conditions have been changed
(such as metal-BP-IDA ratio, temperature, and concen-
tration) in order to obtain better and more stable network
structures of MIGs. All the experiments are carried out
in DMF due to the poor solubility of BP-IDA in other
solvents, the ratio of 4-bpmb to BP-IDA is invariable
(4-bpmb/BP-IDA＝2/1). Firstly, because different met-
al-BP-IDA ratios are able to affect the 3D network
structures of the gels, several groups of experiments are
designed with different metal-BP-IDA ratios from 1∶1
to 6∶1. According to the structures and the specific
surface area of MIG aerogels, metal/BP-IDA＝3/1 is
found to be the optimum proportion (Tables S1 and S4,
Supporting Information). Secondly, the experiments are
studied at six different temperatures from 70 to 160 ℃
(Tables S2 and S4, Supporting Information), owing to
the temperature of reaction can influence the gelation
time and the intensity of gels. Metal-IDA gels can be
formed above 80 ℃, and higher reaction temperature
leads to shorter gelation time and stronger structure. It is
found that 150 ℃ is the optimum temperature. So far,
lots of gels that are sensitive to temperature have been
reported, and gel-to-sol transition was observed upon
heating and the solutions reverted to gel upon cooling.[41]
Interestingly, metal‒IDA gels synthesized can maintain
their gel state and strength at high temperature for sev-
eral days, and these highly stable gels were rarely re-
ported in previous literature. Thirdly, the solution con-
centrations could influence the strength of gels, and ob-
viously concentrated solution led to faster and stronger
gel formation than diluted one. The solutions with vari-
ous concentrations from 0.025 to 0.100 mol•L1 (the
concentration is based on BP-IDA) are used (Tables S3
and S4, Supporting Information). Compared with the gel
formed under 0.100 and 0.025 mol•L1, the concentra-
tion of 0.05 mol•L1 is the optimum proportion for the
gel strength and the aerogel porosity. Taking together,
the optimum metal-IDA gel preparation condition is the
ratio of metal/BP-IDA/4-bpmb＝3/1/2, temperature of
150 ℃, and concentration of 0.05 mol•L1.
The viscoelastic nature of these gels was confirmed
by rheological measurements. Firstly, oscillatory ampli-
tude sweep was performed on the sample in order to
choose the strain at which the dynamic frequency sweep
is required to be carried out. From the frequency sweep
measurements, a strain of 1% was determined to test the
storage modulus (G') and the loss modulus (G") of gels.
As shown in Figure 3, it is obvious that G' is always
higher than G" for either MIG1 or MIG2 over the range
of 0.02－100 rad•s1. Both G' and G" are slightly sensi-
tive to angular frequency and the average G' was about
twelve times higher than G" in the tested range. These
values of mechanical properties were tested 15 d after
synthesis of metal–IDA gels. MIG1 possesses a rela-
O
solvent molecule
O
O
N
O
N N
M
N
O
N
M
N
O
O
solvent molecule
O
Figure 2 Assumed structure of metal-IDA gel.
Figure 3 Dynamic rheology behaviors of MIG1 (a) and MIG2 (b).
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Synthesis of Highly Stable Porous Metal-Iminodiacetic Acid Gels from a Novel IDA Compound
＋
presence of Cr3 was evidenced by a signal at 578 eV
tively high storage modulus (2.6 kPa＜G'＜4 kPa) than
MIG2 (1.9 kPa＜G'＜2.7 kPa), indicating the MIG1 has
a higher degree of cross-linking. The reason may be that
chromium is a heavy metal that has a stronger coordina-
tion ability compared to aluminum. The results indicate
that the MIGs have markedly elastic rather than viscous
characteristics when applying dynamic load and the
metal-IDA gels have permanent network structures.
In order to further explore the network structures of
MIGs, aerogels were prepared by freeze-drying the pre-
pared gels. The morphology and microstructure of the
MIG1 and MIG2 aerogels were observed by SEM and
TEM measurements (Figures 4 and S8, Supporting In-
formation). The SEM images (Figures 4a and S8a,
Supporting Information) show sponge-like and 3D po-
rous network structures of MIG1 and MIG2. The TEM
images (Figures 4b and S8b, Supporting Information)
further reveal that aerogels are irregularly interconnect-
ed to span large void space and sustain the gel matrix
and the particles were amorphous with no long-ranged
order. The X-ray powder diffraction patterns (Figure S9,
Supporting Information) with weak and broad signals
indicate the amorphous nature of the aerogels.
in the Cr 2p3/2 region, and a signal at 587 eV in the Cr
2p1/2 region,[29] respectively (Figure 5a). The
high-resolution spectrum shows a broad peak of N 1s,
indicating the presence of C＝N at 399.5 eV[15] (Figure
5b). IR spectra of the aerogels and BP-IDA, 4-bpmb
(Figure 6) further confirm the coordination of the car-
boxylate and pyridine group to metal ions, as evidenced
by the shift of the C＝O stretching frequency from ca.
1721 cm1 for the uncoordinated carboxylic acid to 1619
cm1, the C＝N stretching frequency[42] from ca. 1418
cm1 for the uncoordinated pyridine to 1384 cm1 for the
aerogels. The thermal stability of the aerogels was stud-
ied by TGA measurement (Figure S11, Supporting In-
formation). The aerogels were heated at a rate of 10 ℃•
min1 to 800 ℃ in nitrogen atmosphere and showed
continuous mass loss from room temperature to 800 ℃.
For these aerogels, the weight loss (10%) at tempera-
tures below 200 ℃ may be due to the loss of solvent
molecules that exactly chelate metal ions in line with the
expectative structure or trapped inside the networks.
Good stability and strength of metal-IDA gels may
originate from their excellent porosity of network struc-
tures. Nitrogen adsorption-desorption measurements at
77 K were performed to investigate the porous property
of MIG1 and MIG2 aerogels. As shown in Figure 7a,
both MIG1 and MIG2 aerogels display a combination of
type I and II sorption isotherms according to the IUPAC
classification. The isotherms exhibit a high gas uptake at
the relative pressure (p/p0) less than 0.02, a flat course at
the middle relative pressure, and sharp gas adsorption at
the high relative pressure, which indicate a significant
microporosity and macroporosity in the MIG aerogels.
The BET specific surface area results are found to be
760 and 430 m2•g1 for MIG1 and MIG2 aerogels, re-
spectively. Owing to their flexible structure in their
networks, MIGs exhibit relatively lower specific surface
area compared with other metal-organic gel counterparts
reported.[43,44] The micropore specific surface area using
the t-plot method is 90 and 50 m2•g1, while the total
pore volume at p/p0＝0.99 is up to 2.5 and 1.7 cm3•g1.
Figure 7b shows the pore size distribution (PSD) pro-
files of MIG1 and MIG2 aerogels based on nonlocal
Figure 4 SEM (a) and TEM (b) micrographs of MIG1 aerogel.
The chemical compositions of MIG1 and MIG2 aer-
ogels were analyzed by X-ray photoelectron spectros-
copy (XPS) measurement as shown in Figures 5 and
S10 (Supporting Information). In the XPS survey spec-
trum of MIG1 aerogel (Figure S10a, Supporting Infor-
mation), the carbon-, oxygen-, nitrogen-, and chromium-
related peaks are detected, which contains C, O, N, and
Cr of 55.2, 31.4, 7.8, and 5.5 at%, respectively. The
Figure 5 X-ray photoelectron spectroscopy (XPS) spectra of Cr 2p (a) and resolved N 1s (b).
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Chen et al.
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to produce MIGs were optimized by varying metal-lig-
and ratio, temperature, and concentration. Rheology
measurement confirms the rigidity and elastic behavior
of metal-IDA gels, and their sponge-like morphologies
were investigated by SEM and TEM observations. In
order to evaluate the 3D network structure of MIGs,
aerogels were acquired by freeze-drying the gels. Nitro-
gen sorption isotherm measurements reveal that MIG
aerogels possess high specific surface area and exhibit
obvious pore size distribution in micropore and
macropore regions. These characteristics make MIGs
have a wide range of potential applications including
separation, catalysis, and drug delivery.
Figure 6 IR spectra of 4-bpmb, BP-IDA, MIG1 and MIG2 aer-
ogels.
Acknowledgement
The financial support of the National Natural Sci-
ence Foundation of China (Nos. 21374024, 21301119,
21304022, and 21574032) is acknowledged.
References
[1] Yang, Q.; Liu, D.; Zhong, C.; Li, J.-R. Chem. Rev. 2013, 113, 8261.
[2] Pei, X.; Chen, Y.; Li, S.; Zhang, S.; Feng, X.; Zhou, J.; Wang, B.
Chin. J. Chem. 2016, 34, 157.
[3] Lu, K.; He, C.; Lin, W. J. Am. Chem. Soc. 2015, 137, 7600.
[4] Mondloch, J. E.; Bury, W.; David, F.-J.; Kwon, S.; DeMarco, E. J.;
Weston, M. H.; Sarjeant, A. A.; Nguyen, S. T.; Stair, P. C.; Snurr, R.
Q.; Farha, O. K.; Hupp, J. T. J. Am. Chem. Soc. 2013, 135, 10294.
[5] Zhang, J.; Su, C.-Y. Coord. Chem. Rev. 2013, 257, 1373.
[6] Xue, C.; Zhong, C. Chin. J. Chem. 2009, 27, 472.
[7] Jung, J. H.; Lee, J. H.; Silverman, J. R.; John, G. Chem. Soc. Rev.
2013, 42, 924.
[8] Tam, A. Y.-Y.; Yam, V. W.-W. Chem. Soc. Rev. 2013, 42, 1540.
[9] Abdallah, B. D. J.; Weiss, R. G. Adv. Mater. 2000, 12, 1237.
[10] Kumar, D. K.; Jose, D. A.; Das, A.; Dastidar, P. Chem. Commun.
2005, 4059.
[11] Li, H.; Tan, X.; Zhang, J. Chin. J. Chem. 2015, 33, 141.
[12] Chen, P.; Li, Q.; Grindy, S.; Niels, H.-A. J. Am. Chem. Soc. 2015,
137, 11590.
[13] Xiao, B.; Zhang, Q.; Huang, C.; Li, Y. RSC Adv. 2015, 5, 2857.
[14] Wei, S.-C.; Pan, M.; Li, K.; Wang, S.; Zhang, J.; Su, C.-Y. Adv.
Mater. 2014, 26, 2072.
[15] Dhara, B.; Patra, P. P.; Jha, P. K.; Jadhav, S. V.; Kumar, G. V. P.;
Ballav, N. J. Phys. Chem. C 2014, 118, 19287.
Figure 7 Nitrogen sorption isotherms of MIG1 and MIG2 aer-
ogels at 77 K (a) and pore size distribution profiles of MIG1 and
MIG2 aerogels calculated by the NLDFT approach (b).
[16] Yang, Q.; Tan, X.; Wang, S.; Zhang, J.; Chen, L.; Zhang, J.-P. Mi-
croporous Mesoporous Mater. 2014, 187, 108.
[17] Cui, L.; Wu, J.; Ju, H. ACS Appl. Mater. Interfaces 2014, 6, 16210.
[18] Lee, H.; Lee, J. H.; Kang, S.; Lee, J. Y.; John, G.; Jung, J. H. Chem.
Commun. 2011, 47, 2937.
density functional theory (NLDFT). The steep peaks are
located at 0.98－1.81 nm in the micropore area, and a
great amount of mesopores and macropores can be
found from 2－100 nm. The results reveal that the ob-
tained aerogels possess the pore size distributions from
micro- to macro-regions. Stable network structures of
these gels make them become porous materials and have
a potential ability to possess gas selective adsorption
performance.
[19] Piepenbrock, M. M.; Clarke, N.; Steed, J. W. Soft Matter 2011, 7,
2412.
[20] Afrasiabi, R.; Kraatz, H.-B. Chem. Eur. J. 2015, 21, 7695.
[21] Blake, K. M.; Johnston, L. L.; Braverman, M. A.; Nettleman, J. H.;
Sposato, L. K.; LaDuca, R. L. Inorg. Chim. Acta 2010, 363, 2233.
[22] Parshamoni, S.; Sanda, S.; Jena, H. S.; Tomar, K.; Konar, S. Cryst.
Growth Des. 2014, 14, 2022.
[23] Dey, R.; Haldar, R.; Maji, T. K.; Ghoshal, D. Cryst. Growth Des.
2011, 11, 3905.
[24] Tang, L.; Bai, L.; Duan, Y.; Xia, W.; Dong, W.; Li, D. Z. Anorg.
Allg. Chem. 2014, 640, 2268.
Conclusions
In summary, a novel aromatic multi-carboxylate
compound BP-IDA is designed and synthesized by an
easy method, and two new types of porous met-
al-organic gels MIG1 and MIG2 have been easily ob-
tained via solvothermal process. The reaction conditions
[25] Ni, L.-B.; Zhang, R.-H.; Liu, Q.-X.; Xia, W.-S.; Wang, H.; Zhou,
Z.-H. J. Solid State Chem. 2009, 182, 2698.
[26] Zhang, J.; Xue, Y.-S.; Li, Y.-Z.; Du, H.-B.; You, X.-Z.
622
www.cjc.wiley-vch.de
© 2016 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Chin. J. Chem. 2016, 34, 617—623

Synthesis of Highly Stable Porous Metal-Iminodiacetic Acid Gels from a Novel IDA Compound
CrystEngComm 2012, 14, 8215.
[35] Sun, F.; Zhang, G.; Zhang, D.; Xue, L.; Jiang, H. Org. Lett. 2011, 13,
[27] Karmakar, A.; Goldberg, I. CrystEngComm 2011, 13, 339.
[28] Zhan, C.; Zou, C.; Kong, G.-Q.; Wu, C.-D. Cryst. Growth Des. 2013,
13, 1429.
[29] Eubank, J. F.; Mouttaki, H.; Cairns, A. J.; Belmabkhout, Y.; Wojtas,
L.; Luebke, R.; Alkordi, M.; Eddaoudi, M. J. Am. Chem. Soc. 2011,
133, 14204.
6378.
[36] Sui, Z.; Zhang, X.; Lei, Y.; Luo, Y. Carbon 2011, 49, 4314.
[37] Yang, T.-H.; Silva, A. R.; Fuc, L.; Shi, F.-N. Dalton Trans. 2015, 44,
13745.
[38] Siddiqi, Z. A.; Shahid, M.; Khalid, M.; Kumar, S. J. Med. Chem.
2009, 44, 2517.
[30] Park, I.-H.; Medishetty, R.; Lee, H.-H.; Herng, T. S.; Ding, J.; Lee, S.
S.; Vittal, J. J. Cryst. Growth Des. 2015, 15, 4156.
[31] Xiang, S.; Li, L.; Zhang, J.; Xin, T.; Cui, H.; Shi, J.; Hu, Y.; Chen,
L.; Su, C.-Y.; James, S. L. J. Mater. Chem. 2012, 22, 1862.
[32] Kennedy, A. R.; Brown, K. G.; Graham, D.; Kirkhouse, J. B.;
Kittner, M.; Major, C.; McHugh, C. J.; Murdoch, P.; Smith, W. E.
New J. Chem. 2005, 29, 826.
[39] Ma, X.; Zhang, J.; Tang, N.; Wu, J. Dalton Trans. 2014, 43, 17236.
[40] Lin, Q.; Yang, Q.-P.; Sun, B.; Fu, Y.-P.; Zhu, X.; Wei, T.-B.; Zhang,
Y.-M. Soft Matter 2014, 10, 8427.
[41] Yao, H.; You, X.-M.; Lin, Q.; Li, J.-J.; Guo, Y.; Wei, T.-B.; Zhang,
Y.-M. Chin. Chem. Lett. 2013, 24, 703.
[42] Dong, Z.; Liu, J.; Yuan, W.; Yi, Y.; Zhao, L. Chem. Eng. J. 2014,
283, 504.
[33] Meng, X.-M.; Zhu, M.-Z.; Liu, L.; Guo, Q.-X. Tetrahedron Lett.
2006, 47, 1559.
[43] Li, L.; Xiang, S.; Cao, S.; Zhang, J.; Ouyang, G.; Chen, L.; Su, C.
Nat. Commun. 2013, 4, 1774.
[34] Ngwendson, J. N.; Amiot, C. L.; Srivastavab, D. K.; Banerjee, A.
Tetrahedron Lett. 2006, 47, 2327.
[44] Xia, W.; Zhang, X.; Xu, L.; Wang, Y.; Lin, J.; Zou, R. RSC Adv.
2013, 3, 11007.
(Cheng, F.)
Chin. J. Chem. 2016, 34, 617—623
© 2016 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.cjc.wiley-vch.de
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