A porous Er(III)–organic framework as a highly efficient catalyst for chemical fixation of CO2 and treatment activity on senile deafness via inducing the cochlear hair cell apoptosis

Article abstract of DOI:10.1007/s13738-020-02111-w

A microporous Er(III)-based metal–organic framework (MOF), whose chemical formula can be written as {[Er(TCPB)(H₂O)]·dioxane·0.5H₂O}_n, has been formed from the tripodal ligand 1,3,5-tris(4-carbonylphenyloxy)benzene (H₃TCPB) by solvothermal synthesis and determined by the single crystal X-ray diffraction and the elemental analysis. With the aid of microporous framework and abundant catalytic sites of open Er(III) sites, the activated 1 is a special catalyst for the synthesis of cyclic carbonates from carbon dioxide and epoxy compounds under the cocatalyst TBAB and gently solvent-less conditions. The treatment activity of the compound on the senile deafness, as well as the influence of the compound on the cochlear hair cell death was explored. Firstly, the cell apoptosis of the cochlear hair cells was estimated via CCK-8 assay. Next, the activation of the caspase-3,8 was evaluated with western blot.

Full text of DOI:10.1007/s13738-020-02111-w

Journal of the Iranian Chemical Society
https://doi.org/10.1007/s13738-020-02111-w
ORIGINAL PAPER
A porous Er(III)–organic framework as a highly eꢀcient catalyst
for chemical ꢁxation of CO and treatment activity on senile deafness
2
via inducing the cochlear hair cell apoptosis
1
1
1
1
1
1
Xiao‑Yan Sun · Jun‑Nan Li · Gui‑Mei Dong · Yan‑Li Tao · Yao Chen · Shu‑Qin Yang
Received: 29 August 2020 / Accepted: 27 October 2020
©
Iranian Chemical Society 2020
Abstract
A microporous Er(III)-based metal–organic framework (MOF), whose chemical formula can be written as {[Er(TCPB)(H
2
O)]·dioxane·0.5H O} , has been formed from the tripodal ligand 1,3,5-tris(4-carbonylphenyloxy)benzene (H TCPB) by
2
n
3
solvothermal synthesis and determined by the single crystal X-ray diꢀraction and the elemental analysis. With the aid of
microporous framework and abundant catalytic sites of open Er(III) sites, the activated 1 is a special catalyst for the syn-
thesis of cyclic carbonates from carbon dioxide and epoxy compounds under the cocatalyst TBAB and gently solvent-less
conditions. The treatment activity of the compound on the senile deafness, as well as the inꢁuence of the compound on the
cochlear hair cell death was explored. Firstly, the cell apoptosis of the cochlear hair cells was estimated via CCK-8 assay.
Next, the activation of the caspase-3,8 was evaluated with western blot.
Keywords MOF · CO ꢂxation · X-ray · Senile deafness
2
Introduction
industry, energy accumulation, ferroelectric industry, water
decomposition, ꢁuorescence sensor industry, drug transport,
and other ꢂelds [4–9]. MOFs have been used as catalysts
in the cycloaddition reaction of carbon dioxide with epoxy
compounds, showing very good activity. However, only
several MOF-based catalysts have been used, porous Ln-
MOFs are regarded as ideal catalysts for the reaction of car-
bon dioxide with epoxy compounds based on the following
factors: (1) porous Ln-MOFs can eꢀectively adsorb carbon
dioxide; (2) large porosity in Ln-MOFs can increase the con-
With the progress of society, the development of medical
and health services, the aging of the population, and the
improvement of people’s quality of life, senile deafness has
become one of the most important diseases that endanger
human health [1]. Senile deafness should get the attention of
people from all over the world. The prevention and treatment
of senile deafness has become a challenge for medical and
health workers. At present, it focuses on the molecular-level
research [2, 3]. The relationship between the senile deafness
and cochlear hair cell apoptosis was explored and becoming
the research hotspots in this ꢂeld.
3
+
tent of epoxide and substrate concentration; (3) Ln ions
can be used as Lewis acid center to improve the catalytic
activity; (4) steady Ln-MOFs can be recycled to save money
[10–18]. Thus, it is necessary to detect Ln-MOF-based cata-
lysts for chemical immobilization of carbon dioxide with
epoxy compounds.
Metal–organic frameworks (MOFs) are inorganic organic
hybrid structure based on metal ions or clusters by combin-
ing with organic compounds, which have the characteristics
of customizable pore size and high speciꢂc surface area.
Based on the above properties, MOFs have attracted a lot
of attention in catalysis industry, gas storage, and extraction
Bearing these in mind, in this study, a microporous
Er(III)-based metal–organic framework (MOF), whose
chemical terms can be written as {[Er(TCPB)(H O)]·dio
2
xane·0.5H O} , has been formed from the tripodal ligand
2
n
1
,3,5-tris(4-carbonylphenyloxy)benzene (H TCPB) by sol-
3
*
Shu-Qin Yang
vothermal synthesis and determined by the single crystal
X-ray diꢀraction and the elemental analysis. With the aid
of microporous framework and abundant catalytic sites of
open Er(III) sites, the activated 1 is a special catalyst for
Y_shuqin62@yeah.net
1
Department of Otorhinolaryngology, Weifang People’s
Hospital, Weifang, Shandong, China
Vol.:(0
1
123456789)
3

Journal of the Iranian Chemical Society
the synthesis of cyclic carbonates from carbon dioxide and
epoxy compounds under the cocatalyst TBAB and gently
solvent-less conditions. In biological study, the inhibitory
activity of the compound on the cochlear hair cell apop-
tosis was explored. The results of the Cell Counting Kit-8
suggested that the compound had a signiꢂcant inꢁuence on
increasing the viability of the cochlear hair cells in a dose-
dependent manner. Moreover, the analysis of the western
blot proved that the activation level of the caspase-3,8 was
signiꢂcantly increased.
Table 1 Reꢂnement details and crystallographic parameters for com-
plex 1
Empirical formula
Formula weight
Temperature (K)
Crystal system
Space group
a (Å)
C H ErO
27 17 10
668.66
273.15
Monoclinic
P2/c
16.5529 (2)
11.42690 (10)
b (Å)
c (Å)
18.3681 (3)
α (°)
β (°)
90
111.793 (2)
γ (°)
Volume (Å )
90
Experimental
3
3225.99 (8)
Z
4
Chemicals and measurements
3
ρcalc (g/cm )
1.377
2.647
7386/6/344
1.069
R =0.0336, ωR =0.0882
R =0.0541, ωR =0.0945
0.92/–1.14
2,014,157
μ (mm−
1
)
Unless otherwise noted, materials were obtained from the
markets and used without deeper reꢂne. Infrared (IR) spectra
Data/restraints/parameters
Goodness-of-ꢂt on F
Final R indexes [I≥2σ (I)]
Final R indexes [all data]
Largest diꢀ. peak/hole/e Å
CCDC
2
−
1
(
400–4000 cm ) were recorded through an EQUINOX-55
1
2
FT-IR spectrometer. Elemental analyses were operated via
the Perkin-Elmer 2400C Elemental analyzer. Gas absorption
was measured by the ASAP 2020 analyzer. The catalytic
yield was computed and determined on the Thermo Fisher
Trace ISQ GC/MS device.
1
2
−3
Cell viability
Preparation and characterization for {[Er(TCPB)
Cell Counting Kit-8 (CCK-8) was operated in this research
to detect the improvement activity of the compound on
the cochlear hair cells. This preformation was carried
out under the illustration of the manufacturers with some
changes. In a word, the cochlear hair cells in the logical
growing phage were gathered and cultivated into the tis-
(H O)]·dioxane·0.5H O} (1)
2 2 n
Complex 1 is formed by mixing 45 mg Er(NO ) ·6H O,
3
3
2
2
0 mg H TCPB, and DMF:dioxane:H O (ratio is 1:1:2).
3
2
After stirring, the mixture was set in a pyrex glass tube and
heated at 110 °C last for 72 h. After lowering to the nor-
mal environment, achromatic chunk-shaped crystals 1 were
6
sue glass garden at the ultimate fate of 10 cell/well. The
apoptosis inducer was added into cells for pre-treatment,
then the compound was used at the content of 1, 2, 5 mg/
ml. The cells were then cultured in the incubator with a
temperature of 37 °C and a 5% carbon dioxide concentra-
tion. After 24 h incubator, the absorbances of each well
were measured, and the viability of the cells was analyzed.
obtained in 37% yield based on H TCPB. Anal. Cald. For
3
1
(C H ErO ): the carbon content is 48.12; the hydro-
3
1
26
12.5
gen content is 3.39. Found: the carbon content is 48.16, the
hydrogen content is 3.80.
In order to obtain the data of X-ray, we use the Oxford
Xcalibur E diꢀractometer. Statistical analysis of various
strength data was performed using crysalispro software
and the results were converted to HKL format. The pattern
of SHELXS based on direct means was applied for estab-
lishing the primary framework patterns, and the pattern of
SHELXL-2014 based on least square method was altered.
The atom except hydrogen atom is reꢂned by using diꢀerent
heterogenous parameters. Next, the whole of H atoms with
applying AFIX program to fasten on the C atom. Table 1
displays the speciꢂc parameters of complex 1.
Western blot
To explore the inhibitory eꢀect of the compound on the
cochlear hair cells death, the western blot was conducted
in this research total according to the protocols. Brieꢁy,
the cochlear hair cells were gathered and cultivated into
6
the tissue glass garden at the ultimate fate of 10 cell/well.
The apoptosis inducer was added into cells for pre-treat-
ment, then the compound was used at the content of 1, 2,
5
mg/ml. After treatment, the total protein was extracted.
1
3

Journal of the Iranian Chemical Society
After measuring the protein concentration, the expression
of the caspase-3,8 was determined.
length of 2.32(0) Å. During the combination of Er-MOF,
III
H TCPB ligand is fully deprotonated by six Tb ions and
3
1
1
1
1
1
1
linked with (κ –κ )–(κ –κ )–(κ –κ )–μ structure (Fig. 1b).
6
The contiguous Er(III) ions are linked by carboxylate O
Results and discussion
to construct tetranuclear {Er (COO) (DMF) } SBUs,
4
10
4 n
3
−
which are further extended by TCPB ligands to form a
Molecular structures
three-dimensional [Er(TCPB)] net including two various
n
one-dimensional channels. Among them, the quadrilateral
channel (12.228 × 19.210 Å) and the rectangular channel
(11.115 × 13.231 Å) are ꢂlled by coordinated DMF mol-
ecules and lattice dioxane, respectively (Fig. 1c). Accord-
ing to topological analysis, when {Er (COO) (DMF) }
According to the single crystal results gathered at natural
temperature and the analysis of its structure, the results
reveal that the complex 1 forms crystals in the P2/c group,
where is a monoclinic space, and exhibits a three-dimen-
sional structure with one-dimensional pathway extending
along the c-axis. The asymmetric part of 1 contains single
Er(III) ion, single lattice dioxane molecule, a half lattice
4
10
4 n
3
−
SBUs and TCPB ligands are used as 8-c nodes and 4-c
nodes respectively, the ultimate three-dimensional structure
of 1 can be written as a (4,8)-c network with stoichiom-
3
−
4
2
8
17
3
water molecule, a fully deprotonated TCPB ligand, and
a coordination water molecule (Fig. 1a). The coordination
sphere of the central Er(III) ion presents a twisted {ErO8}
double-capped prism geometry, which consists of seven car-
boxyl O atoms (O1A, O1, O2A, O5B, O6C, O8, and O9) in
etry (4-c) (8-c) and the marker symbol {4 ·6 } {4 ·6 ·8 }
2 2
(Fig. 1d).
Gas adsorption and chemical ꢀxation of CO2
3−
four various TCPB connectors and single oxygen atom in a
coordination water molecule (O10). The range of the length
of Er–O bond is 2.252(4)–2.668(0) Å, with an average bond
As discussed above, complex 1 shows one-dimensional
channels along an axis, and the estimated void was 32.5% for
solvent, which might be potentially used for the gas sorption.
3
−
Fig. 1 a View for the asymmetry part of 1. b The connection pattern for the TCPB ligand. c The three-dimensional framework of 1 showing
the one-dimensional pathways. d The (4,8)-connection net of 1
1
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Journal of the Iranian Chemical Society
Furthermore, high density and uncoordinated N sites of open
positions with the high density of exposed pyridinyl groups
in the channels. At the aim of understanding the interaction
of skeleton along with adsorbate more deeply, according to
adsorption isotherms of 273 and 298 K, using virial analysis
metal sites might be potential used for CO chemical ꢂxa-
2
tion. In order to obtain 1s solvent-free sample, the newly
prepared sample was immersed in methanol for 72 h, and
1
a’ s solvent-free sample was obtained via supercritical CO
approach, it was found that the adsorption heat of 1a for CO
2
2
activation. As shown in Fig. 2a, the CO sorption isotherm
(Q ) was 29.0 kJ/mol under zero coverage (Fig. 2c). The
2
st
of activated 1a at 195 K has a typical kind I adsorption iso-
observed values exceeded the MOFs at the recently reported
therm, which veriꢂes its permanent microporous properties.
free nitrogen donor sites as well as open metal sites. The
1
a′ s Brunauer–Emmett–Teller surface area was determined
strong electric charge induced force between guest CO mol-
2
2
to be ~504 m /g. For compound 1a, at 1 bar pressure, the
ecules and positively charged open metal sites, as well as the
3
maximum absorption of CO is 72.8 cm /g at 273 K and
interaction between acidic CO molecules in pore along with
2
2
3
4
8.4 cm /g at 298 K, and little nitrogen is absorbed in the
Lewis basic N atoms in 1a framework, are essential for the
same case (Fig. 2b). The CO adsorption ability of 1a
absorption of large amounts of carbon dioxide.
2
around room temperature is higher than some Ln-MOFs
The distinctive position of open metal in pore of 1a and
the position of free nitrogen donor sites provide us with the
scope of catalytic experiments. We chose the conditions of
relatively mild (25 °C and 0.1 MPa) with the co-catalyst
TBAB to obtain 1a catalytic ability for the conversion of
propylene oxide (PO) and carbon dioxide (Scheme 1). The
yield of the product was 9%, exhibiting that 1a had a low
activity under the room temperature and constant pres-
sure conditions (Table 2, entry 3). Nevertheless, at room
with much higher BET surface areas such as [{Sm(BTB)
2
3
(
H O)}·H O] (BET of 946 m /g, 29 cm /g for carbon diox-
2 2 n
2
ide at 273 K), [{Gd(BTB)(H O)}·H O] (BET of 834 m /g,
2
2
n
3
4
1 for CO cm /g at 273 K), {[Tb(FDA) (DMF)]·DMF}
2 1.5 n
2
3
(
BET of 1004 m /g, 61·cm /g for carbon dioxide at 273 K)
2
3
and JXNU-3 (BET of 646·m /g, 40·cm /g for carbon dioxide
at 298 K). The relative high CO adsorption capacity of 1a
2
might be due to the synergistic eꢀects of the alfresco metal
Fig. 2 a Carbon dioxide adsorption data were collected at 195 K. b The N as well as the CO sorption data for 1a around room temperature. c
2
2
CO adsorption isotherm in 1a
2
1
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Journal of the Iranian Chemical Society
Scheme 1 CO cycloaddition
2
by diꢀerent epoxides
Table 2 Epoxides and CO
2
Entry
1
Catalysts
Epoxides
Products
Yield(%)
5.2
cycloaddition in diꢀerent
reaction conditions
1a
2
3
4
5
TBAB
10.8
9.0
1a/TBAB
1a/TBAB
1a/TBAB
>98.9
98.3
6
1a/TBAB
83.1
7
8
1a/TBAB
1a/TBAB
90.9
40
The number of mole amounts are epoxy compound of 20 mmol, 0.2 mmol catalyst 1a, as well as TBAB
which is 2 mmol; The reactivation conditions in entry 3: 25 °C, 0.1 MPa and 2 days; items 1–2 and 4–8:
4
h, 60 °C and 1.0 MPa
temperature along with 1.0 MPa, catalytic experiments
compounds substituted via diꢀerent functional groups was
tested in items 5–8. This might be due to the hindrance of
corresponding large size products as well as diꢀerent epoxy
compounds, this slows down reactants diꢀusion. By com-
parison, the catalytic eꢃciency of TBAB or 1a for PO is
with TBAB and 1a as cocatalysts for 4 h provided a strong
catalytic activity for the reaction of PO and CO to pro-
2
pylene carbonate, and the yield rate was 98.9% (Table 2,
entry 4). Furthermore, the addition of CO rings to epoxy
2
1
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Journal of the Iranian Chemical Society
Based on former studies and the crystal framework of
, a hypothesis about the catalytic process was advance
1
3
+
(
Fig. 3). Firstly, the exoteric Er sites were created by
removing the coordination water molecules, and then these
water molecules participated in absorbing and coordinat-
ing with the O atoms in the epoxy compounds to further
polarize the epoxy ring. Secondly, the polarization ring
−
is attacked by Br of TBAB to construct an exoteric ring
with intermediate O anion. O anion attacks the contiguous
carbon dioxide molecules quickly, and carbon dioxide mol-
ecules are absorbed and polarized by the weak Lewis basic
pyridine N position on the pathway surface of 1. At the
same time, O anion from polarized carbon dioxide attacks
−
the Br coordinated epoxy carbon atoms to complete the
cyclization. Therefore, it could be deduced that the addi-
tion of weak Lewis acidic and basic sites centers in one
framework can promote the whole cycloaddition process
synergistically.
Compound increased the viability of the cochlear
hair cells
Fig. 3 The mechanism of cycloaddition of epoxides with carbon
dioxide catalyzed by 1a was preliminarily proposed
The compound was synthesized with novel structure, and its
inꢁuence on the cochlear hair cells viability was measured
with CCK-8. Figure 4 indicates that after stimulating with
apoptosis inducer, the cell activity was markedly reduced,
which is dramatically diꢀerent from the treatment group.
While the compound treatment could obviously increase the
viability, and the promotion ability of the compound on the
viability of the cochlear hair cells was dose dependent.
very low at 60 °C along with 1.0 MPa (entries 1 and 2).
With the addition of epoxidized substrates molecular weight,
the cyclocarbonate yield reduced in varying degrees. The
yields of 3-butoxy-1,2-styrene carbonate along with propyl-
ene carbonate, 4-bromomethyl-1,3-dioxolan-2-one as well
as 4-cloromethyl-1,3-dioxolan-2-one were 40.0%, 90.9%,
8
3.1%, and 98.3%, respectively (Table 2). Moreover, the
Compound inhibited the activation of the caspase‑3
and caspase‑8 in the cochlear hair cells
catalytic ability of 1a was compared with other lanthanide-
based MOFs renowned for cycloaddition of carbon dioxide,
and surprisingly, the reaction conditions used in this experi-
ment are more gentle than the formerly used instances of Ln-
MOFs such as Gea-MOF1 (Pressure: 2 MPa, temperature:
As we proved in the above results, the compound could
increase the viability of the cochlear hair cells in the quan-
tity-dependent method, suggesting that the compound may
has the anti-apoptosis activity. During the cell apoptosis,
1
20 °C, PO yield: 89%) and Gd-MOF (Pressure: 2 MPa,
temperature: 80 °C, PO yield: 98%).
Fig. 4 Increased viability of
the cochlear hair cells after
using compound. The cochlear
hair cells were pre-treated with
apoptosis inducer, and then
added with compound at the
content of 1, 2, 5 mg/ml. The
activity of the cochlear hair
cells was calculated by CCK-8
1
3

Journal of the Iranian Chemical Society
reducing the activation ability of caspase-3,8 in the cochlear
hair cells.
Data Availability The data used to support the ꢂndings of this study
are included within the article.
Compliance with ethical standards
Conflicts of Interest The author(s) declare(s) that there is no conꢁict of
interest regarding the publication of this paper.
Fig. 5 Inhibited activation of the caspase-3,8 in the cochlear hair
cells. The cochlear hair cells were preconditioned with apoptosis
inducer, and then added with compound at the content of 1, 2, 5 mg/
ml. The expression power of the caspase-3,8 in the cochlear hair cells
was measured with western blot
References
1
2
3
4
.
.
.
.
F.E. Musiek, G.D. Chermak, B. Cone, Int. J. Audiol. 58, 605–617
(
2019)
O.G. Barsottini, J.L. Pedroso, C.R. Martins, M.C. França, P.M.
Albernaz, Cerebellum 18, 1011–1016 (2019)
the activation of the caspase-3,8 was increased. So, in this
research, the expression level ofcaspase-3,8 in the cochlear
hair cells was explored. The results in Fig. 5 suggested that
under the treatment of the compound, the activation of cas-
pase-3,8 in the cochlear hair cells was obviously reduced.
This result revealed that the compound could increase the
cochlear hair cells viability via inhibiting the caspase-3,8
activation.
A. Kurz, M. Grubenbecher, K. Rak, R. Hagen, H. Kühn, Eur.
Arch. Otorhinolaryngol. 276, 3317–3325 (2019)
Z. Hasan, S.H. Jhung, ACL Appl. Mater. Interfaces 7, 10429–
1
0435 (2015)
5
6
.
.
J.X. Li, Z.X. Du, J. Clust. Sci. 31, 507–511 (2020)
J.X. Li, Z.X. Du, Q.Y. Pan, L.L. Zhang, D.L. Liu, Inorg. Chim.
Acta 509, 119677 (2020)
7
8
9
.
.
.
J.X. Li, Z.X. Du, L.L. Zhang, D.L. Liu, Q.Y. Pan, Inorg. Chim.
Acta 512, 119890 (2020)
H. Du, C. Ma, W. Ma, H. Wang, Process. Appl. Ceram. 12, 303–
3
12 (2018)
C. Duan, Y. Yu, J. Xiao, X. Zhang, L. Li, P. Yang, J. Wu, H. Xi,
Sci. China Mater. 63, 667–685 (2020)
Conclusion
1
1
1
1
0. R. Chandra, S. Mukhopadhyay, M. Nath, Mater. Lett. 164, 571–
5
74 (2016)
In general, we have smoothly created a microporous Er(III)-
based metal–organic structure from the tripodal ligand
1. Y.H. Han, Z.Y. Zhou, C.B. Tian, S. Du, Green Chem. 18, 4086–
4091 (2016)
2. Y.H. Han, C.B. Tian, L. Ping, S. Du, J. Mater. Chem. A 3, 24525–
1
,3,5-tris(4-carbonylphenyloxy)benzene by solvothermal
2
4531 (2015)
synthesis. By virtue of microporous framework and plenti-
ful catalytic sites of open Er(III) sites, the activated 1 is a
special catalyst for the synthesis of cyclic carbonates from
carbon dioxide and epoxy compounds under the cocatalyst
TBAB and gently solvent-less conditions. The data of the
Cell Counting Kit-8 proved that the compound had a signiꢂ-
cant positive eꢀect on increasing the viability of the cochlear
hair cells in a quantity dependent method. Moreover, the
data of the western blot proved that the activation ability of
the caspase-3,8 was signiꢂcantly increased. In a word, the
compound has great protective activity on senile deafness by
3. W. Wang, L. Wang, Z. Li, Z. Xie, Chem. Commun. 52, 5402–5405
(
2016)
14. R. Babu, A.C. Kathalikkattil, R. Roshan, J. Tharun, D.W. Kim,
D.W. Park, Green Chem. 18, 232–242 (2016)
1
1
5. J.X. Li, Z.X. Du, Z. Naturforsch. 70b, 505–511 (2015)
6. Q.Q. Xiao, G.Y. Dong, Y.H. Li, G.H. Cui, Inorg. Chem. 58,
1
5696–15699 (2019)
17. Z. Han, Y. Yu, Y. Zhang, B. Dong, A. Kong, Y. Shan, J. Mater.
Chem. A 3, 23716–23724 (2015)
1
8. A.K. Gupta, N. Guha, S. Krishnan, P. Mathur, D.K. Rai, J. CO2
Util. 39, 101173 (2020)
1
3