A pillar-layered Cd(II) metal-organic framework for selective detection of organic explosives

Article abstract of DOI:10.1080/00958972.2017.1350656

The detection of explosives is crucial for homeland security, environmental cleaning, and military issues. As a new class of porous materials, metal-organic frameworks (MOFs) are promising platforms for the detection of organic explosives. In this work, a new pillar-layered Cd(II) MOF, [CdL_0.5dpe_0.5]·2H₂O (BUT-202, H₄L?=?4,8-disulfonaphthalene-2,6-dicarboxylic acid, dpe?=?1,2-bis(4-pyridyl)ethylene), was synthesized and characterized by single-crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis, infrared spectroscopy, and elemental analysis. BUT-202 has good fluorescent properties, which can be selectively quenched by trace amounts of 2,4,6-trinitrophenol (TNP) in DMF with low detection limit of 0.2?μM.

Full text of DOI:10.1080/00958972.2017.1350656

Journal of Coordination Chemistry
ISSN: 0095-8972 (Print) 1029-0389 (Online) Journal homepage: http://www.tandfonline.com/loi/gcoo20
A pillar-layered Cd(II) metal-organic framework for
selective detection of organic explosives
Qi Yang, Bin Wang, Shu-Nan Sheng, Hong-Shi Xian & Ya-Bo Xie
To cite this article: Qi Yang, Bin Wang, Shu-Nan Sheng, Hong-Shi Xian & Ya-Bo Xie (2017): A
pillar-layered Cd(II) metal-organic framework for selective detection of organic explosives, Journal
of Coordination Chemistry, DOI: 10.1080/00958972.2017.1350656
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Date: 18 July 2017, At: 06:24

Journal of Coordination Chemistry, 2017
https://doi.org/10.1080/00958972.2017.1350656
A pillar-layered Cd(II) metal-organic framework for selective
detection of organic explosives
Qi Yanga, Bin Wanga, Shu-Nan Shenga, Hong-Shi Xianb and Ya-Bo Xiea
adepartment of Chemistry and Chemical engineering, Beijing university of technology, Beijing, Pr China;
bshanghai institute of space Power-sources, shanghai, Pr China
ABSTRACT
ARTICLE HISTORY
received 24 april 2017
accepted 15 June 2017
The detection of explosives is crucial for homeland security,
environmental cleaning, and military issues. As a new class of
porous materials, metal-organic frameworks (MOFs) are promising
platforms for the detection of organic explosives. In this work,
a new pillar-layered Cd(II) MOF, [CdL0.5dpe0.5]·2H2O (BUT-202,
H4L = 4,8-disulfonaphthalene-2,6-dicarboxylic acid, dpe = 1,2-bis(4-
pyridyl)ethylene), was synthesized and characterized by single-crystal
X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis,
infrared spectroscopy, and elemental analysis. BUT-202 has good
fluorescent properties, which can be selectively quenched by trace
amounts of 2,4,6-trinitrophenol (TNP) in DMF with low detection limit
of 0.2 μM.
KEYWORDS
metal-organic framework;
selective detection; organic
explosive; fluorescent
quenching
1. Introduction
Selective and sensitive detection of highly explosive and explosive-like substances has
become a serious issue concerning national security and environmental protection [1–5].
Among explosive substances, 2,4,6-trinitrophenol (TNP) is commonly used in dyes, fireworks,
matches, glass, and leather industries because of its explosive power [6, 7]. In addition, TNP
has also been recognized as a toxic pollutant. Thus, selective detection of TNP is very impor-
tant for tracing buried explosives and environmental monitoring [8–11].
Detection of highly explosive substances includingTNP is mainly based on trained canines
[12] and modern analytical techniques such as gas chromatography coupled with mass
spectrometry (GC–MC) [13], surface-enhanced Raman spectroscopy [14], mass spectrometry
CONTACT ya-Bo Xie
xieyabo@bjut.edu.cn
supplemental data for this article can be accessed at https://doi.org/10.1080/00958972.2017.1350656.
© 2017 informa uK limited, trading as taylor & francis Group

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Q. YANG ET AL.
(MS) [15], thermal neutron analysis [16], electrochemical procedures [17], and ion mobility
spectroscopy (IMS) [18, 19]. However, all these methods are time consuming, expensive, and
require complex equipment and trained personnel [20]. Therefore, there is an urgent need
for researchers to develop portable, reliable, and inexpensive methods/technologies for the
detection of highly explosive substances.
Compared with traditional analytical techniques, fluorescence sensing is a promising
technology in the detection of organic explosives owing to its advantages of low cost, elec-
tronic tunability, easy portability, and operability, etc. [21, 22]. The challenge of developing
this technology rests with selection of fluorescent materials, which should clearly and solely
respond to the checked molecules. As a new class of porous materials, metal-organic frame-
works (MOFs), constructed from organic ligands and metal ions or clusters through coordi-
nation bonds, have been considered as good platforms for detection/sensing applications
because of their advantages of high surface area, design ability of the framework, strong
interactions between the framework and guest molecules as well as excellent optical prop-
erties [23–26]. As efficient fluorescent sensors, MOFs have been utilized for detecting metal
ions [27–29], DNA [30, 31], volatile organic compounds (VOCs) [32–35], energetic compounds
[36], etc. Till now, several MOFs based on Zn/Cd have been reported for detection of nitro-
based explosives and show good performance [37–41], however, the selective detection of
single explosive nitroaromatic compound in the mixture of nitroaromatic compounds is still
challenging.
In this work, a pillar-layered Cd(II) MOF, [CdL0.5dpe0.5]·2H2O (BUT-202, BUT = Beijing
University of Technology), was synthesized through the reaction of light emitting ligand
acid, 4,8-disulfonaphthalene-2,6-dicarboxylic acid (H4L), and Cd(NO3)2·4H2O in the presence
of 1,2-bis (4-pyridyl) ethylene as additional ligand. The fluorescence of BUT-202 can be selec-
tively quenched by trace amounts of TNP in DMF with low detection limit of 0.2 μM.
2. Experimental
2.1. Materials and general methods
All reagents and solvents (AR grade) were purchased from commercial sources and used
without purification. FT–IR data were acquired on a SHIMADZU IR Affinity-1 instrument. TGA
data were obtained on a TGA-50 (SHIMADZU) thermogravimetric analyzer with a heating
rate of 10 °C min−1 under air. Powder X-ray diffraction (PXRD) patterns were recorded on a
Ragiku Smartlab3 Diffractometer using Cu-Kα radiation (λ = 1.541874 Å) at room tempera-
ture. Simulation of the PXRD pattern was performed by the single-crystal data and diffrac-
tion-crystal module of the Mercury program. The fluorescence data were collected on a
F-4600 fluorescence spectrometer. Elemental microanalyses (EA) were performed by a Vario
Macro cube Elementar. UV–Vis spectra were obtained with a UV-2600 spectrophotometer
from 250 to 800 nm at room temperature.
2.2. Synthesis of H4L
The ligand acid was synthesized according to the literature procedure with some modifica-
tion [42, 43]. Fuming sulfuric acid (SO3, 20 wt%; 20 mL) was slowly added to a 100 mL three-
neck flask containing 4 g (18.5 mmol) naphthalene-2,6-dicarboxylic acid under stirring. The

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reaction mixture was stirred at 120 °C for 12 h. After cooling to room temperature, the mixture
was placed into 50 mL concentrated HCl solution and white crude product precipitated. The
powder was filtered and washed with concentrated HCl solution three times (30 mL each
time). Then pure product was dried at 80 °C in an oven. Yield 6.0 g (~86%) based on naph-
thalene-2,6-dicarboxylic acid. 1H NMR (DMSO-d6, 400 MHz) δ = 9.61 (s, 2H), 8.50 (s, 2H). FT–IR
(KBr pellet, cm−1): 1686(s), 1592(w), 1421(s), 1295(s), 1251(s), 1188(s), 1043(s), 916(w), 803(w),
765(w), 734(w), and 607(m).
2.3. Preparation of [CdL0.5dpe0.5]·2H2O (BUT-202)
A mixture of Cd(NO3)2·4H2O (10 mg, 0.03 mmol), H4L (13 mg, 0.035 mmol), dpe (3 mg,
0.019 mmol), N,N-dimethylacetamide (DMA) (1.6 mL), and 0.8 mL H2O were added to a 5 mL
vial and sealed. The vial was then heated in an oven at 80 °C for 48 h. After cooling to room
temperature, the resulting light yellow crystals were harvested by filtration and washed with
DMA and acetone, and then dried in air. FT–IR (KBr, cm−1): 1695(w), 1610(s), 1560(m), 1400(m),
1359(m), 1249(m), 1174(s), 1023(m), 980(w), 838(m), 787(w), 594(s), and 552(m). Elemental
analysis calculated (%): C, 33.82; H, 2.58; S, 7.517; N, 3.29. Found: C, 34.43; H, 2.66; S, 7.427;
N, 3.44.
2.4. Single-crystal X-ray diffraction
The crystal data of BUT-202 were collected on a Rigaku Supernova CCD diffractometer
equipped with a graphite-monochromatic enhanced Cu Kα radiation (λ = 1.54184 Å) at 100 K.
The data-sets were corrected by empirical absorption correction using spherical harmonics,
implemented in the SCALE3 ABSPACK scaling algorithm [44]. The structure of BUT-202 was
solved by direct methods and refined by full-matrix least-squares on F2 with anisotropic
displacement using the SHELXTL software package [45]. Non-hydrogen atoms were refined
with anisotropic displacement parameters during the final cycles. Hydrogens of the ligands
were calculated in ideal positions with isotropic displacement parameters. Details of the
structural refinements are listed in Table S1 of the Supporting Information and CIF file, and
some of the bond lengths and bond angle data are summarized inTable S2 of the Supporting
Information.
2.5. Fluorescence measurement
2.5.1. Fluorescence titration experiment
In a typical experiment, 2 mg of finely ground BUT-202 was weighed and added to a cuvette
containing 2.5 mL of DMF under stirring. The fluorescence upon excitation at 307 nm of
BUT-202 suspension was measured in situ after incremental addition of freshly prepared
analytic solutions (1 mM, 20 μL addition each time). The mixed solution was stirred at a
constant rate to maintain its homogeneity. All the experiments were performed in triplicate,
and consistent results were reported (Figure 2 and Figure S6 of the Supporting Information).
2.5.2. Selective detection experiment
Similar to that in fluorescence titration experiment, 2 mg of finely ground BUT-202 was
added to a cuvette containing 2.5 mL of DMF under stirring. Fluorescence of the obtained

4
Q. YANG ET AL.
suspension was recorded. Then, 1 mM DMF solutions of 3-NP (or 2,4-DNT, 2,6-DNT, 3-NT,
2-NT, NB, DMNB) and 1 mM DMF solutions of TNP were alternatively introduced (twice for
each) into the suspension in such a sequence: 3-NP (20 μL), 3-NP (20 μL), TNP (20 μL), TNP
(20 μL), 3-NP (20 μL), and 3-NP (20 μL). The process was repeated until the total volume of
added analytic solutions reached 320 μL. After each addition, the fluorescence of the sus-
pension was monitored (Figure S9 of the Supporting Information).
3. Results and discussion
3.1. Synthesis and general characterizations of BUT-202
Solvothermal reaction of H4L with Cd(NO3)2·4H2O in the presence of dpe in DMA-water sys-
tem yielded block-shaped single crystals of [CdL0.5dpe0.5]·2H2O (BUT-202). The phase purity
of bulk samples of BUT-202 was determined by PXRD. As shown in Figure S1 of the Supporting
Information, the experimental PXRD pattern matches well with the diffractogram simulated
from single-crystal data. The thermogravimetric analysis (TGA) plots of BUT-202 are shown
in Figure S2 of the Supporting Information. There are two distinct weight losses before 200 °C,
with weight losses of 4.3 and 4.2%, respectively, which are caused by the sequential loss of
coordinated water. After a clear platform, the main skeleton decomposes. The thermal sta-
bility of BUT-202 is to about 450 °C. In addition, as shown in Figure S4 of the Supporting
Information, slight blue shifts of the characteristic bands of the carbonyl group in BUT-202
compared with that of their corresponding acid ligands could be observed, illustrating the
metal coordination of carboxylate groups in the ligands.
3.2. Structure of BUT-202
Single-crystal X-ray diffraction data show that BUT-202 crystallizes in the monoclinic P21/n
space group. The asymmetric unit of BUT-202 consists of one Cd(II), half a L4− ligand, half a
dpe ligand, and two lattice water molecules. Each Cd(II) is six-coordinate by two carboxylic
oxygens (O1 and O2) from one L4− ligand, sulfonic O5, N1 from one dpe ligand and O6 and
O7 from two water molecules (Figure 1(a)). The Cd–O bond distances vary from 2.2262(16)
to 2.5188(15) Å, while the Cd–N1 bond length is 2.2403(18) Å, which are all similar to values
of reported MOFs [46, 47]. The L4− is tetradentate, with two carboxylic groups with bidentate
chelate modes and two monodentate sulfinic groups. The Cd(II) ions are connected by L4−
ligands to form a 2-D sheet structure (Figure 1(b)), which is further connected by dpe ligands
via the Cd–N connection to generate a 3-D pillar-layered framework (Figure 1(c)). Each L4− links
four Cd(II) ions, and accordingly, the L4− can be regarded as a four-connected node. Each
Cd(II) links two L4− ligands and one dpe ligand, so the Cd(II) atom is a three-connected node.
Thus, the 3-D structure of BUT-202 can be simplified as a 3,4-coordinated bi-nodal net with
O
SO3H
O
fuming sulfuric acid
HO
OH
OH
HO
SO3H
O
O
Scheme 1. synthetic procedure of h4l ligand acid.

JOURNAL OF COORDINATION CHEMISTRY
5
the point symbol {8·102}2{84·102}, which corresponds to the 3,4T48 topology (Figure 1). Similar
topology has been observed in {[Cd(btbb)0.5(btec)0.5(H2O)]·2H2O}n [48].
3.3. Detection of organic explosives
3.3.1. General fluorescence
Due to the excellent fluorescent emission of H4L, BUT-202 was explored for application in
the detection of explosive nitroaromatic compounds based on fluorescent sensing. The solid
state luminescent properties of BUT-202, free H4L, and dpe were first checked at room
temperature. As shown in Figure S4 of the Supporting Information, free H4L and dpe exhibit
fluorescent emissions at 395 and 369 nm upon excitations at 317 and 450 nm, respectively.
Compared with the free ligands, BUT-202 shows red-shifted emissions at 439 nm based on
excitation at 317 nm. The fluorescent properties of BUT-202 dispersed in different solvents
of DMF, DMSO, acetone, methanol, 1,4-dioxane and acetonitrile, respectively, were examined
(Figure S5 of the Supporting Information). Emission of BUT-202 is strong in DMF, MeCN, and
1,4-dioxane, however, DMSO and acetone can quench the emission of BUT-202. Thus, the
detection experiments were carried out in DMF.
3.3.2. TNP selective detection based on fluorescent quenching
To explore the detection ability of BUT-202 for a trace quantity of organic explosives, fluo-
rescent quenching titrations were performed with sequential addition of 1 mM organic
explosives DMF solution to the BUT-202 DMF solution. For comparison, some other aromatics
and aliphatic nitro compounds were also tested. Here, 11 analytes including TNP, 2,4-dini-
trotoluene(2,4-DNT), 2,6-dinitrotoluene (2,6-DNT), 3-nitrotoluene (3-NT), 2-nitrotoluene
Figure 1. (a) Coordination environment of Cd(ii) in BUT-202; (b) two-dimensional (2-d) sheet generated
by Cd(ii) ions and l4− ligands in BUT-202; (c) schematic view of the 3-d framework built by 2-d Cd(ii)/l4−
layers and dpe pillars in BUT-202 (color scheme: Cd, green; n, blue; s, yellow; o, red; C, gray. hydrogens
on the ligands are omitted for clarity).

6
Q. YANG ET AL.
Figure 2. effect on the emission spectra of BUT-202 dispersed in dmf upon incremental addition of 1 mm
of (a) tnP and (c) to; sV plots of (b) tnP and (d) to.
(2-NT), 4-nitrophenol (4-NP), 3-nitrophenol (3-NP), nitrobenzene (NB), 2,3-dimethyl-2,3-dini-
trobutane (DMNB), Toluen (TO), and Chlorobenzene (CB) were checked (Figure 2 and Figure
S6 of the Supporting Information). The fluorescence intensity of BUT-202 is heavily
dependent on the identities of the analyte added. TNP is the most effective quencher of all
analytes and TO show negligible effect on its fluorescence. Figure S7 shows the percentage
of fluorescent quenching in terms of adding a certain amount of different analytes at room
temperature. Obviously, TNP gives the highest quenching efficiencies of 70% for BUT-202
(Figure 2(a)). In addition, 4-NP also leads to relatively high quenching efficiency of 46%,
whereas quenching efficiencies are low for the remaining analytes (Figure S6 of the
Supporting Information). The quenching efficiencies of BUT-202 for these analytes follow
the order of TNP > 4-NP > NB > 2,4-DNT > 3-NT > 2-NT > 2,6-DNT > DMNB > CB > TO.
The fluorescent quenching efficiency can be quantitatively explained by the Stern–Volmer
(SV) equation: (I0/I) = Ksv[A] + 1, where I0 is the original fluorescent intensity, I indicates the
fluorescent intensity in the presence of the analyte, [A] represents the concentration of the
analyte (mM), and Ksv represents the quenching constant (M−1) [20]. The SV curve of TNP is
linear at low concentration (R2 = 0.9971) and deviates linearly when it reaches a higher con-
centration; the other analytes gave linear SV plots (Figure 2 and Figure S8 of the Supporting
Information). The nonlinear properties of the SV curve of TNP is likely due to self-adsorption
or energy transfer process [49]. The Ksv value of BUT-202 toward TNP was calculated to be
2.2 × 104 M−1, which is comparable to that of some reported fluorescent sensors (Table S3
of the Supporting Information). Based on the Ksv values and the standard deviations (Sb) for

JOURNAL OF COORDINATION CHEMISTRY
7
three repeated fluorescent measurements of blank solutions, the detection limits (3Sb/Ksv)
of BUT-202 toward TNP was calculated to be 0.2 μM.
The above results demonstrate that BUT-202 has high quenching efficiencies toward
TNP, but very poor toward 2,4-DNT, 2,6-DNT, 3-NT, 2-NT, NB, and DMNB. Motivated by these
findings, we further checked the selective detection abilities of BUT-202 toward TNP in the
presence of these analytes. As is shown in Figure S9 of the Supporting Information, the
emission intensity of BUT-202 only shows slight changes in the presence of excess 3-NP (or
2,4-DNT, 2,6-DNT, 3-NT, 2-NT, NB, and DMNB); upon introducing TNP into the mixture of the
above solution, the fluorescence was significantly quenched. This result reveals that the
interference from 3-NP (or 2,4-DNT, 2,6-DNT, 3-NT, 2-NT, NB, and DMNB) can be neglected,
indicating the high quenching selectivity of BUT-202 toward TNP. These results can be easily
visualized by plotting the percentage fluorescence intensity versus volume of analyte added.
As shown in Figure 3, the stepwise decrease in fluorescence intensity clearly demonstrates
the selectivity of BUT-202 toward TNP, even in the presence of a higher concentration of
3-NP (or 2,4-DNT, 2,6-DNT, 3-NT, 2-NT, NB, and DMNB). The highly selective detection ability
makes BUT-202 a reliable sensing material for TNP.
To better understand the good selectivity of BUT-202 toward TNP, the mechanism of
fluorescence quenching was studied. Due to the limited pore size in BUT-202, the quenching
process only happened on the surface. The detection of a fluorescent MOF toward organic
explosives is commonly related to two processes, photoinduced electron transfer (PET)
[50–52] and fluorescence resonance energy transfer (FRET) [53–55]. PET is a deactivation
process involving an internal redox reaction between the excited state of the fluorophore
and another species able to donate or to accept electrons. For a fluorescent MOF sensor, the
conduction band (CB) lies at a higher energy level than the lowest unoccupied molecular
orbitals (LUMOs) of an analyte, which leads to a driving force for the electron transfer from
the MOF to the analyte, thus resulting in fluorescence quenching. Generally, the lower the
LUMO energy levels of an analyte, the better quenching efficiency observed. The LUMO
energy levels of the analytes, which are arranged in a descending energy order, are shown
in Figure S10 of the Supporting Information. The LUMO energies are in good agreement
with the maximum quenching efficiency observed for TNP, but the order of observed
Figure 3. selective detection of tnP on BUT-202 in the presence of 2,4-dnt (or 2,6-dnt, 3-nt, 2-nt, nB,
and dmnB) in dmf.

8
Q. YANG ET AL.
quenching efficiency is not fully in accord with the LUMO energies of other nitroaromatics.
These results indicate that PET is not the only mechanism for fluorescence quenching
observed in these systems.
FRET is another reason for the observed fluorescent quenching. FRET occurs only when
the emission spectrum of a fluorophore overlaps with the absorption spectrum of the accep-
tor. As shown in the UV−Vis absorption spectra of the analytes and BUT-202 (Figure S11 of
the Supporting Information), the absorption band of TNP has the greatest degree of overlap
with the emission spectra of BUT-202, followed by 3-NP,4-NP, 3-NT, and 3,6-DNT. Clearly, the
extent of the overlap is consistent with the quenching efficiencies for nitroaromatics as
discussed above. As a result, the coexistence of PET and FRET makes TNP and 4-NP show
higher photoluminescence quenching effect compared with other checked analytes.
4. Conclusion
A novel fluorescent MOF (BUT-202) was synthesized and characterized, containing a sul-
fonated carboxylate ligand H4L, nitrogen containing auxiliary dpe and cadmium ion. The
luminescence of BUT-202 is caused by interaction of ligand and metal ions, and the fluo-
rescence intensity of BUT-202 is dependent on the kind of solvent, and the fluorescence
intensity is largest in DMF. In addition, BUT-202 can also selectively respond to explosive
TNP in DMF even in the presence of other nitro compounds. The selectivity is controlled by
electron and energy transfer mechanism and hydrogen bonding between TNP and the
framework. The good selectivity of TNP has potential applications in explosive detection
and selective fluorescent probes.
Supplementary material
Crystallographic data for the structure reported in this article has been deposited on the Cambridge
Crystallographic Data Center (CCDC No. 1537643). The material can be obtained free of charge via
https://www.ccdc.cam.ac.uk/deposit.
Disclosure statement
No potential conflict of interest was reported by the authors.
Funding
This work was financially supported by the NSFC [grant number U1407119].
References
[1] Y. Wang, A. La, Y. Ding, Y. Liu, Y. Lei. Adv. Func. Mater., 22, 3547 (2012).
[2] A. Lan, K. Li, H. Wu, D.H. Olson, T.J. Emge, W. Ki, M. Hong. Angew. Chem. Int. Ed., 48, 2334 (2009).
[3] S.S. Nagarkar, B. Joarder, A.K. Chaudhari, S. Mukherjee, S.K. Ghosh. Angew. Chem. Int. Ed., 52, 2881
(2013).
[4] I.H. Park, R. Medishetty, J.Y. Kim, S.S. Lee, J.J. Vittal. Angew. Chem. Int. Ed., 53, 5591 (2014).
[5] L.A. Pinnaduwage, A. Gehl, D.L. Hedden, G. Muralidharan, T. Thundat, R.T. Lareau, T. Sulchek,
L. Manning, B. Rogers, M. Jones, J.D. Adams. Nature, 425, 474 (2003).
[6] M.E. Germain, M.J. Knapp. Chem. Soc. Rev., 38, 2543 (2009).

JOURNAL OF COORDINATION CHEMISTRY
9
[7] Y. Salinas, R. Martinez-Manez, M.D. Marcos, F. Sancenon, A.M. Costero, M. Parra, S. Gil. Chem. Soc.
Rev., 41, 1261 (2012).
[8] H. Ma, C. He, X. Li, O. Ablikim, S. Zhang, M. Zhang. Sensors and Actuators B: Chemical, 230, 746 (2016).
[9] J. Ni, J. Yan, L. Zhang, D. Shang, N. Du, S. Li, J. Zhao, Y. Wang, Y. Xing. Tetrahedron Lett., 57, 4978
(2016).
[10] S.S. Nagarkar, A.V. Desaia, S.K. Ghosh. CrystEngComm, 18, 2994 (2016).
[11] A. Kumar, P.S. Chae. Sens. Actuators B, 240, 1 (2017).
[12] K.G. Furton, L.J. Myers. Talanta, 54, 487 (2001).
[13] K. Hakansson, R.A. Zubarev, R.V. Coorey, V.L. Talrose, P. Hakansson. Rapid Commun. Mass Spectrom.,
13, 1169 (1999).
[14] J.M. Sylvia, J.A. Janni, J.D. Klein, K.M. Spencer. Anal. Chem., 72, 5834 (2000).
[15] J.C. Mathurin, T. Faye, A. Brunet, J.C. Tabet. Anal. Chem., 72, 5055 (2000).
[16] G. Vourvopoulos, P.C. Womble. Talanta, 54, 459 (2001).
[17] M. Krausa, K. Schorb. J. Electroanal. Chem., 461, 10 (1999).
[18] E. Wallis, T.M. Griffin, N. Popkie, M.A. Eagan, R.F. McAtee, D. Vrazel, J. McKinly. Chem. Biol. Sensing,
5795, 54 (2005).
[19] G. Eiceman. J. Stone. Anal. Chem., 76, 390 (2004).
[20] B. Wang, X. Lv, D. Feng, L. Xie, J. Zhang, M. Li, Y. Xie, J. Li, H. Zhou. J. Am. Chem. Soc., 138, 6204 (2016).
[21] X. Sun, Y. Wang, Y. Lei. Chem. Soc. Rev., 44, 8019 (2015).
[22] Y. Zhang, Y. Fu, D. Zhu, J. Xu, Q. He. Chin. Chem. Lett., 27, 1429 (2016).
[23] L.E. Kreno, K. Leong, O.K. Farha, M. Allendorf, R.P. Van Duyne, J.T. Hupp. Chem. Rev., 112, 1105 (2011).
[24] Y. Cui, Y. Yue, G. Qian, B. Chen. Chem. Rev., 112, 1126 (2012).
[25] M.D. Allendorf, C.A. Bauer, R.K. Bhakta, R.J.T. Houk. Chem. Soc. Rev., 38, 1330 (2009).
[26] Z. Hu, B.J. Deibert. Chem. Soc. Rev, 43, 5815 (2014).
[27] S. Zhang, J. Li, D. Du, J. Qin, S. Li, W. He, Z. Su, Y. Lan. J. Mater. Chem. A, 3, 23426 (2015).
[28] C.Q. Zhang, Y. Yan, Q.H. Pan, L.B. Sun, H.M. He, Y.L. Liu, Z.Q. Liang, J.Y. Li. Dalton Trans., 44, 13340
(2015).
[29] M. Zheng, H.Q. Tan, Z.G. Xie, L.G. Zhang, X.B. Jing, Z.C. Sun. ACS Appl. Mater. Interfaces., 5, 1078
(2013).
[30] H.Q. Zhao, G.H. Qiu, Z. Liang, M.M. Li, B. Sun, L. Qin, S.P. Yang, W.H. Chen, J.X. Chen. Anal. Chim.
Acta, 922, 55 (2016).
[31] H. Tan, G. Tang, Z. Wang, Q. Li, J. Gao, S. Wu. Anal. Chim. Acta, 940, 136 (2016).
[32] S. Homayoonnia, S. Zeinali. Sens. Actuators B, 237, 776 (2016).
[33] M.S. Hosseini, S. Zeinali, M.H. Sheikhi. Sens. Actuators B, 230, 9 (2016).
[34] C. Montoro, F. Linares, E.Q. Procopio, I. Senkovska, S. Kaskel, S. Galli, N. Masciocchi, E. Barea, J.A.
Navarro. J. Am. Chem. Soc., 133, 11888 (2011).
[35] K. Yang, F. Xue, Q. Sun, R. Yue, D. Lin. J. Environ. Chem. Eng., 1, 713 (2013).
[36] Y. Guo, X. Feng, T. Han, S. Wang, Z. Lin, Y. Dong, B. Wang. J. Am. Chem. Soc., 136, 15485 (2014).
[37] D. Singh, C.M. Nagaraja. Cryst. Growth Des., 15, 3356 (2015).
[38] D. Singh, C.M. Nagaraja. Dalton Trans., 43, 17912 (2014).
[39] Y.J. Deng, N.J. Chen, Q.Y. Li, X.J. Wu, X.L. Huang, Z.H. Lin, Y.G. Zhao. Cryst. Growth Des., 17, 3170
(2017).
[40] C. Zhang, Y. Che, Z. Zhang, X. Yang, L. Zang. Chem. Commun., 47, 2336 (2011).
[41] S. Pramanik, C. Zheng, X. Zhang, T.J. Emge, J. Li. J. Am. Chem. Soc., 133, 4153 (2011).
[42] I. Papadaki, C.D. Malliakas, T. Bakas, P.N. Trikalitis. Inorg. Chem., 48, 9968 (2009).
[43] N. Zhang, Q. Liu, Y. Wang, L. Chen, Z. Wen. Inorg. Chem. Commun., 20, 299 (2012).
[44] G.M. Sheldrick. SHELXTL 2008/4, Structure Determination Software Suite, Bruker AXS, Madison,
Wisconsin, USA.
[45] SCALE3 ABSPACK scaling algorithm. CrysAlis RED, Oxford Diffraction Ltd., Version 1.171.32.38.
[46] C. Qiao, X. Qu, Q. Yang, Q. Wei, G. Xie, S. Chen, D. Yang. Green Chem., 18, 951 (2016).
[47] H. Wang, F.Y. Yi, S. Dang, W.G. Tian, Z.M. Sun. Cryst. Growth Des., 14, 147 (2014).
[48] L. Liu, J. Ding, M. Li, X. Lv, J. Wu, H. Hou, Y. Fan. Dalton Trans., 43, 12790 (2014).
[49] H. Sohn, M.J. Sailor, D. Magde, W.C. Trogler. J. Am. Chem. Soc., 125, 3821 (2003).
[50] S. Dadashi-Silab, S. Doran, Y. Yagci. Chem. Rev., 116, 10212 (2016).

10
Q. YANG ET AL.
[51] M.A. Fox. Photochem. Photobiol., 52, 617 (1990).
[52] A. Molinari, A. Maldotti, R. Amadelli. Catal. Today, 281, 71 (2017).
[53] L. Kong, J. Zhu, W. Wang, L. Jin, Y. Fu, B. Duan, L. Tan. Spectrochim. Acta Part A Mol. Biomol. Spectrosc.,
173, 675 (2017).
[54] R.M. Clegg. Curr. Opin. Biotechnol., 6, 103 (1995).
[55] F. Tian, J. Lyu, J. Shi, M. Yang. Biosens. Bioelectron., 89, 123 (2017).