Ferrocene containing N-tosyl hydrazones as optical and electrochemical sensors for Hg2+, Cu2+ and F? ions

Article abstract of DOI:10.1016/j.tet.2019.03.023

Ferrocene containing N-tosyl hydrazones as selective and sensitive optical and electrochemical chemosensors were synthesized and characterized by ¹H NMR, ¹³C NMR, ESI-MS and X-ray analysis. The cation and anion binding studies were c

Full text of DOI:10.1016/j.tet.2019.03.023

Accepted Manuscript
Ferrocene containing N-tosyl hydrazones as optical and electrochemical sensors for
2+
2+
−
Hg , Cu and F ions
Li Ling, Jianfeng Hu, Hao Zhang
PII:
S0040-4020(19)30298-4
DOI:
https://doi.org/10.1016/j.tet.2019.03.023
TET 30209
Reference:
To appear in: Tetrahedron
Received Date: 27 December 2018
Revised Date: 8 March 2019
Accepted Date: 11 March 2019
Please cite this article as: Ling L, Hu J, Zhang H, Ferrocene containing N-tosyl hydrazones as
2+
2+
−
optical and electrochemical sensors for Hg , Cu and F ions, Tetrahedron (2019), doi: https://
doi.org/10.1016/j.tet.2019.03.023.
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ACCEPTED MANUSCRIPT
Colorimetric changes
Electrochemical changes
UV-vis changes

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Ferrocene Containing N-tosyl Hydrazones as Optical and
Electrochemical Sensors for Hg2+, Cu2+ and F− Ions
Li Linga,b, Jianfeng Hua,b, Hao Zhanga,b,c
*
a College of Chemistry & Chemical Engineering, Inner Mongolia University, Hohhot 010021, P. R. China.
b Inner Mongolia Key Laboratory of Fine Organic Synthesis, Hohhot 010021, P. R. China.
c State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese
Academy of Sciences, Changchun 130022, P. R. China
Keywords: ferrocene, hydrazone, optical signal, electrochemical signal
Abstract
Ferrocene containing N-tosyl hydrazones as selective and sensitive optical and
1
electrochemical chemosensors were synthesized and characterized by H NMR, 13C
NMR, ESI-MS and X-ray analysis. The cation and anion binding studies were carried
1
out using various techniques including electrochemistry, UV-vis and H NMR
spectroscopy. Chemosensors 2a and 2b have shown excellent selective recognition
toward Hg2+, Cu2+ and F− through optical and electrochemical signals. The colour of
2a and 2b in solution changed visibly from pale yellow to red upon addition of
Hg2+ion, while the color of solution changed from pale yellow to yellow green upon
addition of Cu2+, which can be easily detected by the naked eye.
1 Introduction
Heavy metals are found naturally in the earth.1 They become concentrated as a
result of human caused activities and can enter plant, animal, and human tissues via
inhalation, diet, and manual handling.2 Among the heavy metals, mercury is one of
the most toxic metal ions and is widely used in industry, such as coal mining, wood
pulping, and chemical manufacturing, and in other products of daily life. It can be
easily absorbed and accumulated from the environment by living organisms and
causes DNA damages, mitosis impairment, central nervous and endocrine systems
disruption.3 In additon, copper is essential to human health as a trace dietary mineral.4
*
Corresponding author at: College of Chemical & Chemical Engineering, Inner Mongolia University, Hohhot
010021, P. R. China.
E-mail addresses: haozhang@imu.edu.cn, zh_hjf@hotmail.com (H. Zhang).
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However, the excess Cu2+ ion may cause several neurological diseases, such as
Parkinson’s disease, epileptic seizures, kidney and liver damages.5 On the other hand,
amongst potential anions of environmental concern, fluoride is one of particular
important biologically functional anions owing to its established role in dental care6
and treatment of Osteoporosis7. While excessive use may cause fluorosis resulting in
the discoloration of teeth.8,9
nucleophilic
cation sensing
R1
N
R3
C
N
H
R2
acidic
elctrophilic
anion and cation sensing,
Hꢀbonding
anion sensing
Fig. 1. The structure of the hydrazone group.
Therefore, selective detection and sensing mercury, copper and fluoride ions
have received much attention from the scientific community. One of the most elegant
ways of achieving sensor design is to functionalize a receptor with selective
recognition units and physical signal response units (redox shifts, color changes and
fluorescence quenching or enhancement). Ferrocene unit is often applied to redox
sensors due to its unique electrochemical properties and easy functionalization.10,11
Recently, hydrazone functional group has proved to be a versatile ion recognition unit
for both cations and anions,12-22 since the functional diversity of its structure. As
shown in Figure 1 the nucleophilic nitrogen atom, electrophilic imine carbon, and
acidic N-H proton, enables its use in highly sensitive and selective sensor of cations,
anions, and even neutral molecules. However, chemosensors combing ferrocene and
hydrazone functional groups are rarely investigated.23-25 Herein, ferrocene containing
N-tosyl hydrazones 2a and 2b have been synthesized and its capability of optical and
redox sensing of cations and anions has been demonstrated.
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2. Results and discussion
2.1. Synthesis and characterization
Ferrocene containing N-tosyl hydrazones 2a and 2b were prepared according to
the literature procedures.26 As shown in Scheme 1, acetyl ferrocene 1a and 1,1’-
diacetyl- ferrocene 1b reacted with p-toluenesulfonyl hydrazide in methanol to give
compound 2a and 2b in 86% and 80% yields, respectively. (Scheme 1). Compounds
1
2a and 2b were characterized by H NMR, 13C NMR and HRMS (ESI-TOF). In
addition, the structure of compound 2a and 2b were also confirmed by single-crystal
X-ray diffraction analysis (Figure 2 and 3). The cantions and anions recognition
properties of the chemosensors have been established by UV-vis spectroscopy,
electrochemistry and 1H NMR titration.
O
O
H
N N S
TsNHNH2 (1.5)
O
Fe
Fe
methanol, r.t., 0.5h
1a
2a
O
O
O
H
N S
O
N
N
TsNHNH2 (3.0)
Fe
Fe
O
methanol, 60oC, 4h
N S
H
O
2b
1b
Scheme 1. Synthesis of ferrocene containing N-tosyl hydrazone.
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Fig. 2. Molecular structure of 2a. Selected bond lengths (Å) and angles (deg): N1-C5 = 1.286(4),
N1-N2= 1.417(3), S1-N2 = 1.635(3), S1-O1 = 1.420(2), S1-O2 = 1.443(2), S1-C6 = 1.749(4);
N1-C5-C4 = 116.3(3), C5-N1-N2 = 113.5(2), N1-N2-S1 = 114.1(2), N2-S1-C6 = 108.40(14),
O1-S1-N2 = 108.56(15), O2-S1-N2 = 103.18(14).
Fig. 3. Molecular structure of 2b. Selected bond lengths (Å) and angles (deg): N1-C6 = 1.276(8),
N1-N2= 1.411(7), S1-N2 = 1.643(5), S1-O1 = 1.440(5), S1-O2 = 1.429(7), S1-C7 = 1.756(6);
N1-C6-C14 = 125.0(6), C6-N1-N2 = 115.9(5), N1-N2-S1 = 111.5(4), N2-S1-C7 = 107.1(3),
O1-S1-N2 = 104.6(3), O2-S1-N2 = 107.3(3).
2.2. UV–vis absorption studies
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The UV-vis spectrum of 2a and 2b (Figure 4) in CH3CN (1×10−4 M) exhibits
high-energy (HE) absorption bands at 280 nm, produced by π-π* charge transfer (CT)
transition of the phenyl group, and low energy (LE) absorption band at 445nm
corresponds to ferrocene-centered metal-to-ligand charge transfer (MLCT). The
UV−vis binding interaction studies of 2a and 2b in CH3CN (1×10−4 M) against
cations such as Li+, Na+, K+, Mg2+, Ca2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Pb2+, Cd2+, Ag+
and Hg2+ as perchlorate salts, showed selective response to Cu2+ and Hg2+ (Figure 4).
Fig. 4. (a) UV–vis absorption spectra of chemosensor 2a observed upon addition of 1 equiv. of
various metal ions in CH3CN (1×10−4 M). (b) UV–vis absorption spectra of chemosensor 2b
observed upon addition of 1 equiv. of various metal ions in CH3CN (1×10−4 M).
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Fig. 5. UV–vis absorption titration spectra of chemosensor 2a with Cu(ClO4)2(a) and Hg(ClO4)2(b)
in CH3CN (1×10−4 M); UV–vis absorption titration spectra ofchemosensor 2b with Cu(ClO4)2(c)
and Hg(ClO4)2(d) in CH3CN (1×10−4 M).
The change in the UV−vis absorbance spectra of 2a in CH3CN due to the
stepwise addition of Cu2+ and Hg2+ ion are shown in Figure 4a and b. Upon addition
of Cu2+ (Figure 5a), absorption band at 445nm decreased and absorption band from
550-800 nm increased, with a color change from pale yellow to yellow green (Figure
6). While after addition of 1 equiv. of Hg2+ (Figure 5b), absorption band at 445nm
increased with a 65 nm red shift, which is accountable for the change of color from
pale yellow to red (Figure 6). Motivated by the obvious color changes of 2a to Cu2+
and Hg2+in CH3CN, visual test paper was prepared. Changes in color from pale
yellow to orange red and pale yellow to yellow green were immediately observed by
naked eye on the test paper after addition of Hg2+ and Cu2+ ions in water (1×10-3 M)
followed by the addition of dropwise of CH3CN (Figure S30).
Fig. 6. Visual color changes of chemosensor 2a upon addition of various metal ions (1 equiv.) in
CH3CN (1×10−4 M).
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During the titration of Cu2+ to 2b, a well defined isosbestic points were observed
at 300 nm. This is indicative of the presence of the complexing equilibrium of 2b with
Cu2+. Meanwhile absorption band at 283 nm decreased with a concomitant increase of
absorption band at 350 nm (Figure 5c). When the titration of Hg2+ to 2b, intensity of
absorption band at 283 nm and 350 nm enhanced concurrently (Figure 5d).
Binding assays using the method of continuous variations (Job’s plot) are
consistent with a 1:1 stoichiometry in 2a/Cu2+, 2b/Cu2+ and 2b/Hg2+ complexes
(Figure 5a, 5c and 5d, inset). Job’s plot of 2a with Hg2+ indicated the formation of 2:1
complexes (Figure 5b, inset). This result has also been confirmed by ESI-MS, where a
peaks at m/z 458.9882 for [2a+Cu2+], m/z 993.0837 for [2a+2a+Hg2+-H+], m/z
669.0401 for [2b+Cu2+] and m/z 807.0682 for [2b+Hg2+-H+], were observed.
Following the BenesiꢀHildebrand equation,27,28 the apparent binding constants were
1
1
1
observed to be 9.90×103 Mꢀ for 2a-Cu2+, 2.3×1013 Mꢀ for 2a-Hg2+, 3.2×103 Mꢀ for
1
2b-Cu2+ and 4.4×103 Mꢀ for 2b-Hg2+ (Figure S13 and S15). Detection limits could
reach 2.66×10−5 M for 2a-Cu2+, 7.60×10-6 M for 2a-Hg2+, 3.55×10−5 M for 2b-Cu2+
and 3.06×10−5 M for 2b-Hg2+ (Figure S14 and S16).
The anion binding properties of receptors 2a and 2b were investigated using
UV-visible studies. When a set of anions (OAc−, NO3 , HSO4 , H2PO4 , F−, Cl−, Br−,
as TBA+ salts) were added to the solution of 2a and 2b (1×10−4 M) in CH3CN, only
F− promote remarkable spectral changes (Figure 7). The changes in the UV−vis
absorbance spectra of 2a and 2b due to the stepwise addition of F− ion are shown in
Figure 8. After the addition of 1 equiv. of F−, the absorption bands at 350 nm
increased. Binding assays using the method of continuous variations (Job’s plot)
suggest a 1:1 binding model for receptor/anion stoichiometry, with binding constants
−
−
−
1
1
K= 1.0×104 Mꢀ , K = 1.7×103 Mꢀ , in the cases of 2a and 2b, respectively (Figure
S17). Detection limits could reach 1.64×10−5 M for 2a-F− and 1.91×10-5 M for 2b-F−
(Figure S18).
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Fig. 7. (a) UV–vis absorption spectra of chemosensor 2a observed upon addition of 1 equiv. of
various anions in CH3CN (1×10−4 M). (b) UV–vis absorption spectra of chemosensor 2b observed
upon addition of 1 equiv. of various anions in CH3CN (1×10−4 M).
Fig. 8. UV–vis absorption titration spectra of chemosensors 2a (a) and 2b (b) with F− in CH3CN
(1×10−4 M).
The competitive experiments in the presence of Cu2+ and Hg2+ ions mixed with 1
equivalent of Li+, Na+, K+, Mg2+,Ca2+, Fe2+, Co2+, Ni2+, Zn2+, Pb2+, Cd2+ and Ag+ ions
were carried out. As shown in Figure S31 and Figure S32, no significant variations in
the UV−vis absorbance spectra were obtained. While both of Cu2+ and Hg2+ ions are
present in the solution, only Cu2+ ion can be detected from the UV−vis signal (Figure
S33). Specificity of anion detection is evaluated by adding interfering anions (OAc−,
−
−
−
NO3 , HSO4 , H2PO4 , Cl−, Br−) into F− solution. As shown in Figure S34, 2a can be
used as an excellent sensor for F− detection in the presence of the competing anions.
2.3. Electrochemical studies
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Fig. 9. Cyclic Voltammetry and Differential Pulse Voltammetry spectra of 2a (a), (b) and 2b (c), (d)
observed upon addition of 1 equiv of various metal ions in CH3CN (100 ꢁM), containing 0.1 M
[(n-C4H9)4NPF6] as supporting electrolyte.
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Fig. 10. Cyclic Voltammetry and Differential Pulse Voltammetry of chemosensor 2a with
Cu(ClO4)2(a), (b) and Hg(ClO4)2(c), (d) in CH3CN (1×10−4 M), containing 0.1 M [(n-C4H9)4NPF6]
as supporting electrolyte.
Fig. 11. Cyclic Voltammetry and Differential Pulse Voltammetry of chemosensor 2b with
Cu(ClO4)2(a), (b) and Hg(ClO4)2(c), (d) in CH3CN (1×10−4 M), containing 0.1 M [(n-C4H9)4NPF6]
as supporting electrolyte.
10

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The metal recognition properties of chemosensors 2a and 2b were also evaluated
by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) analysis in
CH3CN solutions containing 0.1 M [(n-C4H9)4NPF6] as supporting electrolyte.
Compounds 2a and 2b both display a reversible one-electron-oxidation process at E1/2
= 0.218 and 0.446 V, respectively, due to the ferrocene/ferrocenium redox couple. No
perturbation of the CV and DPV voltammograms of 2a and 2b were observed in the
presence of Li+, Na+, K+, Mg2+, Ca2+, Fe2+, Co2+, Ni2+, Zn2+, Cd2+, Ag+ and Pb2+ as
their appropriate salts (Figure 9). However, on stepwise addition of Cu2+ ion to 2a,
original peak gradually decreased and negatively shifted to E1/2=0.041 V (Figure 10a).
While, upon stepwise addition of Hg2+ ion to 2a, a clear evolution of the oxidation
wave from E1/2 = 0.218 to E1/2 = 0.059 V was observed, and maximum perturbation of
the CV was obtained with 1 equiv. of Hg2+ ion added (Figure 10c). The DPV of 2a
illustrated the similar results (Figure 10b and d). As for compound 2b, on stepwise
addition of Cu2+ ion, a clear shift of the oxidation wave from E1/2=0.444 V to
E1/2=0.115 V was observed accompanied by a decrease in current intensity (Figure
11a). When the stepwise addition of Hg2+ ion to 2b, the oxidation peak negatively
shifted to E1/2 = 0.146 V with 1 equiv. of added Hg2+ ion (Figure 11c). Changes of the
DPV titration experiment of 2b with Cu2+ and Hg2+ (Figure 11b and d) confirmed the
results of the CV titration experiment.
The recognition behavior of receptor 2a and 2b toward anions was also studied
by electrochemistry. It was observed that addition of F− to 2a and 2b promotes
remarkable changes in the redox behavior (Figure 12). On the addition of increasing
amounts of F− ions, oxidation peak decreased and shifted anodically accompanied by
increasing of two new oxidation peak (Figure 13a, c). It was also observed that in the
presence of excess of F− the CV wave of 2a and 2b becomes irreversible. The results
of the DPV titration experiment matched exactly with that of the CV studies (Figure
13b, d).
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Fig. 12. Cyclic Voltammetry and Differential Pulse Voltammetry spectra of 2a (a), (b) and 2b (c),
(d) observed upon addition of 1 equiv. of various anions in CH3CN (100 ꢁM), containing 0.1 M
[(n-C4H9)4NPF6] as supporting electrolyte.
12

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Fig. 13. Cyclic Voltammetry and Differential Pulse Voltammetry of chemosensors 2a (a), (b) and
2b (c), (d) with F− in CH3CN (1×10ꢀ M), containing 0.1 M [(n-C4H9)4NPF6] as supporting
4
electrolyte.
2.4. Binding studies.
The binding properties of chemosensor 2a with Hg2+ were evaluated by 1H NMR
studies in deuterated DMSO solution (Figure 14). The complexation process induces
obvious upfield changes in the chemical shifts in the amino proton Ha (ꢂδ = 0.0182
ppm) and phenyl proton Hb next to sulphone substituent group (ꢂδ = 0.0114 ppm).
Meanwhile phenyl proton Hb next to methyl substituent downshifted for 0.0210 ppm.
The signal corresponding to methyl group proton Hc and Hd slightly downshifted for
0.0058 ppm and 0.0068 ppm, respectively. The downfield shifts of the
cyclopentadienyl ring protons (He, Hf) in ferrocene were observed in smaller
magnitude (ꢂδ = 0.0028-0.0066 ppm). From the magnitude of these observed shifts, it
can be surmised that complexation exerts a more powerful effect on the imine group
and phenyl group than ferrocene group. The sulphur atom is surrounded with one
phenyl group and two oxygen atom, which makes sulphur atom difficult to coordinate
with Hg2+. Finally, it can be concluded that the plausible binding mode of Hg2+ is the
oxygen atom of the sulphone group and N atom of the imine group (Figure 14).
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Fig. 14. Evolution of the1H NMR spectra of 2a upon addition of 2.0 equiv. Hg2+in the DMSO
solution.
Fig. 15. Evolution of the1H NMR spectra of 2a upon addition of 2.0 equiv. F-in the DMSO
solution.
14

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1
The binding properties of chemosensor 2a with F− were also evaluated by H
NMR studies in deuterated DMSO solution (Figure 15). The signal for the amine
proton Ha exhibited a downfield shift of ꢂδ = 0.0022 ppm on adding 0.5 equivalent of
F− ions. On further addition of 1 equivalent of F− ions the signal for the Ha proton
disappeared, demonstrating that the binding process involve initial formation of
H-bond between the amine proton Ha and F− ions followed by deprotonation. The
binding process induces noticeable upfield changes in the chemical shifts of the
phenyl ring protons (ꢂδ = 0.1773 ppm) and monosubstituted cyclopentadienyl ring
protons (ꢂδ = 0.1065, 0.1531 ppm). Similarly, The signal corresponding to methyl
group proton Hc and Hd also got shifted by 0.0784 ppm and 0.1168ppm respectively.
1
From the magnitude of the observed H chemical shifts, it can be concluded that the
F− ions have hydrogen bond effect not only with amine protons but also with phenyl
protons and methyl protons.
3. Conclusions
In conclusion, we have described new ferrocene containing hydrazones 2a and
2b through combining the redox activity of the ferrocene unit with the binding ability
of hydrazone, and examined its binding properties towards various guest cations and
anions using electrochemical, spectral and optical techniques. Ferrocene containing
hydrazones 2a and 2b exhibits high binding affinity and sensitivity for Hg2+, Cu2+ and
F− ions. The Fc/Fc+ redox couple was significantly cathodically shifted on
complexation with Cu2+ and Hg2+. Interestingly, When Hg2+ ion was added into the
solution of 2a, 2b the color changed from pale yellow to red. As for Cu2+ ion was
added into the solution of 2a and 2b, the color changed from pale yellow to yellow
green, which allows their potential use for “naked-eye” detection. Moreover, Addition
of F− ions induced changes in UV-vis absorption spectra and electrochemical signals.
It has been demonstrated that hydrazones 2a and 2b can bind with F− through
H-bonding between hydrazone N-H proton and the F− as proved by 1H NMR titration.
4 Experimental
15

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4.1. Materials and methods
All reagents were used as received from commercial sources without further
purification. All solvents were purified according to literature techniques. For column
chromatography, 200–300 mesh silica gel (Qingdao, China) was employed. The cyclic
voltammetry (CV) and differential pulse voltammetry (DPV) were performed with a
conventional three-electrode configuration consisting of glassy carbon as the working
electrode, platinum as an auxiliary electrode and Ag/Ag+ as a reference electrode. The
concentration of the sample solutions was 100 ꢁM in CH3CN containing 0.1 M
1
[(n-C4H9)4NPF6] as supporting electrolyte and the scan rate was 0.1 Vsꢀ . The UV–vis
spectra were carried out in CH3CN solutions of 100 ꢁM concentration.
4.2. Instrumentation
All NMR experiments were carried out on a Bruker AVANCE 500MHz nuclear
magnetic resonance spectrometer using CDCl3 or DMSO-d6 as the solvent with
tetramethylsilane as the internal standard. Chemical shift values (δ) were given in
parts per million. HRMS data were obtained on a Bruker QTOF mass spectrometer.
The melting points were determined on an X-4 binocular microscope melting point
apparatus and uncorrected. The UV–vis absorption spectra were recorded with
Shimadzu UV-2700 ultraviolet and visible spectrophotometer. The CV and DPV
measurements were carried out on the Autolab PGSTAT302N potentiostat (Metrohm
Autolab B. V.). X-ray single-crystal data were collected using Mo Kα (λ = 0.710 73 Å)
radiation on a Bruker APEX II diffractometer equipped with a CCD area detector.
4.3. Synthetic procedure
4.3.1 Synthesis of chemosensor 2a
A solution of pure TsNHNH2 (15 mmol) in methanol (30 mL) was stirred and
heated to 60 °C until the TsNHNH2 dissolved. The mixture was cooled to room
temperature. Then a solution of acetyl ferrocene 1a (10 mmol) in methanol was
dropped into the mixture slowly. After approximately 0.5h, the crude products could
be obtained as solid precipitate. The precipitate was washed with petroleum ether then
o
1
removed in vacuo to give yellow solid 2a in 86% yield. mp 187-189 C. H NMR
16

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(500 MHz, DMSO) δ 10.00 (s, 1H), 7.81 (d, J = 7.9 Hz, 2H), 7.43 (d, J = 7.8 Hz, 2H),
4.49 (s, 2H), 4.29 (s, 2H), 3.93 (s, 5H), 2.36 (s, 3H), 2.04 (s, 3H). 13C NMR (126
MHz, DMSO) δ 155.1, 143.0, 136.4, 129.1, 127.6, 69.6, 68.9, 66.8, 20.9, 15.0. HRMS
(ESI-TOF) m/z: [M]+ calcd. for C19H20FeN2O2S 396.0595; Found: 396.0594.
4.3.2 Synthesis of chemosensor 2b
A solution of pure TsNHNH2 (30 mmol) in methanol (60 mL) was stirred and
heated to 60 °C until the TsNHNH2 dissolved. Then, 1,1’- diacetyl- ferrocene (10
mmol) was added into the mixture slowly. After refluxing for 4 h, the crude product
could be obtained as solid precipitate. The precipitate was washed with petroleum
ether then removed in vacuo to give yellow solid 2b in 80% yield. mp 180-181 oC. 1H
NMR (500 MHz, DMSO) δ 9.93 (s, 2H), 7.79 (d, J = 7.6 Hz, 4H), 7.43 (d, J = 7.6 Hz,
4H), 4.34 (s, 4H), 4.08 (s, 4H), 2.39 (s, 6H), 1.75 (s, 6H). 13C NMR (126 MHz,
DMSO) δ 154.9, 143.7, 136.7, 129.7, 128.1, 84.1, 71.3, 68.0, 21.5, 15.2. HRMS
(ESI-TOF) m/z: [M+Na]+ calcd for C28H30FeN4NaO4S2 629.0956; Found: 629.0959.
Acknowledgements
This work was supported by the National Natural Science Foundation of China
(Grant No. 21861028), Natural Science Foundation of Inner Mongolia
(2017MS0206) and Grassland Talent Innovative Teams of Inner Mongolia
Autonomous Region.
Supplementary data
Supplementary data (The crystal structure of compound 2a and 2b has been deposited
at the Cambridge Crystallographic Data Centre (http://www.ccdc.cam.ac.uk/) with
deposition number CCDC 1887250 and 1887251) associated with this article can be
found in the online version, at http://xx.
References and notes
1
Nagajyoti, P. C.; Lee, K. D.; Sreekanth, T. V. M. Environ. Chem. Lett. 2010, 8,
17

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199-216.
2
3
4
5
6
Prodi, L.; Bolletta, F.; Montalti, M.; Zaccheroni, N. Coordin. Chem. Rev. 2000,
205, 59-83.
Tchounwou, P. B.; Ayensu, W. K.; Ninashvili, N.; Sutton, D. Environ. Toxicol.
2003, 18, 149-175.
Bost, M.; Houdart, S.; Oberli, M.; Kalonji, E.; Huneau, J.–F.; Margaritis, I. J.
Trace Elem. Med. Bio. 2016, 35, 107–115.
Kozlowski, H.; Janicka-Klos, A.; Brasun, J.; Gaggelli, E.; Valensin, D.; Valensin,
G. Coord. Chem. Rev. 2009, 253, 2665-2685.
Kirk, K. L. In Biochemistry of the Elemental Halogens and Inorganic Halides;
Kirk, K. L., Eds.; Plenum press, New York, 1991; Chapter Biochemistry of
Inorganic Fluoride, pp 19-68.
7
8
9
Kleerekoper, M. Endocrinol. Metab. Clin. North. Am. 1998, 27, 441-452.
Geddes, C. D. Meas. Sci. Technol. 2001, 12, R53-R88.
Kissa, E. Clin. Chem. 1987, 33, 253-255.
10 Beer, P. D.; Hayes, E. J. Coord. Chem. Rev. 2003, 240, 167-189.
11 Gale, P. A.; García-Garrido, S. E.; Garric, J. Chem. Soc. Rev. 2008, 37, 151-190.
12 Tatum, L. A.; Su, X.; Aprahamian, I. Acc. Chem. Res. 2014, 47, 2141-2149.
13 Su, X.; Aprahamian, I. Chem. Soc. Rev. 2014, 43, 1963-1981.
14 Yang, Y.; Gao, C. Y.; Liu, J.; Dong D. Anal. Methods-UK 2016, 8, 2863-2871.
15 Aprahamian, I. Chem. Commun. 2017, 53, 6674-6684.
16 Xiang, Y.; Tong, A. J.; Jin, P. Y.; Ju, Y. Org. Lett. 2006, 8, 2863–2866.
17 Liao, Z. C.; Yang, Z. Y.; Li, Y.; Wang, B. D.; Zhou, Q. X. Dyes Pigments 2013, 97,
124-128.
18 Goswami, S.; Chakraborty, S.; Paul, S.; Halder, S.; Maity, A. C. Tetrahedron Lett.
2013, 54, 5075-5077.
19 Zhou, L. L.; Zhang, X. H.; Wu, S. K. Chem. Lett. 2004, 33, 850-851.
20 Shao, J.; Lin, H.; Yu, M.; Cai, Z. S.; Lin, H. K. Talanta 2008, 74, 1122-1125.
21 Hu, S. Z.; Guo, Y.; Xu, J.; Shao, S. J. Org. Biomol. Chem. 2008, 6, 2071-2075.
22 Sun, Y.; Liu, Y.; Guo, W. Sensor Actuat. B-Chem. 2009, 143, 171-176.
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23 Fang, Y.; Zhou, Y.; Rui, Q.; Yao, C. Organometallics 2015, 34, 2962-2970.
24 Lakshmi, N. V.; Mandal, D.; Ghosh, S.; Prasad, E. Chem. Eur. J. 2014, 20,
9002-9011.
25 Mishra, S.; Dewangan, S.; Giri, S.; Mobin, S. M.; Chatterjee, S. Eur. J. Inorg.
Chem. 2016, 35, 5485-5496.
26 Ling, L.; Hu, J. F.; Huo, Y. H.; Zhang, H. Tetrahedron 2017, 73, 86-97.
27 Yang M. H.; Thirupathi P.; Lee K. H. Org. Lett. 2011, 13, 5028-5031.
28 Shortreed, M.; Kopelman, R.; Kuhn, M.; Hoyland, B. Anal. Chem. 1996, 68,
1414-1418.
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ACCEPTED MANUSCRIPT
Highlights:
ꢀ New and simple ferrocenyl hydrazone chemosensors were designed
and synthesized by using an easy way.
ꢀ Chemosensors 2a and 2b has proved to be a versatile ion recognition
ability for both cations and anions.
ꢀ Hg2+, Cu2+ and F− ions are detectable by using colorimetric, optical
(UV–vis) and electrochemical signals.
ꢀ The color of the solution containing chemosensors 2a and 2b changed
from pale yellow to red upon the addition of Hg2+, while the color
changed to yellow green when Cu2+ ions were added.