Tuning uracil derivatives for the AIE-based detection of pyrene at a nano-molar level: single-crystal X-ray structure and DFT support

Article abstract of DOI:10.1039/d0nj03024d

Single crystal X-ray structurally characterized azo-uracil derivative (L) is explored for the selective detection of pyrene via aggregation-induced emission (AIE) with 99-fold fluorescence enhancement. In the presence of pyrene, non-fluorescent L emits green light and allows pyrene detection to as low as 3.6 × 10-9 M. Three model probes (L1, L2 and L3) were employed to support the proposed sensing mechanism. Further, silica-immobilized L efficiently removes pyrene from its reservoir. This journal is

Full text of DOI:10.1039/d0nj03024d

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Tuning of uracil derivative for AIE based detection of pyrene at
nano-molar level: Single crystal X-ray structure and DFT support
Mahuya Banerjeea, Milan Ghosh,a Sabyasachi Ta,a Subhasis Ghosha and Debasis Das*a
Also 4Received 00th
January 20xx,
Accepted 00th January
20xx
Single crystal X-ray structurally characterized azo-uracil derivative (L) is explored for selective
detection of pyrene via aggregation induced emission (AIE) with 99-fold fluorescence enhancement.
In presence of pyrene, non-fluorescent L emits green light that allows to detect as low as 3.6×10-9 M
pyrene. Three model probes (L1, L2 and L3) have been employed to support the proposed sensing
mechanism. The silica immobilized L efficiently removes pyrene from its reservoir.
DOI:
10.1039/x0xx00000x
www.rsc.org/
KEYWORDS: Azo-uracil, sensor, nano-molar, fluorescence, naked eye, AIE, pyrene.
toxicity in living organism.11-12 Its epoxides are extremely
1. Introduction
toxic, mutagenic and/or carcinogenic to microorganisms and
higher systems including human.13 The exposure to pyrene
generates nephropathy, kidney damage, and haematological
changes.14-15 Several pyrene derivatives cause skin, lung,
bladder, liver and stomach cancer.16-18 The hydrophobic pyrene
accumulates in cell membrane and lipid tissues.19 The soil
contaminated with pyrene is alarming for food security,
particularly for grains, fruits, vegetables, drinking water and
meat.20-22 The benzo-pyrene (BaP) binds to DNA to cause lung
cancer, damage white blood cell, reproductive system and
CYP450 enzymes.23-27 Dry cleaning of garments may lead to
pyrene toxicity.28-30 Its unique spectral feature, particularly
high extinction coefficient is useful to gather information about
molecular organization and protein conformation.31-34 The
pyrene derivatives have been used as fluorescence probe to
study the solvent micro-environment.35 Hence, trace level
Development of optical probe for selective detection and
estimation of toxic small molecules is an emerging research
area.1-2 Economic evolution and energy exploitation demands
consumption of significant amount of polyaromatic
hydrocarbons (PAHs) that lead to environment contamination.3
This is due to incomplete combustion of PAHs,4-5 most of
which are carcinogenic/ mutagenic.6-8a Extreme harmful
effects like cell damaging, cyto-toxicity, mutagenicity, and
nerve damaging effects have brought them under the umbrella,
“ten most toxic classes” of organic compounds by U.S. Centre
for Disease Control and Prevetion.8b They are capable to
change the protein and nucleic acid structures.9-10 Pyrene, one
of the most important members of PAHs family, imparts
Department of Chemistry, The University of Burdwan, Burdwan, 713104,
West Bengal, India.
Correspondence: <ddas100in@yahoo.com2>; phone, +91-342- 2533913; fax,
+91-342-2530452
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selective detection and estimation of pyrene is demanding. designed, synthesised and employed to unveil the plausible
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DOI: 10.1039/D0NJ03024D
However, similarities of pyrene with other PAHs is the primary mechanism of interaction. Interestingly, silica immobilized
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obstacle for its selective detection. For example, pyrene and probe (L) efficiently removes pyrene from real samples.
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most of the PAHs are prone to aggregation that causes shift of
2. Results and discussion
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the emission peak that hinders their selective recognition.36-37
Four new compounds (L, L1, L2 and L3) have been
Pyrene is primarily determined by chromatography,
synthesised (yield, 93-96%) and characterized by different
particularly high-performance liquid chromatography.38-39
spectroscopic techniques (Scheme1, Figure S1-S17, ESI).
However, fluorescence technique is much more superior to
Among them, L shows very weak emission at 373 nm upon
other methods in terms of sample preparation, operational
excitation at 336 nm (Figure S5, ESI). On the other hand, L1,
simplicity, inexpensive methodology, rapidity, direct
L2 and L3 exhibit weak emission at 396 nm, 388 nm and 351
visualization/perception and higher sensitivity.40-42
nm upon excitation at 302 nm, 300 nm and 282 nm respectively
Recently, graphene quantum dot is employed for fluorescence
(Figure S9, S13 and S17, ESI).
recognition of pyrene in aqueous medium51b. Moreover, a
The absorption spectrum of L (20 µM, DMSO/H2O, 4/1, v/v,
pyrene–antipyrine conjugate has been used for detection of
HEPES buffer, pH 7.4) exhibits peaks at 256 nm (ε, 8.8×105
pyrene in DMSO/H2O (4/1) media.43
M−1 cm−1) and 403 nm (ε, 5.66×103 M−1 cm−1), assigned to π–
On the other hand, uracil derivatives are primary target for
π* and n–π* transitions respectively.52
several organic synthesis44 and used as drug carrier.45-52a Its
2.1. Single crystal X-ray structure of L
unique, non-toxic properties inspired to study photo-physical
The ORTEP view of L along with atom numbering scheme is
interactions with living organism. Azo compounds play
presented in Figure 1. The refinement parameters of L that
significant role in several biological reactions, like protein
crystallizes in ‘P-1’ space group (CCDC No. 1869304) are
synthesis, inhibition of carcinogenesis and nitrogen fixation.51b
presented in Table S1-S2 (ESI). The azo bond (N3‒N001)
Interestingly, number of hetero atoms, ring size and substituent
distance, ~1.315Ǻ is comparable to literature value (1.28–
significantly influence over the π-acidity of azoheterocycle that
1.30Å).45 It is to be noted that in L, one N is protonated (N7)
regulate its physical, chemical, electrochemical and photo-
while Cl‒ presents as counter ion which is primarily responsible
physical properties.51c It is noteworthy to mention that we have
for hydrogen bonding. The packing diagram with
reported Cu(II) catalyzed cyclization of azouracil to anticancer
intermolecular hydrogen bonding is shown in Figure S18, ESI.
active triazole derivative very recently.51d
Other crystal parameters including bond angles and bond
Herein, we report another azouracil derivative (L) for detection
lengths are close to reported values.
of nano-molar pyrene via aggregation induced emission.
2.2. Impact of pH
Moreover, three model probes, viz. L1, L2 and L3 have been
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Presence of pH susceptible donor sites in L demands to
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2.3. Effect of medium
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DOI: 10.1039/D0NJ03024D
investigate the influence of pHon spectroscopic properties53. It
is observed that the emission profile of L remains almost
unaltered in the pH span, 3.0 -12.0. Several sets of mixtures of
L and pyrene, adjusted to different pH (3.0-12.0) have been
tested and found that the difference in emission intensities of L
in presence and absence of pyrene is maximum near
physiological pH 7.4 (Figure S19, ESI). Hence, the entire
experiment has been performed at pH 7.4.
Effect of solvent composition on the spectroscopic interaction
between L and pyrene have been studied in several semi-
aqueous media such as DMSO /H2O (4/1, v/v); MeOH/H2O
(4/1, v/v); EtOH/H2O (4/1, v/v); CH3CN/H2O (4/1, v/v) and
DMF/H2O (4/1, v/v). Significant interactions, observed in
DMSO/H2O (4/1, v/v) have insisted to monitor the entire
studies in this media.27
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Scheme 1 Synthetic protocol of the probes
Figure 1 ORTEP view of the L (protonated form)
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2.4. Interference studies
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DOI: 10.1039/D0NJ03024D
The emission spectrum of L is significantly perturbed by
pyrene (λEm, 506 nm, λEx, 336 nm) while other tested PAHs
like naphthalene (λEm, 331 nm), anthracene (λEm, 408 nm),
anthanthrene (λEm, 418 nm), acenaphthene (λEm, 332 nm),
acephenanthrene (λEm, 298 nm), phenanthrene (λEm, 292 nm),
chrysene (λEm, 302 nm), benzo[a]pyrene (λEm, 412 nm),
acridine (λEm, 438 nm), and picene (λEm, 286 nm) remain
silent38 under similar condition mentioned supra (Figure 2).
The same results have been found when the above sets of
experiment is monitored by absorption spectroscopy. In
presence of pyrene, the absorbance of L significantly enhances
at 403 nm while other tested common PAHs remain spectator
(Figure 3).
2.5. Spectroscopic monitoring of L-pyrene interaction
Pyrene induces green emission to L without any interference
from other tested common PAHs mentioned supra (Figure
S20, ESI). The changes of emission intensity of L upon gradual
addition of pyrene is presented in Figure 4. Upon gradual
addition of pyrene to L, the emission intensity at 385 nm
decreases while it increases at 506 nm with an iso-emissive
point at 445 nm. The formation of a charge transfer (CT)
adduct between pyrene (donor) and L (acceptor) through π-π
stacking is proposed that inhibits the PET process resulting
enhancement of emission intensity by 99-fold and fluorescence
quantum yield by 26-fold (λEx, 336 nm).
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Figure 2
Figure 3
Change in spectra of L (20 μM) in presence of common PAHs: Figure 2 (Emission, λEx, 336 nm) and Figure 3 (absorption). Media: DMSO/H2O, 4/1, v/v,
20 mM HEPES buffer, pH 7.4
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Figure 4 Changes in the emission spectra of L (20 µM) upon addition of pyrene at room temperature in mentioned media (λEx = 336 nm); [pyrene] = 0.0001,
0.001, 0.01, 0.1, 1, 10, 100, 400, 600, 800, 1000, 1200, 1400, 1500, 2000, 2500 and 3000 µM).
Likewise, upon gradual addition of pyrene to L, the weak Moreover, [pyrene-L] adduct may exists in static-dynamic
absorption at 403 nm increases while the bare eye pale yellow excimer equilibrium37 involving syn- and anti- forms (Schemes
color turns to intense yellow (Figure 5). Other tested common 2-3). To strengthen the proposed CT process, pyrene-1-
PAHs (mentioned supra) remain spectator without any change carboxaldehyde is used instead of pyrene whereby emission
in spectra/ color.
intensity remains almost unaltered (Figure S23b, ESI),
The plot of emission intensity vs. concentration of pyrene (λEm corroborating our proposition. The presence of electron
= 506 nm, Figure S22, ESI) allows to determine its detection withdrawing -CHO group (-I effect) hinders the CT process
limit, 3.6×10-9 M following 3σ/ K method (inset, Figure S21, from pyrene moiety to L.
ESI)54. The corresponding interaction constant, determined In addition, the [L-pyrene] CT adduct undergoes aggregation
applying Hill equation55-56 on fluorescence titration data is in presence of water through inter-molecular hydrogen bond
9.59×105 M–1 (Figure S22, ESI). The Job’s plot56-57 indicates involving –NH2 moiety of L and H2O that stabilizes the syn-
1:1 (mole ratio) interaction between L and pyrene (Figure form leading to stable static excimer (Scheme 3; Scheme S1,
S23a, ESI).
ESI). Thus, water assisted aggregation of [L-pyrene] CT
adduct is responsible for significant fluorescence
enhancement.
2.6. Sensing mechanism
The L displays weak emission at 373 nm (λEx = 336 nm) due to
PET process (Figure S5, ESI). Upon addition of pyrene, the
emission intensity at 373 nm gradually decreases with
concomitant increase at 506 nm (Figure 4). This is primarily
due to formation of charge transfer (CT) adduct between
pyrene (donor) and azouracil (acceptor) (Scheme S2, ESI).
The necessity of water for aggregation of [L-pyrene] CT
adduct is reflected in Figure S24 (ESI) where pyrene is
gradually added to L in pure DMSO medium, resulting much
lower fluorescence enhancement than that observed in aqueous
DMSO media.
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To further corroborate the proposed sensing mechanism, three uracil moiety hinders stabilization of its static excimer in
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DOI: 10.1039/D0NJ03024D
model probes, viz. L1, L2 and L3 have been designed presence of water through inter-molecular H-bonding (Scheme
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judiciously (Scheme 1). Interestingly, the L1 contains –OH S3, ESI). Hence AIE is not observed for L2. Thus, presence of
(+R effect) instead of –NO2 group (-R effect) present in L. –NH2 group is probably essential for AIE process. On the other
Again, L2 has thio-uracil in place of uracil moiety that lacks - hand, failure of L3 to pyrene recognition indicates the necessity
CH3 having +I effect. On the other hand, the L3 is a non-uracil of the uracil moiety (Figure S27, ESI).
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azo-compound. Interestingly, the electron density on the In addition, general red shift of the FTIR spectrum of the [L-
molecule plays a key role to the AIE based recognition pyrene] adduct compared to free L corroborates their
involving CT process (Scheme S2). Moreover, the stability and interaction (Figures S4, S28, ESI)56.
the extent of charge transfer is highly influenced by the
electron density on the donor unit. While the presence of –NO2
group lowers the electron density on the aromatic unit and
subsequently to the azo-moiety (–N=N–) of L, the reverse is
true for L1 due to presence of –OH group. The effect is
reflected in the CT process. The experimental results support
this line of thinking. Upon gradual addition of pyrene (0.0001-
3000 µM) to L (20 μM, DMSO/H2O, 4/1, v/v), the emission
intensity gradually increases from 612 a.u. to 2498 a.u whereas
it enhances from 116 a.u. to 456 a.u. for L1 (Figure S25, ESI).
The maximum fluorescence enhancement is observed for L2
(128 a.u. - 642 a.u.) indicating strong CT adduct formation with
pyrene (Figure S26, ESI). However, lack of –NH2 group at
2.7. Dynamic light scattering (DLS) studies
The DLS studies support water assisted aggregation of L in
presence of pyrene. Upon gradual addition of pyrene (0.0001
µM to 3000 µM) to L (20 µM), the average particle size (Zav)
remain almost unaltered. With increasing water (DMSO to
DMSO/H2O, 4/1, v/v, pH 7.4), the Zav increase to 175 nm,
indicating aggregation. The Zav value further enhances from
175 nm to 796 nm with increasing water content from
DMSO/H2O (4/1, v/v) to (1/1, v/v), keeping concentration of L
and pyrene unaltered37 (Figure 6). The DLS study indicates that
L1 and L2 remain reluctant towards water assisted AIE based
detection of pyrene (Figures S29- S30, ESI).
Scheme 2 Charge transfer (CT) adduct
Figure 5 Changes in absorption spectra of L (20 µM) vs. [pyrene] in same
media; [pyrene] = 0.0001, 0.001, 0.01, 0.1, 1, 10, 100, 400, 600, 800, 1000,
1200, 1400, 1500, 2000, 2500 and 3000 µM).
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Scheme 3 Plausible sensing mechanism
2.8. 1HNMR titration
indicating plausible tautomerism (between –NH2 and –N=N-
functionalities) of L that arose due to π-π interaction with
pyrene (Figure S2, ESI). Additionally, all aromatic protons up-
field shifted due to enhanced electron density in the ring via
π-π interaction with pyrene, leading to excimer formation.
Upon
The proposed sensing mechanism is further corroborated by
1HNMR titration in DMSO-d6 (Figure 7). Upon addition of 0.5
equiv. pyrene to L, alkyl protons shifted up-field from 2.46 to
2.39 ppm, indicating their interaction with pyrene. Moreover,
‘d’ and ‘e’ protons (Figure S2, ESI) shifted up-field from 7.91
to 7.85 ppm and 8.32 to 8.29 ppm, indicating their interaction
with pyrene. On the other hand, ‘p’ and ‘q’ protons also shifted
up-field from 11.91 and 12.96 ppm respectively. Upon addition
of 1.0 equiv. pyrene to L, both ‘p’ and ‘q’ protons disappeared
addition of 3.0 equiv. pyrene, the peaks broaden, probably due
to exchange between free and aggregated forms of L (Figure
7).
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Figure 7 Changes in HNMR spectra of L in absence
and presence of pyrene in DMSO-d6 (for signals “p” and
“q” see Figure S2.
Figure 6 DLS of [L- pyrene] adduct with increasing water
content/pyrene content of the media (DMSO/H2O)
aggregation of [L-pyrene] adduct (DMSO/ H2O, v/v), and
monomer-excimer emission of pyrene is shown in Figure 10.
The ratio of emission intensities (EI) of respective excimers,
viz. EI [L-pyrene] at 506 nm/ EI [pyrene] at 461 nm is 16.1 (DMSO/
H2O, 4/1, v/v, pH 7.4).
2.9. Role of water in AIE process
The emission properties of [L-pyrene] adduct is influenced by
the water content of the media (DMSO/H2O) (Figure 8). The
emission intensity of L (λEm, 336 nm) enhances almost 40 fold
and 56 fold at 50% H2O (v/v) and 90% H2O (v/v) respectively,
a signature of aggregation. Further increase of water content
2.10. Fluorescence life time studies
results turbidity, hindering measurement of emission The fluorescence life time data corroborate the proposed
intensity.37 The aggregation process has also been monitored interaction mechanism (Figure 11). The average life-time of L
using absorption spectroscopy. Gradual addition of H2O (25- is 0.236 ns in DMSO. In presence of pyrene (1: 1, mole ratio),
80%, v/v) to DMSO solution of [L-pyrene] adduct results the life time increases to 2.2361 ns. Increasing water content
broadening and red shift of the peak from 403 nm to 437 nm gradually enhances the fluorescence life time from 92.2356 ns
55-58
(Figure 9). Side by side presentation of water assisted (25%, v/v). Moreover, the quantum yield
from 5.36% to 26.27%.
(ϕ) increases
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Figure 9 Influence of water on the absorption spectra of [L-pyrene] adduct.
Figure 8 Influence of water on emission intensities of [L-pyrene] adduct (λEx,
336 nm) (% indicates water content of the media, DMSO/ H2O, v/v).
Figure 10 Water assisted aggregation of [L-pyrene] adduct (DMSO/ H2O, 4/1,
v/v, pH 7.4).
Figure 11 Fluorescence life time decay of [L-pyrene] adduct in presence
and absence of water (λEm = 506 nm).
Table S4 (ESI) reveals close proximity of experimental and
theoretical (non-scale) IR frequencies, in terms of band
positions, intensities and shape. The deviations that have been
observed are not unusual because theoretical calculations have
been performed in gas phase.
2.11. Theoretical studies
The geometry of L and [L-pyrene] CT adduct in gas phase
have been optimized without restrictions of symmetry in
singlet ground state, along with gradient-corrected density
functional theory (DFT) with three-parameter fit of exchange
and correlation functional of Becke (B3LYP) that include
correlation functional of Lee et al. (LYP).59-61 The method is
known as RTD-B3YLP-FC. Their structural parameters are
summarized in Tables S3-S4 (ESI). The total energy and dipole
moment of the L are -1093.22688 a. u. and 14.1660 Debye
respectively. It has C1 point group with a triclinic lattice
system. The unit cell lengths are 15.27 (a), 7.50 (b) and 3.46
and c respectively (Figure 12).
The peak at 402 nm in theoretical gas phase absorption
spectrum (Figure S30, ESI) matches to that observed
experimentally at 403 nm in DMSO/H2O (4/1, v/v, HEPES
buffer, pH 7.4). Theoretical spin-allowed electronic transitions
of L are summarized in Table S6 (ESI). Out of 158 orbitals
(both alpha and beta), the 79th orbital is HOMO (-0.21524eV)
and 80th orbital is LUMO (-0.15295 eV). The HOMO -LUMO
energy gap is 0.0623 eV (Figure 13). In [L-pyrene], out of 264
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orbitals (both alpha and beta), the 132th orbital is HOMO (- are summarized in Table S7 (ESI). TD-DFTVicewalAcrtuicllaetOionlninse
DOI: 10.1039/D0NJ03024D
0.12290eV) and 133th orbital is LUMO (-0.09440 eV). The (Tables S6-S7) also support experimental findings. The
HOMO -LUMO energy gap is 0.0285 eV (Figure 13). Lower excitation spectrum of the L at 336 nm (Figure S5, ESI)
energy gap in [L-pyrene] indicates its stability (Scheme 2). matches the theoretical TD-DFT data at 336 nm and 365 nm of
Theoretical spin-allowed electronic transitions of [L-pyrene] [L-Pyrene] adduct (Table S6- S7).
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Figure 12 DFT optimized geometry
Figure 13 HOMO-LUMO energy gap
2.12. Application
2.12.i. Real sample analysis and solid phase extraction (Table 1)
37-38
The L is employed
to determine pyrene in pond and tap pyrene, its FTIR spectra is measured before and after sorption
water samples following standard addition method. For this of pyrene. Moreover, the L immobilised silica is used for solid
purpose, a known amount of pyrene is added to water samples phase extraction (SPE) of pyrene56-58, 62-67 from its reservoir
(collected from pond in Durgapur-Asansol industrial area, one (Table 2). The sorbed pyrene on silica immobilised L is eluted
of the most polluted places in West Bengal, India and tap water by DMSO/H2O (4/1, v/v) and concentration of pyrene in the
collected from our research laboratory). The samples are then eluent is measured by the developed method. Both complete
analysed for determination of pyrene following the developed sorption and desorption of pyrene on silica immobilised L is
method (Figure 14).62
ascertained from non-fluorescence nature of the effluent and
The immobilization of L on silica (150-200 mesh) have been eluent, upon exposure of UV-light (Figure 16). Figure S31
performed following literature.62 L (1.5g) and silica (10.5g) are (ESI) displays the red shifted FTIR spectrum of the silica
mixed together in 25 mL MeOH and refluxed for 3h while the immobilized
L
before and after consuming pyrene.
solution color turns pale yellow (Figure 15). The solvent is Interestingly, after passing pyrene through silica immobilized
removed under vacuum. A glass column (10 cm × 1 cm) is L, the bed becomes intense yellow, indicating retention of
packed with the immobilized L maintaining the bed volume, pyrene by silica immobilized L (Figure 15).
10 mL. To establish the binding of silica immobilized L to
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Figure 15 Color of silica immobilized L before and after sorption of
pyrene
Figure 14 Calibration plot for pyrene estimation.
Figure 16 The emission spectra (left) and UV light irradiated colours (right) of the sample before and after passing through silica immobilised L
Table 1 Determination of pyrene in water
Pond water
Sample No.
P1
Added (10-3 M)
Found (10-3 M)
Recovery (%)
97.80 ± 1.23
20
19.56
P2
P3
15
12
14.78
11.80
98.53 ± 1.03
98.30 ± 1.62
Tap water
Sample No.
Added (10-3 M)
Found (10-3 M)
19.12
Recovery (%)
95.60 ± 1.26
93.80 ± 1.61
T1
T2
20
15
14.07
T3
12
11.16
93.01 ± 1.10
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Table 2 Solid phase extraction (SPE) of pyrene using silica immobilized L
View Article Online
DOI: 10.1039/D0NJ03024D
Solid phase extraction
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Sample
S1
Pyrene added (10-3 M)
Pyrene estimated (10-3 M)
Recovery (%)
94.86±1.12
30
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28.46
23.12
S2
92.48±1.32
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3.2. Effect of pH
3. Experimental
The solution of L (100 µM, DMSO/ H2O, 4/1, v/v) is diluted
with HEPES buffer (20 mM) solution to prepare working
solution of L (20 μM) of appropriate pH (3.0 to 12.0). Then,
pyrene (37.5 mg, 0.18 mmol, 20 μM) dissolved in HEPES
buffer is added to the solution of L (20 μM) in different sets,
maintained at different pH. The emission intensities of
different sets of solutions are measured at room temperature.
3.3. 1H NMR titration
Materials and equipment used, general method of UV-Vis and
fluorescence titration have been discussed in detail in ESI.
3.1. Selectivity and interference studies
Studies on plausible interference from common competing
PAHs during pyrene sensing have been performed in two
different ways. In first experiment, different competing PAHs
are added to the [L-pyrene] system in different sets while in the
other, mixture of PAHs including pyrene is added to the L. In
first case, the emission intensity remains unaltered while
emission intensity increased to the same extent to that of the
[L-pyrene] system in second case. These results indicate the
selectivity of L for pyrene and non-interference of other
competing PAHs during recognition of pyrene by L (Figure
S20, ESI).
Three different sets containing L (3.56 mg dissolved in 700 μL
DMSO-d6) and pyrene (0.5, 1.0, 3.0 equiv. pyrene dissolved in
minimum volume of D2O) are prepared by sonication and
1HNMR spectra of the mixture are recorded.
3.4. Calculation of detection limit
For this purpose, fluorescence titration of L with pyrene is
Thus, to check plausible interference, relative emission performed. The concentration at which a sharp change in
intensities of [L-pyrene] (1:1, 20 µM) adduct are measured in emission intensity is observed, multiplied by the concentration
presence of other PAH (20 µM) in DMSO/H2O (4/1, v/v, pH of L to calculate the detection limit.62
7.4) (λEx = 336 nm).
3.5. Determination of association constant
The binding constant calculated using Hill’s equation,62
To check the selectivity of L for pyrene, different PAH (10
mM) is mixed with L (20 μM) in different sets along with a set
where all PAHs are mixed together with L. Then the emission
intensity of all the sets are measured.
log[Y/(1-Y)] = n log[G] + log Kapp where, Y, n, [G] and Kapp
represent the fraction of L binding sites filled, Hill coefficient,
concentration of pyrene and association constant respectively.
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The value of Hill coefficient describes the cooperativity of L (L),
ARTICLE
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6-amino-5-(4-hydroxy-phenylazo)-1,3-dimethyl-1H-
View Article Online
DOI: 10.1039/D0NJ03024D
binding in the following way: n > 1, positive cooperativity; n pyrimidine-2,4-dione (L1), 5-(4-nitro-phenylazo)-2-thioxo-
= 1, non-cooperativity and n < 1, negative cooperativity. Y is 2,3-dihydro-1H-pyrimidin-4-one (L2) and 4-(4-nitro-
determined by the equation of (Fx-F0)/(Fmax-Fx), where F0, Fx, phenylazo)-benzoic acid (L3). In general, diazotization of
and Fmax are the emission intensities of L in absence of pyrene, acidic solution of respective amine (1.0 mmoL, 138 mg for L,
at an intermediate pyrene concentration, and at a concentration L2 and L3 while 139 mg for L1) using sodium nitrite (76 mg,
of complete interaction respectively. The value of K thus 1.1 mmol) at 0-50C followed by coupling with 6-amino-1, 3-
evaluated is 9.59×105 M–1, indicating strong interaction dimethyl uracil (1.0 mmoL, 155 mg for L and L1, 128 mg 2-
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between the L and pyrene.
thiouracil for L2 and 122 mg benzoic acid for L3), dissolved in
saturated sodium bicarbonate solution at pH 6-7. The colourful
solid azo compounds are separated by filtration and dried in
vacuuo.
3.6. Determination of quantum yield
The fluorescence quantum yields of L and its adduct with
pyrene are determined using pyrene as reference with a known
R value, 0.2 in DMSO/H2O (4/1, v/v, HEPES buffer, pH
7.4).64 The L, [L-pyrene] adduct and reference dye are excited
at 336 nm, maintaining almost equal absorbance (0.1) and
emission intensities. The area of the emission spectrum is
integrated using the software available in the instrument and
the quantum yield is calculated following the equation 64, S/R
L
The yellow L is obtained in 97% yield. Anal. calcd. for
C12H12N6O4 (%): C, 43.37; H, 3.98 and N, 27.62; found, C,
43.87; H, 4.01 and N, 27.97. QTOF–MS ES(+) (Figure S1,
ESI) [M + H]+ = 305.1259 (100%), [M+Na]+ = 327.1095
(17%). 1HNMR (Figure S2, ESI) (DMSO-d6, δ, ppm): 12.92 (s,
1H, =NH), 11.91 (s, 1H, =N-NH, azo moiety); 8.32-8.30 (d,
2H, Ar–H); 7.86-7.85 (d, 2H, Ar–H); 3.37-3.26 (m, 6H, N–
CH3); 3.24 (s, 2H, -NH2); 13CNMR (Figure S3, ESI) (DMSO-
d6, δ, ppm): 28.46 (-CH3); 28.57 (-CH3); 29.27 (-CH3); 30.07
(-CH3); 121.76 (=CH); 125.64 (=CH); 146.02 (-C=O); 146.77
(-C=O ); 150.04 (=C-NH2). FTIR (cm-1) (Figure S4, ESI) υ(–
NH2), 3546; ν(aromatic C–H), 2976; υ(sp3C-H), 1651; υ(–
C=C), 1500; υ(–N=N–), 1448; υ(–C–N), 1303. The L emits at
373 nm (λEx = 336 nm, Figure S5, ESI). The absorption
spectrum of L (20 µM, DMSO/H2O, 4/1, v/v, HEPES buffer,
pH 7.4) exhibits strong peaks at 256 nm (ε = 8.8×105 M−1 cm−1)
and 403 nm (ε = 5.66×103 M−1 cm−1) (Figure S5, ESI).
2
2
= [AS/AR]×[(Abs)R/(Abs)S]×[S /R ] where S and R are the
fluorescence quantum yield of the sample and reference
respectively, AS and AR are area under the emission spectra of
the sample and reference respectively, (Abs)S and (Abs)R are
optical densities of the sample and reference solution at
corresponding excitation wavelength; S and R are refractive
indices of the sample and reference respectively.68-69
3.7. Synthesis
3.7.1. General method (Scheme 1)
The azo compounds37 that have been synthesized are 6-amino-
1,3-dimethyl-5-(4-nitro-phenylazo)-1H-pyrimidine-2,4-dione
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L1
8.44 (d, 2H, Ar–H); 8.22-8.11 (d, 2H, Ar–H); 7.61V‒ie7w.5A8rtic(lde ,O2nlHine,
DOI: 10.1039/D0NJ03024D
The red-brown compound is obtained in 94% yield. Anal. Ar–H); 7.48‒7.41 (d, 2H, Ar–H); FTIR (cm-1) (Figure S16,
calcd. for C12H13N5O3 (%): C, 52.36; H, 4.76; N, 25.44; found, ESI) υ(–O‒H), 3454; υ(–C=C), 1560; υ(–N=N–),1483; υ(–
C, 52.37; H, 4.71 and N, 25.47. QTOF–MS ES(+) (Figure S6, NO2), 1388; υ(–C–N), 1340, υ(–C–O), 1109. The L3 emits at
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ESI) [L1+Na]+
=
298.4137 (100%), [L1+CH3OH+H]+ 351 nm (λEx = 282 nm, Figure S17, ESI).
1
=308.3629 (17%); HNMR (Figure S7, ESI) (DMSO-d6, δ,
ppm): 13.48 (s, 1H, –N-NH); 12.49 (s, O-H); 8.71-8.69 (d, 2H,
Ar–H); 7.54-7.44 (d, 2H, Ar–H); 3.07-3.04 (m, 6H, N–CH3);
3.02 (s, 2H, -NH2); FTIR (cm-1) (Figure S8, ESI) υ(–NH2),
3321; ν(‒O‒H), 3144; υ(–C=O), 1718,1669; υ(–C=C), 1516;
υ(–N=N–), 1441; υ(–C–N), 1293. The L1 emits at 396 nm (λEx
= 302 nm, Figure S9, ESI).
4. Conclusion
Single crystal X-ray structurally characterized azo-uracil
derivative (L) is exploited for selective detection of pyrene at
nano-molar in aqueous DMSO media via aggregation induced
green emission with 99-fold fluorescence enhancement. The
pyrene assisted inhibition of photo-induced electron transfer
(PET) in L is triggered by water leading to AIE enhancement
through static-dynamic excimer equilibrium involving syn and
anti-forms of L in the charge transfer (CT) complex. Studies
on other three model compounds, viz. L1, L2 and L3 help to
elucidate the interaction process. The interaction constant and
LOD values are 9.59×105 M–1 and 3.6×10-9 M respectively.
The developed method is useful for trace level determination
of pyrene in real samples. Silica immobilised L efficiently
removes pyrene from its reservoir. The present report is not
only a new method of pyrene detection at nanomolar level, it
explores a new horizon in the field of AIE.
L2
The yellow compound is obtained in 82% yield. Anal. calcd.
for C10H7N5O3S (%): C, 43.32; H, 2.54; N, 25.26; found, C,
43.34; H, 2.51 and N, 25.27. QTOF–MS ES(+) (Figure S10,
ESI) [L2+H]+ = 278.4180 (93%), [L2+CH3OH+H]+ =310.6752
1
(80%); HNMR (Figure S11, ESI) (DMSO-d6, δ, ppm): 7.93-
7.91 (d, 2H, Ar–H); 7.56-7.54 (d, 2H, Ar–H); 7.40 (s, 1H,
‒C=C‒H); 5.82 (s, 1H, S=C-NH‒C=O); 5.80 (s, 1H, S=C-
NH‒HC); FTIR (cm-1) (Figure S12, ESI) υ(–NH2), 3454; υ(–
C=O), 1708,1678; υ(–C=C), 1565; υ(–N=N–),1506; υ(–NO2),
1376; υ(–C–N), 1216. The L2 emits at 388 nm (λEx = 300 nm,
Figure S13, ESI).
Conflicts of interest
No conflicts to declare.
L3
Acknowledgement
The brown compound is obtained in 89% yield. Anal. calcd.
for C13H9N3O4 (%): C, 57.57; H, 3.34; N, 15.49; found, C,
57.54; H, 3.35 and N, 15.47. QTOF–MS ES(+) (Figure S14,
ESI) [L3+H2O+H]+ = 290.3860(98%), [L3+Na]+ = 294.1680
MB sincerely acknowledges State DST (West Bengal) for
fellowship. MG is grateful to CSIR (New Delhi) for
fellowship.
5. Reference
1
(56%); HNMR (Figure S15, ESI) (DMSO-d6, δ, ppm): 8.46-
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ARTICLE
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4
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7
1. C. T. Chen, Chem. Mater. 2004, 16, 4389–4400.
2. M. E. Germain and M. J. Knapp, Chem. Soc. Rev.,
2009, 38, 2543-2555.
12. M. J. Benecky, R. W. Wine, C. G. Kolvenbach, and
View Article Online
DOI: 10.1039/D0NJ03024D
M. W. Mosesson, Biochemistry, 1991, 30,
4298−4306.
8
9
3. J. F. Collins, J. P. Brown, S. V. Dawson, and M. A.
Marty, Regul Toxicol Pharmacol., 1991, 13, 170-
184.
13. (a) S. Ouvrard, P. Leglize and J. L. Morel., Int J
Phytoremediation., 2014, 16, 46-61. (b) S. A.
Nsibande, and P. B. C. Forbes, RSC Adv., 2020, 10,
12119-12128.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
4. K. Srogi, Environ Chem Lett., 2007, 5, 169–195.
5. D. F. Kalf, T. Crommentuijn, and E. J. V. D.
Plassche, Ecotoxicol Environ Saf., 1997, 36, 89-97.
6. B. J. Finlayson-Pitts, and Jr. J.N. Pitts, Science, 1997,
276, 1045–1052.
14. M. Machala, J. Vondracek, L. Blaha, M. Ciganek,
and J.V. Neca, Mutat Res., 2001, 497, 49-62.
15. Y. Zhang, S. Dong, H. Wang, S. Tao and R. Kiyama.
Environ Pollut., 2016, 213, 809-824.
7. Z. Fiala, A. Vyskocil, V. Kraják, V. Masín, S.
Emminger, V. Srb and J. Tejral, Acta Medica, 1999,
42, 77–89.
16. J. Zhang, L. Chang, H. Jin, Y. Xia, L. Wang, W. He,
W. Li, And H. Chen, Exp Biol Med., 2016, 241,
1516-1523.
8. (a) R. Goldman, L. Enewold, E. Pellizzari, J. B.
Beach, E. D. Bowman, S. S. Krishnan and P. G.
Shields, Cancer Res., 2001, 61, 6367–6371. (b)
Agency for Toxic Substances and Disease Registry
(ATSDR). Toxicological profile for naphthalene.
Atlanta, GA: U. S. Department of Health and Human
Services; 1996.
17. H. A. Herner, J. E. Trosko and S. J. Masten, Environ.
Sci. Technol., 2001, 35, 3576–3583.
18. T. Yoshikawa, L. P. Ruhr, W. Flory, D. Giamalva,
D. F. Church and W. Pryor, Toxicol. Appl. Pharm.,
1985, 79, 218-226.
19. Z. Zhang, Z. Zhang, H. Lu, Q.Yang, H. Wu, J.Wang,
and J. Wu, Mol Neurobiol. 2017, 54, 1874–1886.
20. L. Bielská, M. Kah, G. Sigmund, T. Hofmann, and S.
Höss, Sci. Total Environ., 2017, 595, 132–140.
21. M. Ahmad, A.U. Rajapaksha, J. E. Lim, M. Zhang,
N. Bolan, D. Mohan, M. Vithanage, S.S. Lee, and
Y.S. Ok, Chemosphere, 2014, 99, 19–33.
9. C. E. Boström, P. Gerde, A. Hanberg, B. Jernström,
C. Johansson, T. Kyrklund, A. Rannug, M.
Törnqvist, K. Victorin, and R. Westerholm, Environ
Health Perspect. 2002, 3, 451-488.
10. H. Choi, and J. Spengler, Environ Int., 2014, 63, 173-
181.
22. J. Akkanen, And J.V.K. Kukkonen, Environ.
Toxicol. Chem., 2003, 22, 518–524.
11. M. J. Benecky, C. G. Kolvenbach, R. W. Wine, J. P.
DiOrio and M. W. Mosesson, Biochemistry, 1990,
29, 3082−3091.
23. P. C. Conlon, J. Yang, Y. Wu, Y. Chen, K. Martinez,
Y. Kim, N. Stevens, A. A. Marti, S. Jockusch, N. J.
This journal is © The Royal Society of Chemistry 20xx
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Page 16 of 19
ARTICLE
Journal Name
1
2
3
4
5
Turro, and W. Tan, J. Am. Chem. Soc., 2008, 130,
33. T. Annable, R. Buscall, R. Ettelaie and D.
View Article Online
DOI: 10.1039/D0NJ03024D
336–342.
Whittlestone, J. Rheol. 1993, 37, 695−726.
6
7
8
9
24. M. M. McCallister, M. Maguire, A. Ramesh, Q.
Aimin, S. Liu, H. Khoshbouei, M. Aschner, F. F.
Ebner, and D. B. Hood, NeuroToxicology., 2008, 29,
846–854.
34. C. Krejtschi and K. Hauser, Eur. Biophys. J. 2011,
40, 673−685.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
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51
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53
54
55
56
57
58
59
60
35. T. A. Pham, F. Song, M.-T. Nguyen and M. Stöhr,
Chem. Commun., 2014, 50, 14089-14092.
36. S. Samanta, S. Goswami, Md. N. Hoque, A. Ramesh
and G. Das, Chem. Commun., 2014, 50, 11833-
11836.
25. R.S. Clark, S.T. Pellom, B. Booker, A. Ramesh, T.
Zhang, A. Shanker, M. Maguire, P.D. Juarez, M. J.
Patricia, M. A. Langston, M.Y. Lichtveld and D. B.
Hood, Environ Research. 2016, 146, 173–84.
26. A. Ramesh, F. Inyang, D.D. Lunstra, M.S. Niaz, P.
Kopsombut, K. M. Jones, D.B. Hood, E.R. Hills, and
A.E. Archibong, Exp Toxicol Pathol., 2008, 60, 269-
80.
37. (a) A. Ghosh, A. Sengupta, A. Chattopadhyay and D.
Das, Chem. Commun., 2015, 51, 11455-11458; (b)
V. N. S. Occello, A. V. Veglia, Anal. Chim. Acta.,
2011, 689, 97-102.
38. (a) S. Nandi, S. Adhikari, S. Mandal, A. Banerjee and
D. Das, J Mol Recognit., 2016, 29, 303-307. (b) A.
Malik, P. Verma, A. K. Singh and K. P. Singh,
Environ. Monit. Assess. 2011, 172, 529–545.
39. R. Gautam, A. Srivastava, and S. M. Jachak,
Phytochem. Anal., 2011, 22, 153-157.
27. IARC Monographs, Supplement/World Health
Organization, International Agency for Research on
Cancer, 1987, 7, 1–440.
28. R. Sinha, M. Kulldorff, M. J. Gunter, P. Strickland
and N. Rothman, Adenoma Cancer Epidemiol
Biomarkers Prev., 2005, 14, 2030-2036.
40. A.; Chattererjee, M.; Santra, N.; Won, S. Kim, J.K.
Kim, S.B. Kim, and K.H. Ahn, J. Am. Chem. Soc.,
2009, 131, 2040-2041.
29. M. F. Denissenko, A. Pao, M. Tang and G. P. Pfeifer,
Science, 1996, 18, 430-432.
30. J. Gündel, and J. Angerer, J Chromatogr Sep Tech,
2000, 738, 47-55.
41. M. Ghosh, S. Mandal, S. Ta, and D. Das, Sens.
Actuators B Chem., 2017, 249, 339-347.
31. R. P. Haugland, M. T. Z. Spence, I. D. Johnson, and
A. Basey, The handbook: A guide to fluorescent
probes and labeling technologies, 10th ed.,
Molecular Probes, Eugene, 1995.
42. B.-R. Gao, H.-Y. Wang, Y.-W. Hao, L.-M. Fu, H.-H.
Fang, Y. Jiang, L. Wang, Q. D. Chen, H. Xia, L.-Y.
Pan, Y.-G. Ma, and H.-B. Sun, J. Phys. Chem. B.,
2010, 114, 128-134.
32. D. S. Karpovich, and G. J. Blanchard, J. Phys.
Chem., 1995, 99, 3951−3958.
43. M. Ghosh, S. Ta, S. Lohar, S. Das, P. Brandão, V.
Felix and D. Das, J. Mol. Recognit., 2019, 32, e2771.
16 | J. Name., 2012, 00, 1-3
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Page 17 of 19
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Journal Name
ARTICLE
1
2
3
4
5
6
7
8
9
44. (a) A. Patasz, and D. Ciez, Eur. J. Med. Chem., 2015,
97, 582-611. (b) N. Boudet, and P. Knochel, Org.
Lett., 2006, 8, 3737-3740.
Huang, Q. Gao, Y. Liu, X. Kou and D. Xiao,
View Article Online
DOI: 10.1039/D0NJ03024D
Spectrosc Lett., 2015, 48, 748-756. (f) R. A. Wilson,
C. J. Seliskar, G. Talaska, and W. R. Heineman,
Anal. Chem., 2011, 83, 3725–3729.
45. D. Debnath, S. Roy, B.-H. Li, C.-H. Lin and T. K.
Misra, Spectrochim. Acta A, 2015, 140, 185–197.
46. R. Karpicz, V. Gulbinas, and A. Undzenas, J. Chin.
Chem. Soc., 2000, 47, 589–595.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
53. (a) S. Piotto, S. Concilio, L. Sessa, R. Diana, G.
Torrens, C. Juan, U. Caruso, and P. Iannelli,
Molecules, 2017, 22, 1372. (b) A. Ghorai, J. Mondal,
R. Chandra and G. K. Patra. Dalton Trans., 2015, 44,
13261-13271. (c) M. Ghosh, S. Ta, J. S. Matalobos
and D. Das, Dalton Trans., 2018, 47, 11084-11090.
47. M.A. Metwally, E. A. Latif, F.A. Amer, and G.
Kaupp, Dyes Pigm., 2004, 60, 249–264.
48. Y.K. Zhao, W.B. Chang, and Y.X. Ci, Talanta, 2003,
59, 477–484.
54. M. Ghosh, S.Ta, M. Banerjee, M. Mahiuddin, S.
Khanra, S. K. Hira, P. P. Manna, and D. Das, J.
Photochem. Photobiol. A., 2018, 367, 32-38.
55. Y. G. Sidir, İ. Sidir, H. Berber and E. Taşal, J. Mol.
Liq., 2011, 162, 148-154.
49. N. Menek, E. Eren, and S. Topcu, Dyes Pigm., 2006,
68, 205–210.
50. D. Rawata, S. R. Sharma, S. Karmakara, A. L. Singh
and V. Mishra, Ecotoxicol.
Environ. 2018, 148,
528-537.
56. M. Ghosh, S. Ta, M. Banerjee, Md. Mahiuddin, and
D. Das, ACS Omega, 2018, 3, 4262–4275.
51. (a) E. Merino, Chem. Soc. Rev., 2011, 40, 3835–
3853; (b) T. A. Farghaly and Z. A. Abdallah,
Arkivoc, 2008, 17, 295-305. (c) J. Sivamani and A.
Siva, Sens. Actuators B Chem, 2017, 242, 423-433.
(d) M. Banerjee, M. Ghosh, S. Pradhan, J. S.
Matalobos, A. Rej, S. K. Hira, and D. Das. ACS Appl.
Bio Mater., 2019, 2, 1184−1196.
57. A. Ghorai, J. Mondal, R. Chandra and G. K. Patra.
Dalton Trans., 2015, 44, 13261-13271.
58. (a) M. Ghosh, A. Ghosh, S. Ta, J. S. Matalobos, and
D. Das. ChemistrySelect, 2017, 2, 7426–7431. (b) M.
Banerjee, S. Ta, Ghosh, M. Ghosh, A. and D. Das,
ACS Omega, 2019, 4, 10877-10890.
52. (a) C. Carrillo-Carrión, B. M. Simonet and M.
Valcárcel, Anal. Chim. Acta, 2009, 652, 278–284. (b)
Nsibande S. A. and Forbes P. B. C, RSC Adv., 2020,
10, 12119–12128. (c) O. Adegoke and P.B.C.
Forbes, Talanta, 2015, 146, 780-788. (d) S.A.
Nsibande, H. Montaseri and P.B.C. Forbes, Trends
Anal. Chem. 2019, 115, 52-69. (e) L. Wang, Z.
59. A. Pandey, S. K. Ashthana, A. Prakash, J. K. Roy, I.
Tiwari, and K. K. Upadhyay, Dalton Trans., 2019,
48, 2068-2076.
60. A. Bhattacharya, J. P. Naskar, S. Majumder, R.
Ganguly, P. Mitra and S. Chowdhury, Inorg. Chim.
Acta, 2015, 425, 124-133.
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ARTICLE
61. P. Saha, J. Naskar, A. Bhattacharya, R. Ganguly, B.
Journal Name
1
2
3
4
5
6
7
8
68. (a) B. F. Parker, Z. Zhang, L. Rao and J. Arnol,
View Article Online
DOI: 10.1039/D0NJ03024D
Saha and S. Chowdhury, J. Coord. Chem., 2016, 69,
303-317.
Dalton Trans., 2018, 47, 639-644.
69. W. H. Melhuish, J. Phys. Chem., 1961, 65, 229-
62. (a) C. Lee, W. Yang, R. G. Parr, Phys. Rev. Sect. B,
1988, 37, 785-789; (b) P.J. Hay, W.R. Wadt, J.
Chem. Phys., 1985, 82, 270-295.
9
235.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
70. F. I. El-Dossoki, J .Chin. Chem. Soc., 2007, 54,
1129-1137.
63. (a) A. Sahana, S. Das, A. Banerjee, S. Lohar, D.
Karak, D. Das, J Haz. Mater., 2011, 185, 1448–1457.
(b) S. Adhikari, A. Ghosh, M. Ghosh, Guria, S. and
D. Das, Sens. Actuators B: Chem., 2017, 251, 942-
950. (c) M. Banerjee, M. Ghosh, S. Ta, J. Das, and
D. Das, J. Photochem. Photobiol. A, 2019, 377, 286–
297.
64. (a) M. Ghosh, S. Ta, M. Banerjee, M. Mahiuddin,
P.P. Manna, and D. Das, ChemistrySelect 2018, 3,
6145-6151; (b) A. Ghorai, J. Mondal, S.
Bhattacharya, and G. K. Patra, Anal. Methods, 2015,
7, 10385-10393.
65. S. Shit, M. Nandy, D. Saha, L. Zhang, W. Schmitt,
C. Rizzoli & T.N, Guru Row, J. Coord. Chem., 2016,
69, 2403-2414.
66. A. Ghosh, S. Ta, M. Ghosh, S. Karmakar, A. Banik,
T. K. Dangar, S. K. Mukhopadhyay and D. Das,
Dalton. Trans., 2016, 45, 599-606.
67. Y. Shen, Z. Liu, X. Yang, H. Wang, Z. Chai, and D.
Wang, Ind. Eng. Chem. Res., 2017, 56, 12708–
12716.
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