Bis-triazole with indole pendant Organosilicon framework: Probe for recognition of Pb2+ ions

Article abstract of DOI:10.1016/j.molstruc.2021.129963

Trace lead (II) ions detection platform by adjoining an indole group, bis-triazole molecules and a silatranyl motif, has been proposed in this article. The receptor has been prepared by employing click chemistry methodology and the hybrid network was successfully identified by elemental analysis, IR and NMR (¹H, ¹³C) spectroscopy. Absorption spectra analysis marked that the sensor exhibit an exclusively fastidious response to Pb²⁺ ions with a measured detection limit of 0.032μM at 1:1 stiochiometry. Further, computational studies have been carried out to get an insight into their structure and properties.

Full text of DOI:10.1016/j.molstruc.2021.129963

Journal of Molecular Structure 1231 (2021) 129963
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstr
Bis-triazole with indole pendant Organosilicon framework: Probe for
recognition of Pb2+ ions
Gurjaspreet Singha,∗, Pinky Satijaa, Akshpreet Singhb, Pawana, Mohita, Jashan Deep Kaura,
Anita Devia, Anamika Sainia, Jandeep Singhc
a Department of Chemistry, Panjab University, Chandigarh 160014, India
b Department of Chemistry, GGDSD College, Sector-32, Chandigarh, India
c Department of Chemistry, Lovely Professional University, Phagwara-144411, India
a r t i c l e i n f o
a b s t r a c t
Article history:
Trace lead (II) ions detection platform by adjoining an indole group, bis-triazole molecules and a sila-
tranyl motif, has been proposed in this article. The receptor has been prepared by employing click chem-
istry methodology and the hybrid network was successfully identified by elemental analysis, IR and NMR
(1H, 13 C) spectroscopy. Absorption spectra analysis marked that the sensor exhibit an exclusively fastid-
ious response to Pb2+ ions with a measured detection limit of 0.032μM at 1:1 stiochiometry. Further,
computational studies have been carried out to get an insight into their structure and properties.
Received 8 November 2020
Revised 27 December 2020
Accepted 12 January 2021
Available online 27 January 2021
Keywords:
Organosilicon
Indole
© 2021 Elsevier B.V. All rights reserved.
1,2,3-triazole
1,2,4-triazole
Pb2+ ion
sensor
1. Introduction
Agency for Research on Cancer) and WHO has marked out the limit
(threshold value) for Pb2+ in food and water at 10 ppb (10μgL−1
)
In recent years, environmental pollution is booming day by day
due to large amount of perilous elements as a result of their wide
industrial use. Lead is the second most bountiful, toxic and non-
biodegradable pollutant. It has paramount significance in cosmetic
products like skin whitening creams, lip-sticks, blusher, kohl, eye
shadows, hair dyes, food additives, wine factories, baby toys, lead
pipes, lead batteries, paints, pigments, utensils, computer screen,
etc [1–5]. Agglomeration of lead in human body causes lead poi-
soning and can form complexes with nitrogen, oxygen, and sul-
fur containing biological molecules, resulting in enzyme inhibition
process through hydrogen bond breaking. Due to the wide expo-
sure, it affects the soft tissues and multiple body organs like blood,
teeth, bones, kidney, central nervous system, cardiovascular system
and reproductive system, and could conduct generation to gener-
ation by absorption through skin or inhalation from air and wa-
ter. Lead has potential to harm breast milk that exerts physiolog-
ical diseases, such as mortality, intelligence deficiency, neurolog-
ical disorders, and muscle paralysis [6–8]. The IARC (International
[9,10]. The permissible limit of blood lead level is 5g/dl for chil-
dren and 10g/dl for adult according to the Centre for disease con-
trol (US) [5]. Therefore, the discovery of new architecture with ef-
fective monitoring is quiet essential and intellectually demanding
task.
Silatrane associated to the class of tricyclic cage like hyperva-
lent heterocycle with silicon atom fixed in the cage and an exo-
cyclic substituent at trans-position [11]. The uniqueness of these
atrane molecules is the reciprocity between nitrogen and silicon
atoms through dative bond which diminish susceptibility to hy-
drolysis and transmit stability [12]. Silatranes have ample of ap-
plications in diverse disciplines such as in organic synthesis [13],
sensing [14,15], sol-gel processes, catalysis [16], agriculture [17],
and in medicine [18]. Indole nucleus has been identified as a ubiq-
uitous moiety, extract from mushroom, construction of many natu-
ral products, strong anion binding chemosensor and it has been vi-
tal in therapeutic chemistry and pharmaceutical industry ascribed
to their inherent bustle for the treatment of numerous diseases,
especially HIV-1, antiviral, anti-oxidant, anti- tuberculosis, antibac-
terial, antifungal, hepatitis B and hepatitis C [19–28]. On the basis
of aforementioned facts, we have designed bis-triazole with indole
pendant organosilicon framework for the detection of Pb2+ ions
over other metal cations.
∗
Corresponding Author: Dr. Gurjaspreet Singh, Professor, Department of Chem-
istry, P.U., Chandigarh, India
E-mail address: gjpsingh@pu.ac.in (G. Singh).
https://doi.org/10.1016/j.molstruc.2021.129963
0022-2860/© 2021 Elsevier B.V. All rights reserved.

G. Singh, P. Satija, A. Singh et al.
Journal of Molecular Structure 1231 (2021) 129963
2. Experimental Section
Synthesis of compound (3): The quantities used were as:
2(1.00g, 5.4 mmol), 4-amino-1,2,4triazole (0.45g, 5.3mmol). Yield:
79%. M.p.:126°C-128°C. Anal. Calcd. For C14 H11 O5: C, 67.46; H, 4.45;
2.1. Materials and Methods
N, 28.10; Found: C, 67.41; H, 4.37; N, 27.98. IR (cm−1): 3266 (C C-
≡
All commercially available chemicals were of analytical grade
and used as received without further purification such as
indole-3-Carboxaldehyde (merck), 4-amino-1,2,4-triazole (avra), 3-
chlorpropyltriethoxysilane (merck), sodium azide (Merck) and tri-
ethanolamine (merck). The infrared spectra were recorded on a
Thermo Scientific NICOLET IS50 spectrophotometer. The 1H and 13C
NMR spectra were conducted on a JEOL (AL 400 MHz) spectrom-
eter. Electronic spectral measurements were measured by using
JASCO V-530 double beam spectrophotometer.
≡
H), 3113(N=CH), 2114(C C), 1599 (C=N), 1455 (CH3-C), 1287 (CH2-
N), 1160 (O-CH2), 927 (C-C). 1H NMR (CDCl3): δ(400MHz) = 10.05
(s, 1H, CH=N) (azomethine), 8.72, 8.59 (s, 2H, CH=N(Ar), 7.35–8.36
(m, 5H, Ar), 4.96-4.97 (d, J =7.2, 2H,-NCH2-), 2.58-2.59 (t, J = 7.0,
1H, -C CH). 13C (CDCl3): δ(101 MHz) = 184.3, 152.9, 138.2, 137.5,
≡
136.7, 134.1, 125.6, 124.5, 123.4, 122.4, 118.4, 109.6, 75.8, 75.6, 36.4.
2.3. Synthesis of organotriethoxysilane (4)
Under N2 atmosphere, indole tethered triazole alkyne (3) was
added to 1:1 tetrahydrofuran:triethylamine (THF/Et3N) solvent
mixture and this reaction mixture was stirred for 15 min at room
temperature. Then, a pinch of catalyst [CuBr(PPh3)3] was loaded
and slow addition of 3-azidopropyltriethoxysilane (AzPTES) was
done. The mixture was refluxed for 6h. The reaction was then
brought to room temperature and filtered the reaction mixture to
remove the catalyst, then evaporated under reduced pressure. Fur-
2.2. Synthesis of indole crowned 1,2,4-triazole schiff’s base alkyne (3)
Indole-3-carboxaldehyde alkyne (2) (1.0 eq) was dissolved in
ethanol and gradual addition of 1 equivalent of 4-amino-1,2,4-
triazole was done. The solution was refluxed for 24h and off white
coloured precipitates were obtained after recrystallized from chlo-
roform.
Scheme 1. Synthesis of Bis-triazole indole pendant Silatranyl framework (5). Reagents and conditions: (i) K2CO3, N,N-dimethylformaminde (DMF), 16h Stir (ii) Ethanol, 24 h
Reflux. (iii) 3-azidopropyltriethoxysilane, tetrahydrofuran:triethylamine (THF:TEA) (1:1) (iv)[CuBr(PPh3)3], 6h reflux.(v) Triethanol amine, KOH, toluene, 5h reflux.
2

G. Singh, P. Satija, A. Singh et al.
Journal of Molecular Structure 1231 (2021) 129963
Fig. 1. Bar graph representation at 302nm of silatrane (5) in the presence of various metal ions
Fig. 2. UV–Vis spectra of silatrane (5) with gradual addition of Pb2+ ions
Fig. 4. B-H equation and Job’s plot of sensor 5
ther the residue obtained was followed by the addition of ether.
The brown coloured solid (4) was obtained, filtered using filtration
unit under nitrogen atmosphere.
Synthesis of Compound
4 The quantities used were as:
3
(1.00g), 3-azido propyl triethoxysilane (0.99g). Yield: 86%.
M.p.:176°C-178°C (Charring). Anal. Calcd. For C23H32N8O3Si: C,
55.62; H, 6.49; N, 22.56; Found: C, 55.61; H, 6.45; N, 22.49. IR
(cm−1): 784, 1078 (Si-O), 1258(O-CH2), 1601 (C=N), 2876, 2925,
2964 (propyl chain). 1H NMR (CDCl3): δ(400 MHz)= 9.98(s, 1H,
CH=N(azomethine)), 8.30(s, 2H, CH=N(Ar)), 7.42 (s, 1H, Tz-H),
7.25-7.80 (m, 5H,Ar), 5.40 (s, 2H, -OCH2-), 4.27-4.31(t, J = 7.4 Hz,
2H,-N3CH2-), 3.70-3.78 (m,J = 7.1 Hz, 6H, -OCH2CH3), 1.94-1.98 (m,
2H, -CCH2C-), 1.15-1.21 (t, J = 7.3 Hz, 9H, -OCH2CH3), 0.50-0.54 (t,
Fig. 3. Bar graph representation of increasing concentration (10 μM, 20 μM, 35
μM, 40 μM, 35 μM, 50 μM) of metal ions with respect to compound 5
3

G. Singh, P. Satija, A. Singh et al.
Journal of Molecular Structure 1231 (2021) 129963
5.46 (s, 2H, -OCH2-), 4.26-4.29(t, J = 7.4 Hz, 2H, -N3CH2-), 3.69-
3.72 (t,J = 5.2 Hz, 6H, -OCH2CH2-), 2.77-2.80 (t,J = 5.3 Hz, 6H, -
CH2N-), 1.89-1.97(m, 2H, -CCH2C-), 0.33-0.37 (t, 2H, -SiCH2-). 13C
NMR (CDCl3): δ(101 MHz) = 184.7, 141.9, 138.4, 128.9, 128.2, 125.4,
125.2, 123.1, 122.0, 110.3, 65.9, 59.4, 57.7, 53.7, 51.0, 43.1, 29.48,
26.0, 21.6, 15.2, 12.8.
3. Results and Discussion
3.1. Synthetic Aspects
The synthesis of Bis triazole with indole pendant organosila-
trane was obtained by employing four step preparation proce-
dures as given in Scheme 1. Firstly, the synthesis of compound
(2) was done which involves the reaction of indole motif (1) with
propargyl bromide in the presence of K2CO3 as base. Compound
(2) on treatment with 4-amino-1,2,4-triazole in ethanol formed in-
dole crowned schiff’s base alkyne (3). Further, this indole tethered
schiff’s base alkyne (3) adds 1,2,3-triazole unit using ‘‘click reac-
tion’’ by reacting with 3-azidopropyltriethoxysilane in the presence
of THF:TEA and Cu (I) as catalyst to form indole schiff’s base al-
lied triazole silane (4). The silane was clipped with triethanolamine
framework via “trans esterification” reaction to form bis-triazole
indole pendant silatrane network (5) as displayed in Scheme 1.
Fig. 5. Energy minimized structure of alkyne (3), Silane (4) and Silatrane (5)
2H, -SiCH2-). 13C NMR (CDCl3, 101 MHz,): δ =142.5, 138.2, 137.0,
125.5, 124.3, 123.3, 123.2, 122.2, 118.7, 110.1, 109.9, 65.9, 58.5, 52.6,
42.1, 24.1, 18.3, 15.3, 7.4.
2.4. Synthesis of Bis triazole with indole pendant organosilatrane (5)
Dean-Stark assembly hinged with two necked round bottomed
flask was firstly flame dried by using the schelenk vaccum line.
Then under nitrogen atmosphere, functionalized organotriethoxysi-
lane (4) was taken in 20 ml toluene, stirred until reactant was
dissolved and then addition of catalytic amount of KOH and tri-
ethanolamine was done. After that, the reaction mixture was re-
fluxed for 5h. Thereafter, the solvent was evaporated which was
followed by addition of ether (5 ml). The solid obtained was left
for overnight stirring and then filtered under nitrogen and dried
under vacuum resulting into desired organosilatrane 5 in excellent
yields.
3.2. Spectroscopic characterization
In the IR spectra of compounds, all newly synthesized com-
pounds exhibited strong absorption signals in the range 1599–1618
cm−1 assigned to C=N stretching vibrations of azomethine group.
The bands appeared in the domain 2114 cm−1and 3266cm−1 corre-
≡
≡
sponding to C C and C C-H bond respectively for indole-triazole
schiff’s base alkynes(3). In silane (4), this stretching frequency dis-
appear after the formation of 1,2,3-triazole ring, a linker moiety.
Also, the spectra showed desired signal in the region of 1050-
1100 cm−1 due to Si-O bond. The signal appeared at around 555-
585 cm−1 confirms the formation of silatranes (Si←N). In the 1H
spectra of all compounds, a singlet in the region δ = 9.98-10.05
ppm assigned to CH=N proton. Alkynyl proton appears around
δ = 2.40–2.60 ppm appear as triplet, -OCH2 protons of alkynyl
group from δ = 4.68–4.80 ppm appear as singlet. However in
Synthesis of Compound 5: The quantities used were as: 4
(1.00g, 2.0mmol), triethanol amine (0.29g, 2.0mmol). Yield: 84%.
M.p.:189°C-192°C (Charring). Anal. Calcd. for C23H29N9O3Si: C,
54.42; H, 5.76; N, 24.83; Found: C, 54.32; H, 5.72; N, 24.74. IR
(cm−1): 2880, 2961 (propyl chain), 1618 (C=N), 794, 1084 (Si-O),
587 (N→Si). 1H NMR (CDCl3): δ(400 MHz) = 9.98(s, 1H, CH=N),
8.29-8.31(s, 2H, CH=N(Ar)), 7.81 (s, 1H, Tz-H), 7.17-7.52 (m, 5H,Ar),
Fig. 6. Pictorial representation of 3 and 4 with HOMO–LUMO density plot and ࢞EHOMO–LUMO calculated at B3LYP/6-311G(d) level of theory
4

G. Singh, P. Satija, A. Singh et al.
Journal of Molecular Structure 1231 (2021) 129963
Table 1
Table 3
Ground state molecular orbital energies (EHOMO
Values of LOD, LOQ, Association Constant (ka) and Stiochiometry for sensor 5
,
ELUMO
)
and energy gap
(࢞ELUMO–HOMO; in eV) and dipole moment of Compounds (3-5) calculated in gas
Sensor + Metal
Association
phase.
ion
LOD
LOQ
Constant(ka)
Stiochiometry
1:1
ꢀE(eV)
5+ Pb2+
0.0324μM 0.108μM
12.9 × 108M−1
Compound Identity
Dipole moment
HOMO
LUMO
E(LUMO-HOMO)
3
4
5
9.65
9.52
17.49
-6.19
-5.36
-5.91
-1.79
-1.30
-1.62
4.39
4.06
4.29
case of triazole functionalized silane(4), propyl chain peak ap-
pears at (0.5-0.6) ppm, (2.1-2.2) ppm and (4.4-4.5) ppm, ethoxy
peak appeared at (1.8-1.9) ppm and (3.8-3.9) ppm. Moreover tria-
zole proton appears at 7.42-7.81ppm. In addition to this, the sig-
nal appeared at 8.29-8.71corresponds to the CH=N group associ-
ated with 1,2,4-triazole ring. When triethoxy silanes undergo trans-
esterification reaction, there is formation of silatranyl cage whose
signal appeared as two triplets due to NCH2 and OCH2protons
Silatranyl derivative (5) showed escalation in the absorbance
band centered at 359nm with a blue and hyperchromic shift,
which again indicates the interaction between lead ions and com-
pound 5 (Fig 2).
Furthermore, the UV absorption spectra of 5 were executed
with increasing concentration of different metal ions. The result
implied that there is a steady increase in the absorption inten-
sity with Pb2+ ions only as shown in Fig 3. However, in the pres-
ence of any other cations, no remarkable change in the absorption
band was noticed. The receptors (5) have shown binding with lead
ions, herein we endeavour to verify the strength of binding of re-
ceptor (5) towards Pb2+ions. B–H (Benesi-Hildebrand) relation was
employed to determine the association constant (Ka) as shown in
Fig 4.
at δ
=
2.77-2.80 and 3.69-3.72, respectively, assigned to the
Si(OCH2CH2)3N moiety. Similar trend of shifting is noticed in the
13C spectrum of the compounds. In the 13C NMR spectra, carbons
of alkynyl moiety appear in the range of δ 75.6-75.8 ppm and
CH=N group appear at 184.3-184.7 ppm. When triazole silanes are
formed from alkynes, there is disappearance of signals of alkynyl
group and some new signals are appeared at 7.4, 18.3 and 52.6
ppm are due to propyl chain, 24.1 and 58.5 are due to ethoxy
group.
The evaluation for B-H plot is made between [A-Ao]−1 vs
[Pb2+]n in a manner to have linearity of regression, where [A-Ao]
means the change in absorbance intensity of the receptor in the
presence of analyte recorded at particular wavelength. The associ-
ation constant was evaluated from the slope of the [A- Ao]−1 vs.
3.3. Photophysical Study
Sensing prospective of silatranyl derivative (5) towards differ-
ent metal cations was evaluated. The absorption titration were
prosecute with the compound (5) by gradual addition of 10μM
[Pb2+
]
graph and the values are mentioned in Table 1, recom-
−1
stock solutions of various metal cations (1=Cu2+, 2=Rb2+,3=Ce3+
,
,
mend the robust connection between the receptor and the lead
ions.
4= Co2+, 5=Zn2+, 6= Fe2+, 7=Sn2+, 8=K+, 9=La3+, 10=Ba2+
11=Cd3+, 12=Hg2+, 13= Ni2+) as their nitrate ions. The ubieties of
versatile binding sites in derivative (5) instigate us to reconnoitre
their conduct towards different metal ions. The binding ability of
compound 5 toward different metal ions was assessed and shown
in Fig 1.
The detection limit (3σ/k), quantification limits (LOQ) (10σ/k)
for Pb2+ using probes(5)were calculated as given in Table 1.The
method of continuous variation (Job’s plot) was also used to mark
the1:1stoichiometry (host:guest) as shown in Fig 4(b) for com-
pound 5. Many research studies have been adapted on attaining
Table 2
Analysis of various sensing systems for the detection of Pb2+ ions.
Pb2+ Sensors
Measured Signal
Stiochiometry
LOD
References
Ester Appended Organosilatrane
UV/Fluorescence
UV/Fluorescence
UV/Fluorescence
Fluorescence
UV-Vis
-
1.65 × 10−6
2.5 × 10−8
6.78 × 10−6
16.7nM
[29]
Rhodamine based chemosensor
-
[30]
Thiodicarboxaldehyde based schiffs base Nano film
Graphene Quantum dot gold nano particle
Bis-triazole Indole pendant Silatrane
1:1
-
[31]
[32]
1:1
0.032μM
Present Work
Scheme 2. Proposed binding mode for 5 with Pb2+ ions
5

G. Singh, P. Satija, A. Singh et al.
Journal of Molecular Structure 1231 (2021) 129963
ing vibrational spectroscopy which suggests the binding of metal
with nitrogen of schiffs base and triazole ring (Page S12). In IR
spectrum, schiff base (–CH=N) frequency shifted from 1653 to1648
cm−1 and there were changes in the peak region of 1400 to1600
cm−1 ascribed to the triazole ring. These positive shifts signify the
role of the Nitrogen atoms of these moieties in the binding with
lead ion.
3.5. Computational investigation
Density functional theory (DFT) has been broadly used to eval-
uate an extensive variety of molecular properties and electron cor-
relation contributions especially in systems having electron conju-
gation and electron lone pairs. The optimized geometry of Com-
pounds (3-5) with B3LYP/6311-G(d) method are portrayed in Fig 5.
According to FMO theory, HOMO and LUMO are the pivotal factors
that influence bioactivity. The energy (Table 3) and pictorial inter-
pretation of the HOMO and the LUMO of compounds (3-5) have
been shown in Fig 6 and Fig 7.
It revealed that electron density in both HOMO and LUMO or-
bital of 3 and 4 is mainly delocalized on CH=N (Schiff’s base) and
1,2,4-triazole ring.
Further understanding the binding behaviour of receptor (5)
and its complex with Pb2+ ions was done using DFT study
(Figure 8). The geometry was optimized by using B3LYP/LAND2Z
for its complex with Pb2+ ions. It was observed that HOMO–LUMO
energy gap got decreased after complexation from 4.29 to 1.54 eV
which reveals the higher stability of 5-Pb2+ complex.
Fig. 7. Pictorial representation of Silatrane (5) with HOMO–LUMO density plot and
࢞EHOMO–LUMO calculated at B3LYP/6- 311G(d) level of theory
selective and a low detection limit (LOD) of Pb2+ ions as given in
Table 2.
Our approach was found to be much simpler and convenient as
compared to other sensors.
4. Conclusion
3.4. Binding Aspects
We report here a quick, low cost and environment friendly
sensing approach entailing Bis- triazole indole functionalized
organosilatrane for selective detection of Pb (II) ions through col-
orimetric method. This probe has low detection limit of 0.032μM.
Due to presence of numerous coordinating sites, the receptor 5 had
great tendency to chelate and demonstrated selectivity for Pb2+
ions with binding constant of 12.9 × 108M−1 and 1: 1 stiochiom-
etry as suggested by B-H plot and Job’s methodology. Theoretical
Indole, azomethine linkage, 1,2,4-triazole, 1,2,3-triazole moi-
eties are fascinating building block of D-π-A molecular structures,
clubbed together to form multifunctional heteroaromatic conju-
gated silatrane 5. The receptors are peachy for coordination to lead
ion in appuretenant pattern as shown in Scheme 2. The coordina-
tion mechanism of receptor (5) and Pb2+ has been explained us-
Fig. 8. Comparison of HOMOLUMO energy gap between receptor (5) and its complex
6

G. Singh, P. Satija, A. Singh et al.
Journal of Molecular Structure 1231 (2021) 129963
investigations were carried out to get an insight into their molec-
ular structures.
[7] G. Attia, S. Rahali, S. Teka, N. Fourati, C. Zerrouki, M. Seydou, S. Chehimi,
S. Hayouni, J.P. Mbakidi, S. Bouquillon, M. Majdoub, R.B. Chaabane, Sens. Ac-
tuators B Chem. 276 (2018) 349–355.
[8] B.S. Boruah, R. Biswas, Opt. Fib. Tech. 46 (2018) 152–156.
[9] A.K. NS, A. S, P. Malingapp, J. Environ. Chem. Eng. 6 (2018) 6939–6946.
[10] S. Venkatesh, T. Li, X.S. Wang, C.C. Yeung, K. Pei, Q.J. Sun, W. Wu, R.K.Y. Li,
M.H.W. Lam, P.K.L. Chan, J.J. Wylie, V.A.L. Roy, Anal. Chem. 90 (2018)
7399–7405.
Declaration of Competing Interest
There is no conflict of interest.
[11] G. Singh, S. Girdhar, A. Singh, A. Saroa, P. Satija, V. Verma, J. Singh, Silicon 11
(2019) 2575–2582.
[12] G. Singh, A. Singh, P Satija, G. Sharma, Shilpy, J. Singh, J. Singh, K.N. Singh,
A. Kaur, New J. Chem. 43 (2019) 5525–5530.
CRediT authorship contribution statement
Gurjaspreet Singh: Supervision, Project administration. Pinky
Satija: Conceptualization, Investigation. Akshpreet Singh: Method-
ology. Pawan: Writing - original draft. Mohit: Writing - review &
editing. Jashan Deep Kaur: Resources. Anita Devi: Data curation.
Anamika Saini: Validation. Jandeep Singh: Visualization.
[13] G. Singh, S. Rani, S. Gawri, S. Sinha, R. Sehgal, New. J. Chem. 41 (2017)
11626–11639.
[14] G. Singh, S.Rani Sanchita, G. Sharma, P. Kalra, N. Singh, V. Verma, Sens. Actua-
tors B Chem. 266 (2018) 861–872.
[15] G. Singh, P. Satija, A. Singh, Sushma, G. Sharma, Mohit, Pawan, Suman and
Priyanka, ChemistrySelect 5 (2020) 1–9.
[16] G. Singh, S. Rani, A. Arora, H.Duggal Sanchita, D. Mehta, Mol. Cat. 431 (2017)
15–26.
Acknowledgements
[17] G. Singh, G. Sharma, Sanchita, P. Kalra, D. R Batish, Vikas Verma, J. Sci. Food
Agric. 98 (2018) 5129–5133.
[18] G. Singh, A. Arora, S.S. Mangat, S. Rani, H. Kaur, K. Goyal, R. Sehgal, I.K. Mau-
rya, R. Tewari, D.C. Lazarte, S. Sahoo, N. Kaur, Euro. J. Med. Chem. 108 (2016)
287–300.
The authors are thankful to the DST (Inspire Fellowship in the
form of SRF) and CSIR for providing financial support.
[19] J.A. Homer, J. Sperry, J. Nat. Prod 80 (2017) 2178–2187.
[20] J.C. Marecki, S. Aarattuthodiyila, A.K. Byrd, N.R. Penthala, P.A. Crooks,
K.D. Raney, Bioorg. Med. Chem. Lett. 29 (2019) 430–434.
[21] S.S.A. Abidi, Y. Azim, A.K. Gupta, C.P. Pradeep, J. Mol. Struc. 1166 (2018)
202–213.
Supplementary materials
Supplementary material associated with this article can be
found, in the online version, at doi:10.1016/j.molstruc.2021.129963.
[22] H. Yu, G.A. Kraus, Tetrahedron Lett 59 (2018) 1424–1426.
[23] N. Saleh, A. Voituriez, J. Org. Chem. 81 (2016) 4371–4377.
[24] C. Lorton, A. Voituriez, J. Org. Chem. 83 (2018) 5801–5806.
[25] V.M. Norwood, R.W. Huigens, Chem. Bio. Chem. 20 (2019) 2273–2297.
[26] C.F. Wan, S.T. Yang, H.Y. Lin, Y.J. Chang, A.T. Wu, Luminescence 29 (2014)
500–503.
References
[1] J. Liu, A.M. Kaczmarek, R.V. Deun, Sens. Actuators
B
Chem. 255 (2018)
2163–2169.
[27] S.A. Patil, S.A. Patil, R. Patil, Chem. Biol. Drug Des. 89 (2017) 639–649.
[28] S. Suzen, S.S. Cihaner, T. Coban, Chem. Biol. Drug Des. 79 (2012) 76–83.
[29] G. Singh, A.Singh Sanchita, G. Sharma, P. Kalra, P. Satija, S.Soni Diksha,
V. Verma, Inorg. Chim. Acta 490 (2019) 85–92.
[30] C.Y. Li, Y. Zhou, Y.F. Li, X.F. Kong, C.X. Zou, C. Weng, Anal. Chim. Acta 774 (2013)
79–84.
[2] Y. Fanga, B. Cuia, J. Huang, L. Wang, Sens. Actuators
414–420.
B Chem. 284 (2019)
[3] H.L. Fanga, H.X. Zhenga, M.Y. Oua, Q. Meng, D.H. Fana, W. Wang, Sens. Actua-
tors B Chem. 153 (2011) 369–372.
[4] J.R. Zeng, C.C. Cheng, B.R. Huang, C.H. Huang, J.K. Chen, Sens. Actuators
Chem. 243 (2017) 234–243.
B
[31] N. Karachia, O. Azadi, R. Razavi, A. Tahvili, Z. Parsaee, J. Photochem. Photobio.
A Chem. 360 (2018) 152–165.
[5] A. Ghosh, S. Das, S. Kundu, P.K. Maiti, P. Sahoo, Sens. Actuators B Chem. 266
(2018) 80–85.
[32] X. Niu, Y. Zhong, R. Chen, F. Wang, Y. Liu, D. Luo, Sens. Actuators B Chem. 255
(2018) 1577–1581.
[6] R.N. Ma, L.L. Wang, M. Zhang, L.P. Jia, W. Zhang, L. Shang, W.L. Jia, H.S. Wang,
Sens. Actuators B Chem. 257 (2018) 678–684.
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