Synthesis of Nitrogen Containing Chalcone: A Highly Sensitive and Selective Fluorescent Chemosensor for the Fe3+ Metal Ion in Aqueous Media

Article abstract of DOI:10.1007/s10895-020-02534-x

Title compound (PTPO) was synthesized by the reaction of 2-acetyl pyridine with 3,4,5-trimethoxy benzaldehyde. The structure of the compound has been confirmed by spectroscopic techniques. Interaction of chalcone with different metal cations was analyzed based on the fluorescence behavior. Results show that chalcone act as on-off switching fluorescent chemosensor for selective and sensitive detection iron metal ion. Mechanism of quenching and complexation were resolute by Benesi-Hildebrand, Stern-Volmer plot and Job-plot.

Full text of DOI:10.1007/s10895-020-02534-x

Journal of Fluorescence
https://doi.org/10.1007/s10895-020-02534-x
ORIGINAL PAPER
Synthesis of Nitrogen Containing Chalcone: A Highly Sensitive
3+
and Selective Fluorescent Chemosensor for the Fe Metal Ion
in Aqueous Media
1,2
1
1
Abdullah M. Asiri & Mona Mohammad Al-Amari & Salman A. Khan
Received: 1 November 2019 /Accepted: 2 April 2020
#
Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract
Title compound (PTPO) was synthesized by the reaction of 2-acetyl pyridine with 3,4,5-trimethoxy benzaldehyde. The structure
of the compound has been confirmed by spectroscopic techniques. Interaction of chalcone with different metal cations was
analyzed based on the fluorescence behavior. Results show that chalcone act as on-off switching fluorescent chemosensor for
selective and sensitive detection iron metal ion. Mechanism of quenching and complexation were resolute by Benesi-Hildebrand,
Stern-Volmer plot and Job-plot.
.
.
.
Keywords Pyridine: chalcone Metal ion Sensor Quenching
Introduction
consideration has been rewarded to fluorescent chemosensors
and some novel molecules have been design and synthesized
[6]. In certain, an active fluorescent sensor for various metal
ion is an arrangement capable to intermingle with various
metal ion in solution stage signifying the existence by chang-
ing the emission behavior, such as hypsochromic shift or
bathochromic shift or fluorescence intensity (enhance or
quench) [7]. Two different mechanisms have worked on fluo-
rescent chemosensor behavior called Chelation Enhanced
Fluorescence effect (CHEF) and Chelation Enhancement
quenching effect (CHEQ) [8]. Iron is an indispensable metal
in the human body, which play an impertinent role for the
oxygen-transport in the form of oxyhaemoglobin and play
actions as cofactor in different metabolic reaction in the hu-
man body [9]. Nevertheless, excess and deficiency of the iron
metal in the human body cased different disease such as
Parkinson and Alzheimer due to the excess of iron [10] and
anemia and damage the liver and kidneys due to the deficiency
of iron [11]. Thus, determination of iron in metabolic process
and ecological systems is incredibly important [12]. On the
other hand, fluorescence chemosensor is one of the most sig-
nificant and easiest techniques for the identification of metal
ion [13]. Many heterocyclic compound have been reported as
fluorescent chemosensor for the detection of iron metal ion
but these heterocyclic compounds are not easy to synthesize
Push-pull chromophores consisting electron push group and
electron pull group connected through conjugated π-bridge.
Organic compounds containing with push and pull group,
generally accountable for the fluorescence because of
intaramolecular charge transfer form pull to pull through the
π-bond conjugations [1]. Organic compound having the fluo-
rescence properties are utilizing in the different field of the
optoelectronic devices such as third-order nonlinear optical
properties, organic light emitting diodes [2], organic
photovoltaies etc. [3], one of the most important application
of these type of molecules are use as fluorescent chemosensor
for the identification of various toxic metal ions by the fluo-
rescence quenching or enhancement mechanism [4].
Chalcone has the α, β- unsaturated ketone framework its push
group joint with the α, β- unsaturated ketone so, carbonyl
group work as pull, so hole molecule can be used as push-
pull chromophore [5]. In the past one decade, great
*
Salman A. Khan
sahmad_phd@yahoo.co.in
1
2
Chemistry Department, Faculty of Science, King Abdulaziz
University, P.O. Box 80203, 21589 Jeddah, Saudi Arabia
[14–17]. Therefore, it is urgent to design novel and simple
Center of Excellence for Advanced Materials Research (CEAMR),
King Abdulaziz University, P.O. Box 80203, 21589 Jeddah, Saudi
Arabia
chromophore, which is applicable for the detection of iron
metal by the fluorescent chemosensor. In the present

J Fluoresc
manuscript we synthesized chalcone 1-(pyridin-2-yl)-
-(3,4,5-trimethoxyphenyl)prop-2-en-1-one by the reaction
Result and Discussion
3
of 2-acetyl pyridine with 3,4, 5-trimethoxy benzaldehyde for
the detection of iron metal ion.
Chemistry
The chalcone (PTPO) has been synthesized via reaction of 2-
acetyl pyridine with 3,4,5-trimethoxy benzaldehyde under
normal condition [18]. The purified of PTPO was character-
1
13
Experimental
ized by FT-IR, H-NMR and C-NMR. The FT-IR spectrum
−
1
of the PTPO showed two sharp peaks at 1667 and 1607 cm
All the chemical 2-acetyl pyridine, 3,4, 5-trimethoxy benzal-
dehyde, sodium hydroxide, and all the solvents were parched
from the Sigma-Aldrich and used as received without further
purification. The stock solution of the hydroxyl chalcone
due to the polar C = O and non-polar C = C group and and
absent of two peaks that represent the aldehyde hydrogen at ~
2720 and 2820 indicated formation of α, β-unsaturated ke-
tone by the reaction of aldehyde and ketone. The structure of
1
(
DHPO) was prepared in DMF and ten different metal salts
PTPO was further conformed by the H-NMR spectra, the
were prepared in double distilled water. All the conduct ex-
periment was executed at 25 temperature.
spectrum of PTPO showed two doublets signal at δ 7.88 and
8.20 with the J value 16.2 and 15.6 Hz indicated the formation
of chalcone, J value indicating the CH = CH part of the α, β-
unsaturated ketone is the trans conformation. The C-NMR
spectrum of the chalcone was measured at 125 MHz in
o
1
3
Apparatus
CDCl . The spectrum peaks are in good conformity of the
3
A FT-IR spectrum was recorded on a Nicolet Magna 520 FT-
IR spectrometer. H-NMR and C-NMR experiments were
structure of PTPO, details of the peaks were given in the
experimental section.
1
13
performed in CDCl on a Brucker DPX 600 MHz spectrom-
3
eter using tetramethylsilane (TMS) as internal standard, at
room temperature. Melting points was recorded on a
Thomas Hoover capillary melting apparatus without correc-
tion. UV–Vis electronic absorption spectra were acquired on a
Shimadzu UV-1650 PC spectrophotometer. Absorption spec-
tra were collected using a 1 cm quartz cell. Steady state fluo-
rescence spectra were measured using Shimadzu RF 5301 PC
spectrofluorometer with a rectangular quartz cell.
Sensitive Fluorescent Chemosensor of PTPO for Metal
Ion
In order to examined the selective and sensitive chemosensor
behavior of chalcone (PTPO) for ten different metal cations by
the fluorescence spectra. The effect of the ten different metal
2
+
2+
3+
2+
3+
2+
2+
2+
ions namely Co , Hg , Fe , Cu , Al , Cd , Sr , Ni ,
3
+
2+
Cr and Mn on the photophysical properties of the hydroxy
chalcone PTPO in the DMF/ Water (9:1, V/V) as shown in
Fig. 1. Emission spectra of PTPO displayed extremely good
peak when excited at 350 nm wavelength and no more
Synthesis of 1-(pyridin-2-yl)-3-(3,4,5-trimethoxyphenyl)
prop-2-en-1-one (PTPO)
6
5
4
3
00
00
00
00
PTPO
2
+
A solution of 2-acetyl pyridine (1.14 ml, 0.01 mol) and 3,4,5-
trimethoxybenzaldehyde (2 g, 0.01 mol) in an ethanolic solu-
tion of NaOH (3 g in 20 ml ethanol) was stirred for 5 h at room
temperature and allowed to stand overnight. Then the reaction
mixture was poured into crushed ice water, the precipitated
solid was filtered off and recrystallized from ethanol. Yellow
Co
Hg
Fe
2+
3
+
2+
Cu
3+
Al
2+
Cd
−
1
solid; % yield: 94.4%; m.p. 159-159.6; IR (KBr) νmax/cm :
083 (= CH), 2997 (C-H), 1667 (C = O), 1607 (C = C), 1576
C = C aromatic), 1311 (Aromatic C—N), 1120 (C—O), 982
2+
Sr
Ni
3
200
100
0
2+
(
(
3
+
Cr
1
alkene bending disubstituted). H NMR (600 MHz CDCl ) δ:
3
2+
Mn
8
.77 (1H1, d, J = 4.8), 7.53 (1H2, td, J = 4.8, 7.2), 7.93 (1H3,
dd, J = 1.2, 7.8), 8.22 (1H4, d, J = 7.2), 7.88 (1H7, d, J = 16.2),
4
00
450
500
550
600
650
8
3
1
1
.20 (1H8, d, J = 15.6), 6.98 (2H10, 14, s), 3.95 (6H15-17, s),
1
3
.92 (3H16). C NMR (600 MHz, CDCl ) δ: 148.5, 126.9,
Wavelength (nm)
3
−
5
− 5
37.3, 123.1, 154.0 (Pyridine moiety), 188.9 (C = O), 130.6,
40.8 (alkene moiety), 119.9, 106.1, 153.4, 145.2, 56.2, 61.0
Fig. 1 Emission spectra of 1.0 × 10 moldm of PTPO upon addition
5 2+ 2+ 3+ 2+ 3+ 2+ 2+ 2+ 3+
−
of 5.0 × 10 M Co , Hg , Fe , Cu , Al , Cd , Sr , Ni , Cr and
2
+
Mn in DMF/ water (9:1, v/v)
(
benzene moiety).

J Fluoresc
6
5
4
3
2
1
00
00
00
00
00
00
0
50
4
3
2
0
0
0
10
0
r
u
u
l
Fe
Co
i
r
+ C
Sr
Fe
Cd
+
Al
PO + Cd
+ Ni
+
+
PTPO
e
+
Fe +
Fe + A
F
e
PO + Mn
PTPO
+ Fe + C +
+
+
Fe + Sr + Fe + N
PO
PTPO +P TH Pg O +
PTPO +P CT PO
T
PTPO PTPO +TC
P
+ F
+ Fe + Mn
PTPO + Co
P
PTPO
PTPO +
PO
PO
PO
PO
PT
PO + Fe + Hg
PT
PO
PO
PT
T
PT
P
PT
PT
PT
Fig. 2 Emission of PTPO in presence of different metal ions
3
+
Fig. 3 Competitive experiments in the PTPO + Fe system with
−
5
3+]
− 5
interfering metal ion [PTPO] = 1 × 10 M, [Fe = 5 × 10 M, and
significant effect on the fluorescence intensity after addition of
n+
− 5
[
M ] = 5 × 10 M, excited at 350 nm
2
+
2+
3+
2+
3+
2+
2+
9
eqiv of metal ion Co , Hg , Fe , Cu , Al , Cd , Sr ,
2
+
3+
2+
Ni , Cr and Mn as shown in Fig. 2. On the other hand
upon addition of equivalent amount of Fe metal ion to the
PTPO, the fluorescence intensity shifted red shift from 496 to
Where ɸ is the calculated fluorescence quantum yields of the
f
3
+
3+
PTPO absence and presence of Fe in DMF, ɸr is the fluorescence
quantum yield of the quinine sulfate as reference dye, I is the inte-
grated fluorescence intensity, A and Ar are the absorbance of the
PTPO and reference and n is the refractive index of the DMF.
Fluorescence quantum yield of PTPO was calculated to be 0.012
5
21 nm with decreased the fluorescence intensity 10-fold and
the fluorescence color also changing from yellow to brown
color like an on-off fluorescence response. The fluorescence
3
+
3+
quantum yield of PTPO in the absence of Fe metal ion was
calculated to be 0.37 with respect to quinine sulfate (0.54) by
the Eq. 1 [19].
in the presence of Fe metal ion, which is greatly lower than the
3
+
absence of Fe metal ion. This fluorescence quenching performance
was examined due to chelation-enhanced quenching sensing mecha-
nism (Scheme 1).
2
I  Ar  n
3+
The fluorescence intensity of Fe ion was almost unaffected by
Φf ¼ Φr
ð1Þ
Ir  A  n2r
the addition of competing metal ion (Co , Hg , Fe , Cu , Al ,
2+
2+
3+
2+
3+
Scheme 1 Synthetic diagram
indicating the synthesis of PTPO
3
+
and interaction with the Fe ion

J Fluoresc
5
4
3
2
1
00
00
00
00
00
0
0.010
0
0
0
0
0
0
0
0
.009
.008
.007
.006
.005
.004
.003
.002
4
00
450
500
550
600
650
20000
40000
60000
80000 100000
3
+
Wavelength (nm)
Fig. 4 Emission spectra of PTPO (1 × 10 M) exposed to various
1
/[Fe ] M
−
5
Fig. 6 Benesi-Hildebrand plot for PTPO (1 × 10− 5M) at various
3+
concentration of Fe in DMF: water (9:1, v/v)
3+
concentration of Fe ion
2
+
2+
2+
3+
2
3+
Cd , Sr , Ni , Cr and Mn ) as shown Fig. 3, the ionic strength
PTPO with different concentration of the Fe ion were found be-
−
4
− 4
range of all metals are 1.5 × 10 to 7.5 × 10 M. These results
tween 8.03 and 4.73.
3+
suggested that molecules PTPO could be used as Fe selective
fluorescent chemosensor.
To explore the association constant and binding stoichimerty
3
+
between the PTPO with Fe metal ion, which is fundamental in
relation to the fluorescence chemosensor properties, we have creat-
ed the benesi-Hildebrand plot from the Eq. 2 [20].
3+
The fluorescence quenching activities of the Fe was explored
3+
during emission spectrum of PTPO upon Fe ion was gradually
titrated (Fig. 4). The fluorescence intensity of the PTPO gradually
3+
The plot between 1/ (F-F ) vs. 1/ Fe as presented in Fig. 3,
o
3+
decreased with increased the concentration of the Fe metal ion and
exhibited the linearity of Benesi-Hildebrand, indicated complexation
3
+
− 5
3+
when the mount of Fe added was about 9 × 10 M, the fluoresce
intensity of the PTPO almost reached a minimum due to utilized of
between PTPO with Fe metal having 1 : 1 stoichiometric ratio.
1
1
1
1
3+
¼
þ
X
Â
Ã
ð2Þ
PTPO for the complexation with Fe metal ion. Initially the fluo-
rescence intensity of PTPO was quickly reduced after addition of
0
F−Fo
o
3þ
F−F
Kapp ðF−F Þ F
e
3+
low concentration of ranges of Fe as presented in Fig. 5 and in the
Where F is the emission intensity of the PTPO molecule
absence of Fe3 + metal ion, Fo is the emission intensity of
PTPO in the presence of Fe metal ion and Kapp is the evident
association constant. The Benesi-Hildebrand plot between 1/ F-
−
5
range 3 to 9 × 10 M its showed good linear response (R = 0.98),
which was capable to quantitatively analyzed the coordination of
3+
3+
the Fe metal ion with PTPO molecule. ] The pH of the PTPO and
1
6
4
5
4
3
2
1
00
00
00
00
00
0
1
12
1
0
8
6
4
2
0
0
2
4
6
8
10
0
2
4
6
8
10
3
+
-5
3+
[Fe ] x 10
-5
[
Fe ] x 10
−
5
3+
Fig. 7 Stren-Volmer plot for PTPO (1 × 10− 5M) at various concentration
3+
Fig. 5 Inset: Fluorescence titrations cure of PTPO (1 × 10 M) with Fe
in aqueous solution
of Fe ion

J Fluoresc
trimethoxy benzaldehyde undernormal condition. In this
cram, it was focused on the effect of ten different metal ions
on the physicochemical properties of the chalcone (PTPO) as
fluorescent chemosensor for the detraction of metal ions by
using fluorescence spectra. The fluorescence spectra of PTPO
did not affected by the presence of any metal ions among the
3
3
2
2
2
2
2
1
1
1
1
2
0
8
6
4
2
0
8
6
4
2
3
+
3+
ten metal ions exemption Fe metal ion. F metal ion de-
creased the emission intensity of PTPO spectacularly when
3
+
the concentration of Fe metal ion increased. The bonding
3
+
or interaction of the Fe with PTPO has been found by Job
plot methods and its showed 1:1 stoichiometry. The complex-
3
+
ation reaction of PTPO with respect to Fe has explained by
the Benesi-Hildebrand, Stern-volmer and Job plot proposed
that 1: 1 ratio complex formation and the non linearity of the
Stern-volmer plot designated that decreased the emission in-
tensity through the dynamic and static system.
0
.0
0.2
0.4
0.6
3+
0.8
1.0
3
+
X= [Fe ] / [Fe + PTPO]
3
+
Fig. 8 Job’s plot, Fluorescence Intensity vs. mole fraction of Fe Job’s
Acknowledgements This project was funded by the Deanship of
Scientific Research (DSR) at King Abdulaziz University, Jeddah, Saudi
Arabia under grant no. KEP-PhD-19-130-41. The authors, therefore, ac-
knowledge with thanks DSR for technical and financial support.
plot
3
+
Fo vs. 1/ Fe showed linearity as showed in Fig. 6 indicate
complexation between the PTPO and Fe metal ion having 1:
stoichiometric ratio. The Kapp association constant for the
complexation between PTPO molecule and Fe metal ion
was predictable from this nonlinear curve fitting process of the
fluorescence titration data was found to be 7.02 × 10 M .
The fluorescence quenching behavior of the PTPO with
Fe metal ion was further understood by the Stern-Volmer
plot and the coverage of fluorescence quenching has been
quantitatively investigated by the Sterm-Volmer Eq. 3:
3+
1
3
+
References
−
8
− 1
1. Pigot C, Noirbent G, Bui T, Peralta S, Gigmes D, Nechab M,
Dumur F (2019) Push-Pull Chromophores Based on the
Naphthalene Scaffold: Potential Candidates for Optoelectronic
Applications. Materials (Basel) 12:1342
3
+
2
.
Kowar MP, Nosidlak N, Gondek E, Kityk IV, Bures F, Kulhanek J,
Karasinski P (2016) Optoelectronic features of Y-shaped push–pull
molecules based on imidazole. Opt Quant Electron 48:82
Io
I
Â
þÃ
3
3. Raheem AA, Kamaraj S, Sannasi V (2018) Praveen C (2018) New
D–π-A push–pull chromophores as low band gap molecular semi-
conductors for organic small molecule solar cell applications. Org
Chem Front 5:777
¼
1 þ Ksv Fe
ð3Þ
where, I and Io are the fluorescence intensity of the PTPO in
the absence and presence of Fe metal ion and K is the Stern-
Volmer constant. The Stern-Volmer constant (Ksv) was de-
signed by the plot of Stern-Volmer and originate 1.54 M with
3
+
4
.
Burganov TI, Katsyuba SA, Sharipova SM, Kalinin AA, Monari A,
Assfeld X (2018) Novel quinoxalinone-based push–pull chromo-
phores with highly sensitive emission and absorption properties
towards small structural modifications. Phys Chem Chem Phys
20:21515–21527
sv
−
1
2
correlation coefficient (R ) equal to 0.96 as shown Fig. 7. The
elevated value of the Stern-Volmer constant indicates the effec-
5. Teo KY, Tiong MH, Wee HY, Jasin N, Liu ZO, Shiu MY, Tang
JY, Tsai JK, Rahamathullah R, Khairul WM, Tay MG (2017) The
influence of the push-pull effect and a p-conjugated system in con-
version efficiency of bis-chalcone compounds in a dye sensitized
solar cell. J Mol Stru 1143:432–448
3+
tual interaction involving the PTPO with Fe metal ion [21].
3
+
Binding stoichiometry of Fe with POPT also deter-
mined by the Job plot method [22], we calculated that the
3
+
binding stoichiometry of POPT and Fe was 1: 1 by
Job’s plot, and the fluorescence intensity would reach
the maximum value when the mole fraction was 0.5 as
mentaion in Fig. 8.
6. Suresh S, Bhuvanesh N, Prabhu J, Thamilselvan A, Rajkumar SR,
J, Kannanc K, Kannan VR, Nandhakumar R, R (2018) Pyrene
3+
based chalcone as a reversible fluorescent chemosensor for Al
ion and its biological applications. J Photo Chem Photobiol Chem
A: 359:172–182
7
.
.
Zhang Q, Ma R, Li Z, Zizhong Liu Z (2020) A multi-responsive
crown ether-based colorimetric/fluorescentchemosensor for highly
selective detection of Al , Cu and Mg . Spectro Chemca Acta
A 228:117857
Afaneh AT, Schreckenbach G (2015) Fluorescence Enhancement/
Quenching Based on Metal Orbital Control: Computational Studies
of a 6-Thienyllumazine-Based Mercury Sensor. J Phys Chem A 29:
8106–8116
3
+
2+
2+
Conclusions
8
The title donor-π-acceptor chromophore (PPTO) has been
synthesized by the reaction of 2-acetyl pyridine with 3,4, 5-

J Fluoresc
9
.
Khan AA, Rahmani AH, Aldebasi YH, Salah M. Aly SM (2014)
Biochemical and Pathological Studies on Peroxidases –An Updated
Review. Glob J Health Sci 6:87–98
16. Farhi A, Firdaus F, Saeed H, Mujeeb A, Shakir M, Owais M (2019)
A quinoline-based fluorescent probe for selective detection and
real-time monitoring of copper ions – a differential colorimetric
approach. Photochem Photobiol Sci 18:3008–3015
17. Yang D, Dai C, Hu Y, Liu S, Weng L, Luo Z, Cheng Y, Lianhui
Wang L (2017) A New Polymer-Based Fluorescent Chemosensor
Incorporating Propane-1,3-Dione and 2,5-Diethynylbenzene
Moieties for Detection of Copper(II) and Iron(III). Polymers 9:267
1
1
1
0. Altamura S, Muckenthaler MU (2009) Iron toxicity in diseases of
aging: Alzheimer’s disease, Parkinson’s disease and atherosclero-
sis. J Alzheimers Dis 16:879–895
1. Gkamprela E, Deutsch M, Pectasides D (2017) Iron deficiency
anemia in chronic liver disease: etiopathogenesis, diagnosis and
treatment. Ann Gastroenterol 30:405–413
2. Lane DJR, Merlot AM, Huang MLH, Bae DH, Jansson PJ, Sahni S,
Kalinowski DS, Richardson DR (2015) Cellular iron uptake, traf-
ficking and metabolism: Key molecules and mechanisms and their
roles in disease. BBA-Mol Cell Res 1853:1130–1144
3. Formica M, Fusi V, Giorgi L, MauroMicheloni M (2012) New
fluorescent chemosensors for metal ions in solution. Coord Chem
Rev 256:170–192
1
8. Khan SA, Asir AM (2017) Green synthesis, characterization and
biological evaluation of novel chalcones as anti bacterial agents.
Arabian J Chem 10:2890–2895
1
9. Wurth C, Grabolle M, Pauli J, Spieles M, Ute Resch-Genger UR
(2011) Comparison of Methods and Achievable Uncertainties for
1
the Relative and Absolute Measurement of Photoluminescence
Quantum Yields Anal. Chem 83:3431–3439
2
0. Benesi HA, Hildebrand JH, J. H (1949) A Spectrophotometric
Investigation of the Interaction of Iodine with Aromatic
Hydrocarbons. J Am Chem Soc 71:2703–2707
1
4. Ding X, Zhang F, Bai Y, Zhao J, Chen X, Ge M, Sun W (2017)
Quinoline-based highly selective and sensitive fluorescent probe
specific for Cd2 + detection in mixed aqueous media. Tet Lett 58:
2
2
1. Lakowicz JR (2006) Principles of Fluorescence Spectroscopy, third
edn. Springer, New York
2. Job P (1928) Formation and stability of inorganic complexes in
solution. Ann Chim 9:113–203
3
868–3874
1
5. Paisuwan W, Rashatasakhon P, Ruangpornvisuti V,
Sukwattanasinitt M, AnawatAjavakoma A (2019)
Dipicolylamino quinoline derivative as novel dual fluorescent de-
tecting system for Hg2+ and Fe3+. Sens Bio-Sens Res 24:100283