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).