Microwave assisted synthesis, spectroscopic and photophysical properties of novel pyrazol-3-one containing push -pull chromophore

Article abstract of DOI:10.1016/j.molstruc.2019.127103

The present work deals with synthesis of pyrazole-3-one containing Schiff base as a push-pull chromophore and its photophysical studies. The title compound 4-((9-ethyl-9H-carbazol-3-yl) methylene) amino-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (

Full text of DOI:10.1016/j.molstruc.2019.127103

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Microwave assisted synthesis, Spectroscopic and photophysical properties of
novel Pyrazol-3-one containing push -pull chromophore
Mohie E.M. Zayed, Parveen Kumar, Salman A. Khan
PII:
S0022-2860(19)31209-8
DOI:
https://doi.org/10.1016/j.molstruc.2019.127103
MOLSTR 127103
Reference:
To appear in:
Journal of Molecular Structure
Received Date:
Accepted Date:
13 April 2019
19 September 2019
Please cite this article as: Mohie E.M. Zayed, Parveen Kumar, Salman A. Khan, Microwave
assisted synthesis, Spectroscopic and photophysical properties of novel Pyrazol-3-one containing
push -pull chromophore, Journal of Molecular Structure (2019), https://doi.org/10.1016/j.molstruc.
2019.127103
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Microwave assisted synthesis, Spectroscopic and photophysical properties of novel Pyrazol-3-one containing push -pull
chromophore
1
,*
2
Mohie E. M. Zayed , Parveen Kumar , Salman A. Khan*
Department of Chemistry, Faculty of Science, King Abdulaziz University, P. O. Box 80203, Jeddah 21589, Saudi Arabia
Deparment of Chemistry, DAV college Faridabad, Haryana, India
1
2
*
Corresponding author e-mail: mohiem@yahoo.com (M. E. M. Zayed), sahmad_phd@yahoo.co.in (S. A. Khan)
Graphical Abstract
50
0.28
0.24
0.20
0.16
0.12
0.08
0.04
0.00
4
5
45
DMSO
DMF
40
4
0
5
EtOH
MeOH
DMSO
DMF
35
30
25
CMC
3
CHCl
3
EtOH
MeOH
CH Cl
2
2
CHCl
3
30
25
20
15
CH CN
3
CH CN
3
Dioxane
THF
20
15
Dioxane
THF
n-Hexane
n-Hexane
1
0
5
0
10
325
350
375
400
425
400
450
500
550
600
0.0000
0.0004
0.0008
0.0012
-3
0.0016
Wavelength (nm)
Wavelength (nm)
[
CTAB] mol. dm

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Microwave assisted synthesis, Spectroscopic and photophysical properties of
novel Pyrazol-3-one containing push -pull chromophore
1
,*
2
Mohie E. M. Zayed , Parveen Kumar , Salman A. Khan*
1Department of Chemistry, Faculty of Science, King Abdulaziz University, P. O. Box 80203,
Jeddah 21589, Saudi Arabia
2Deparment of Chemistry, DAV college Faridabad, Haryana, India
*
Corresponding
author e-mail:
mohiem@yahoo.com
(M.
E.
M.
Zayed),
sahmad_phd@yahoo.co.in (S. A. Khan)
Abstract: The present work deals with synthesis of pyrazole-3-one containing Schiff base as a
push-pull chromophore and its photophysical studies. The title compound 4-((9-ethyl-9H-
carbazol-3-yl) methylene) amino-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (EDPO)
derived from the reaction of 9-ethyl-3-carbazole carboxaldehyde with 4-amino phenazone under
microwave irradiation for 4 min achieving 94.8 % yield. The structure of chromophore (EDPO)
was established on the basis of elemental analysis and spectroscopic techniques. Photophysical
properties such as transition dipole moments, stokes shift, oscillator strength and fluorescence
quantum yields was investigated in ten different solvents. It was observed that the intensity of the
absorbance and emission of EDPO increased on the basis of the solvent polarity (n-Hexane to
DMSO). In addition the effect of the surfactants CTAB and SDS on the EDPO were also studied
to determine the critical micelle concentration of the cationic and anionic surfactants CTAB and
SDS.
Keywords: Pyrazole-3-one, Schiff base; Stokes shift; Surfactants; CMC
1

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1
. Introduction
Within the last few decades, organic compounds functionalized with nitrogen atoms became
enormously investigated and growing area of organic chemistry [1]. Due to the presence of
nitrogen atoms, organic compounds possess strange and unique properties, which applicable in
many branches of contemporary life sciences [2]. Nitrogen containing heterocyclic organic
molecules play major role in the field of agriculture [3], biological and pharmaceutical [4] and
additional in recent times were also used as ionic liquid [5], organocatalysts [6], and polymeric
materials [7]. Pyrazol-3-one is 5-membered nitrogen containing heterocyclic compound with
carbonyl group present at number two position have received significant consideration [8]. It is
commendable of note that pyrazol-3-one compounds have been reported to show a broad range
of bioactive molecule, like anticancer, antitumor, antifungal, anti-HIV, and antidepressant [9-11].
Since last two decades, pyrazol-3-one derivatives are used as metal sensors such as Pd (II)
sensor, Hg (II) sensor Cu (II) sensor, Zn (II) sensor, organic light emitting diodes sensing of
DNA and live cell sensor [12]. Pyrazol-3-one framework have oxygen atom joined with carbon
by the double bond we can say oxygen use as acceptor (A), has synthesized by one pot-synthesis.
Many one-pot reactions have been reported for the synthesis of various heterocyclic compounds
[
13]. If donor (D) group such as NR , OR, containing long pi (π) bond conjugated system joined
2
with the pyrazol-3-one ring is known as donor acceptor chromophore [14]. Donor (D) acceptor
A) containing compounds are applicable in the field of material sciences such as multi-
(
functional, optoelectronic materials [15], electroluminescent [16], photovoltaic devices [17],
light emitting diodes [18], and electroluminescent [19]. Intramolecular electron transfer
processes from the donor group to acceptors group are playing important role to determine the
photophysical and photochemical properties of organic molecules constituting π-donor-acceptor
2

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conjugated system such as transition dipole moments, stokes shift, oscillator strength and
fluorescence quantum yields [20]. Interaction of D-ℼ -ꢀ chromophore with the cationic and
anionic surfactants such as cetyltrimethylammonium bromide (CTAB) and Sodium dodecyl
sulphate (SDS) have been studied by the enhancement or quenched of the emission spectra to
determine the critical micelle concentration (CMC) of the surfactants are also important
application of the D-ℼ -ꢀ chromophore. Various mane reactions have been reported such as
Perkin condensation [21], Knoevenagel condensation [22], Cross-coupling reactions [23], Aldol
condensation [24], Suzuki cross-coupling reaction [25] and Erlenmeyer-Plochl reaction [26] for
the synthesis of such type of chromophores. Condensation reaction is also applicable for the
synthesis of push -pull chromophores. Azomethine generally prepare by the condensation of
amine and aldehyde or ketone. Reaction of push and pull group containing aldehyde and amine
generally synthesized the push –pull Schiff base. During the literature review, we found lot of work
have been made on the optical properties of donor (D)-π- acceptor (A) chromophores with their
photophysical and physicochemical properties, but very rare examples reported optical properties of push
and pull group containing heterocyclic Schiff base. In the present manuscript we synthesized
push -pull chromophores by the reaction of 9-ethyl-3-carbazolecarboxaldehyde with 4-
aminophenazone under microwave irradiation. Physicochemical and parameters such as
extinction coefficient, oscillator strength, transition dipole moment, stokes shift and fluorescence
quantum yield of the EDPO were calculated in the different solvents to see the effect of the
solvents with EDPO on the basis of solvents polarity. EDPO was also applicable for
determination of critical micelle concentration (CMC) of cationic and anionic surfactant such as
cetyltrimethyl ammonium bromide (CTAB) and sodium dodecylsulfate (SDS).
2
. Experimental
3

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2
.1.
Reagents and chemicals
Require reagents and solvents for the present work are of analytical grade purchased from Acros
Organic and used directly. Carbazole, ethyl iodine, 4-amino phenazone, cetyl
trimethylammonium bromide (CTAB) and sodium dodeyl sulfate (SDS) were pursed from
Sigma-Aldrich. The stock solution of EDPO was prepared in DMSO and stock solution of
CTAB and SDS was prepared in double distilled water. Absorbance and fluorescence was
recorded at room temperature. 9-Ethyl-3-carbazole carboxaldehyde was prepared according to
the published methods [27].
2
.2.
Equipment
The purity of the EDPO was confirmed by the 0.2 mm 60F-254 silica gel coated TLC plate and
the melting point of the chromophore was recorded by Sturat Scientific Co. Ltd. apparatus. IR
1
13
spectrum of chromophore was recorded with Perkin-Elmer 100-FT-IR spectrometer. H & C-
NMR signal of the compound was recorder in DMSO-d6 at 600/ 125 MHz on a Bruker
AVANCE. The UV-Vis absorption and emission spectra of the EDPO was recorded with
Shimadzu UV-1650 PCUV/VIS spectrophotometer and Shimadzu RF 5301PC
spectrofluorophotometer.
2
.3.
Synthesis of 4-((9-ethyl-9H-carbazol-3-yl) methylene) amino)-1,5-dimethyl-2-
phenyl-1,2-dihydro-3H-pyrazol-3-one (EDPO)
Title compound EDPO was synthesized by the equimolar reaction of ethyl-3-carbazole
carboxaldehyde (0.011 mol, 2.50 g) and 4-amino phenazone (0.011 mol, 2.27 g) in the minimum
amount of (10 ml) EtOH and in 50 ml conical flask one drop of HCl was added in the reaction
mixture, then the conical flask was taken in a domestic microwave oven. The reaction was
irradiated under 210 watt microwave irradiation for 4 min. After completion the reaction,
4

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mixture was allowed to cool and obtained solid was recrystalized in chloroform and ethanol (8:2)
[28]
o
-1
Yellow solid; % yield: 94.8%; m.p: 191 C; IRv cm : 2977 (C-H), 1658 (C=N), 1679 (C=O),
max
1
1
626 (C=C), 1148 (N-N); H-NMR (DMSO-d ) δ: 10.08 (s, 1H, CHAzomethine), 8.69 (s, H3,
6
CHAromatic), 8.26 (dd, H1, CHAromatic, J = 7.80 Hz), 8.18 (dd, H2, CHAromatic, J = 7.0 Hz), 7.68 -
7
6
2
1
1
1
.32 (m, 5H, CHAromatic), 7.18 (d, 1H, CHAromatic, J = 7.2Hz), 7.06 (d, 1H, CHAromatic, J = 7.0 Hz),
.96 (d, 1H, CHAromatic J = 7.6Hz), 4.51 (q, 2H, N-CH -CH , J = 7.4 Hz), 3.12 (s, 3H, N-CH ),
2
3
3
1
3
.62 (s, 3H, -CH ), 1.54 (t, 3H, N-CH -CH , J = 6.8Hz); C-NMR (DMSO-d ): 163.07 (C=O),
3
2
3
6
52.33 (C=N), 142.52, 138.10, 136.47, 135.32, 134.93, 129.22, 129.02, 127.98, 125.87, 124.45,
23.09, 122.08, 120.18, 119.32, 118.88, 109.17 (Ar-C), 37.88 (N-CH ), 36.18 (N-CH -CH ),
3
2
3
4.87 (CH ), 10.29 (N-CH -CH ); EI-MS (m/z, %): 409.35 (M+1, 38); Anal. Calc for
3
2
3
C H N O: C, 76.45; H, 5.92; N, 13.72; Found C, 76.35; H, 5.85; N, 13.64.
2
6
24
4
3
. Results and Discussion
.1. Characterization of EDPO
-((9-ethyl-9H-carbazol-3-yl) methylene)
pyrazol-3-one (EDPO) was synthesized by reaction of 9-ethyl-3-carbazolecarboxaldehyde with
-aminophenazone under microwave irradiation (Scheme 1). Structure of EDPO was
3
4
amino)-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-
4
1
13
characterized by the FT-IR, H-NMR, C-NMR, EI-MS m/z (rel. int.%), and elemental analysis.
-1
Structure of EDPO was confirmed by the IR spectra due to characteristic band at 1688 cm of
-1
the ν (C=O), peak for aldehyde is shifted to a lower frequency of 1656 cm for C=N conformed
aldehyde converted to azomethine. Further evidence for the formation of EDPO was obtained
1
from the H NMR spectra, which provide diagnostic tools for the positional elucidation of the
5

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protons. Assignments of the signals are based on the chemical shifts and intensity patterns. The
aromatic protons of EDPO is shows multiplets in the range 7.32-7.68 ppm for 5 aromatic
protons. A singlet signal is due to CH=N, azomethine proton in the EDPO was observed at 10.08
ppm respectively and other two singlets at 3.22 and 2.62 ppm for the N-CH and C-CH protons.
3
3
1
3
C-NMR (CDCl ) spectrum of EDPO was recorded in CDCl and spectral signals are in good
3
3
agreement with the suggested functional groups. The carbonyl carbon of the EDPO generally
1
3
appears at δ 163.07 in C NMR spectra. The azomethine carbon give rise to characteristic signal
at δ 152.33 for C=N carbon. Details of 13C-NMR spectra of EDPO have presented in the
experimental section. Finally, characteristic peaks were observed in the EI-MS mass spectra of
EDPO as well as the molecular ion peak. The mass spectrum of EDPO shows a molecular ion
+
.
peak (M ) at m/z 409.35.
3
.2. Absorption and fluorescence spectral behavior of EDPO in different solvents
The absorptions and emission spectra of the EDPO has been recorded in ten different solvent on
the basis of polarity such as dimethyl sulfoxide (DMSO), dimethyl formamide (DMF),
chloroform (CHCl ), dicholoro methane (CH Cl ), acetonitrile (CH CN), 1,4-dioxane,
3
2
2
3
tetrahydrofuran (THF), n-Hexane at room temperature. As shown in the Figure 1. Maximum
absorption band of the EDPO was significantly affected on the polarity of the solvents. The
absorption maxima of the EDPO shifted to longer wavelength red shift 13 nm from n-hexane
(
332 nm) to DMSO (345 nm) (bathochromic shift) and intensity of the absorption increased
hyperchromic shift) when polarity of the solvent increased indicating the EDPO chromophore
(
has more polar nature in ground state. The molar absorption coefficient (Ɛ) also effected with the
polarities of the solvents its value were presented in Table 1. As expected bathochromic shift
(red shift) when increase the polarity of the solvents like n-Hexane to DMSO is due to
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intramolecular charge transfer (ICT) from push group (carbazole) to pull group (carbonyl group)
[29].
On excitation at 350 nm, the fluorescence spectrums of the EDPO were strongly correlates with
the polarities of the solvents. As shown in Figure 2 the EDPO chromophore displayed one broad
band which characterized electronic transition from S to S . It was examined that the
1
o
bathochromic shift in the emission maxima with the polarity of the solvent increases 26 nm from
n-Hexane (419 nm) to DMSO (445 nm) were more than the bathochromic shift in the absorption
maxima (Table 1). The excited state energy of EDPO chromophore was more affected with
solvent polarities as compared to the ground state energy of the EDPO indicated due to the π-π*
transition [30].
The empirical Dimroth polarity parameters E (30) of the different solvent correlate with the
T
absorption energy (E ) and emission energy (E ) of the EDPO in various solvent as mention in
a
f
Figure 3. One dimensional correlation between different polarity of solvent and absorption,
emission energy were acquired by the following equations [31].
E = 87.60 – 0.067 x E (30)
(1)
(2)
a
T
E = 72.54 – 0.092 x E (30)
f
T
3
.3.
Determination of transition dipole moment and oscillator strength
The solvatochromic behavior of EDPO enable to determine the different dipole moments
between the singlet excited state and ground state ∆μ = μ –μ .
e
g
Lippert-Mataga equation can be used to obtain these variations on the optical properties of
EDPO [32].
2
2

 st  abs em

f Const.
(3)
3
h ca
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where,  st is represent the stokes shift as mention in the table 1, the value of stokes shift
increasing with increasing the polarity of the solvents (n-Hexane to DMSO), signifying
strong stabilization of excited state in polar solvent, h is the plank constant, a is the raids
cavity, c is the velocity of light and ∆f is the orientation polarizability of the different
solvents have explained by following equation (eq. 4).
2

2
1
 1
f 

(4)
2
 1 2 1
where η and ε are the refractive index of the solvents and dielectric constant correspondingly.
The plot of stokes shift (  st ) versus orientation polarizability (∆f) as showed Figure 4. The
linear associations between orientation polarizability versus stokes shift identified that stokes
shift was dependent on the polarity of the solvents’ or polarizability. The dipole moments (

) different between ground and excited state of EDPO was calculated by using Lippert –
Mataga equation (3). At the Equation 3 the a is the cavity radius of the EDPO was estimated
by the following equation (5)
1
/ 3

3M 
a  


(5)

4
N d


Where N is the Avigadro number, M is molecular mass and d is the assumed density of the
3
chromophore of 1g / cm . The dipole moment different of EDPO was found 7.68 Debye (Figure 4).
Positive vale indicated that excited state is more polar than ground state [33].
The transition dipole moments of the EDPO chromophore between ground state and excited state in
different solvent were calculates as following equation (eq. 6) [34]. The values were listed in Table 1.
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f
2


(6)

7
4
.72 10 Emax
-1
where f is the oscillator strength and Emax is the maximum energy of the absorption in cm .
The oscillator strength (f) of the EDPO chromophore in different solvent were calculated by
the following equation (7)

9
f  4.32 10

 
d
(7)

is the wavenumber (cm ). The calculated
-1
-1
-1
Where Ɛ is the dielectric constant (M cm ) and
values of the oscillator strength (f) in different solvent were present in the Table 1. The oscillator
strength of the EDPO was directly dependent to the polarity of the solvent.
3
.4.
Fluorescence quantum yields of EDPT
The fluorescence quantum yields (ɸ ) of the EDPO in different solvents were calculated with
f
the reference of the standard dye (Quinine sulphate ɸ = 0.55 in 0.1 M H SO solution). The
r
2
4
flowing equation was applied for the calculation of fluorescence quantum yields (ɸ ) for the
f
EDPO [35].
2
I x A x n
r
Ir x Axn

 
(8)
r
f
2
r
Where ɸ is the calculated fluorescence quantum yields of the EDPO in different solvent, ɸ
f
r
is the fluorescence quantum yield of the Quinine sulphate as standard dye, I is the integrated
emission intensity, A is the absorbance of EDPO and reference dye at the excited wave
length and n is the refractive index of the solvent.
The fluorescence quantum yield (ɸ ) of EDPO depending on the polarity of the solvents,
f
because the fluorescence spectra have an effected on solvent polarity. The value ɸ in
f
different solvents were listed in Table 1. In addition the relationship between of value
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fluorescence quantum yield of the EDPO in different solvents and E (30) of the different
T
solvent were shown in Figure 5, where E (30) is the solvent polarity parameter identified by
T
Reichardt [37]. The obtained data displayed that significantly dependent to the solvent
properties such as polarizabilty and hydrogen bonding. The fluorescence quantum yield
increased when solvent polarity increased (0.05 in n-Hexane to 0.12 in DMSO). This
phenomenon can be explained by the negative solvatokinetic effects. On the other, the
fluorescence quantum yield of EDPO in highly polar solvent such as EtOH, and MeOH
showed week as comparing to the other solvents having less polarity due the hydrogen
bonding between the solutes and alcoholic solvents.
3
.5.
The effect of the cationic and anionic surfactants such ascetyl trimethyl ammonium bromide
CTAB) and Sodium dodecyl sulphate (SDS) on the fluorescence spectrum of EDPO dye. The
Effect of surfactant on fluorescence spectra of EDPO
(
chosen of these two specific surfactants due to the ionic charged obsessed by the EDPO can be
prejudiced by the positively charged and negatively charged surfactant. Thus, the emission
behavior of the EDPO dye was based on the charge interaction between EDPO dye with CTAB
or SDS. The fluorescence emission spectrum of the EDPO was measured in the absence of the
CTAB and SDS. The fluorescence intensity of the EDPO increases with increase the
concentration of the both type of the surfactants. The emission intensity of the EDPO increase
-4
-3
with increases the concentration of CTAB (1 x 10 to 1.8 x 10 M) and as same the fluorescence
-3
intensity of the EDPO increases with increasing the concentrations of the SDS (2 x 10 to 1.8 x
-2
-5
1
0 M) such enrichment of the fluorescence strength of 1x 10 M of EDPO at unchanging molar
concentration with an increase the concentration of the CTAB and SDS as presented in the
Figure 6 & Figure 7. The fluorescence band maximum observed at 430 nm in water and red
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shifted 55 nm and 50 nm on adding the CTAB and SDS, respectively. This shift is accompanied
by a uniform increasing the emission intensity. The spectral shift and enhancement of the
fluorescence intensity can be rationalized is due to the enrolment of polar, conformationally
relaxed intramolecular charge transfer states, whose stability is expected to be influenced by
changing the micropolarity of the micelle domains. In addition to polarity, hydrogen-boning
effect also plays a role at the binding site. So it is clear that EDPO in the surfactants CTAB and
SDS can be located in interfacial regions with 4-((9-ethyl-9H-carbazol-3-yl) methylene) amino-
1
,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (EDPO) fragment inside hydrophobic
alkyl chains to ward polar environment favoring efficient hydrogen bonding. In the Present of
different concentration of the CTAB and SDS with sudden change the intensity of the
-4
-
fluorescence spectra of EDPO taking place at surfactant concentration 8.96 x 10 and 6.38 x 10
3
-3
mol dm , which are very near to critical micelle concentration of the CTAB and SDS surfactant
Figure 8 and Figure 9 [38]. Thus the molecules EDPO can be use as probe analyzes the CMC of
the cationic and anionic surfactants.
4
. Conclusion
The pyrazole-3-one containing push-pull chromophore (EDPO) has been synthesized by the
reaction of 9-ethyl-3-carbazole carboxaldehyde with 4-amino phenazone under microwave
irradiation, obtained higher yield 94.8 % in a less reaction time by a simple and usual
1
13
workup. The structure of EDPO was established on the basis of IR, H-NMR, C-NMR and
EI-MS spectroscopic techniques and elemental analysis. The photophysical behavior of the
EDPO was described in ten solvents on the basis of the different polarity. The chromophore
EDPO showed good photophysical properties depending on the solvent polarity it showed
bathochromic shift when the polarity of the solvent increased n-Hexane to DMSO. The
1
1

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emission intensity, transition dipole moments, stokes shift, oscillator strength and
fluorescence quantum yields of the chromophore EDPO increased when the polarity of
solvents increased. In addition the effect of the surfactants CTAB and SDS on the EDPO
were also studied and it can be use as probe to determine the critical micelle concentration
(CMC) of the cationic and anionic surfactants CTAB and SDS.
Acknowledgments
This project was funded by the deanship of Scientific Research (DSR) at King Abdulaziz
University, Jeddah, under grant no. G-480-130-38. The authors, therefore, acknowledge with
thanks DSR for technical and financial support.
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Mole. Stru.1195 (2019) 670-680.
CH3
N
H
O
H2N
CH3
N
O
N
EtOH
Microwave
One drop HCl
CH3
N
N
H C
3
H
N
O
(EDPO)
N
Scheme 1: Schematic diagram for the synthesis of EDPO
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Table 1: Spectral data of EDPO in different solvents

μ 12
-
1
ε
(cm )
ET (30)
Kcal
Φf
Solvent
f
 (nm)  (nm)
f
Debye
ab
em
N
-1
-1
ET
M cm
-1
mol
DMSO
0.263
0.441
0.404
0.654
0.762
0.259
----
54.1
43.8
51.9
55.4
39.1
40.7
45.6
36
345
445
26390
23800
0.68
0.63
7.04
6.75
7.01
7.01
6.16
6.25
6.76
6.69
5.58
4.81
6514
6717
7202
0.12
DMF
EtOH
0.274
0.288
0.308
0.208
0.255
342
337
337
338
336
338
336
336
332
444
445
447
428
428
439
437
426
419
0.11
24000 0.69
0.082
MeOH
CHCl3
CH Cl
23900
21400
21500
23780
23000
17600
13400
0.69
0.53
0.55
0.64
0.63
0.44
0.33
7302 0.100
6221 0.105
6397 0.104
2
2
Acetonitrile 0.304
0.472
0.164
0.210
6806
0.059
0.11
Dioxan
THF
0.021
0.10
6878
6287
6254
37.4
31.1
0.057
0.051
n-Hexane 0.0014 0.006
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0.28
0.24
0.20
0.16
0.12
0.08
0.04
0.00
DMSO
DMF
EtOH
MeOH
CHCl
3
CH Cl
2
2
CH CN
3
Dioxane
THF
n-Hexane
325
350
375
400
425
Wavelength (nm)
-5
-3
Figure 1: Electronic absorption spectra of 1 10 mol dm of EDPO in different solvents.
45
40
35
30
25
20
15
10
5
DMSO
DMF
EtOH
MeOH
CHCl
3
CH CN
3
Dioxane
THF
n-Hexane
0
4
00
450
500
550
600
Wavelength (nm)
-5
-3
Figure 2: Emission spectra of 1 10 mol dm of EDPO in different solvents.
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90
85
80
75
70
65
E
a
E
f
30
35
40
45
50
55
-1
E (30) Kcal mol
T
Figure 3: Plot of energy absorption (E ) and emission (E ) versus E (30) of different solvents
a
f
T
7
7
7
6
6
6
400
200
000
800
600
400
0
.25
0.26
0.27
0.28
0.29
0.30
0.31
Delta f
Figure 4: Plot of ∆f versus Stokes shift (∆).
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0.13
0.12
0.11
0.10
0.09
0.08
0.07
0.06
0.05
35
40
45
50
55
-1
E (30)kcal mol
T
Figure 5: Plot of  versus E (30) of different solvents.
f
T
5
4
4
3
3
2
2
1
1
0
5
0
5
0
5
0
5
0
5
0
4
25 450 475 500 525 550 575 600 625
Wavelength (nm)
-5
-3
Figure 6: Emission spectrum of 1x10 mol dm of EDPO at different concentrations of CTAB,
-4
-4
-4
the concentrations of CTAB at increasing emission intensity are 0.0, 2 x 10 , 4 x 10 6 x 10 , 8
x 10 , 10 x 10 , 12 x 10 , 16 x 10 and 18 x 10 mol dm .
,
-4
-4
-4
-4
-4
-3
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4
4
3
3
2
2
1
1
5
0
5
0
5
0
5
0
5
0
4
00
450
500
550
600
Wavelength (nm)
-5
-3
Figure 7: Emission spectrum of 1x10 mol dm of EDPO at different concentrations of SDS, the
-3
-3
-3
-
concentrations of SDS at increasing emission intensity are 0.0, 2 x 10 , 4 x 10 , 6 x 10 , 8 x 10
3
-3
-3
-3
-3
-3
,
10 x 10 , 12 x 10 , 16 x 10 and 18 x 10 mol dm .
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50
45
40
35
30
25
20
15
10
CMC
0.0000
0.0004
0.0008
0.0012
0.0016
-3
[CTAB] mol. dm
Figure 8: Plot of I versus the concentration of CTAB
f
48
44
40
36
32
28
24
20
0.000
0.004
0.008
0.012
0.016
-3
[SDS] mol dm
Figure 9: Plot of I versus the concentration of SDS
f
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►
4-((9-ethyl-9H-carbazol-3-yl) methylene) amino-1,5-dimethyl-2-phenyl-1,2-
dihydro-3H-pyrazol-3-one (EDPO)
►
►
Physicochemical and Photophysical investigations of EDPO dye
Determine the critical micelle concentration (CMC) of CTAB and SDS