Synthesis, characterization, electrochemistry and optical properties of new 1,3,5-trisubstituted ferrocenyl pyrazolines and pyrazoles containing sulfonamide moiety

Article abstract of DOI:10.1016/j.jorganchem.2012.08.011

This article describes the synthesis and characterization of a series of new 3-ferrocenyl-1-(4-sulphamylphenyl)-5-aryl-4,5-dihydro-1H-pyrazolines and the corresponding pyrazole derivatives derived from ferrocenyl chalcones and 4-hydrazino benzenesulfonamide hydrochloride. The compounds were characterized by spectroscopic means and the structure of the new ferrocenyl pyrazoline (3a) was determined by means of X-ray crystallography. The optical properties of these compounds were studied by means of UV/visible absorption spectroscopy and fluorescence spectroscopy (both steady state and time-resolved) in dichloromethane solvent. Electrochemical study revealed that all the compounds exhibited reversible oxidation behavior at 521-543 mV corresponding to ferrocene pyrazolines (3a-l) and 621-645 mV corresponding to ferrocene pyrazoles (4a-j) respectively, as confirmed by the i_pc/i_pa = 0.92-1.00.

Full text of DOI:10.1016/j.jorganchem.2012.08.011

Journal of Organometallic Chemistry 718 (2012) 64e73
Contents lists available at SciVerse ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Synthesis, characterization, electrochemistry and optical properties of new 1,3,5-
trisubstituted ferrocenyl pyrazolines and pyrazoles containing sulfonamide
moiety
,
a
a
b
Ch. Kiran Kumar a, Rajiv Trivedi a , K. Ravi Kumar , L. Giribabu , B. Sridhar
*
a Inorganic and Physical Chemistry Division, CSIR-Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad 500607, Andhra Pradesh, India
b X-Ray Crystallography Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500607, Andhra Pradesh, India
a r t i c l e i n f o
a b s t r a c t
Article history:
This article describes the synthesis and characterization of
a series of new 3-ferrocenyl-1-(4-
Received 20 March 2012
Received in revised form
3 August 2012
sulphamylphenyl)-5-aryl-4,5-dihydro-1H-pyrazolines and the corresponding pyrazole derivatives
derived from ferrocenyl chalcones and 4-hydrazino benzenesulfonamide hydrochloride. The compounds
were characterized by spectroscopic means and the structure of the new ferrocenyl pyrazoline (3a) was
determined by means of X-ray crystallography. The optical properties of these compounds were studied
by means of UV/visible absorption spectroscopy and fluorescence spectroscopy (both steady state and
time-resolved) in dichloromethane solvent. Electrochemical study revealed that all the compounds
exhibited reversible oxidation behavior at 521e543 mV corresponding to ferrocene pyrazolines (3ael)
Accepted 7 August 2012
Keywords:
Ferrocene
Pyrazoline
Pyrazole
Sulfonamide
Electrochemistry
Fluorescence
and 621e645 mV corresponding to ferrocene pyrazoles (4aej) respectively, as confirmed by the ipc
ipa ¼ 0.92e1.00.
/
Ó 2012 Elsevier B.V. All rights reserved.
1. Introduction
substituted planar ring system. Recently Supuran et al., have re-
ported on the biological properties of several metallocene based
triazoles having sulfonamide derivatives [38], however, reports on
ferrocenyl pyrazolines containing sulfonamide group are scarce in
the literature. There is an increased interest in the design and
synthesis of small molecules exhibiting fluorescent property.
Hence, it would be of significant interest to explore a combined
influence of the electrochemical property of ferrocene as well as the
emission properties of the sulfonamide containing pyrazolines/
pyrazoles in a single hybrid molecule.
Herein we report the synthesis, characterization and optical
properties of 1,3,5-trisubstituted ferrocenyl pyrazolines and cor-
responding pyrazoles containing sulfonamide moiety. While UVe
visible, fluorescence spectroscopies and electrochemical analysis
were carried out on all these compounds, structure determination
using single crystal X-ray crystallography was also done for the
compound 3a.
Ferrocene and its derivatives have displayed remarkable inter-
disciplinary activities ranging from their applications in material
science, catalysis to biological assays [1,2]. Among these derivatives,
ferrocene heterocycles containing moieties like condensed imid-
azoles [3,4], triazoles [5e8], guanidine [9], oxazoles [10,11], and
pyrimidines [12e14] have predominantly attracted remarkable
interest due to their widespread applications in various fields of
chemistry including medicine [15], supramolecular chemistry
[16,17], material science [18,19] and sensors [20]. Pyrazoles and
pyrazolines, belonging to one such heterocyclic ring system, have
propensity as blue light emitting fluorescent agents with high
quantum yields [21e24] and hole transport tendency [25e28]. In
recent times, Zhao et al. [29,30], and several others [31,32] have
reported on the synthesis, characterization and optical properties
of numerous ferrocenyl pyrazoline derivatives.
Further, it is well documented that sulfonamide hybrids, an
important class of compounds, display a diverse range of biological
and photophysical properties [33e37]. These properties are
enhanced by attaching the sulfonamide groups within a central
2. Results and discussion
2.1. Scheme of synthesis
The synthetic route for the target compounds is outlined in
Scheme 1. The first step involves the base-catalyzed Claisene
* Corresponding author. Tel.: þ91 40 27191667.
E-mail address: trivedi@iict.res.in (R. Trivedi).
0022-328X/$ e see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2012.08.011

Ch.K. Kumar et al. / Journal of Organometallic Chemistry 718 (2012) 64e73
65
Scheme 1. Synthesis of 1,3,5-trisubstituted ferrocenyl pyrazolines (3ael) and pyrazoles (4aej) from acetylferrocene.
Schmidt condensation of acetylferrocene 1, with the corresponding
substituted benzaldehydes to prepare 3-ferrocenyl-1-aryl-2-
propen-1-ones (2ael) according to the literature procedures
[39,40]. Reaction between the ferrocenyl chalcones (2ael) and 4-
hydrazino benzenesulfonamide hydrochloride in ethanol and ace-
tic acid mixture (1:2, 12 ml/1 mmol) at 95e100 ꢀC for 21e22 h gave
the target compounds. The progress of the reaction was monitored
by TLC (1:1, pet ether:chloroform), the reaction mixture was cooled,
filtered, washed with water, dried and the products were purified
by flash column chromatography on neutral alumina. The final step
involves the oxidation of the pyrazoline compounds (3aej) with
DDQ (1.2 equiv) at room temperature in dichloromethane solvent
[41]. After the completion of the reaction (8e9 h), the reaction
mixture was passed through a small pad of neutral alumina using
2% methanol in chloroform to get the pyrazole derivatives.
Crystallization from dichloromethane gave the analytically pure
product (4aej). Pyrazoline compounds with nitro substituents
(3k and 3l) did not give any products even at reflux temperatures
for prolonged time.
6.7 ppm in the 1H spectrum and the absence of sp3 carbons in 13C
spectrum of compounds (4aej) indicated the formation of pyrazole
ring. A broad signal at
d 6.60e6.95 ppm (3ael) and d 4.75e
4.90 ppm (4aej) for the eNH2 protons indicated the presence of
the sulfonamide group (for pyrazoline compounds more polar
DMSO-d6 was used as solvent whereas for pyrazole compounds less
polar CDCl3 was used as solvent for the NMR analysis). All the other
additional peaks observed were in agreement with the respective
aromatic substituents and ferrocene ring. The HR-MS spectral
values and elemental analysis data were also in agreement with the
proposed structure.
2.3. Single crystal X-ray structure of 3a
The molecular structure of the 3-ferrocenyl pyrazoline 3a was
determined by means of X-ray diffraction studies and its crystal-
lographic data and structural refinement parameters are given in
Supplementary material. Red crystals of 3a were obtained through
slow evaporation of the chloroform solution. The compound crys-
tallized in the triclinic space group P1. The atom numbering
scheme is given in Fig. 1, which shows a perspective view of
compound 3a. The pertinent bond length and bond angle data are
listed in Supplementary material. The structure consists of a pyr-
azoline ring with the carbon atom C13 substituted by ferrocene and
a benzene-sulfonamide group attached to the nitrogen atom N1. In
the ORTEP diagram, the asymmetric unit of 3a contains 3-
ferrocenyl-pyrazoline ligand and two chloroform solvates. The
2.2. Structural characterization
The structure of the new compounds was established on the
basis of FT-IR, 1H NMR, 13C NMR, HR-MS and elemental analysis. The
FT-IR spectrum of both pyrazoline (3ael) and pyrazole compounds
(4aej) showed the presence of two weak bands in the region of
3580e3520 cmꢁ1, 3290e3200 cmꢁ1 for typical hydrogen bonded e
NH2 stretching bands and two strong bands at 1345e1315 cmꢁ1
and 1160e1150 cmꢁ1 for the characteristic bands of SO2 func-
tional group. This clearly indicates the presence of the benzene-
sulfonamide group [42]. Apart from these, strong characteristic
bands at 1610e1590 cmꢁ1 and 1530e1510 cmꢁ1 for the compounds
pyrazoline ring (C11/C12/C13/N1/N2) adopts an envelope confor-
mation with puckering parameter Q ¼ 0.250(3) A and
4
¼ 316.7(8)ꢀ.
ꢀ
ꢀ
Atom C13 is displaced by 1.216(3) A from the mean plane defined by
the atoms N1/N2/C11/C12 (Supplementary material). The two
cyclopentadienyl rings (C1eC5) and (C6eC10) of the ferrocenyl
moiety are parallel with the dihedral angle of 0.66(14)ꢀ and the
ferrocenyl moiety is in the eclipsed form. In addition to the regular
features, it was observed that the sulfonamide group forms an eight
member centrosymmetric dimer via NeH/O hydrogen bond
(4aej) confirm the presence of n(C]C) and n(C]N) respectively for
the pyrazole moiety [40,41]. All the other additional bands
observed in the IR spectra belonged to the aromatic substituents
and the ferrocene ring.
The 1H NMR spectra of pyrazoline compounds (3ael) displayed
interactions [N3eH1N/O1; 0.78(4), 2.24(4), 2.996(5) A,
ꢀ
three sets of signals with an ABX pattern at
d
2.90e3.10 ppm (4-
163(4)ꢀ; ꢁx ꢁ 1, ꢁy, ꢁz þ 2] (Fig. 2). Such eight member dimer via
hydrogen bonds involving sulfonamide groups is prevalent in the
literature [43,44]. Furthermore, Zhao and co-workers have reported
significant inter and intramolecular hydrogen bonding within the
crystal lattice of ferrocenyl pyrazoline compounds [29,30]. It was
observed that only one chloroform solvate is involved in CeH/O
Htrans), 3.85e4.05 ppm (4-Hcis) and 5.25e5.60 ppm (5-H) cor-
d
d
responding to the C4 and C5 hydrogens on the pyrazoline ring. This
was further confirmed by the appearance of three signals at
d
150.5e151.6 ppm (C3),
d
43.0e44.6 ppm (C4) and
d
56.1e62.5 ppm
6.2e
(C5) in the 13C NMR spectra. The presence of a singlet at
d

66
Ch.K. Kumar et al. / Journal of Organometallic Chemistry 718 (2012) 64e73
Fig. 1. ORTEP diagram of 3a (showing the atom-labeling scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms are represented by circles of arbitrary
radii.).
interaction with sulfonamide group [C26eH26/O2; 0.98, 2.40,
possess some ferrocene character [32]. As can be seen in Fig. 3,
lower wavelength band (275e285 nm) of pyrazoles was found to be
more intense than that of pyrazoline derivative due to the conju-
gation of C5-aromatic ring of pyrazole. On the other hand, the
intensity of the longer wavelength band was almost identical for
pyrazolines and pyrazoles (Fig. 3). No appreciable change in the
absorption spectra was observed due to the substituent effect on
C5-phenyl ring for both pyrazolines and pyrazole compounds.
ꢀ
ꢀ
3.295(5) A, 152 ; ꢁx, ꢁy, 2 ꢁ z]. The other chloroform solvate is
included in the crystal lattice by weak Vander walls interactions.
2.4. Absorption spectroscopy
Electronic absorption spectra of the ferrocenyl pyrazolines (3ae
l) and ferrocenyl pyrazoles (4aej) were recorded in dichloro-
methane solvent (Fig. S1, Supplementary material). Two distinct
absorption bands, 275e285 nm and 345e360 nm were observed
for all these compounds. These two bands were attributed to the
2.5. Electrochemistry
The electrochemical characterization of the compounds 3ael
and 4aej, was performed by means of cyclic voltammetry (CV) in
DMSO as a solvent (Figs. 4 and S2), using a three-electrode cell
consisting of a glassy carbon working electrode, a platinum wire
auxiliary electrode and standard calomel electrode (SCE) as the
reference electrode with a scan rate of 100 mV sꢁ1. Tables 1 and 2
p
/
p* transition of pyrazole/pyrazoline moiety and the intra-
molecular charge transfer (ICT, from N1 to the benzenesulfonamide
group) respectively. Ferrocene moiety also displayed MLCT band
between 320 and 360 nm, hence the band at 345e360 nm may
Fig. 2. Part of the crystal structure of 3a, showing the centrosymmetric dimer between
the sulfonamide groups through NeH/O hydrogen bonds. CeH/O bond interactions
are also shown. For the sake of clarity, H atoms not involved in hydrogen bonding have
been omitted.
Fig. 3. Comparative UVevis spectra of selected pyrazoline and pyrazole compounds in
dichloromethane.

Ch.K. Kumar et al. / Journal of Organometallic Chemistry 718 (2012) 64e73
67
Table 1
Characterization data for 3-ferrocenyl-1-(4-sulphamylphenyl)-5-aryl-4,5-dihydro-
1H-pyrazoline: cyclic voltammetry data obtained from voltammograms (vs. SCE) of
compounds 3ael in DMSO/0.5e1.0 mM with TBAP (supporting electrolyte) at 25 ꢀC
at scan rate of 100 mV/s. Eo0xð ¼ Epc þ Epa=2Þ, ΔEp (¼Epc ꢁ Epa), ipc/ipa (ratio between
cathodic and anodic peak current), Er0ed (reduction potential),
coefficient).
3
(extinction
em
Comp. Eo0x
code
ΔEp
(mV) (mV)
ipc/ipa Er0ed
lambasx; nm
l
Stokes
Quantum
max
(V)a
(
3
ꢂ 104) (nm) shift (nm) yieldb
3a
3b
3c
3d
3e
3f
3g
3h
3i
523
532
532
541
539
544
540
531
521
526
547
90.3 1.00 ꢁ1.26 352 (4.64) 406 54
96.9 1.00 ꢁ1.65 356 (2.17) 406 50
91.9 0.98 ꢁ1.69 351 (2.46) 406 54
88.5 1.00 ꢁ1.55 348 (2.13) 406 58
89.4 0.99 ꢁ1.52 349 (2.11) 406 60
90.0 1.00 ꢁ1.55 351 (1.89) 406 55
96.0 1.00 ꢁ1.51 351 (1.71) 406 55
90.2 1.00 ꢁ1.29 352 (2.59) 406 54
92.3 0.97 ꢁ1.23 352 (2.89) 406 54
93.7 0.92 ꢁ1.25 351 (1.97) 406 55
90.0 1.00 ꢁ1.01 348 (2.09) 406 58
0.021
0.012
0.014
0.012
0.013
0.009
0.009
0.014
0.021
0.010
0.004
0.003
3j
3k
3l
Fig. 4. Comparative electrochemical oxidative potential curves of selected compounds
in dimethyl sulfoxide solvent vs. SCE at RT.
546 123.8 0.77
ꢁ1.03 345 (3.05) 406 61
a
Irreversible.
b
Quantum yield calculated by using quinine sulfate in 0.1 M H2SO4 as reference
summarizes the redox potential data of all investigated
compounds. Each compound undergoes one reversible oxidation.
Wave analysis suggested that, in general, the oxidation was
compound.
reversible (ipc/ipa ¼ 0.92e1.0) and the diffusion-controlled (ipc
/ )
n1/2
The change in the emission intensity as well as the quantum yields
in pyrazoles may be due to the change in the electronic structure of
the C5-aromatic group. For instance, the fluorescence emission of
4f (4-bromo) was red-shifted by 38 nm compared to 4c (4-
methoxy). This behavior indicates that the molecule emits from
a relatively more polar ICT state. Solvatochromism was observed on
increasing the polarity of the medium leading to the red-shift of the
fluorescence band (Figs. S4 and S5).
The fluorescence quantum yield of all these compounds (3ael,
4aej) have been estimated using quinine sulfate as a standard
(Experimental section) and are collected in Tables 1 and 2 The
fluorescence quantum yields of pyrazolines were found to be
smaller than those of pyrazoles. The quantum yields of 3a and 3g
were found to be higher (w0.021) while the nitro-substituted
compounds exhibited poor quantum yield (0.003 and 0.004).
Similarly, 4g and 4i were more fluorescent (w0.050) in pyrazole
series while 4c and 4f show poor quantum efficiency (w0.010).
Better quantum efficiencies of the pyrazoles can be explained due
constant in the scan rate ( ) range (50e500 mV/s) for one-electron
n
transfer (ΔEP) was 89e97 mV for the ferrocene/ferrocenium (FcH/
FcHþ) couple. An anodic shift was observed in the oxidation of all
compounds (521e543 mV for 3ael and 621e645 mV for 4aej) with
respect to neat ferrocene (440 mV). The shift in the oxidation
potential of compounds (4aej) was due to extended conjugation in
heterocyclic ring. The overall anodic shift of oxidation potential of
ferrocene is due to the substituent effect of pyrazoline and pyr-
azoles subunits. Reduction potentials of pyrazolines (3ael) are
observed in the span range of ꢁ1.01 to ꢁ1.69 V and these may arise
from the functionalized pyrazoline rather than from the ferrocene
entity, whereas pyrazoles (4aej) were observed in the span range
of ꢁ622 to ꢁ646 mV as irreversible wave due to the ferrocenyl
moiety.
2.6. Fluorescence
The fluorescence emission profile of ferrocenyl pyrazolines (3ae
l) and ferrocenyl pyrazoles (4aej) was recorded in dichloro-
methane solvent (Figs. 5 and S3). The emission maxima and
quantum yields are collected in Tables 1 and 2. All the ferrocenyl
pyrazoline compounds (3ael) showed a single fluorescence emis-
sion band having maxima at 406 nm and shoulder at 430 nm. It was
observed that the emission band of these compounds was red-
shifted (50e60 nm) with respect to the absorption band maxima.
The structured fluorescence emission spectra (Fig. 4) of these
compounds suggested that the molecule emits from a locally
excited (LE) state having identical geometry with that of ground
state geometry [45]. On the other hand, a relatively less structured,
single fluorescence emission band (Fig. S3) was observed for pyr-
azoles (4aej) having the emission maxima between 425 and
460 nm. These fluorescence emission bands were more red-shifted
with respect to the corresponding absorption spectra indicating the
influence of extended conjugation on singlet state (S1). From
Tables 1 and 2 it was observed that, the fluorescence emission
maxima of pyrazolines (3ael) do not show any effect of the
substituent at C5-aromatic ring (lack of conjugation with N1 atom),
whereas the pyrazoles (4aej) display some changes due to the
conjugation of C5-aromatic ring with N1-aromatic ring. The non-
emissive nature of pyrazolines was probably due to the lack of
conjugation between the chromophore and the C5-aromatic ring.
Fig. 5. Comparative fluorescence spectra of selected pyrazoline and pyrazole
compounds in dichloromethane.

68
Ch.K. Kumar et al. / Journal of Organometallic Chemistry 718 (2012) 64e73
Table 2
4. Experimental
Characterization data for 3-ferrocenyl-1-(4-sulphamylphenyl)-5-aryl-1H-pyrazo-
line: cyclic voltammetry data obtained from voltammograms (vs. SCE) of
compounds 4aej in DMSO/0.5e1.0 mM with TBAP (supporting electrolyte) at 25 ꢀC
at scan rate of 100 mV/s. Eo0xð ¼ Epc þ Epa=2Þ, ΔEp (¼Epc ꢁ Epa), ipc/ipa (ratio between
4.1. General information
cathodic and anodic peak current), Er0ed (reduction potential),
coefficient).
3
(extinction
All reagent grade chemicals were purchased from Sigmae
Aldrich; 4-hydrazino benzene-sulfonamide hydrochloride was
purchased from Alfa Aesar and used as supplied. All the reactions
were performed under argon using oven-dried glassware with
magnetic stirring. TLC was performed on aluminum plates pre-
coated with Silica Gel 60 F254 (E. Merck), the spots were detected
visually and by UV light at 254 and 366 nm, respectively. Column
chromatography was performed on neutral Alumina (Brockmann
activity I). Melting points were determined using a Toshniwal
apparatus and are uncorrected. FT-IR spectra were recorded on
a Thermo Nicolet Nexus 670 spectrophotometer using KBr discs. 1H
and13C NMR spectra were recorded at room temperature on Bruker
Avance 300 or Varian Inova 500 spectrometer in CDCl3 or DMSO-d6
em
Comp. Eo0x
ΔEp
ipc/ipa Er0ed
(mV)a
lambasx; nm
l
Stokes
Quantum
max
code
(mV) (mV)
(
3
ꢂ 104) (nm) shift (nm) yieldb
ꢁ644 351 (2.52) 432
4a
4b
4c
4d
4e
4f
4g
4h
4i
645 100
640 101
0.94
1.00
81
84
77
85
87
81
93
0.010
0.025
0.011
0.027
0.029
0.007
0.048
0.054
0.023
0.014
ꢁ641 349 (2.30) 433
ꢁ621 344 (2.01) 421
ꢁ644 348 (1.79) 433
ꢁ644 347 (2.17) 435
ꢁ640 348 (1.39) 429
ꢁ643 353 (1.84) 446
621
633
638
643
634
636
636
634
89.0 0.98
84.2 1.00
80.0 1.00
91.0 1.01
83.0 1.00
84.2 0.98
85.3 0.98
94.8 1.02
ꢁ643 353 (1.67) 459 106
ꢁ646 355 (1.14) 456 101
ꢁ643 353 (1.16) 457 104
4j
a
Irreversible.
as solvent; chemical shifts (d) were reported in parts per million
b
Quantum yield calculated by using quinine sulfate in 0.1 M H2SO4 as reference
downfield with TMS as an internal standard. Coupling constants (J)
were given in hertz. Multiplicities were reported as s (singlet),
d (doublet), dd (doublet of doublet), t (triplet), m (multiplet), and
brs (broad singlet). For HR-MS, m/z values were expressed in atomic
mass units.
compound.
to the reduced non-radiative decay path (planar pyrazole moiety
and suppressed C5-aromatic ring rotation).
In order to understand the excited state properties, the fluo-
rescence decay curves of few pyrazolines (3a, 3c, 3g) and pyrazoles
(4a, 4c, 4g) were obtained on a time correlated single photon
counting instrument (Experimental section). The decay parameters
and average lifetimes are summarized in Table 3. As shown in
Table 3, the pyrazoles have more average lifetime than that of
pyrazolines. This observation clearly indicates that for the pyrazole
compounds, the emitting state was an ICT. Usually, the ICT state has
longer average lifetime (than LE state) due to the solvation (reor-
ientation of solvent molecules around the probe molecule) in the
excited state [45].
4.2. General procedure for the preparation of 1,3,5-trisubstituted
pyrazoline (3aek)
Appropriate 3-ferrocenyl-1-aryl-2-propen-1-ones (0.5 mmol)
and 4-hydrazino benzene-sulfonamide hydrochloride (0.55 mmol,
1.1 equiv) were taken in a 6 ml ethanol:acetic acid mixture (1:2)
under argon and the contents were heated at 95e100 ꢀC. The
progress of the reaction was monitored by TLC (1:1, pet ether:-
chloroform). After completion of reaction (22 h), the reaction
mixture was cooled and the solvent was evaporated by co-distilled
using ethyl acetate to give a brown solid which was washed several
times with chilled water and dried. Purification was done by
repeated column chromatography on neutral alumina using chlo-
roform to separate any unreacted chalcone compounds and then
with 2% methanol in chloroform to give a yellow color band of
product. Crystallization from chloroform and methanol gave the
analytically pure product in 49e74% yield.
3. Conclusion
A series of new 3-ferroceny-1-(4-sulfamylphenyl)-5-aryl-4,5-
dihydro-1H-pyrazoline
(3ael)
and
3-ferroceny-1-(4-
sulfamylphenyl)-5-aryl-1H-pyrazole (4aej) derivatives were
prepared and characterized by various spectroscopic techniques.
Electrochemical studies of these compounds reveal reversible
oxidation behavior. There was no significant effect of the substit-
uents on the absorption spectra of pyrazolines and pyrazoles. The
substituents and the solvent polarity influenced the fluorescence
properties from pyrazolines to pyrazoles. From fluorescence spectra
it was evident that the pyrazolines (3ael) emitted from LE state
while the pyrazoles (4aej) emitted from ICT state. The fluorescence
decay (lifetime) studies of these compounds further confirmed the
nature of the emitting state of these compounds. It can be
concluded that the photophysical properties of the pyrazoles were
superior to the pyrazolines.
4.2.1. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-phenyl-4,5-dihydro-
1H-pyrazoline (3a)
According to the general procedure, the reaction of 158 mg of
chalcone 2a and 123 mg of 4-hydrazino benzenesulfonamide
hydrochloride furnishes 121 mg (50%) of 3a as red solid. M.p. 196e
197 ꢀC. 1H NMR (500 MHz, DMSO-d6, ppm):
d 3.01 (1H, dd,
3J ¼ 12.2 Hz, 2J ¼ 4.8 Hz, 4-Htrans, pyrazoline), 3.84 (1H, dd,
3J ¼ 12.2 Hz, 2J ¼ 4.8 Hz, 4-Hcis, pyrazoline), 4.04 (5H, s, C5H5), 4.36
(2H, br s, meta-C5H4), 4.53 (1H, s, ortho-C5H4), 4.67 (1H, s, ortho-
C5H4), 5.34e5.40 (1H, br s, pyrazoline), 6.67e6.75 (2H, br s, NH2),
6.94 (2H, d, J ¼ 8.5 Hz, sulfonamide), 7.25e7.30 (3H, m, C6H5), 7.33e
7.37 (2H, m, C6H5), 7.57 (2H, d, J ¼ 8.5 Hz, sulfonamide). 13C NMR
Table 3
Fluorescence decay parametersa of selected compounds in dichloromethane solvent.
(75 MHz, DMSO-d6, ppm): d 44.4, 61.4, 151.4 (pyrazoline), 69.0, 69.3
Comp.
name
s1
s2
savg
c2
(C5H5), 66.6, 67.2 (ortho-C5H4), 69.8, 69.9 (meta-C5H4), 76.2 (ipso-
C5H4), 111.3, 125.6, 127.1, 127.5, 129.0, 132.0, 141.6, 145.9 (aromatic).
FT-IR {KBr,
(CeH)Al, 1590
nas(SO2), 1152 ns(SO2), 1093 ns(CeN), 861
n
(cmꢁ1)}: 3355 and 3251
n
(NH2), 3081
(C]N)Ar, 1392 nb(CeH), 1319
(CeH)Ar, 734 (C]C)oop
n(CeH)Ar, 2927
3a
3c
3g
4a
4c
4g
1.56 (58.5)
1.51 (68.5)
1.41 (71.2)
2.21 (72.5)
1.92 (78.6)
1.36 (66.9)
2.95 (41.5)
2.87 (31.5)
2.89 (28.8)
7.47 (27.2)
5.07 (21.4)
3.95 (33.1)
2.47
2.14
2.11
3.48
3.23
2.88
1.34
1.54
1.66
1.61
1.60
1.55
n
n(C]C)Ar, 1506 n
n
n
,
700 n(C]C)oop, 539 and 477 nas(CpeFeeCp). HR-MS: found, m/z
486.0943 [M þ H]þ, calculated for C25H24O2N3FeS: 486.0933. Anal.
Calculated for C25H23O2N3FeS: C, 61.86; H, 4.78; N, 8.66; S, 6.61.
Found: C, 61.12; H, 4.56; N, 8.52; S, 6.60.
a
The decay parameters are collected by using a laser excitation (lex ¼ 301 ns)
source, lifetimes are expressed in nano-seconds (ns).

Ch.K. Kumar et al. / Journal of Organometallic Chemistry 718 (2012) 64e73
69
4.2.2. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-(2-methoxyphenyl)-
4,5-dihydro-1H-pyrazoline (3b)
H), 1323 nas(SO2), 1233
n
(C5H4), 1154
n
(C]C)Ar, 1092
n
(CeH)Ar, 834
n
(CeH)Ar, 547 and 479 nas(CpeFeeCp). HR-MS: found, m/z 492.0509
According to the general procedure, the reaction of 173 mg of
chalcone 2b and 123 mg of 4-hydrazino benzenesulfonamide
hydrochloride furnishes 147 mg (57%) of 3b as brown solid. M.p.
[M þ H]þ, calculated for C23H22O2N3FeS2: 492.0497. Anal. Calcu-
lated for C23H21O2N3FeS2: C, 56.22; H, 4.31; N, 8.55; S, 13.05. Found:
C, 56.38; H, 4.26; N, 8.41; S, 13.1.
169e170 ꢀC. 1H NMR (500 MHz, DMSO-d6, ppm):
d 2.88 (1H, dd,
3J ¼ 12.0 Hz, 2J ¼ 4.9 Hz, 4-Htrans, pyrazoline), 3.80 (1H, dd,
3J ¼ 12.0 Hz, 2J ¼ 4.9 Hz, 4-Hcis, pyrazoline), 3.99 (3H, s, eOCH3),
4.03 (5H, s, C5H5), 4.34 (2H, br s, meta-C5H4), 4.52 (1H, s, ortho-
C5H4), 4.66 (1H, s, ortho-C5H4), 5.88 (1H, dd, 3J ¼ 11.0 Hz, 2J ¼ 4.9 Hz,
pyrazoline), 6.63e6.69 (2H, br s, NH2), 6.82 (1H, t, J ¼ 7.3 Hz,
aromatic), 6.93 (1H, d, J ¼ 7.3 Hz, aromatic), 7.01 (1H, d, J ¼ 7.3 Hz,
aromatic), 6.88 (2H, d, J ¼ 8.5 Hz, sulfonamide), 7.58 (2H, d,
J ¼ 8.5 Hz, sulfonamide) 7.23 (1H, t, J ¼ 7.3 Hz, aromatic). 13C NMR
4.2.5. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-(2-furan)-4,5-
dihydro-1H-pyrazoline (3e)
According to the general procedure, the reaction of 153 mg of
chalcone 2e and 123 mg of 4-hydrazino benzenesulfonamide
hydrochloride furnishes 122 mg (52%) of 3e as brown powder. M.p.
188e189 ꢀC. 1H NMR (500 MHz, CDCl3, ppm):
d 3.30 (1H, dd,
3J ¼ 11.8 Hz, 2J ¼ 4.8 Hz, 4-Htrans, pyrazoline), 3.80 (1H, dd,
3J ¼ 11.8 Hz, 2J ¼ 4.8 Hz, 4-Hcis, pyrazoline), 4.17 (5H, s, C5H5), 4.40
(2H, d, J ¼ 11.8 Hz, meta-C5H4), 4.55 (1H, s, ortho-C5H4), 4.75 (1H, s,
ortho-C5H4), 4.58 (2H, br s, NH2), 5.36 (1H, dd, 3J ¼ 7.8 Hz,
2J ¼ 4.2 Hz, pyrazoline), 6.23 (1H, s, aromatic), 6.30 (1H, s,
aromatic), 7.10 (2H, d, J ¼ 9.0 Hz, sulfonamide), 7.39 (1H, s,
aromatic), 7.73 (2H, d, J ¼ 9.0 Hz, sulfonamide). 13C NMR (75 MHz,
(75 MHz, DMSO-d6, ppm):
d 43.0, 56.1, 151.0 (pyrazoline), 55.0 (e
OCH3), 68.3 (C5H5), 66.0, 66.6 (ortho-C5H4), 69.3, 69.4 (meta-
C5H4), 75.9 (ipso-C5H4), 110.4, 110.8, 120.0, 125.1, 126.9, 127.8, 131.1,
145.7, 155.5 (aromatic). FT-IR {KBr,
(NH2), 3084 (CeH)Ar, 2947 (CeH)Al, 1590
N)Ar, 1395 nb(CeH), 1318 nas(SO2), 1241 ns(CeO), 1154
n
(cmꢁ1)}: 3366 and 3245
n
n
n
n
(C]C)Ar, 1508
(SO2)s,1097
ns(CeN), 866 n(CeH)Ar, 751 n(CeH)Ar, 481 nas(CpeFeeCp). HR-MS:
n(C]
n
DMSO-d6, ppm):
67.2 (ortho-C5H4), 69.9, 70.1 (meta-C5H4), 76.1 (ipso-C5H4), 111.9,
124.4, 126.1, 126.9, 127.4, 132.8, 145.2, 145.9 (aromatic). FT-IR {KBr,
(cmꢁ1)}: 3349 and 3268
(NH2), 3112 (CeH)Ar, 2932 (CeH)Al, 1598
(C]C)Ar, 1517 (C]N)Ar, 1398 nb(CeH), 1329 nas(SO2), 1159 (C]
C)Ar, 1099 (CeH)Ar, 844 (CeH)Ar, 475 nas(CpeFeeCp). HR-MS:
d 44.4, 57.4, 151.5 (pyrazoline), 68.7 (C5H5), 66.6,
found, m/z 516.1047 [M þ H]þ, calculated for C26H26O3N3FeS:
516.1038. Anal. Calculated for C26H25O3N3FeS: C, 60.59; H, 4.89; N,
8.15; S, 6.22. Found: C, 60.92; H, 4.75; N, 8.13; S, 6.19.
n
n
n
n
n
n
n
n
n
4.2.3. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-(4-methoxyphenyl)-
4,5-dihydro-1H-pyrazoline (3c)
found, m/z 476.0809 [M þ H]þ, calculated for C23H22O3N3FeS:
476.0847. Anal. Calculated for C23H21O3N3FeS: C, 58.12; H, 4.45; N,
8.84; S, 6.75. Found: C, 58.38; H, 4.36; N, 8.91; S, 6.83.
According to the general procedure, the reaction of 173 mg of
chalcone 2c and 123 mg of 4-hydrazino benzenesulfonamide
hydrochloride furnishes 137 mg (53%) of 3c as pale brown solid.
4.2.6. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-(3-bromophenyl)-
4,5-dihydro-1H-pyrazoline (3f)
M.p. 153e154 ꢀC. 1H NMR (500 MHz, DMSO-d6, ppm):
d 3.80 (1H,
dd, 3J ¼ 12.0 Hz, 2J ¼ 5.0 Hz, 4-Hcis, pyrazoline), 3.78 (3H, s, eOCH3),
4.11 (5H, s, C5H5), 4.39 (2H, d, J ¼ 7.0 Hz, meta-C5H4), 4.56 (1H, s,
ortho-C5H4), 4.70 (1H, s, ortho-C5H4), 5.28 (1H, dd, 3J ¼ 12.0 Hz,
2J ¼ 5.0 Hz, pyrazoline), 6.38e6.50 (2H, br s, NH2), 6.88 (2H, d,
J ¼ 9.0 Hz, sulfonamide), 7.63 (2H, d, J ¼ 9.0 Hz, sulfonamide), 6.97
(2H, d, J ¼ 8.0 Hz, aromatic), 7.19 (2H, d, J ¼ 8.0 Hz, aromatic). 13C
According to the general procedure, the reaction of 197 mg of
chalcone 2f and 123 mg of 4-hydrazino benzenesulfonamide
hydrochloride to furnishes 154 mg (55%) 3f as orange powder. M.p.
137e138 ꢀC. 1H NMR (500 MHz, DMSO-d6, ppm):
d 3.04 (1H, dd,
3J ¼ 18.0 Hz, 2J ¼ 5.0 Hz, 4-Htrans, pyrazoline), 3.85 (1H, dd,
3J ¼ 18.0 Hz, 2J ¼ 5.0 Hz, 4-Hcis, pyrazoline), 4.11 (5H, s, C5H5), 4.41
(2H, d, J ¼ 7.0 Hz, meta-C5H4), 4.56 (1H, s, ortho-C5H4), 4.72 (1H, s,
ortho-C5H4), 5.32e5.38 (1H, m, pyrazoline), 6.60e6.67 (2H, br s,
NH2), 6.97 (2H, d, J ¼ 8.5 Hz, sulfonamide), 7.66 (2H, d, J ¼ 8.5 Hz,
sulfonamide), 7.25e7.31 (2H, m, aromatic), 7.40e7.44 (2H, m,
NMR (75 MHz, DMSO-d6, ppm): d 44.0, 60.9, 151.3 (pyrazoline) 54.9
(eOCH3), 68.3 (C5H5), 66.5, 67.1 (ortho-C5H4), 69.7, 69.8 (meta-
C5H4), 76.3 (ipso-C5H4), 111.3, 114.2, 126.8, 127.0, 131.9, 133.5, 145.8,
158.4 (aromatic). FT-IR {KBr,
(CeH)Ar, 2922 (CeH)Al, 1592
H), 1331 nas(SO2), 1245 ns(CeO), 1152 ns(SO2), 1094 ns(CeN), 820
n
(cmꢁ1)}: 3364 and 3287
n
(NH2), 3013
n
n
n
(C]C)Ar, 1512
n
(C]N)Ar, 1401 nb(Ce
aromatic). 13C NMR (75 MHz, DMSO-d6, ppm):
d 44.2, 60.7, 151.5
(pyrazoline), 66.9 (C5H5), 66.5, 67.2 (ortho-C5H4), 69.0, 69.7 (meta-
C5H4), 75.9 (ipso-C5H4), 111.3, 122.0, 124.6, 127.1, 128.3, 130.4, 131.2,
n
(CeH)Ar, 748 n(CeH)Ar, 538 and 489 nas(CpeFeeCp). HR-MS: found,
m/z 516.1053 [M þ H]þ, calculated for C26H26O3N3FeS: 516.1038.
Anal. Calculated for C26H25O3N3FeS: C, 60.59; H, 4.89; N, 8.15; S,
6.22. Found: C, 60.65; H, 4.82; N, 8.23; S, 6.35.
132.3, 144.3, 145.6 (aromatic). FT-IR {KBr,
(NH2), 3034 (CeH)Ar, 2947 (CeH)Al, 1591
N)Ar, 1397 nb(CeH), 1316 nas(SO2), 1229 (C5H4), 1154 ns(SO2), 1096
(C-Br), 1000 (CeBr), 826 (CeH)Ar, 742 (CeH)Ar, 539 and 483
n
(cmꢁ1)}: 3356 and 3254
n
n
n
n(C]C)Ar, 1510 n(C]
n
n
n
n
n
4.2.4. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-(2-thiophene)-4,5-
dihydro-1H-pyrazoline (3d)
nas(Cp-Fe-Cp). HR-MS: found, m/z 564.0057 [M þ H]þ, calculated for
C25H23O2N3BrFeS: 564.0038. Anal. Calculated for C25H22O2N3BrFeS:
C, 61.99; H, 4.58; N, 8.68; S, 6.62. Found: C, 62.11; H, 4.49; N, 8.76;
S, 6.72.
According to the general procedure, the reaction of 161 mg of
chalcone 2d and 123 mg of 4-hydrazino benzenesulfonamide
hydrochloride furnishes 126 mg (51%) of 3d as brown powder. M.p.
222e223 ꢀC. 1H NMR (500 MHz, DMSO-d6, ppm):
d
3.15 (1H, d,
4.2.7. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-(4-bromophenyl)-
4,5-dihydro-1H-pyrazoline (3g)
J ¼ 16.0 Hz, 4-Htrans, pyrazoline), 3.85 (1H, dd, 3J ¼ 12.0 Hz,
2J ¼ 5.0 Hz, 4-Hcis, pyrazoline), 4.16 (5H, s, C5H5), 4.43 (2H, s, meta-
C5H4), 4.65 (1H, s, ortho-C5H4), 4.74 (1H, s, ortho-C5H4), 5.80e5.89
(1H, dd, J ¼ 8.0 Hz, pyrazoline), 6.96 (1H, s, aromatic), 6.98e7.01
(2H, br s, NH2), 7.05 (2H, d, J ¼ 8.0 Hz, sulfonamide), 7.11 (1H, s,
aromatic), 7.39 (1H, s, aromatic), 7.57 (2H, d, J ¼ 8.0 Hz, sulfon-
According to the general procedure, the reaction of 197 mg of
chalcone 2g and 123 mg of 4-hydrazino benzenesulfonamide
hydrochloride furnishes 138 mg (49%) of 3g as orange powder. M.p.
141e142 ꢀC. 1H NMR (500 MHz, DMSO-d6, ppm):
d 2.98 (1H, dd,
3J ¼ 12.8 Hz, 2J ¼ 9.0 Hz, 4-Htrans, pyrazoline), 3.77e3.90 (1H, dd,
3J ¼ 12.8 Hz, 2J ¼ 9.0 Hz, 4-Hcis, pyrazoline), 4.09 (5H, s, C5H5), 4.36
(2H, s, meta-C5H4), 4.54 (1H, s, ortho-C5H4), 4.65 (1H, s, ortho-
C5H4), 5.31e5.40 (1H, m, pyrazoline), 6.61e6.70 (2H, br s, NH2), 6.93
(2H, d, J ¼ 8.3 Hz, sulfonamide), 7.60 (2H, d, J ¼ 8.3 Hz, sulfon-
amide), 7.21 (2H, d, J ¼ 8.2 Hz, aromatic), 7.49 (2H, d, J ¼ 8.2 Hz,
amide). 13C NMR (75 MHz, DMSO-d6, ppm):
d 44.5, 57.5, 151.4
(pyrazoline), 68.9 (C5H5), 66.4, 67.0 (ortho-C5H4), 69.6, 69.7 (meta-
C5H4), 75.9 (ipso-C5H4), 111.6, 124.9, 125.2, 126.2, 126.8, 132.4, 145.0,
145.9 (aromatic). FT-IR {KBr, (NH2), 3102
n
(cmꢁ1)}: 3355 and 3257
n
n
(CeH)Ar, 2926 (CeH)Al, 1592 n(C]C)Ar, 1507 n(C]N)Ar, 1390 nb(Ce
n

70
Ch.K. Kumar et al. / Journal of Organometallic Chemistry 718 (2012) 64e73
aromatic). 13C NMR (75 MHz, DMSO-d6, ppm):
d
44.1, 60.8, 151.4
3J ¼ 12.0 Hz, 2J ¼ 5.0 Hz, 4-Htrans, pyrazoline), 3.90 (1H, dd,
3J ¼ 12.0 Hz, 2J ¼ 5.0 Hz, 4-Hcis, pyrazoline), 4.04 (5H, s, C5H5), 4.36
(2H, d, J ¼ 9.0 Hz, meta-C5H4), 4.54 (1H, s, ortho-C5H4), 4.69 (1H, s,
ortho-C5H4), 5.52 (1H, dd, 3J ¼ 12.0 Hz, 2J ¼ 5 Hz, pyrazoline), 6.56
(2H, s, NH2), 7.00 (2H, d, J ¼ 9.0 Hz, sulfonamide), 7.57 (2H, d,
J ¼ 9.0 Hz, sulfonamide), 7.39 (1H, d, J ¼ 8.0 Hz, aromatic), 7.43e7.48
(2H, m, aromatic), 7.74 (1H, s, aromatic), 7.78e7.82 (2H, br s,
aromatic), 7.86 (1H, d, J ¼ 8.0 Hz, aromatic). 13C NMR (75 MHz,
(pyrazoline), 68.9 (C5H5), 66.5, 67.0 (ortho-C5H4), 69.7, 69.8 (meta-
C5H4), 75.9 (ipso-C5H4), 111.3, 120.4, 127.0, 127.8, 131.8, 132.1, 140.9,
145.7 (aromatic). FT-IR {KBr,
(CeH)Ar, 2920 (CeH)Al, 1590
H), 1314 nas(SO2), 1231 (C5H4), 1156 ns(SO2), 822
n
(cmꢁ1)}: 3362 and 3258
n(C]C)Ar, 1508 n
n
(NH2), 3021
(C]N)Ar, 1400 nb(Ce
(CeH)Ar, 541 and
n
n
n
n
492 nas(CpeFeeCp). HR-MS: found, m/z 564.0034 [M þ H]þ,
calculated for C25H23O2N3BrFeS: 564.0038. Anal. Calculated for
C25H22O2N3BrFeS: C, 61.99; H, 4.58; N, 8.68; S, 6.62. Found: C, 61.99;
H, 4.62; N, 8.72; S, 6.52.
DMSO-d6, ppm):
d 44.3, 61.7, 151.4 (pyrazoline) 69.0 (C5H5), 66.6,
67.2 (ortho-C5H4), 69.8, 69.9 (meta-C5H4), 76.2 (ipso-C5H4), 111.3,
123.6, 124.1, 126.0, 126.4, 127.1, 127.5, 217.6, 129.0, 132.0, 132.3,
4.2.8. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-(2-chlorophenyl)-
4,5-dihydro-1H-pyrazoline (3h)
139.2, 145.9 (aromatic). FT-IR {KBr,
(NH2), 3056 (CeH)Ar, 2923 (CeH)Al, 1664
C)Ar, 1510 (C]N)Ar, 1398 nb(CeH), 1317 nas(SO2), 1153 ns(SO2), 1097
(CeH)Ar, 820 (CeH)Ar, 743 (CeH)Ar, 537 and 473 nas(CpeFeeCp).
HR-MS: found, m/z 536.1099 [M
H]þ, calculated for
n
(cmꢁ1)}: 3338 and 3245
n
n
n
n(C]C)Ar, 1591 n(C]
According to the general procedure, the reaction of 175 mg of
chalcone 2h and 123 mg of 4-hydrazino benzenesulfonamide
hydrochloride furnishes 146 mg (56%) of 3h as orange solid. M.p.
n
n
n
n
þ
216e217 ꢀC. 1H NMR (500 MHz, DMSO-d6, ppm):
d
2.98 (1H, dd,
C29H26O2N3FeS: 536.1089. Anal. Calculated for C29H25O2N3FeS: C,
65.05; H, 4.71; N, 7.85; S, 5.99. Found: C, 65.12; H, 4.86; N, 7.94; S,
6.09.
3J ¼ 12.0 Hz, 2J ¼ 5.0 Hz, 4-Htrans, pyrazoline), 3.91 (1H, dd,
3J ¼ 12.0 Hz, 2J ¼ 5.0 Hz, 4-Hcis, pyrazoline), 4.08 (5H, s, C5H5), 4.38e
4.42 (2H, br s, meta-C5H4), 4.57 (1H, s, ortho-C5H4), 4.70 (1H, s,
ortho-C5H4), 5.66 (1H, dd, 3J ¼ 12.0 Hz, 2J ¼ 5.0 Hz, pyrazoline),
6.55e6.67 (2H, br s, NH2), 6.90 (2H, d, J ¼ 9.0 Hz, sulfonamide), 7.66
(2H,d, J ¼ 9.0 Hz, sulfonamide), 7.08 (1H, d, J ¼ 7.0 Hz, aromatic),
7.21 (1H, t, J ¼ 7.0 Hz, aromatic), 7.28 (1H, t, J ¼ 7.0 Hz, aromatic),
7.50 (1H, d, J ¼ 7.0 Hz, aromatic). 13C NMR (75 MHz, DMSO-d6,
4.2.11. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-(3-nitrophenyl)-4,5-
dihydro-1H-pyrazoline (3k)
According to the general procedure, the reaction of 181 mg of
chalcone 2k and 123 mg of 4-hydrazino benzenesulfonamide
hydrochloride furnishes 129 mg (49%) of 3k as pale brown solid.
ppm):
d
43.0, 59.1, 151.7 (pyrazoline), 69.0 (C5H5), 66.6, 67.2 (ortho-
M.p. 181e182 ꢀC. 1H NMR (500 MHz, DMSO-d6, ppm):
d 3.0 (1H, d,
C5H4), 69.8, 69.9 (meta-C5H4), 75.8 (ipso-C5H4), 111.1, 126.6, 127.2,
127.2, 127.7, 129.7, 129.4, 130.1, 131.1, 132.3, 145.5 (aromatic). FT-IR
J ¼ 6.0 Hz, 4-Htrans, pyrazoline), 3.92 (1H, dd, 3J ¼ 12.0 Hz,
2J ¼ 6.0 Hz, 4-Hcis, pyrazoline), 4.08 (5H, s, C5H5), 4.36e4.39 (2H, br
s, meta-C5H4), 4.56 (1H, s, ortho-C5H4), 4.67 (1H, s, ortho-C5H4),
5.56e5.63 (1H, m, pyrazoline), 6.69e6.74 (2H, br s, NH2), 6.96 (2H,
d, J ¼ 8.0 Hz, sulfonamide), 7.60e7.65 (3H, m, aromatic), 7.69 (1H, d,
J ¼ 7.0 Hz, aromatic), 8.14 (1H, d, J ¼ 8.0 Hz, aromatic), 8.18 (1H, s,
{KBr,
H)Al, 1592
1154 ns(SO2), 1094 ns(CeN), 821
n
(cmꢁ1)}: 3356 and 3262
n
(NH2), 3054
(C]N)Ar, 1400 nb(CeH), 1338 nas(SO2),
(CeH)Ar, 751 (CeH)Ar, 542 and
n(CeH)Ar, 2930 n(Ce
n
(C]C)Ar, 1513 n
n
n
492 nas(CpeFeeCp). HR-MS: found, m/z 520.0540 [M þ H]þ,
calculated for C25H23O2N3ClFeS: 520.0543. Anal. Calculated for
C25H22O2N3ClFeS: C, 57.76; H, 4.27; N, 8.08; S, 6.17. Found: C, 58.09;
H, 4.15; N, 8.13; S, 6.25.
aromatic). 13C NMR (75 MHz, DMSO-d6, ppm):
d 44.2, 60.8, 151.5
(pyrazoline), 69.0 (C5H5), 66.5, 67.2 (ortho-C5H4), 69.7, 69.9 (meta-
C5H4), 76.0 (ipso-C5H4), 111.3, 122.0, 124.7, 128.3, 130.4, 131.2, 132.3,
144.4, 145.6 (aromatic). FT-IR {KBr,
(NH2), 3071 (CeH)Ar, 3053 (CeH)Ar, 2919
C)Ar, 1524 nas(NO2), 1509 (C]N)Ar, 1401 nb(CeH), 1357 ns(NO2),
1328 nas(SO2), 1239 (C5H4), 1156 ns(SO2), 839 (CeH)Ar, 741 (Ce
n
(cmꢁ1)}: 3362 and 3253
4.2.9. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-(4-chlorophenyl)-
4,5-dihydro-1H-pyrazoline (3i)
n
n
n
n(CeH)Al, 1590 n(C]
n
According to the general procedure, the reaction of 175 mg of
chalcone 2i and 123 mg of 4-hydrazino benzenesulfonamide
hydrochloride furnishes 135 mg (52%) of 3i as brown solid. M.p.
n
n
n
H)Ar, 542 and 485 nas(CpeFeeCp). HR-MS: found, m/z 531.0793
[M þ H]þ, calculated for C25H23O4N4FeS: 531.0783. Anal. Calculated
for C25H22O4N4FeS: C, 56.61; H, 4.18; N, 10.56; S, 6.05. Found: C,
56.82; H, 4.21; N, 10.79; S, 5.99.
111e112 ꢀC. 1H NMR (500 MHz, CDCl3, ppm):
d 2.99 (1H, dd,
3J ¼ 12.0 Hz, 2J ¼ 7.0 Hz, 4-Htrans, pyrazoline), 4.07 (1H, dd,
3J ¼ 12.0 Hz, 2J ¼ 4.0 Hz, 4-Hcis, pyrazoline), 4.07 (5H, s, C5H5), 4.35
(2H, d, J ¼ 8.0 Hz, meta-C5H4), 4.50 (1H, s, ortho-C5H4), 4.63 (1H, s,
ortho-C5H4), 5.21 (1H, dd, 3J ¼ 12.0 Hz, 2J ¼ 7.0 Hz, pyrazoline), 6.93
(2H, d, J ¼ 9.0 Hz, sulfonamide), 7.33 (2H, d, J ¼ 9.0 Hz, sulfon-
amide), 7.19 (2H, d, J ¼ 8.0 Hz, aromatic), 7.65 (2H, d, J ¼ 8.0 Hz,
4.2.12. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-(4-nitrophenyl)-4,5-
dihydro-1H-pyrazoline (3l)
According to the general procedure, the reaction of 181 mg of
chalcone 2l and 123 mg of 4-hydrazino benzenesulfonamide
hydrochloride furnishes 133 mg (50%) of 3l as orange red solid. M.p.
aromatic). 13C NMR (75 MHz, CDCl3þDMSO-d6, ppm):
d 44.3, 61.3,
150.3 (pyrazoline), 68.6, 68.9 (C5H5), 66.0, 66.6 (ortho-C5H4), 69.3,
69.4 (meta-C5H4), 75.9 (ipso-C5H4), 111.1, 113.9, 126.2, 126.7, 131.3,
134e135 ꢀC. 1H NMR (500 MHz, DMSO-d6, ppm):
d 3.91 (1H, dd,
3J ¼ 11.8 Hz, 2J ¼ 4.5 Hz, 4-Hcis, pyrazoline), 4.08 (5H, s, C5H5), 4.37
(2H, s, meta-C5H4), 4.56 (1H, s, ortho-C5H4), 4.63 (1H, s, ortho-C5H4),
5.44e5.54 (1H, m, pyrazoline), 6.52e6.66 (2H, br s, NH2), 6.92 (2H,
d, J ¼ 8.2 Hz, sulfonamide), 7.62 (2H, d, J ¼ 8.0 Hz, sulfonamide), 7.53
(2H, d, J ¼ 9.1 Hz, aromatic), 8.22 (2H, d, J ¼ 9.1 Hz, aromatic). 13C
132.9, 145.5, 158.3 (aromatic). FT-IR{ KBr,
(NH2), 3069 (CeH)Ar, 2919 (CeH)Al, 1592
N)Ar, 1397 nb(CeH), 1349 nas(SO2), 1239 (C5H4), 1158 ns(SO2), 858
(CeH)Ar, 839 n(CeH)Ar, 542 and 485 nas(Cp-Fe-Cp). HR-MS: found,
n
(cmꢁ1)}: 3354 and 3249
n
n
n
n(C]C)Ar, 1521 n(C]
n
n
m/z 520.0548 [M þ H]þ, calculated for C25H23O2N3ClFeS: 520.0543.
Anal. Calculated for C25H22O2N3ClFeS: C, 57.76; H, 4.27; N, 8.08; S,
6.17. Found: C, 57.53; H, 4.35; N, 8.19; S, 6.29.
NMR (75 MHz, DMSO-d6, ppm): d 44.0, 60.8, 151.5 (pyrazoline) 69.0
(C5H5), 66.7, 67.1 (ortho-C5H4), 69.9, 75.7 (meta-C5H4), 79.0 (ipso-
C5H4), 111.4, 124.3, 127.2, 132.5, 145.6, 146.8, 149.1 (aromatic). FT-IR
{KBr,
H)Al, 1592
1328 nas(SO2), 1241
n
(cmꢁ1)}: 3358 and 3249
n
(NH2), 3053
n
(CeH)Ar, 2919
n
(Ce
4.2.10. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-(2-napthyl)-4,5-
dihydro-1H-pyrazoline (3j)
n
(C]C)Ar, 1512 nas(NO2), 1397 nb(CeH), 1349 ns(NO2),
n(C5H4), 1158 ns(SO2), 858 n(CeH)Ar, 839
n
(Ce
According to the general procedure, the reaction of 183 mg of
chalcone 2j and 123 mg of 4-hydrazino benzenesulfonamide
hydrochloride furnishes 198 mg (74%) of 3j as brown solid. M.p.
H)Ar, 542 and 485 nas(CpeFeeCp). HR-MS: found, m/z 531.0797
[M þ H]þ, calculated for C25H23O4N4FeS: 531.0783. Anal. Calculated
for C25H22O4N4FeS: C, 56.61; H, 4.18; N, 10.56; S, 6.05. Found: C,
56.55; H, 4.16; N, 10.70; S, 6.12.
124e125 ꢀC. 1H NMR (500 MHz, DMSO-d6, ppm):
d 3.10 (1H, dd,

Ch.K. Kumar et al. / Journal of Organometallic Chemistry 718 (2012) 64e73
71
4.3. General procedure for the preparation of 1,3,5-trisubstituted
n
(NH2), 1592
n(C]C)Ar, 1515
n
(C]N)Ar, 1411 nb(C-H), 1336 nas(SO2),
pyrazoles (4aej)
1249 ns(CeO), 1154 ns(SO2), 1099 ns(CeN), 538 and 489 nas(CpeFee
Cp). HR-MS: found, m/z 514.0873 [M þ H]þ, calculated for
C26H24O3N3FeS: 514.0888. Anal. Calculated for C26H23O3N3FeS: C,
60.83; H, 4.52; N, 8.18; S, 6.25. Found: C, 60.91; H, 4.49; N, 8.23; S,
6.21.
DDQ (0.3 mmol, 1.2 equiv) in 10 ml of dry dichloromethane is
added drop wise to
a solution of appropriate pyrazoline
compounds (3aej, 0.25 mmol) dissolved in 20 ml of dry dichloro-
methane and stirred at room temperature. The progress of the
reaction was monitored by TLC (1:1, pet ether:chloroform). After
the completion of reaction (8e9 h), the reaction mixture was
passed through a pad of neutral alumina using 2% methanol in
chloroform as eluent to give a yellow color band of product.
Crystallization from dichloromethane gave the analytically pure
product in 49e69% yield.
4.3.4. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-(2-thiophene)-1H-
pyrazoline (4d)
According to the general procedure, the reaction of 122 mg of
pyrazoline 3d and 68 mg of DDQ furnishes 71 mg (59%) of 4d as
yellow powder. M.p. decomposes at 220e221 ꢀC. 1H NMR
(300 MHz, CDCl3, ppm): d 4.16 (5H, s, C5H5), 4.34 (2H, s, meta-C5H4),
4.74 (2H, s, ortho-C5H4), 4.88 (2H, br s, NH2), 6.61 (1H, s, pyrazole),
6.96 (1H, s, aromatic), 7.45 (2H, d, J ¼ 8.0 Hz, sulfonamide), 7.11 (1H,
s, aromatic), 7.39 (1H, s, aromatic), 7.87 (2H, d, J ¼ 8.0 Hz, sulfon-
4.3.1. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-phenyl-1H-
pyrazoline (4a)
According to the general procedure, the reaction of 122 mg of
pyrazoline (3a) and 68 mg of DDQ furnishes 73 mg (61%) of 4a as
red solid. M.p. decomposes at 181e182 ꢀC. 1H NMR (300 MHz,
amide). 13C NMR (75 MHz, DMSO-d6, ppm):
d 66.3 (ortho-C5H4),
68.4 (meta-C5H4), 68.5 (C5H5), 76.8 (ipso-C5H4), 105.7, 109.4, 111.3,
124.2, 126.5, 133.7, 141.7, 142.8, 151.5 (aromatic). FT-IR {KBr,
(cmꢁ1)}: 3349 and 3262
(NH2), 1592 (C]C)Ar, 1507 (C]N)Ar,
n
CDCl3, ppm):
d
4.16 (5H, s, C5H5), 4.36 (2H, s, meta-C5H4), 4.78 (2H,
n
n
n
s, ortho-C5H4), 4.92 (2H, br s, NH2), 6.57 (1H, s, pyrazole), 7.29 (2H,
1323 nas(SO2), 1153 ns(SO2), 479 nas(CpeFeeCp). HR-MS: found, m/z
490.0262 [M þ H]þ, calculated for C23H20O2N3FeS2: 490.0277. Anal.
Calculated for C23H19O2N3FeS2: C, 56.45; H, 3.91; N, 8.59; S, 13.10.
Found: C, 56.50; H, 3.87; N, 8.62; S, 13.03.
m, C6H5), 7.39 (3H, m, C6H5), 7.47 (2H, d, J ¼ 8.5 Hz, sulfonamide),
7.85 (2H, d,
J
¼
8.5 Hz, sulfonamide). 13C NMR (75 MHz,
CDCl3þDMSO-d6, ppm):
(C5H5), 106.4, 123.8, 126.9, 128.1, 129.6, 141.5, 141.9, 143.2, 151.6
(Aromatic). FT-IR {KBr, (NH2), 1590 (C]
(cmꢁ1)}: 3359 and 3242
C)Ar, 1506 (C]N)Ar, 1319 nas(SO2), 1152 ns(SO2), 485 nas(CpeFeeCp).
HR-MS: found, m/z 484.0756 [M
H]þ, calculated for
d 66.2 (ortho-C5H4), 68.1 (meta-C5H4), 68.9
n
n
n
4.3.5. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-(2-furan)-1H-
pyrazoline (4e)
According to the general procedure, the reaction of 120 mg of
pyrazoline 3e and 68 mg of DDQ furnishes 76 mg (63%) of 4e as
yellow solid. M.p. decomposes at 197e198 ꢀC. 1H NMR (300 MHz,
n
þ
C25H22O2N3FeS: 484.0776. Anal. Calculated for C25H21O2N3FeS: C,
62.12; H, 4.38; N, 8.69; S, 6.63. Found: C, 62.40; H, 4.31; N, 8.71; S,
6.72.
CDCl3, ppm):
d 4.12 (5H, s, C5H5), 4.32 (2H, br s, meta-C5H4), 4.74
(2H, br s, ortho-C5H4), 6.72 (1H, s, pyrazole), 6.31 (1H, s, aromatic),
6.45 (1H, s, aromatic), 6.65 (1H, s, aromatic), 6.85 (2H, s, NH2), 7.56
(2H, d, J ¼ 8.5 Hz, sulfonamide), 7.98 (2H, d, J ¼ 8.5 Hz, sulfon-
4.3.2. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-(2-methoxyphenyl)-
1H-pyrazoline (4b)
According to the general procedure, the reaction of 129 mg of
pyrazoline (3b) and 68 mg of DDQ furnishes 72 mg (56%) of 4b as
brown solid. M.p. 162e163 ꢀC. 1H NMR (300 MHz, CDCl3, ppm):
amide). 13C NMR (75 MHz, DMSO-d6 þ CDCl3, ppm):
d 66.1 (ortho-
C5H4), 68.2 (meta-C5H4), 68.9 (C5H5), 76.7 (ipso-C5H4), 105.3, 109.5,
111.0, 124.0, 126.3, 133.9, 141.9, 142.9, 151.6 (aromatic). FT-IR {KBr,
n
d
3.40 (3H, s, eOCH3), 4.20 (5H, s, C5H5), 4.39 (2H, s, meta-C5H4),
(cmꢁ1)}: 3355 and 3248
n
(NH2), 1598 (C]C)Ar, 1517 (C]N)Ar, 1319
n
n
4.79e4.91 (4H, br s, ortho-C5H4 and NH2), 6.50 (1H, s, pyrazole),
6.85 (1H, d, J ¼ 8.3 Hz, aromatic), 7.05 (1H, d, J ¼ 7.6 Hz, aromatic),
7.36 (2H, d, J ¼ 7.6 Hz, aromatic), 7.42 (2H, d, J ¼ 9.0 Hz, sulfon-
amide), 7.80 (2H, d, J ¼ 9.0 Hz, sulfonamide). 13C NMR (75 MHz,
nas(SO2), 1149 ns(SO2), 485 nas(CpeFeeCp). HR-MS: found, m/z
474.0496 [M þ H]þ, calculated for C23H20O3N3FeS: 474.0502. Anal.
Calculated for C23H19O3N3FeS: C, 58.36; H, 4.05; N, 8.88; S, 6.77.
Found: C, 58.50; H, 4.17; N, 8.82; S, 6.79.
CDCl3 þ DMSO-d6, ppm):
d 54.4 (eOCH3), 66.2 (ortho-C5H4), 68.1
(meta-C5H4), 68.9 (C5H5), 107.1, 110.9, 119.0, 120.3, 122.0, 125.9,
130.2, 130.4, 140.1, 140.8, 142.9, 151.2, 155.6 (aromatic). FT-IR {KBr,
(cmꢁ1)}: 3358 and 3239
(NH2), 1590 (C]C)Ar, 1508
1328 nas(SO2), 1251 ns(CeO), 1159 (SO2)s,1099 ns(CeN), 871
4.3.6. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-(3-bromophenyl)-
1H-pyrazoline (4f)
n
n
n
n
(C]N)Ar
,
According to the general procedure, the reaction of 141 mg of
pyrazoline 3f and 68 mg of DDQ furnishes 83 mg (59%) of 4f as
n
n
(Ce
H)Ar, 488 nas(CpeFeeCp). HR-MS: found, m/z 514.0876 [M þ H]þ,
calculated for C26H24O3N3FeS: 514.0882. Anal. Calculated for
C26H23O3N3FeS: C, 60.83; H, 4.52; N, 8.18; S, 6.25. Found: C, 60.79;
H, 4.58; N, 8.12; S, 6.19.
brown solid. M.p. 97e98 ꢀC. 1H NMR (300 MHz, CDCl3, ppm):
d 4.14
(5H, s, C5H5), 4.35 (2H, s, meta-C5H4), 4.75 (2H, s, ortho-C5H4), 4.8
(2H, br s, NH2), 6.57 (1H, s, pyrazole), 7.10e7.24 (2H, m, aromatic),
7.48 (2H, d, J ¼ 9.0 Hz, sulfonamide), 7.50e7.56 (2H, m, aromatic),
7.90 (2H, d, J ¼ 9.0 Hz, sulfonamide). 13C NMR (75 MHz, DMSO-
4.3.3. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-(4-methoxyphenyl)-
1H-pyrazoline (4c)
According to the general procedure, the reaction of 129 mg of
pyrazoline 3c and 68 mg of DDQ furnishes 89 mg (69%) of 4c as pale
brown solid. M.p. 100e101 ꢀC. 1H NMR (300 MHz, CDCl3, ppm):
d6 þ CDCl3, ppm):
d 66.2 (ortho-C5H4), 68.2 (meta-C5H4), 68.9
(C5H5), 106.8, 121.9, 123.8, 126.4, 126.9, 129.7, 130.7, 130.9, 131.2,
141.5, 141.6, 142.0, 151.8 (aromatic). FT-IR {KBr,
(cmꢁ1)}: 3349 and
3242 (NH2), 1591 (C]C)Ar, 1510 (C]N)Ar, 1316 nas(SO2), 1154
ns(SO2), 1101
n
n
n
n
n
(C-Br), 487 nas(CpeFeeCp). HR-MS: found, m/z
d
3.85 (3H, s, eOCH3), 4.14 (5H, s, C5H5), 4.33 (2H, t, J ¼ 2.3 Hz, meta-
561.9866 [M þ H]þ, calculated for C25H21O2N3BrFeS: 561.9881.
Anal. Calculated for C25H20O2N3BrFeS: C, 53.40; H, 3.59; N, 7.47; S,
5.70. Found: C, 53.49; H, 3.64; N, 7.39; S, 5.62.
C5H4), 4.74 (2H, t, J ¼ 2.3 Hz, ortho-C5H4), 4.82 (2H, br s, NH2), 6.52
(1H, s, pyrazole), 6.90 (2H, d, J ¼ 8.3 Hz, aromatic), 7.20 (2H, d,
J ¼ 8.3 Hz, aromatic), 7.50 (2H, d, J ¼ 9.0 Hz, sulfonamide), 7.87 (2H,
d, J ¼ 9.0 Hz, sulfonamide). 13C NMR (75 MHz, DMSO-d6 þ CDCl3,
4.3.7. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-(4-bromophenyl)-
1H-pyrazoline (4g)
ppm):
d 55.3 (eOCH3), 66.9 (ortho-C5H4), 68.9 (meta-C5H4), 69.5
(C5H5), 106.8, 114.2, 122.3, 124.7, 127.2, 130.6, 139.7, 143.3, 144.0,
According to the general procedure, the reaction of 120 mg of
pyrazoline 3g and 68 mg of DDQ furnishes 82 mg (58%) of 4g as
152.8, 159.9 (aromatic). FT-IR {KBr,
n
(cmꢁ1)}: 3359 and 3292

72
Ch.K. Kumar et al. / Journal of Organometallic Chemistry 718 (2012) 64e73
brown solid. M.p. 108e109 ꢀC. 1H NMR (300 MHz, CDCl3 þ DMSO-
found, m/z 534.0916 [M þ H]þ, calculated for C29H24O2N3FeS:
534.0933. Anal. Calculated for C29H23O2N3FeS: C, 65.30; H, 4.35; N,
7.88; S, 6.01. Found: C, 65.33; H, 4.38; N, 7.86; S, 5.17.
d6, ppm): d 4.17 (5H, s, C5H5), 4.32 (2H, s, meta-C5H4), 4.74 (2H, br s,
ortho-C5H4), 6.75 (2H, s, NH2), 6.59 (1H, s, pyrazole), 7.18 (2H, d,
J ¼ 8.0 Hz, aromatic), 7.43 (2H, d, J ¼ 8.0 Hz, aromatic), 7.51 (2H, d,
J ¼ 9.0 Hz, sulfonamide), 7.90 (2H, d, J ¼ 9.0 Hz, sulfonamide). 13C
4.4. Single crystal X-ray diffraction studies
NMR (75 MHz, CDCl3 þ DMSO-d6, ppm):
d 66.2 (ortho-C5H4), 68.2
(meta-C5H4), 68.9 (C5H5), 106.5, 122.0, 123.9, 126.3, 126.9, 128.6,
131.3, 141.5, 141.9, 142.0, 151.7 (aromatic). FT-IR {KBr,
(cmꢁ1)}:
3358 and 3262 (NH2),1590 (C]C)Ar,1508 (C]N)Ar,1316 nas(SO2),
X-ray data for the compound was collected at room temperature
using a Bruker Smart Apex CCD diffractometer with graphite
n
n
n
n
ꢀ
monochromated MoK
a
radiation (
l
¼ 0.71073 A) with
u-scan
1161 ns(SO2), 498 nas(CpeFeeCp). HR-MS: found, m/z 561.9871
[M þ H]þ, calculated for C25H21O2N3BrFeS: 561.9881. Anal. Calcu-
lated for C25H20O2N3BrFeS: C, 53.40; H, 3.59; N, 7.47; S, 5.70. Found:
C, 53.36; H, 3.57; N, 7.51; S, 5.72.
method [46]. Preliminary lattice parameters and orientation
matrices were obtained from four sets of frames. Unit cell dimen-
sions were determined using 9132 reflections in the range of
2.37 <
q
< 27.92ꢀ for 3a. Integration and scaling of intensity data
were accomplished using SAINT program. The structure was solved
by direct methods using SHELXS97 [47] and refinement was carried
out by full-matrix least-squares technique using SHELXL97 [47].
Anisotropic displacement parameters were included for all non-
hydrogen atoms. The hydrogen atoms attached to nitrogen atom
were located in a difference density map and refined isotropically.
All other H atoms were positioned geometrically and treated as
4.3.8. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-(2-chlorophenyl)-
1H-pyrazoline (4h)
According to the general procedure, the reaction of 129 mg of
pyrazoline 3h and 68 mg of DDQ furnishes 85 mg (66%) of 4h as
brown solid. M.p. 161e162 ꢀC. 1H NMR (500 MHz, CDCl3, ppm):
d
4.16 (5H, s, C5H5), 4.36 (2H, s, meta-C5H4), 4.75 (2H, s, ortho-C5H4),
4.81 (2H, s, NH2), 6.58 (1H, s, pyrazole), 7.45 (1H, d, J ¼ 8.0 Hz,
aromatic), 7.31e7.43 (3H, m, aromatic), 7.43 (2H, d, J ¼ 9.0 Hz,
sulfonamide), 7.82 (2H, d, J ¼ 9.0 Hz, sulfonamide). 13C NMR
ꢀ
riding on their parent
Uiso(H) ¼ 1.2Ueq(c) for H atoms].
C
atoms [CeH
¼
0.93e0.97 A and
(75 MHz, CDCl3 þ DMSO-d6, ppm):
d 66.3 (ortho-C5H4), 68.3 (meta-
4.5. Electrochemistry
C5H4), 69.0 (C5H5), 107.9, 122.4, 126.4, 126.6, 129.4, 130.1, 131.3,
133.2, 140.0, 140.6, 151.6 (aromatic). FT-IR {KBr,
(cmꢁ1)}: 3362 and
3253 (NH2), 1597 (C]C)Ar, 1517 (C]N)Ar, 1341 nas(SO2), 1158
n
Cyclic voltammetric measurements of compounds 3aek were
performed using CH instruments model 620C series, version 5.01
interfaced with computer. The electrochemical cell consists of
a three-electrode cell, which involved a glassy carbon as a working
electrode, saturated calomel as a reference electrode, and platinum
wire as the counter electrode. The measurement was performed
using concentrations of samples were 0.5e1.0 mM, in the presence
of 0.1 M tetra-butyl ammonium perchlorate, TBAP (supporting
electrolyte) in dry DMSO under N2 atmosphere at RT.
n
n
n
ns(SO2), 539 and 497 nas(CpeFeeCp). HR-MS: found, m/z 518.0543
[M þ H]þ, calculated for C25H21O2N3ClFeS: 518.0539. Anal. Calcu-
lated for C25H20O2N3ClFeS: C, 57.99; H, 3.89; N, 8.11; S, 6.19. Found:
C, 58.06; H, 3.92; N, 8.08; S, 6.17.
4.3.9. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-(4-chlorophenyl)-
1H-pyrazoline (4i)
According to the general procedure, the reaction of 129 mg of
pyrazoline 3i and 68 mg of DDQ furnishes 85 mg (66%) of 4i as
brown solid. M.p. 127e128 ꢀC. 1H NMR (300 MHz, CDCl3, ppm):
4.6. Fluorescence and lifetime instrumentation
d
4.16 (5H, s, C5H5), 4.36 (2H, s, meta-C5H4), 4.77 (2H, s, ortho-C5H4),
Steady state fluorescence spectra were recorded on a spectro-
fluorimeter (FluoroLog-3, Horiba Jobin Yvon). For fluorescence
quantum yield measurements, the solutions of compounds 3aek in
dichloromethane were optically matched at the excitation wave-
length (350 nm) and then the quantum yield was calculated by
comparing the integrated areas under the emission curves. Quinine
4.83 (2H, s, NH2), 6.56 (1H, s, pyrazole), 7.23 (2H, d, J ¼ 8.3 Hz,
aromatic), 7.37 (2H, d, J ¼ 8.3 Hz, aromatic), 7.47 (2H, d, J ¼ 9.0 Hz,
sulfonamide), 7.89 (2H, d, J ¼ 9.0 Hz, sulfonamide). 13C NMR
(75 MHz, CDCl3 þ DMSO-d6, ppm):
d 66.17 (ortho-C5H4), 68.22
(meta-C5H4), 68.90 (C5H5), 106.43, 123.89, 126.38, 128.11, 128.32,
129.43, 133.87, 141.39, 141.68, 142.01, 151.85 (aromatic). FT-IR {KBr,
(cmꢁ1)}: 3349 and 3256
(NH2), 1601 (C]C)Ar, 1531 (C]N)Ar,
n
sulfate in 0.1 M H2SO4
(
Ff ¼ 0.57, at 22 ꢀC) was used as reference
n
n
n
[45]. The measured Ff values are accurate within ꢃ10%.
1353 nas(SO2), 1163 ns(SO2), 489 nas(CpeFeeCp). HR-MS: found, m/z
518.0543 [M þ H]þ, calculated for C25H21O2N3ClFeS: 518.0548. Anal.
Calculated for C25H20O2N3ClFeS: C, 57.99; H, 3.89; N, 8.11; S, 6.19.
Found: C, 58.02; H, 3.92; N, 8.17; S, 6.25.
Lifetime measurements were made on a picosecond time-
correlated single photon counting (TCSPC) setup (FluoroLog-3
Triple Illuminator, IBH) employing a picosecond NanoLED laser as
excitation source
(lex
¼
301 nm) and photomultiplier tube
(Hamamatsu) having a response time of 500 ps as the detector. The
lamp profile was recorded by placing a scatterer (dilute solution of
Ludox in water) in place of the sample. The width of the instrument
function, which was limited by the full width at half maxima
(FWHM) of the excitation source, was 1.07 ns at 301 nm. Decay
curves were analyzed by nonlinear least-squares iteration proce-
dure using IBH DAS6 (version 2.3) decay analysis software. The
4.3.10. 3-Ferrocenyl-1-(4-sulphamylphenyl)-5-(2-napthyl)-1H-
pyrazoline (4j)
According to the general procedure, the reaction of 134 mg of
pyrazoline 3j and 68 mg of DDQ furnishes 91 mg (68%) of 4j as
brown solid. M.p. 126e127 ꢀC. 1H NMR (300 MHz, CDCl3, ppm):
d
4.17 (5H, s, C5H5), 4.35 (2H, s, meta-C5H4), 4.79 (2H, s, ortho-C5H4),
4.88 (2H, s, NH2), 6.69 (1H, s, pyrazole), 7.53 (2H, d, J ¼ 8.8 Hz,
sulfonamide), 7.29 (1H, s, aromatic), 7.56 (2H, t, J ¼ 4.4 Hz,
aromatic), 7.80e7.86 (5H, m, aromatic), 7.88 (1H, t, J ¼ 4.4 Hz,
aromatic), 7.90 (1H, s, aromatic). 13C NMR (75 MHz, CDCl3 þ DMSO-
quality of the fits was measured by the c
2 values and distribution of
the residuals.
d6, ppm):
d
65.53 (ortho-C5H4), 67.54 (meta-C5H4), 68.87 (C5H5),
Acknowledgements
106.06, 123.05, 124.95, 125.64, 126.40, 126.46, 126.65, 126.90,
127.06, 131.53, 131.71, 140.83, 141.19, 142.51, 151.04 (aromatic). FT-IR
{KBr,
N)Ar, 1329 nas(SO2), 1164 ns(SO2), 531 and 487 nas(Cp-Fe-Cp). HR-MS:
This work was financially supported by the in-house project
MLP-0008. Ch.K.K is grateful to Council of Scientific and Industrial
Research (CSIR), New Delhi for the award of a research fellowship.
n n(NH2), 1638 n(C]C)Ar, 1510 n(C]
(cmꢁ1)}: 3349 and 3233

Ch.K. Kumar et al. / Journal of Organometallic Chemistry 718 (2012) 64e73
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