Synthesis, IR-, NMR- and X-ray investigations on some novel N-hetaryl-dihydro-pyrazolyl ferrocenes. Study on ferrocenes, part 16

Article abstract of DOI:10.1016/j.jorganchem.2005.05.045

Cyclocondensation of 1-aryl-3-ferrocenyl-2-propen-1-ones (1) with hetaryl hydrazines resulted in N-hetaryl-3-aryl-5-ferrocenyl pyrazolines (3, 4). The analogous 3-aryl-1-ferrocenyl-2-propen-1-ones (5) gave the isomeric N-hetaryl-5-aryl-3-ferrocenyl-pyrazolines (6, 10), but in lower yield. The reaction of aryl-chalcones (7) with 4-hydrazino-phthalazinone led to 3,5-bis-aryl-N-hetaryl-pyrazolines (8) or to the corresponding ene-hydrazones (9). The structure of the new compounds was established by IR, ¹H and ¹³C NMR spectroscopy, including DNOE, HMQC, HMBC and DEPT methods. For compounds 1b, 3b and 8b the stereo structure was elucidated also by X-ray diffraction.

Full text of DOI:10.1016/j.jorganchem.2005.05.045

Journal of Organometallic Chemistry 690 (2005) 4018–4026
www.elsevier.com/locate/jorganchem
Synthesis, IR-, NMR- and X-ray investigations
on some novel N-hetaryl-dihydro-pyrazolyl ferrocenes.
q
Study on ferrocenes, part 16
a
b
a
´
´
´
´
Veronika Kudar , Virag Zsoldos-Mady , Kalman Simon ,
a
a,b,
*
´
´
´
Antal Csampai , Pal Sohar
a
Department of General and Inorganic Chemistry, Eo¨tvo¨s Lora´nd University, H-1518 Budapest 112., P.O. Box 32, Hungary
Research Group for Structural Chemistry and Spectroscopy, Hungarian Academy of Sciences – Eo¨tvo¨s Lora´nd University, Pa´zma´ny se´ta´ny 1A,
H-1117 Budapest, Hungary
b
Received 4 March 2005; accepted 10 May 2005
Available online 19 July 2005
Dedicated to Prof. A. Messmer on the occasion of his 80th anniversary
Abstract
Cyclocondensation of 1-aryl-3-ferrocenyl-2-propen-1-ones (1) with hetaryl hydrazines resulted in N-hetaryl-3-aryl-5-ferrocenyl
pyrazolines (3, 4). The analogous 3-aryl-1-ferrocenyl-2-propen-1-ones (5) gave the isomeric N-hetaryl-5-aryl-3-ferrocenyl-pyrazo-
lines (6, 10), but in lower yield. The reaction of aryl-chalcones (7) with 4-hydrazino-phthalazinone led to 3,5-bis-aryl-N-hetaryl-pyr-
1
azolines (8) or to the corresponding ene-hydrazones (9). The structure of the new compounds was established by IR, H and 13C
NMR spectroscopy, including DNOE, HMQC, HMBC and DEPT methods. For compounds 1b, 3b and 8b the stereo structure
was elucidated also by X-ray diffraction.
ꢀ 2005 Elsevier B.V. All rights reserved.
Keywords: Ferrocenes; Enones; Pyrazolines; Hydrazones; Structure by IR; NMR and X-ray
1. Introduction
dynamic of ferrocene reflected in the spectral properties
make the spectroscopic study of this type of compounds
an attractive task.
Ferrocene derivatives containing one or more hetero-
cyclic substituents are useful precursors for the synthesis
of new metallocene derivatives [2–8]. At the same time,
they are also important because of their potential bio-
logical activity [4–6]. Recent publications support that
combination of pharmacologically active N-heterocycles
– among them pyrazolines and pyrazoles – with ferro-
cene moiety can result in favourable change of biological
properties, often associated with decreased toxicity
[6–8]. The unique bonding structure and molecular
In the frame of our research program, previously we
described the preparation and structure investigation of
several new ferrocenyl-triazole, -pyrazole, -pyrazoline
and -pyrazolidine derivatives [9,10] via 1,3-dipolar
cycloaddition of ferrocenyl-hetaryl hydrazones [11]. In
the present article we publish the synthesis and spectro-
scopic properties of some new ferrocenyl-pyrazoline
derivatives substituted with 2-pyridyl- or 4-[phthalazin-
1(2H)on-yl] group on the nitrogen atom, accomplished
by the cyclocondensation of ferrocenyl-chalcone deriva-
tives. Spectroscopic and electrochemical characteristics
of several chalcone analogous ferrocenes [12a,12b] and
some cyclic ferrocenyl-enones [13a,13b] were studied
q
For part 15, see [1].
Corresponding author. Tel.: +36 1 372 2911; fax: +36 1 372 2592.
*
´
E-mail address: sohar@para.chem.elte.hu (P. Sohar).
0022-328X/$ - see front matter ꢀ 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2005.05.045

V. Kudar et al. / Journal of Organometallic Chemistry 690 (2005) 4018–4026
4019
by us earlier. For comparison of chemical and spectro-
scopic properties and due to the known wide-range bio-
logical activity of the phthalazine derivatives [14], the
analogous bis-aryl-N-phthalazinonyl-dihydropyrazoles
were also synthesized.
Meanwhile, our work was completed, recent publica-
tions were published on the synthesis and pharmacolog-
ical properties on some pyrazolines and pyrazoles
containing ferrocene moiety [7,8].
were isolated in much lower (25–30%) yield. The signif-
icantly decreased reactivity of 5a,b relative to that of
1a,b can probably be attributed to the enhanced elec-
tron-releasing effect of the ferrocenyl substituent ex-
erted on the directly attached carbonyl group
(Scheme 2).
In comparison, the reaction of the corresponding 1,3-
bis-arylchalcones (7a,b) with 4-hydrazinophthalazinone
(2b) was also carried out. Applying longer reaction time
(8–12 h) and dilute solution, cyclic products with pyraz-
oline structure (8a,b) were isolated in good yield. From
more concentrated solution within 3–4 h the poorly sol-
uble ene-hydrazones (9a,b), as simple condensation
products, often spontaneously crystallised from the
reaction mixture (Scheme 3).
2. Results and discussion
3-Ferrocenyl-1-aryl-2-propen-1-ones (1a,b) were pre-
pared by base-catalyzed Claisen-Schmidt condensation
of ferrocenecarboxaldehyde with acetophenones accord-
ing to the literature procedures [7,15,16]. In a mixture of
ethanol–acetic acid–water, at reflux temperature the
reaction of these compounds with 2-hydrazinopyridine
(2a) and 4-hydrazino-phthalazinone (2b), respectively,
resulted in N-hetaryl-3-aryl-5-ferrocenyl-pyrazolines
(3a,b and 4b) as new crystalline compounds in 50–75%
yield (Scheme 1).
The reaction of the analogous 1-ferrocenyl-3-aryl-2-
propen-1-ones (5a,b) – prepared [7,15–17] from acetyl-
ferrocene with benzaldehydes – under similar condi-
tions with hetaryl hydrazines 2a,b gave the isomeric
N-hetaryl-3-ferrocenyl-5-aryl-pyrazolines (6a,b), but
longer reaction time was needed even for partial con-
version and the main products after chromatography
3. Structures and spectroscopy
1
The H, 13C and 15N NMR spectral data of the new
compounds are given in Tables 1–4. These data confirm
the supposed structures straightforwardly. The follow-
ing additional facts can be stated:
1
Comparing the H NMR data of positional isomers
3a–6a and 3b–6b, it is sticking that one of the 4-methy-
lene hydrogens is more shielded (3.02 and 2.98 ppm)
than the other (3.73 and 3.68 ppm) for 6a,b, while in
3a,b no such strong shielding is observable (all shifts
are in the interval of 3.60–3.75 ppm). This is due to
the anisotropic effect [18a] of the cis-arranged 5-aryl
R
R
4
O
O
H
2'
3'
3
5
NH
N
N
N
N
5'
N
N
2a NHNH
NHNH2
2
2b
Fe
Fe
Fe
H
N
N
R
HN
1a,b
4b
3a,b
O
a: R = H, b: R = OMe
Scheme 1.
R
R
4
3
O
H
H
2'
3'
5
N
N
N
N
5'
N
2a
NH
2b
Fe
Fe
Fe
N
R
O
10b
5a,b
6a,b
a: R = H, b: R = OMe
Scheme 2.

4020
V. Kudar et al. / Journal of Organometallic Chemistry 690 (2005) 4018–4026
R
H
N
H
O
H
N
Ph
N
N
N
O
O
N
H
Ph
2b
Ph
and/or
H
H
N
R
HN
R
9a,b
7a,b
8a,b
a: R = H, b: R = OMe
Scheme 3.
Table 1
1H NMR dataa of compounds 3a,b, 4b, 6a,b, 8a,b, 9a,b and 10bb
Compound OCH3 CH2
s (3H) (Pos. 4)c
H-5 H-20,50
H-30,40
H-1-5 H-2,6 H-3,5 H-4 H-5/3 H-6/4 H-7/5 H-8/6 NH s
Cpf
(1H)
Pyrazoline
ringd
Substituted
Cp ringe
3-Phenyl/
anisyl groupg
Phthalazinonyl/
a-pyridyl ring
3a
3b
4b
6a
6b
8a
8b
9a
9b
10b
a
–
3.66, 3.75 5.70
3.60, 3.70 5.65
3.35, 3.87 5.51
3.02, 3.73 5.74
2.98, 3.68 5.67
4.05, 4.55
4.06, 4.50
4.31, 4.39
4.55, 4.73
4.53, 4.71
4.07, 4.10 4.16
4.05, 4.10 4.14
7.86 7.46
7.78 6.98
7.73 7.01
ꢀ7.3
7.39 7.38
7.50
7.47
7.82
7.50
7.47
7.85
7.78
7.80
7.78
7.75
6.66
6.63
7.91
6.60
6.57
7.94
7.91
7.81
7.84
7.85
8.19
8.17
8.41
8.04
8.04
8.64
8.58
7.97
7.94
8.69
–
3.86
3.79
–
3.75
–
3.71
–
3.79
3.76
–
–
7.34
8.21
4.10
4.21
12.2
–
–
12.06
11.98
11.2
12.0
9.99
4.36, 4.37 4.09
4.34, 4.35 4.09
7.23 7.35
7.21 6.83
–
–
7.21
8.21
8.15
3.08, 3.88 5.68 ꢀ7.4g
7.29
7.23
7.32
7.25
7.20
7.15
7.25
7.18
4.19
7.70
ꢀ7.4g
2.99, 3.78 5.59
7.35
7.58 6.91
ꢀ7.4h 7.66
7.30 7.13
7.37 6.84
7.29, 7.85 6.35 ꢀ7.4h
7.61 8.42
7.16, 8.28 6.24
3.09, 3.52 5.59
7.42
–
–
8.17
8.40
4.59, 4.61 ꢀ4.37
In CDCl3 (3a,b, 6a,b, 10b) and (8b)/or DMSO-d6 (4b, 8a, 9b) solution (for 9a 4:1 mixture of these solvents) at 500 MHz. Chemical shifts in ppm
(dTMS = 0 ppm), coupling constants in Hz.
b
Assignments were supported by HMQC and for 6a and 8b NOEDIF measurements.
Two ddÕs (2 · 1H), 2J: 16.8 (3a,b, 6a,b, 8a,b), 16.2 (10b), 3J (upfield dd): 4.4 (3a,b, 6a,b), 12.5 (8a,b), 12.2 (10b), 3J (downfield dd ): 11.3 (3a,b), 12.0
c
(6a,b), 11.1 (8a,b, 10b), two dÕs (2 · 1H) for 9a,b, J : 16.3.
d
H(a), NH, and H(b), resp., in the enhydrazino group (9a,b).
e
The H-2,6 and H-3,5 signals (ꢀd and ꢀt) of the phenyl attached to the C-5 (sp3) atom in the pyrazoline ring (8a,b, 9a,b).
f
Unsubstituted ring, for 8a,b and 9a,b the H-4 signal (ꢀt) of the phenyl attached to the C-5 (sp3) atom in the pyrazoline ring.
g
Pos. 5 for 6a,b and 10b.
Two overlapping signals.
h
group which must be then perpendicular to the pyrazo-
line ring in the preferred conformation. The similar ef-
fect can also be stated for 8a,b and 10b.
of the substituted carbon, these shift differences may be
originated from the field effect [18c,20] causing upfield
shifts of carbons substituted by bulkier groups. In 3
and 6, a steric hindrance between N(1)- and 5-substitu-
ents is expectable. In accordance with the aboves, the
C-4 and C-5 lines are upfield shifted in 3a,b, where the
bulkier ferrocenyl moiety is bonded to C-3 instead of
the smaller aryl group.
A small, but significant difference can be observed in
1
the H NMR chemical shift of the HÕs in unsubstituted
Cp ring for the positional isomers 3 and 6 (0.06 ppm).
Thus, the change in electronic distribution in the isomers
is transferred via the sandwich bond and the Fe atom.
The measured 15N chemical shifts (Table 4) demon-
strate the presence of a hydrazone moiety in each com-
pound described here.
As a proof of the steric interaction between the sub-
stituents in Pos. 1 and 5, a significant difference (0.50
1
and 0.46 ppm) can be stated in the H NMR chemical
The a-effect [18b,19] of the ferrocenyl and aryl sub-
stituents on C-3 is hardly different (1.4 and 0.8 ppm
for the pairs 3a–6a and 3b–6b), while for the 13C
NMR chemical shifts of C-4 and C-5 a large differerence
was observed for the isomers (for 3a–6a 4.2 and 3.6 and
for 3b–6b 3.6 and 3.7). Because a substantial difference
in the a-effect is not expectable depending on the nature
shifts of H-20 and H-50 for 3a and 3b. Due to the aniso-
tropic effect of the heterocycle, the H-20 (or H-50) atom of
the Cp ring lying above the plane of the heteroaromatic
ring is more shielded and its signal is upfield shifted (to
4.05 ppm). This effect is absent in 6a and 6b. Instead,
the coplanar arrangement of the Cp ring and the C@N
double bond reveals in a dramatic downfield shift of this

V. Kudar et al. / Journal of Organometallic Chemistry 690 (2005) 4018–4026
4021
signal (to 4.73 and 4.71 ppm) in S-cis orientation to this
bond due to its anisotropic effect [18d].
The separated H,C-20/50 and H,C-30/40 signals of our
ferrocenyl N-heterocycles due to the inherent diastereot-
opy (chirality center C-5) and/or the restricted rotation
of the ferrocenyl moiety around the C(py)–C(Cp) bond.
To prove the contribution of rotational hindrance in
these signal separations we carried out variable temper-
1
ature (DNMR) experiments. The H NMR spectra of
pyrazolines 3a and 6b were measured at 415 and
440 K, respectively. Only a decrease of the signal separa-
tion (DDm) could be observed. From DDm values it can be
established that the contribution of hindered rotation of
the Fc group is responsible in ca. 25–30% for the chem-
ical non-equivalence of H-20 and H-50 atoms. The more
important reason, however, must be the diastereotopy,
in accordance with the literature data [21a,21b].
Our findings on ferrocenyl macrocycles [22] contain-
ing two 1,10-substituted ferrocene moieties bridged by
two –CR@N–N@CR0– binding chains support the role
of restricted rotation in signal separation. DFT calcula-
tions and DNMR measurements confirmed for these
molecules, that in the conformational equilibrium the
rotamers containing the –RC@N–N@CR0– binding
chains coplanar to the Cp rings are strongly preferred.
These molecules are symmetric without chirality centres
and if they are rigid – free internal rotation of the bind-
ing chains or their parts is not possible – the chemically
non-equivalence of C/H-20,50 and C/H-30,40 atom pairs
were observed.
4. X-ray studies
Although chalcone 1b is known for a long time [7,16],
its X-ray study has not been published till now. We re-
port now the single crystal analysis of 1b and two of
our new products, 3b and 8b. The X-ray structures are
depicted in Figs. 1 and 2. The selected bond parameters
can be seen in Table 6.
While there is no difference found in the Fe1–Cp dis-
tances and the parallel arrangement of the two Cp rings
in 1b and 3b, the relative position of these rings is differ-
ent, in 1b it is staggered, in 3b, however, it is eclipsed.
The side-chain in 1b is in elongated conformation, the
enone moiety has S-cis conformation and its torsion an-
gle is 2.6(8)ꢁ. The phenyl ring is nearly coplanar: the an-
gle between the carbonyl and the former ring is 4.0(4)ꢁ.
This might suggest extended conjugation, but the bond
distances does not support such an electron distribution:
˚
˚
(C(1)–C(2) 1.333(6) A, C(2)–C(3) 1.486(7) A, O(2)–C(3)
˚
˚
1.229(6) A, C(3)–C(4) 1.474(7) A).
In both 3b and 8b the central pyrazoline rings have an
envelope structure with the chiral C1 on the tip. The dis-
tances of C1 atoms from the plane of the others are
˚
0.289(10) and 0.356(3) A, respectively.

4022
V. Kudar et al. / Journal of Organometallic Chemistry 690 (2005) 4018–4026
Table 3
Characteristic IR frequencies (cmꢁ1) of compounds 3a,b, 4b, 6a,b, 8a,b, 9a,b and 10b (in KBr discs)
Compound
mNH
Amide-I
band
mC@N
band
cCAr
H
cCAr
H
cCArCAr
mC–O
band
mas Cp–Fe–Cp
and tilt of Cp
banda
bandb
bandc
bandd
3a
3b
4b
6a
6b
8a
8b
9a
9b
10b
a
–
–
–
–
1589
1590e
1588e
1589
1588
1581
1584e
1599
1594
1586
773
769
–
760
830f
829
764h
828
760
820
760
821
827
693
–
–
705
–
693
697
–
502
490g
508
483
487
–
1246
1250
–
1245
–
1247
–
1245
1251e
3250–2750
–
1658
–
–
1657
1661
1660
1652
1656
764h
761
–
3300–2700
ꢀ3160
765
779
781
–
3365, 3250
3310, 3145e
3250–2750
704, 695e
680
–
–
563
–
Diffuse (4b, 8a, 10b), broad (8b).
b
c
Pyridine (3a,b, 6a,b), phenyl (8b, 9b, 10b).
Mono- (a) or p-disubstituted benzene (b).
Monosubstituted benzene.
d
e–g
h
Splitted band with the further maxima at 1606e, 854f and 508g (3b), 1607 (4b), 1607 (8b), 675 (9a), ꢀ2950 broad (9b) and 1028 (10b).
Two overlapping bands (very strong).
ocenyl moieties, respectively. The distinct layers of the
apolar ferrocenyl groups and the polar moieties in the
crystals of 1b run perpendicular to the ab plane while
in the crystals of 3b the ac plane of the unit cell. In 1b
in the apolar layers the ring planes of the ferrocenes of
the symmetry equivalent molecules are perpendicular,
while in 3b in each apolar layer the axes of the symmetry
equivalent ferrocenes are parallel and perpendicular to
the axes of ferrocenes in the neighbouring apolar layer.
In the crystals of 8b, the presence of donor N–H atom
causes significant change in the crystal structure results
in the formation of hydrogen bonds. The intermolecular
hydrogen bonds formed between the O1 carbonyl oxy-
gen and the NH group of [ꢁx + 2,ꢁy,ꢁz + 1] symmetry
equivalent molecule, and inversely. The hydrogen bond-
ing pattern of the crystal shows H-bonded pairs of mol-
ecules. The hydrogen bondings are showed in Table 6.
The distinct layers of the polar naphtalazone moiety
and the apolar rings, respectively, run parallel to the
ac plane of the unit cell. In the polar layers, the planes
of the naphtalazone moieties of the symmetry equivalent
molecules are parallel. The planes of all phenyl groups
are perpendicular to the bc plane of the unit cell (see
Fig. 3).
Table 4
15N NMR chemical shiftsa of compounds 8a,b and 9ab
Compound
N-1
N-2
N-2
N-3
Pyrazoline ringc
Phthalazinone
ring
8a
8b
9a
a
163
161
137
333
328
317
276
275
264
177
177
174
In CDCl3 solution at 50.7 MHz. Chemical shifts in ppm
(dNH3 = 0 ppm).
b
Assignments are based on 15N,1H-HMBC measurements.
For 9a sp3-N (N-1) and sp2-N (N-2).
c
Fig. 1. The ortep diagram of 1b (the ellipsoid probability is 30%).
5. Experimental
The anisyl groups in 3b and 8b, respectively, are
nearly perpendicular to the pyrazoline rings. In 3b the
least-squares planes of the pyrazoline and the closer
Cp rings is 86.4(3)ꢁ. In 8b the phenyl and anisyl rings
have angles to the pyrazoline moiety of 87.7(1)ꢁ and
4.3(1)ꢁ, respectively.
In both 1b and 3b the main crystal building forces are
the dipole–dipole and the dispersion type, second order
interactions between the polar rings and the apolar ferr-
IR spectra were recorded with a Bruker IFS-55 FT-
1
spectrometer using KBr pellets. The H and 13C NMR
spectra were obtained at 500 and 126 MHz by a Bruker
DRX-500 spectrometer in CDCl3 or DMSO-d6 solution,
with the deuterium signal of the solvent as the lock and
Me4Si as internal standard. The standard Bruker micro-
program NOEMULT.AU to generate NOE was used
with a selective pre-irradiation time. DEPT spectra were
run in a standard manner, using only the H = 135ꢁ pulse

V. Kudar et al. / Journal of Organometallic Chemistry 690 (2005) 4018–4026
4023
Fig. 2. The ortep diagram of 3b and 8b (the ellipsoid probability is 30%).
Data processing was carried out by use of the software
supplied with the diffractometer. Structure solutions
with direct methods were carried out with the teXsan
Crystal Structure Analysis Package [23]. Refinements
were carried out using the SHELXL-97 [24] program by
the full matrix, least squares method on F2. All non-
hydrogen atoms were refined anisotropically. Hydrogen
atoms were generated based upon geometric evidence
and their positions were refined by the riding model.
The crystallographic data for compounds 1b, 3b and
8b are summarized in Table 6. Full lists of atomic coor-
dinates, bond lengths, angles and atomic displacement
parameters have been deposited at the Cambridge Crys-
tallographic Data Centre. CCDC-257154, -257152,
-257153 for compounds 1b, 3b and 8b, respectively, con-
tain the supplementary crystallographic data for this pa-
per. These data can be obtained free of charge at
www.ccdc.cam.ac.uk/conts/retrieving.html [or from the
Cambridge Crystallographic Data Centre, 12 Union
Road, Cambridge CB2 1EZ, UK; fax: (internat.) +44-
1223-336-033; e-mail: deposit@ccdc.cam.ac.uk].
Fig. 3. Hydrogen bonds in the molecule of 8b.
to separate CH/CH3 and CH2 lines phased ‘‘up’’ and
‘‘down’’, respectively. The 2D-HMQC spectra were ob-
tained by using the standard Bruker pulse program
HXCO.AU.
The X-ray measurements were made on a Rigaku
AFC6S diffractometer with graphite monochromated
˚
Cu Ka radiation (k = 1.54178 A). The crystals were
mounted on a glass fibre. Cell constants and an orienta-
tion matrix for data collection were obtained from a
least-squares refinement using the setting angles of care-
fully centred reflections. The data were collected at a
temperature of 293 K using the x/2h scan technique.
TLC was performed on aluminium plates precoated
with Silica Gel 60 F254 (E. Merck), the spots were detected
visually or by UV light at 254 and 366 nm, respectively.
Table 5
Physical and analytical data on compounds 3a, 3b, 4b, 6a, 6b, 8a, 8b, 9a, 9b
Compound
m.p. (ꢁC)
Formula
Calculated %
Found %
C
C
H
N
H
N
3a
3b
4b
6a
6b
8a
8b
9a
9b
163–164
168–169
287–290
180–181
164–147
249–250
290–292
198–201
205–206
C
24H21FeN3
C25H23FeN3O
28H24FeN4O2
70.77
68.66
66.68
70.77
68.66
75.39
72.71
75.39
72.71
5.20
5.30
4.80
5.20
5.30
4.95
5.09
4.95
5.09
10.32
9.61
11.11
10.32
9.61
15.29
14.13
15.29
14.13
70.68
68.47
66.43
70.54
68.42
75.28
71.97
75.35
72.92
5.11
5.21
4.72
5.23
5.24
4.94
5.05
5.01
5.04
10.19
9.44
11.10
10.29
9.41
15.16
14.02
15.19
14.05
C
C24H21FeN3
C25H23FeN3O
C23H18N4O
C
24H20N4O2
C23H18N4O
24H20N4O2
C

4024
V. Kudar et al. / Journal of Organometallic Chemistry 690 (2005) 4018–4026
Table 6
˚
The crystal data, selected bond lengths (A), angles (ꢁ) and torsion angles (ꢁ)
1b
3b
8b
Crystal colour, habit
Crystal dimensions (mm3)
Crystal system
Space group
Lattice parameters
Red, needle
0.12 · 0.15 · 0.95
Monoclinic
P21/a
Orange, needle
0.15 · 0.12 · 0.45
Monoclinic
P21/c
Colourless, plate
0.27 · 0.13 · 0.42
Triclinic
ꢀ
P1
˚
a (A)
10.550(2)
7.839(1)
19.200(1)
7.420(2)
16.331(2)
17.004(2)
8.660(2)
15.243(1)
8.486(2)
103.86(1)
105.88(2)
78.61(1)
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
90.817(7)
90.43(1)
Bond lengths
N1–N2
N2–C1
C1–C2
C2–C3
C3–N1
C3–C4
1.369(6)
1.480(6)
1.531(8)
1.519(8)
1.295(7)
1.455(8)
1.410(2)
1.494(3)
1.526(3)
1.502(3)
1.277(3)
1.468(3)
1.333(6)
1.486(7)
1.474(7)
1.229(6)
C3–O2
Angles
C3–N1–N2
N1–N2–C1
N2–C1–C2
C1–C2–C3
C2–C3–N1
C2–C3–C4
C2–C3–O2
O2–C3–C4
108.9(5)
113.0(4)
100.0(4)
102.9(5)
111.9(6)
124.0(6)
108.7(2)
109.6 (1)
100.9(2)
102.1(2)
113.5(2)
125.4(2)
120.4(5)
119.0(5)
120.0(5)
121.1(5)
Torsion angles
C1–C2–C3–O2
C1–C2–C3–C4
C2–C3–C4–C5
C1–C2–C3–N1
C2–C3–N1–N2
C3–N1–N2–C1
N1–N2–C1–C2
N2–C1–C2–C3
2.6(8)
ꢁ177.3(5)
169.7(5)
ꢁ3.4(10)
ꢁ11.4(7)
0.3(7)
ꢁ169.5(2)
ꢁ1.7(4)
13.0(3)
ꢁ5.2(8)
1.1(3)
11.9(7)
ꢁ15.5(2)
ꢁ18.0(6)
22.3(2)
16.2(6)
ꢁ19.9(2)
Hydrogen bond
Donor–Hꢂ ꢂ ꢂAcc.
d(D–H)
N4–H4ꢂ ꢂ ꢂO2(a)
0.962
d(Hꢂ ꢂ ꢂA)
1.831
2.793
178.4
d(Dꢂ ꢂ ꢂA)
\(D–Hꢂ ꢂ ꢂA)
Translation of symmetry codes to equiv. positions: (a)=ꢁx + 2,ꢁy,ꢁz + 1.
Column chromatography was made on silica gel (E.
Merck, 0.020–0.043 mesh).
and by precipitating with water. Yield for 1a
(C19H16FeO) 90%, m.p. 141–142 ꢁC, lit. m.p. 141–
142 ꢁC [16]; for 1b (C20H18FeO2) 87%, m.p. 153 ꢁC, lit.
m.p. 153–154 ꢁC [16]. The analogous 1-ferrocenyl-3-
aryl-2-propen-1-ones (5a and 5b) were prepared by
treatment with a mixture of acetylferrocene and benzal-
dehyde or 4-methoxy-benzaldehyde, resp., in ethanol
with 10% KOH solution, as described for 1a. Yield for
5a (C19H16FeO) 90%, m.p. 140–141 ꢁC, lit. m.p. 141–
142 ꢁC [26]; for 5b (C20H18FeO2) 87%, m.p. 151–
152 ꢁC, lit. m.p. 152–153 ꢁC [16].
4-Hydrazino-phthalazin-1(2H)-one (2b) was pre-
pared, as described in the literature [25]. 3-Ferrocenyl-
1-aryl-2-propen-1-ones 1a and 1b, resp., were obtained
by condensation of ferrocenecarboxaldehyde (5 mmol)
with acetophenone and 4-methoxy-acetophenone, resp.
(5 mmol), in ethanol (4 cm3), applying 10% aqueous
KOH solution (4 cm3) as base catalyst [16]. The reac-
tions were followed by TLC (benzene/EtOAc 4/1).
Products were crystallised by dissolving in methanol

V. Kudar et al. / Journal of Organometallic Chemistry 690 (2005) 4018–4026
4025
Analytical and physical data of the new compounds
are given in Table 5.
recovered. The main product was crystallised from
CH2Cl2/petroleum ether to give pure 6a as orange–red
crystals, yield 24%.
5.1. 5-Ferrocenyl-3-phenyl-1-(2-pyridyl)-2-pyrazoline
(3a)
5.5. 3-Ferrocenyl-5-(p-methoxyphenyl)-1-(2-pyridyl)-2-
pyrazoline (6b)
3-Ferrocenyl-1-phenyl-2-propen-1-one (1a, 1 mmol)
and 2-hydrazino-pyridine (2a, 1.2 mmol) were refluxed
in a mixture of EtOH (8 cm3), AcOH (3 cm3) and H2O
(2 cm3) under nitrogen. After 10 h, further 2a
(1.2 mmol) was added in EtOH (2 cm3)–AcOH (1 cm3)
and the reflux was continued for additional 10 h, while
TLC (benzene/EtOAc 5/1) indicated complete reaction.
The mixture was evaporated and co-distilled several
times with EtOAc and then triturated with a few EtOAc
to give a yellow solid, yield 74%. Purification by column
chromatography with a solvent mixture of N-hexane–
CHCl3–EtOAc (3:1:0.5) and treatment with petroleum
ether afforded yellow needles of pure 3a, yield 56%.
Compound 5b was reacted with 2a, as described
above. After 30 h reflux the reaction mixture was evap-
orated, and the dark residue was extracted with EtOAc,
dried over MgSO4, evaporated and purified by column
chromatography with a mixture N-hexane–CHCl3–
EtOAc (3:2:1) as eluent. The unchanged starting mate-
rial (12%) was recovered. The main product was purified
again by column chromatography with the same solvent
mixture to give pure 6b. Crystallisation from
ether–petroleum ether afforded orange-red crystals,
yield 27%.
5.6. 3,5-Diphenyl-1-{4-[phthalazin-1(2H)-on]-yl}-2-
pyrazoline (8a)
5.2. 5-Ferrocenyl-3-(p-methoxyphenyl)-1-(2-pyridyl)-2-
pyrazoline (3b)
Diphenyl-chalcone (7a, 2 mmol) and 4-hydrazino-
phthalazin-1(2H)-one (2b, 2 mmol) was refluxed in a
mixture of EtOH (10 cm3), AcOH (4 cm3) and H2O
(4 cm3) for 8 h under nitrogen. On cooling pale yellow
crystals of 8a were separated, yield 65%. Re-crystallisa-
tion from EtOH resulted in pure product, yield 52%.
From the mother liquor of the reaction gold-yellow
crystals of 9a were obtained in 12% yield.
3-Ferrocenyl-1-(4-methoxy-phenyl)-2-propen-1-one
(1b) with 2a, in a similar procedure as described at the
synthesis of 3a, after 20 h reflux and subsequent cooling,
gave dark yellow crystals of 3b. Re-crystallisation by
dissolving in EtOAc and precipitating with petroleum
ether gave pure product, yield 53%.
In the mother liquor a small amount (<5%) of a by-
product was indicated but not isolated.
5.7. 3-(p-Methoxyphenyl)-5-phenyl-1-{4-[phthalazin-
1(2H)-on]-yl}-2- pyrazoline (8b)
5.3. 5-Ferrocenyl-3-phenyl-1-{4-[phthalazin-1(2H)-on]-
yl}-2-pyrazoline (4b)
1-p-Methoxyphenyl-3-phenyl-2-propen-1-one
(7b,
Ferrocenyl-p-methoxyphenyl chalcone 1b was reacted
with 4-hydrazino-phthalazin-1(2H)-one (2b) in a similar
procedure as described above. While refluxing, yellow
crystals of 5b separated from the reaction mixture. After
filtration the product was washed with methanol to give
pure 5b in 62% yield.
1 mmol) was reacted with 2b, as described for 8a. After
4 h separation of solid substance was observed. Heating
was continued after adding of EtOH (4 cm3), AcOH
(2 cm3) and H2O (1 cm3) for further 8 h. On cooling
and partial evaporation pale yellow crystals of 8b were
separated in 77% yield. Re-crystallisation from ethanol
afforded pure product in 61% yield.
5.4. 3-Ferrocenyl-5-phenyl-1-(2-pyridyl)-2-pyrazoline
(6a)
5.8. 1,3-Diphenyl-2-propen-1-one {4-[phthalazin-1(2H)-
on]-yl} hydrazone (9a)
1-Ferrocenyl-3-phenyl-2-propen-1-one (5a, 1 mmol)
was reacted with 2-hydrazino-pyridine (2a) as described
for 3a. During the reaction formation of significant
amount of paramagnetic substances was observed. After
refluxing for 20 h the reaction mixture was evaporated
and co-distilled several times with EtOAc. The dark oily
residue was purified by column chromatography first
with chloroform and the main product repeatedly with
benzene–EtOAc (4:1) as eluent. Small amount of by-
products was detected but they were not further investi-
gated. The unchanged starting material (40%) was
1,3-Diphenyl-chalcone (7a, 4 mmol) and 4-hydra-
zino-phthalazin-1(2H)-one (2b, 4 mmol) was refluxed
in a mixture of EtOH (20 cm3), AcOH (8 cm3) and
H2O (8 cm3) under nitrogen for 4 h. The separated
gold-yellow crystals of 9a after cooling were filtered
and washed with EtOH–water (1:1), yield 75%. Crystal-
lisation was made by dissolving the crude product in
CHCl3, then ethanol was added to the solution. Partial
evaporation below 30 ꢁC gave pure product, yield 63%.

4026
V. Kudar et al. / Journal of Organometallic Chemistry 690 (2005) 4018–4026
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5.9. 1-p-Methoxyphenyl-3-phenyl-2-propen-1-one {4-
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Reaction of 7b with 2b, as described for 9a, resulted
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[7] E.A. Vazquez Lopez, E.I. Klimova, T. Klimova, C. Alvarez
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5.10. 3-Ferrocenyl-5-(p-methoxyphenyl)-1-{4-
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1-Ferrocenyl-3-(p-methoxyphenyl) 2-propen-1-one
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1(2H)-one (2b, 1.2 mmol) in a mixture of EtOH
(16 cm3), AcOH (6 cm3) and H2O (4.5 cm3). After 10 h
reflux 0.8 mmol 2b was added and refluxing was contin-
ued for further 20 h. After evaporation the dark oily res-
idue was purified by column chromatography with
eluents benzene-hexane 2:1, then benzene and finally
with benzene–EtOAc 4:1. The main product was puri-
fied again by chromatography using hexane–EtOAc
3:2 ! 2:3 mixture as eluent. By-products (less than
5%) were not investigated. Crystallisation of the main
product from ether–petroleum ether resulted in dark yel-
low crystals, yield 30%.
´
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[10] A. Abran, A. Csampai, A. Kotschy, O. Barabas, V. Harmath, P.
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Acknowledgements
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[18] (a) P. SoharNuclear Magnetic Resonance Spectroscopy, 1, CRC
Press, Boca Raton, FL, 1983, 35–38 & Vol. 2, p. 73;
This work was supported by the Hungarian Scientific
Research Fund (OTKA T-029651, T-043634 and TS-
´
(b) P. SoharNuclear Magnetic Resonance Spectroscopy, 2, CRC
Press, Boca Raton, FL, 1983, p. 89;
´
(c) P. SoharNuclear Magnetic Resonance Spectroscopy, 2, CRC
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044742). The authors are indebted to Dr. Pal Perjesi
Press, Boca Raton, FL, 1983, p. 153;
for a sample of compound 7b, to Dr. Hedvig Med-
zihradszky-Schweiger for analyses, to Dr. Gabor
´
(d) P. SoharNuclear Magnetic Resonance Spectroscopy, 2, CRC
´
Press, Boca Raton, FL, 1983, pp. 154–156.
Magyarfalvi and Dr. Gyo¨rgy Tarczay for recording
the IR spectra.
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