An efficient iminophosphorane-mediated synthesis, NMR-IR spectroscopic and X-ray study of novel ferrocenylimidazole derivatives: Part 10. Study on ferrocenes

Article abstract of DOI:10.1016/S0022-328X(01)01159-7

Starting from ethyl β-ferrocenyl-α-azidoacrylate (2), a series of novel 4-ferrocenylidene-1-aminoimidazolones (6a-j) was prepared in a pathway involving an aza-Wittig reaction followed by condensation of the resulting carbodiimidoester with hydrazines. Fo

Full text of DOI:10.1016/S0022-328X(01)01159-7

Journal of Organometallic Chemistry 634 (2001) 122–130
www.elsevier.com/locate/jorganchem
An efficient iminophosphorane-mediated synthesis, NMR–IR
spectroscopic and X-ray study of novel ferrocenylimidazole
derivativesꢀ
Part 10. Study on ferrocenes
Gyo¨rgy Tu´ro´s a, Antal Csa´mpai a, Ma´tya´s Czugler b, Heinrich Wamhoff c, Pa´l Soha´r a,*
a Research Group for Structural Chemistry and Spectroscopy,
Hungarian Academy of Sciences—Department of General and Inorganic Chemistry, Eo¨t6o¨s Lo´ra´nd Uni6ersity, Pa´zma´ny se´ta´ny 1A, POB 32,
H-1518 Budapest 112, Hungary
b Research Centrum of Chemistry, Institute of Chemistry, Hungarian Academy of Sciences, Budapest, Hungary
c Kekule´ Institute of Organic and Bioorganic Chemistry, Uni6ersity Bonn, Bonn, Germany
Received 3 April 2001; accepted 25 July 2001
Abstract
Starting from ethyl b-ferrocenyl-a-azidoacrylate (2), a series of novel 4-ferrocenylidene-1-aminoimidazolones (6a–j) was
prepared in a pathway involving an aza-Wittig reaction followed by condensation of the resulting carbodiimidoester with
hydrazines. Formation of [1,2,4]triazines of type 7 was not observed. Simultaneously with the formation of 2, an interesting
transformation was also observed to afford a novel imidazolone derivative (3) containing two ferrocenyl groups. The structures
of the products were determined by IR, 1H- and 13C-NMR spectroscopy (including 2D-COSY, DEPT, 2D-HMQC, and
2D-HMBC measurements), and in the case of compound 3 also by single-crystal X-ray analysis. © 2001 Published by Elsevier
Science B.V.
Keywords: Iminophosphorane; Ferrocenylimidazole derivatives; Ferrocenes; Structure elucidation by IR; NMR; X-ray
ferrocenylmethyl[1,2,4]triazines of type 7 or the iso-
meric 6-type 1-amino-4-ferrocenylmethylideneimida-
zolones (Scheme 1). All these reactions resulted
exclusively in imidazolones. The high stability of the
products 6a–j can probably be attributed to a pro-
nounced push–pull character of the enone moiety
bonded to the electron-releasing ferrocenyl group [7].
Attempted cyclisation of N-amino derivatives 6a–e
(R%=H) with triethylorthoformate in the presence of
catalytic amounts of p-toluenesulfonic acid gave imi-
noethers 8a–e in yields of 29–70%, but ring closure to
imidazotriazoles of type 9 did not take place even on
prolonged reflux of the reaction mixtures.
In the reaction of formylferrocene (1) with ethyl-azi-
doacetate conducted in THF under Knoevenagel condi-
tions, besides the expected ethyl-b-ferrocenyl-a-azido-
acrylate (2) a considerable amount (20%) of 1-[ethoxy-
ethoxycarbonylmethyl]-2-ferrocenyl-4-ferro-cenylme-
thylideneimidazole-5(1H)-one (3) was also formed. This
1. Synthesis
In the last few decades the chemistry of ferrocenes
has led to a wide variety of interesting compounds with
valuable catalytic properties and importance in materi-
als science [2]. However, much less attention has been
paid to heterocyclic derivatives of metallocenes with
potential biological activity [3]. In the frame of our
research programme to produce and investigate ferro-
cenyl-substituted heterocycles carrying pharmacophoric
groups, applying a reaction sequence similar to that
elaborated by Molina et al. [4–6], we tried to condense
in situ prepared ethyl b-ferrocenyl-a-alkyl/arylcarbodi-
imidoacrylates (5) with hydrazines in order to obtain
ꢀ Part 9: Ref. [1].
* Corresponding author. Tel.: +36-1-209-0555; fax: +36-1-209-
0602.
E-mail address: sohar@para.chem.elte.hu (P. Soha´r).
0022-328X/01/$ - see front matter © 2001 Published by Elsevier Science B.V.
PII: S0022-328X(01)01159-7

G. Tu´ro´s et al. / Journal of Organometallic Chemistry 634 (2001) 122–130
123
Scheme 1.
(Tables 1–3). Only the following remarks are necessary:
The five-membered ring—g-lactame (type 6)—struc-
ture of the products of the acylation–condensation
reaction sequence follows from the high wCꢀO IR
frequency (1690–1725 cm−1) and in case of com-
pounds 6a–e indirectly from the formation of the imi-
noethers 8a–e with CH(OEt)3. Type 7 d-lactames
should give lower IR frequencies [10] and derivatives
with structures different from 8a–e.
fact can be due to a subsequent transformation of the
initial product (2) with unreacted formylferrocene (1)
and ethyl-azidoacetate. The first step of the proposed
mechanism, outlined in Scheme 2, is the base-catalyzed
nitrogen elimination [8] leading to iminocarbonic acid
ester 10. Its acylation and subsequent addition of etha-
nol afford a b-ferrocenyl-a-azidoacrylamide (10“11“
12), which then reacts with the unchanged formylferro-
cene in a redox process taking place with nucleophilic
addition followed by 1,2-migration of a hydride anion
and simultaneous loss of nitrogen (12“13“14). A
closely related transformation is reported in Ref. [9]. In
the last step, the resulting b-ferrocenylidene-a-ferro-
cenoylaminoacrylamide undergoes intramolecular con-
densation to give 3 as the isolable final product. This
suggestion was supported by the result of a control
experiment in the course of which equimolar amounts
of 1 and 2 were treated with ethyl-azidoacetate under
the same conditions applied also in the original reaction
1“2 which resulted in 3 with a significant yield (17%).
Ring-chain tautomerism in 6a–j must also be consid-
ered. The NH signal of the NHꢁCꢀNRꢀNꢀCꢁNHR
1
moiety is a triplet in the H-NMR spectra of 6a,f,h and
8a proving the preference of the tautomeric form with
endo CꢀN double bond and an NHR (R=CH2Ph)
group.
The significantly higher chemical shifts of the NH
and ArH-2,6 hydrogens in compounds 6b–e and 8b–e
(NH: 7.7–9.7 and 7.1–8.2, ArH-2,6: 7.75–9.0 and
7.69–9.0) as compared to 6a and 8a (NH: 5.67 and
5.47, ArH-2,6: 7.46 and 7.38) may be due to the −I-ef-
fect of the aryl group and its substituents, and can also
suggest the shift of the tautomeric equilibrium to fa-
vour the form containing an exocyclic CꢀN double
bond (more acidic ring-NH and anisotropic deshielding
of the NꢀC bond [11] on the ortho aromatic hydrogens).
2. Structure determination
1
The structures of the new compounds 3, 6a–j and
8a–e follow from the spectral data straightforwardly
To decide between the two tautomers we used H,
13C and 1H,15N 2D-HMBC spectroscopy for com-

Table 1
1H-NMR data a of compounds 6a–j and 8a–e b
Compound
NH2/ꢀCH s (2/1H) c
NH (1H) d
CH2 d (2H)
ꢀCH s (1H)
H-2%,5% (2H)
H-3%,4% (2H)
H-1¦-5¦ (5H)
H-2
H-6
H-3
H-5
H-4
Substituted c-pentane ring
Aryl group e
6a
6b
6c
6d
6e
4.02
4.91 f
4.15 g
5.48
5.67
7.75
4.69
–
–
–
–
5.15
–
4.40
–
–
4.63
–
–
–
–
6.66
6.70
6.82
6.67
6.59
6.70
6.51
6.33
6.62
6.57
6.57
6.76
6.73
6.87
6.87
4.97
4.95
4.95
4.95
4.98
4.88
4.88
4.40
4.48
4.48
4.48
4.45
4.35
4.41
5.56
4.52
4.49
4.31
4.43
4.41
4.50
4.51
4.12
4.14
4.15 g
4.11
4.10
4.09
4.05
4.10
4.18
4.15
4.04
4.09
4.09
4.16
4.16
7.46
7.39
7.37
7.11
7.75
–
7.23
7.39
7.35
7.46
7.23
7.31
7.31
7.04
7.63
–
7.33
–
–
7.30
7.37
7.18 g
7.25 e
7.26
–
7.97
ꢀ7.76 g,h
8.42
ꢀ7.76 g,h
–
8.77
8.11
7.82
7.57
/
5.29
9.69
8.96
7.12
7.88
7.45
ꢀ8.1 g
8.07
7.38
7.69
7.69
–
i
6f
ꢀ3.6 h
10.6
ꢀ7.2 g
9.25
6g k
6h l
7.45 e
7.29 e
ꢀ8.1 g
9.63
9.24
9.34
9.31
5.47
7.17
7.15
4.88, 5.08
6i l
ꢀ5.0 h
6j l
9.52
9.22
9.34
9.32
9.47
9.41
ꢀ5.0 h
4.90
–
7.24
–
8a m
8b m
8c m
8d m
8e m
4.90
4.89
4.97
5.00
–
8.14
8.97
7.74
7.68
7.50
7.18
7.36 g
8.52
7.36 g
a In CDCl3 solution at 500 MHz. Chemical shifts in ppm (lTMS=0 ppm), coupling constants in Hz.
b Assignments were supported by 2D-HSC (HMQC) measurements (except for 6a,f,h,i and 8c).
c NH2, broad s (2H) for 6a–e, NꢁNH, broad s (1H) for 6f–j, ꢀCH, s (1H) for 6a–e.
d RNH or NH (ring, in the tautomeric form), broadened s, t for 6a,f and 8a (J: 6.0).
634
(
e Multiplicity (intensity): ꢀd (2/2×1H) for H-2,6 (6a,f,h and 8a), H-3,6 (6d, 8d) and H-4,6 (6e and 8e), ꢀt for H-3,5 and H-4 (2H and 1H, 6a,f,h and 8a), H-4,5 (1H, 6d and 8d) and H-5
122
(1H, 6e and 8e), ꢀs (1H) for H-2 (6e and 8e), AA%BB%-type spectrum, 2×ꢀd (2×2H) for 6b,c,g,i,j and 8b,c (J: 8.8), the H-3,5 signal is a t for 6c,j and 8c due to FꢁH coupling, J(F,H): ꢀ8.
f Doubled signal, split by 0.01 ppm.
130
g Overlapping signals.
h Broad.
i NCH3, s (3H): 3.19.
k C(sp3)H: 5.15 d (J: 4.5), OH: 6.28 d.
l Signals of the a-pyridyl group, H-3, d (J: 8.3): 6.68 (6h), 6.81 (6i), 6.78 (6j), H-4, dt (J: 7.8, 7.8, 1.8): 7.63 (6h,i), 7.66 (6j), H-5, dd (7.0, 5.0): 6.85 (6h–j), H-6, dd (J: 5.0 and 1.8): ꢀ8.1g (6h,i):
8.06g (6j).
m CH3 t (3H, J: 7.0): 1.27 (6h), 1.35 (6i,j), 1.43 (8d,e), CH2 qa (2H, J: 7.0): 4.09 (8a), 4.20 (8b,c), 4.28 (8d,e).

Table 2
13C-NMR chemical shifts a of compounds 6a–j and 8a–e b,c
Compound
CH2
ꢀCH
C-2
C-4
CꢀO
C-1%
C-2%,5%
C-3%,4%
C-1¦-5¦
C-1
C-2
C-6
C-3
C-5
C-4
Imidazolinone ring
Substituted c-pentane ring
Aryl group
6a
6b
6c
6d
6e
6f
6g
6h
6i
45.7
–
–
–
–
46.6
–
44.9
–
–
45.8
–
120.7
120.6
123.8
122.6
121.0
121.7
121.5
117.0
121.3
120.6
120.8
124.3
123.8
125.3
125.3
154.9
151.3
150.7
153.0
154.0
159.0
152.0
156.7
153.3
153.4
153.9
149.4
149.7
149.3
149.3
135.5
134.3
?
135.3
135.8
?
134.8
136.9
135.3
135.5
135.7
134.5
134.6
134.4
134.2
168.8
166.6
167.5
166.9
167.5
?
165.6
167.9
166.7
166.8
166.1
164.8
164.9
164.6
164.7
79.1
ꢀ78 d
?
71.4
70.2
70.9
70.1
69.9
68.9
70.2
70.2
70.2
69.9
70.2
70.0
70.2
70.2
69.9
70.1
70.1
70.1
70.1
138.6
136.8
134.3
136.3
140.7
138.6
138.4
140.5
138.8
136.2
138.8
136.8
134.4
136.4
138.8
128.5
119.7
129.2
128.1
116.3 f
127.4 f
130.3 f
128.9
129.6
129.0
129.4
116.1 f
128.4
129.6
128.2
126.5
159.2 f
124.1 f
119.5 f
127.4
127.5
127.7
127.2
158.5 f
128.2
128.5
159.1 f
122.7
120.0
/
71.5 e
71.6 g
71.3 g
71.3
120.3 f
118.0 f
116.3 f
127.0
78.8
79.2
79.2
78.9
80.2
79.2
79.3
79.2
78.4
78.5
78.2
78.1
71.5 g
71.2 g
71.0
121.8
123.7
134.8
130.6
71.5 e
70.6 h
71.4 e
71.3 e,i
71.3
121.9
128.5
70.2
70.9
121.9
6j
122.0 f
129.2
8a
8b
8c
8d
8e
71.5 e
71.5 e
71.6 e
71.6 g
120.3
f
–
–
–
120.5 f
117.9 f
116.0 f
116.2
120.8
121.8
126.7 f
132.0 f
138.8
130.0
71.7 g
634
a In CDCl3 solution at 125 MHz. Chemical shifts in ppm (lTMS=0 ppm), coupling constants in Hz.
(
b Assignments were supported by DEPT, for 6b–d,g,j and 8a,b,d,e by HMQC (2D-HSC) and for 6a–e,g,j and 8a,b,d,e also by HMBC (2D-COLOC) measurements.
c Further signals: CF3, qa: ꢀ125 (6d), 125.2 (6e), 124.9 (8d), 124.5 (8e), NCH3 (6f): 43.6, CꢀO (6g): 172.8; C(sp3)H (6g): 74.3, CAr-1 (6g): 141.4, CAr-2,6 (6g): 128.3, CAr-3,5 (6g): 129.0, CAr-4
122
(6g): 128.7, a-pyridyl group, C-2: 158.1 (6h–j), C-3: 108.6 (6h), 10.9.2 (6i,j), C-4: 138.7 (6h–j), C-5: 117.0 (6h), 117.3 (6i,j), C-6: 148.5 (6h–j), CH3: 14.5 (8a), 14.6 (8b,c,e), 14.4 (8d), CH2: 63.6 (8a),
63.9 (8c), 64.0 (8b,e), 63.2 (8d), NꢀCH: 158.2 (8a,b,c,e), 156.8 (8d).
130
d Determined indirectly with limited accuracy from HMBC (2D-COLOC) measurement.
e Overlapping signals.
f Doublet (6c,j and 8c)/quartet (6d,e and 8d,e) split due to F,H-couplings, 1J: 240.7 (6c), 272.0 (6e and 8e), 239.4 (6j), 242.4 (8c), 275.8 (8d), 2J: 22.7 (6c), 29.7 (6d), 22.2 (6j), 22.6 (8c), 30.5
(6e, 8d), 32.5 (8e), 3J: 8.4 (6c), ꢀ8 (6d,e), 7.6 (6j, 8c), 5.1 (8d), 3.8 (with H-2), B3 (with H-4) (8e), 4J: ꢀ3 (6d).
g Interchangeable assignments.
h Two lines (the second one appears at 71.2).
i Broadened signal.

126
G. Tu´ro´s et al. / Journal of Organometallic Chemistry 634 (2001) 122–130
Scheme 2.
Table 3
Characteristic IR frequencies (cm−1) of compounds 6a–j, and 8a–e (KBr discs)
Compound
wNH band (broad or diffuse)
wCꢀO band a
wCꢀN band b
kCArH band
wasCpꢁFeꢁCp and tilt of Cp
6a
6b
6c
6d
6e
6f
6g
6h
6I
6j
8a
8b
8c
8d
8e
3325, 3250
3320, 3190
3380, 3315
3395, 3330
3600–3250
3326
1690
1719
1712
1705
1701
1699
1712 d
1720
1711
1725
1696
1701
1705
1703
1699
1657
1653
1661
1655
1654
1654
1654
1661
750
835
840
767
789
721
826 e
760
828
839
734
824
837
760
696
480
492
514
501
482, 492
481
489
477
502
486
497
573, 489
ꢀ500
490
3500–3300 c
3375
3270
3359, 3295
3400
3370
3370
1651
1653
1655, 1598
1651, 1594
1653, 1588
1657, 1595
1655, 1595
3385
3390
535, 496
a Amide-I-type band of the g-lactame group.
b wCꢀN (ring)\wCꢀN (side chain) for compounds 8a–e.
c Coalesced with the wOH band.
d wCꢀO (side chain),
e kCArCAr band for 6a,e,f,g,h and 8a,e: 70093.
pound 6i. 1H,15N-correlations ꢀCH(a),N-3 and N-
1(pyridine) with H-5(pyridine), H-6(pyridine), and
H(hydrazine-NH), respectively, prove the assignments
for the signals of these nitrogens at 181 and 268 ppm.
Similarly, N-1 must give the line at 157 ppm showing
long-range correlations to both NHs. Thus, the two
exocyclic nitrogens must have overlapping signals at 92
shift at 9.30 ppm and the C-3 of the pyridine ring.
Thus, the tautomeric form with the endocyclic CꢀN
bond is predominant in these compounds independently
from aromatic or aralkyl-type of the N-substituent.
Nevertheless, significant differences were measured, e.g.
for the shifts of the ꢀCH, C-2 and CꢀO carbons (ꢀCH:
120.8 and 123.8–125.3, C-2: 153.9 and 149.3–149.7,
CꢀO: 166.1 and 164.6–164.9) in the benzyl (a) and aryl
(b–e) derivatives of structure 8. A similar but smaller
difference in the carbonyl shift is also observable for 6a
as compared to 6b–e (168.8 and 166.6–167.5), but the
buffering effect of the NHR% group can compensate
here in case of 6-type compounds the change in electron
density about the ring atoms due to −I-effect of the
N-substituents.
1
ppm. Indeed, in the H-dimension two doubled cross-
peaks are identifiable with 1J(N,H): 91 (lNH: 9.30
1
ppm) and 93 Hz (dNH: 9.60 ppm). Since the H signal
at 9.30 ppm has cross-peaks also with N-1 and N-
1(pyridine), while the other at 9.60 ppm with N-1 and
N-3, the first one can be assigned as the hydrazine-NH
and the second one to the exocyclic-NH in position 2.
1
Thus, H,13C-correlation via long-range couplings can
be seen between the NH group having a signal at 9.60
ppm and the ortho-carbons of the N-aryl group (121.9
ppm) and, similarly between the NH-hydrogen having a
It is interesting to note that the H-2%,5% signal (cy-
clopentadienyl ring) is doubled in the case of 6h only,
suggesting hindered rotation (coplanar arrangement of

G. Tu´ro´s et al. / Journal of Organometallic Chemistry 634 (2001) 122–130
127
Fig. 1. Perspective view of the structure of compound 3 showing the X-ray labelling of non-hydrogen atoms and their 50% probability
displacement ellipsoids. Hydrogen atoms are shown as small spheres with constant radius.
the CꢀC double bond and the cyclopentadiene ring) of
the ferrrocenyl moiety. This fact may be interpreted by
a steric hindrance between this group and the benzyl
substituent.
Because of the individual single structure of 3, the
spectral data are given in Section 3 instead of in the
tables.
In the IR spectrum two carbonyl band of relatively
high frequencies (1765 and 1713 cm−1) are present.
Concerning the starting materials and the reaction con-
ditions the presence of a saturated ester group (1713
aligned near-perfectly collinear with angles at the Fe
atom of 177 and 178°, respectively. The cyclopentadi-
enyl rings of the ferrocenyl substituents adopt an al-
most perfect ecliptic conformation and they have the
usual geometry and are also coplanar within one unit.
With respect to the central imidazole ring they have
similar and only slightly differing low dihedral angles
with mean values of 13.3(3) and 22.2(3)°, respectively.
The intramolecular geometry otherwise shows normal
values.
Since no classic hydrogen bonds are possible we only
found five (cf. Table 4) CꢁH···O-type interactions [12].
Two of these are intramolecular and both go to the
same side of the chiral C atom. Here one H-atom of the
ꢁCH2 moiety at C-91 is on one side, while atom O-4
connects H-22 of one of the CH hydrogen of the more
twisted ferrocenyl group. A further disparity in these
interactions is that two of the three intermolecular
CꢁH···O attachments go also to this ether side arm: one
connects to the other hydrogen of the 9-methylene
group while one possible H-atom site of the methyl
termini is also involved. The only interaction of the
other ester side arm goes from O-2 to the ferrocenyl
H-30. Note that virtually identically placed ferrocenyl
H-atoms of the more twisted ferrocenyl group take part
in the interactions. The relative importance of these
forces fixing the respective ferrocenyl can be well as-
sessed from the atomic displacement representations of
Fig. 1. These are noticeably larger for the unbound
ferrocenyl group.
cm−1) and a carbonyl in the strained ring (1765 cm−1
,
g-lactone/lactame) are probable. 1H- and 13C-NMR
signals of two different ethoxy and ferrocenyl groups
appear in the corresponding spectra confirming the
participation of two molecules of formylferrocene and
1
azidoaceticester in the reaction. The H- and 13C-NMR
signals of the atom pairs in positions 2%,5% and 3%,4% are
separated pointing to hindered rotation of the ferro-
cenyl moieties due to steric hindrance or conjugation
and, consequently coplanar arrangement of the substi-
tuted cyclopentadiene (Cp) rings with a double bond.
Two separated CH groups, one of which containing an
sp2 or sp3 carbon and two quaternary sp2 carbon
atoms, one vicinal to one or two heteroatoms (lC:
159.9 ppm) are also present in the molecule.
All the above data are consistent with structure 3 as
determined by X-ray diffraction.
The X-ray crystal structure analysis of 3 revealed the
structure depicted in Fig. 1. The structure shows a
fairly perfect alignment of the Fe in their respective
cyclopentadienyl ligands. Metal atoms have practically
zero slippage with respect to their ring centres and are
1 For X-ray numbering see Fig. 1.

128
G. Tu´ro´s et al. / Journal of Organometallic Chemistry 634 (2001) 122–130
Table 4
Possible CꢁH···O type contacts in the crystal of 3
Type
Intra
Intra
DonorꢁH···acceptor
DꢁH
H···A
D···A
DꢁH···A
C(9)ꢁH(9A)···O(2)
C(9)ꢁH(9B)···O(1)a
C(10)ꢁH(10A)···O(2)a
C(22)ꢁH(22)···O(4)
C(30)ꢁH(30)···O(2)b
1.083
1.083
1.083
1.083
1.083
2.517
2.498
2.462
2.354
2.458
3.102(5)
3.405(5)
3.425(5)
3.189(4)
3.395(6)
112.8
140.6
147.5
132.7
144.2
Note that the CꢁH bond lengths are idealised, thus the geometry proposed here is the best possible one. Estimated S.D.s are only given where
meaningful values exist. Translation of symmetry codes to equivalent positions: (a)=x, 5/2−y, −1/2+z; (b)=1−x, 2−y, 1−z.
3. Experimental
and wR2=0.0891 for 2418 [I\2|(I)] and R1=0.0503
and wR2=0.1028 for all (5218) intensity data. (Good-
ness-of-fit=0.827, extinction coefficient=0.00023(19),
The 1H- and 13C-NMR spectra were recorded in
CDCl3 or DMSO-d6 solution in 5 mm tubes at room
temperature (r.t.), in a Bruker DRX 500 spectrometer
at 500.13 (1H) and 125.76 (13C) MHz, with the deu-
terium signal of the solvent as the lock and TMS as
internal standard. Distortionless enhancement by polar-
isation transfer (DEPT) spectra were run in a standard
manner, using only the [=135° pulse to separate
CH/CH3 and CH2 lines phased ‘up’ and ‘down’, respec-
tively. The 2D-HMQC and 2D-HMBC spectra were
obtained by using the standard Bruker pulse programs
INV4GSSW and INV4GSLRNDSW, respectively. The
IR spectra were recorded as KBr pellets in a Bruker
IFS 55 spectrometer.
Melting points (uncorrected) were determined with a
Boetius apparatus.
A summary of crystallographic data for 3 is compiled
in Table 5. A crystal of 3 was mounted on a glass fibre.
Cell parameters were determined by least-squares of the
setting angles of 25 (10.065[511.49°) reflections.
Table 5
Crystal data and structure refinement parameters for 3
Empirical formula
Formula weight
Temperature (K)
Radiation and wavelength
Crystal system
C30H30Fe2N2O4
594.26
295(2)
Mo–Ka, u=0.71070 A
Monoclinic
,
Space group
P21/c
Unit cell dimensions
,
a (A)
17.441(2)
15.091(2)
10.108(1)
90.00
93.47(1)
90.00
2655.6(5)
4
1.486
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
V (A )
3
,
Z
Dcalc (Mg m−3
)
Absorption coefficient, v (mm−1
F(000)
)
1.132
1232
Crystal colour
Pale yellow
Block
0.20×0.20×0.15
Empirical
0.8486, 0.8053
Intensity data were collected in an Enraf–Nonius CAD
diffractometer (graphite monochromator; Mo–Ka radi-
ation, u=0.71070 A) at 295(2) K in the range 2.345
4
Crystal description
Crystal size (mm)
Absorption correction
Max/min transmission
,
[526.14° using ꢀ/2[ scans. The scan width was
0.50+0.68tg([)° in ꢀ. Backgrounds were measured in
half the total time of the peak scans. The intensities of
three standard reflections were monitored regularly (ev-
ery 60 min). The intensities of the standard reflections
indicated a crystal decay of 4%, and the data were
corrected for decay [13].
A total of 5512 reflections was collected of which
5218 were unique [Rint=0.0209, R(|)=0.1486]; inten-
sities of 2418 reflections were greater than 2|(I). Com-
pleteness to [=0.982. An empirical absorption
correction was applied to the data (the minimum and
maximum transmission factors were 0.8053 and 0.8486)
[14]. The initial structure model was obtained from
direct methods [15] (and subsequent difference
syntheses).
Theta range for data collection (°) 2.345q526.14
Index ranges
05h521, 75k518,
125l512
Reflections collected
Completeness to 2q
Number of standard reflections
Decay (%)
5512
0.982
3
4
Independent reflections
Reflections [I\2|(I)]
Refinement method
5218 [R(int)=0.0209]
2418
Full-matrix least-squares on
F2
Data/restraints/parameters
Goodness-of-fit on F2
Extinction coefficient
Final R indices [I\2|(I)]
R indices (all data)
5218/0/346
0.827
0.00023(19)
R1=0.0465, wR2=0.0891
R1=0.1503, wR2=0.1028
0.000; 0.000
Max and mean shift/estimated
S.D.
Largest difference peak and hole
0.324 and −0.386
−3
Anisotropic full-matrix least-squares refinement [16]
,
(e A
)
on F2 for all non-hydrogen atoms yielded R1=0.0465

G. Tu´ro´s et al. / Journal of Organometallic Chemistry 634 (2001) 122–130
129
Table 6
Physical and analytical data of compounds 6a–j and 8a–e
Compound
Appearance
M.p. (°C)
Formula
Calc. (%)
C
Found (%)
C
H
N
H
N
6a
6b
6c
6d
6e
6f
6g
6h
6i
Purple powder
Orange plates
Purple plates
Orange powder
Orange powder
Red powder
Red needles
Red plates
Red plates
Red plates
Purple powder
Purple powder
Purple powder
Purple powder
Purple powder
181–183
225–227
206–209
203–204
109–112
163–166
212–214
201–204
205–207
196–199
170–172
187–188
162–165
185–187
156–158
C
21H20FeN4O
63.00
57.14
59.40
55.50
55.50
63.76
60.64
65.40
60.36
62.37
63.15
57.98
60.00
56.47
56.47
5.00
4.04
4.20
3.74
3.74
5.31
4.15
4.82
4.02
4.15
5.26
4.41
4.56
4.11
4.11
14.00
13.33
13.86
12.33
12.33
13.52
10.10
14.67
14.08
14.55
12.28
11.76
12.17
10.98
10.98
63.15
57.23
59.56
55.41
55.42
63.64
60.51
65.37
60.43
62.52
63.19
58.01
60.13
56.49
56.50
4.93
4.10
4.18
3.79
3.75
5.26
4.21
4.91
4.11
4.23
5.33
4.45
4.63
4.18
4.20
14.07
13.42
13.91
12.40
12.39
13.58
10.14
14.65
14.12
14.63
12.35
11.84
12.19
11.07
11.02
C20H17ClFeN4O
C20H17FFeN4O
C
C21H17F3FeN4O
C22H22FeN4O
21H17F3FeN4O
C
28H23ClFeN4O3
C26H23FeN5O
C25H20ClFeN5O
6j
C25H20FFeN5O
C24H24FeN4O2
C
C23H21FFeN4O2
C24H21F3FeN4O2
C24H21F3FeN4O2
8a
8b
8c
8d
8e
23H21ClFeN4O2
the maximum and mean shift/estimated S.D. is 0.000
and 0.000.) The maximum and minimum residual elec-
71.6,f,i 72.4,f,h 72.6;f C(sp3)H: 78.0;g ꢀCH: 130.7; C-4:
136.2; C-2: 159.9; CꢀO:a 167.2; CꢀO (C-5): 170.1.
The appropriate 1-amino- (6a–e), 1-(methyl)amino-
(6f), 1-(mandeloyl)amino (6g) and 1-(2-pyridyl)amino-
2-arylamino-4-ferrocenylmethylideneimidazolin-5-ones
(6h–j) were prepared by condensation of compound 4
with the corresponding isocyanates followed by reac-
tion with hydrazine or hydrazine derivatives (yields:
15–92%).
The 1-amino-2-arylamino-4-ferrocenylmethylidenei-
midazolin-5-ones (6a–e) with triethyl orthoformate
gave 1-(ethoxymethylidene)amino derivatives (8a–e) in
yields of 29–70%.
tron density in the final difference map was 0.324 and
−3
,
−0.386 e A
.
The weighting scheme applied was w=1/[|2(Fo2)+
(0.0457P)2+0.0000P] where P=(Fo2 +2F2c)/3. Hydro-
gen atomic positions were calculated from assumed
geometry. Hydrogen atoms were included in structure
factor calculations but they were not refined. The
isotropic displacement parameters of the hydrogen
atoms were approximated from the Ueq value of the
atom they were bonded to, all calculation were per-
formed also using normalised geometries [17].
Compounds 2 and 4 are described in the literature
[4–6].
3.1. General procedure for preparation of 1-amino-,
1-(methyl)amino-, 1-(mandeloyl)amino- and 1-(2-
pyridyl)amino-2-arylamino-4-ferrocenylmethylidene-
imidazolin-5-ones
In the course of the preparation of 2, 1-(1-ethoxy-1-
ethoxycarbonylmethyl)-2-ferrocenyl-(E)-4-ferrocenyl-
methylideneimidazolin-5(1H)-one (3) was also formed
and isolated as a slowly eluting component by chro-
matography over silica (eluent: CHCl3), yield 20%.
IR (KBr disc, cm−1): wCꢀO (g-lactame): 1765; wCꢀO
(ester): 1713; wCꢁO: 1220, 1155, 1124, 1027; ferrocenyl
(wasCpꢁFeꢁCp and tilt vibr. of Cp rings): 505, 479, 457.
1H-NMR (l, ppm, CDCl3, 500 MHz): CH3: 1.01,2 a
1.35,b 2×t (2×3H), J=7.3, 6.9 Hz; CH2: 4.03, qa
(2H),a 3.73 and 3.89, 2×qa (2H),b H-2¦-5¦, 2×s (2×
5H):c 4.13,e 4.17;f H-3%,4%, ꢀs (4×1H):d 4.38,e 4.46,e
4.53,f 4.55,f H-2%,5%, ꢀs:d 5.01 (1H),f 5.06 (1H),e 5.13
(2H); C(sp3)H, s (1H): 5.97; ꢀCH, s (1H): 7.07.
13C-NMR (l, ppm, CDCl3, 126 MHz): CH3: 14.3,a
15.5;b CH2: 62.8,a 64.8;b C-2¦-5¦:c 70.4, 70.6; C-1%:d
73.0,e 78.0;f,g C-2%,5%:d 69.4,e 71.2,e 72.4,f,h 72.7;f C-3%,4%:d
To a solution of 4 (0.4 g, 0.0007155 mol) in anhy-
drous CH2Cl2 (30 ml) the corresponding isocyanate was
added and the mixture was stirred at r.t. for 24 h to
form carbodiimides 5. Then, hydrazine or hydrazine
derivatives (0.0007155 mol) were added to the reaction
mixture to give imidazolinones 6a–j by stirring at r.t.
for another 6 h. The solvent was removed under re-
duced pressure and the crude solid was chro-
matographed on silica (Kieselgel type 9385; eluent:
n-hexane–ethyl acetate 3:1). Recrystallisation from
petroleum ether 40–70 °C gave the pure products.
Product 6g was prepared in the same way but the
solvent was anhydrous tetrahydrofuran in which man-
deloyl hydrazide is fairly soluble (see Table 6).
1-Amino-2-benzyl-4-ferrocenylmethylideneimida-
zolin-5-one (6a) (74%); 1-amino-2-p-chlorophenyl-4-fer-
rocenylmethylideneimidazolin-5-one (6b) (91%); 1-
2 a—Ester group; b—ether group; c,d—cyclopentadiene ring un-
substituted/substituted; e,f—ferrocenyl group bonded to the imida-
zolone ring in position 2/in side chain; g,h,i—two coalesced lines.

130
G. Tu´ro´s et al. / Journal of Organometallic Chemistry 634 (2001) 122–130
amino-2-p-fluoro-phenyl-4-ferrocenylmethylideneimida-
zolin-5-one (6c) (92%); 1-amino-2-a,a,a-trifluoro-o-
grant T-025910) for an in-part support to these investi-
gations. The other authors express their thanks to the
HRF (OTKA) for grant T-29651 and to the Hungar-
ian–German Intergovernmental S&T Cooperation Pro-
gramme (OMFB-WZT) for financial support D-35/99.
tolyl-4-ferrocenylmethylideneimidazolin-5-one
(6d)
(60%); 1-amino-2-a,a,a-trifluoro-m-tolyl-4-ferrocenyl-
methylideneimidazolin-5-one (6e) (52%); 1-(methyl)-
amino-2-benzyl-4-ferrocenylmethylideneimida-
zolin-5-one (6f) (15%); 1-(mandeloyl)amino-2-p-
chlorophenyl-4-ferrocenylmethylideneimidazolin-5-one
(6g) (42%); 1-(2-pyridyl)amino-2-benzyl-4-ferrocenyl-
methylideneimidazolin-5-one (6h) (63%); 1-(2-pyri-
dyl)amino-2-p-chlorophenyl-4-ferrocenylmethyli-
deneimidazolin-5-one (6i) (66%); 1-(2-pyridyl)amino-2-
p-fluorophenyl-4-ferrocenylmethylideneimidazolin-5-
one (6j) (54%).
References
´
[1] A. Abra´n, A. Csa´mpai, A. Kotschy, O. Baraba´s, P. Soha´r, J.
Mol. Struct. 569 (2001) 185.
[2] A. Togni, T. Hayashi (Eds.), Ferrocenes (Homogeneous Cataly-
sis, Organic Synthesis, Materials Science), VCH Verlagsges-
sellschaft, Weinheim, 1995.
[3] (a) K.E. Dombrowski, W. Baldwin, J.E. Sheats, J. Organomet.
Chem. 302 (1986) 281;
(b) E.W. Neuse, M.G. Meirim, N.F. Blam, Organometallics 7
(1988) 2562;
(c) A. Houlton, R.M.G. Roberts, J. Silver, J. Organomet. Chem.
418 (1991) 107.
3.2. General procedure for preparation of 1-(ethoxy-
methylidene)amino-2-arylamino-4-ferrocenylmethyl-
ideneimidazolin-5-ones
[4] P. Molina, A. Pastor, M.J. Vilaplana, M.V. Desamparados,
Organometallics 16 (1997) 5836.
To a solution of 6 (0.0005 mol) in triethyl orthofor-
mate (5 ml) p-tolylsulfonic acid was added in catalytic
amount and the mixture was heated to reflux tempera-
ture under stirring for 2 h. Then, the solvent was
removed under reduced pressure and the crude solid
was chromatographed on silica (Kieselgel type 9385;
eluent: n-hexane–ethyl acetate 1:1). Recrystallisation
from anhydrous ethanol gave the pure products (see
Table 6).
1-(Ethoxymethylidene)amino-2-benzyl-4-ferrocenyl-
methylideneimidazolin-5-one (8a) (70%); 1-(ethoxy-
methylidene)amino-2-p-chlorophenyl-4-ferrocenylme-
thylideneimidazolin-5-one (8b) (64%); 1-(ethoxymethyli-
dene)amino-2-p-fluorophenyl-4-ferrocenylmethylidene-
[5] P. Molina, A. Tarraga, D. Curiel, C.R. de Arellano, Tetrahedron
55 (1999) 1417.
[6] A. Tarraga, P. Molina, D. Curiel, J.L. Lopez, M.V. Desampara-
dos, Tetrahedron 55 (1999) 14701.
[7] W.E. Watts, J. Organomet. Chem. Library 7 (1979) 399 (and
references therein).
[8] D. Knittel, Synthesis (1985) 186.
[9] D.H.R. Barton, A.N. Starratt, J. Chem. Soc. (1965) 2444.
[10] S. Holly, P. Soha´r, in: L. La´ng (Ed.), S. Holly, P. Soha´r
(Collaborators), Theoretical and Technical Introduction to the
Series: Absorption Spectra in the Infrared Region, Akade´miai
Kiado´, Budapest, 1975, p. 113.
[11] P. Soha´r, Nuclear Magnetic Resonance Spectroscopy, vol. 2,
CRC Press, Boca Raton, FL, 1983, p. 89.
[12] For CꢁH···Acceptor interactions: Th. Steiner, Crystallogr. Rev. 6
(1996) 1.
[13] K. Harms, XCAD4 Data Reduction Program for CAD4 Diffrac-
tometers, Philipps-Universita¨t Marburg, Germany, 1996.
[14] A.C. North, D.C. Philips, F. Mathews, Acta Crystallogr. Sect. A
24 (1968) 350.
[15] SHELXS: G.M. Sheldrick, SHELXS-97, Program for Crystal Struc-
ture, University of Go¨ttingen, Go¨ttingen, Germany, 1997.
[16] G.M. Sheldrick, SHELXL-97, Program for Crystal Structure
Refinement, University of Go¨ttingen, Go¨ttingen, Germany,
1997.
imidazolin-5-one
(8c)
(65%);
1-(ethoxymethyli-
dene)amino-2-a,a,a-trifluoro-o-tolyl-4-ferrocenylmethyl-
ideneimidazolin-5-one (8d) (29%); 1-(ethoxymethyli-
dene)amino-2-a,a,a-trifluoro-m-tolyl-4-ferrocenylme-
thylideneimidazolin-5-one (8e) (34%).
Acknowledgements
[17] PLATON: A.L. Spek, Acta Crystallogr. Sect. A 46 (1990) C-34.
ORTEP: M.N. Burnett, C.K. Johnson, ORTEP-III, ORNL Report
6895, 1996.
M.C. thanks the Hungarian Research Fund (OTKA