Aerobic Fujiwara-Moritani alkenylation and dienylation of ferrocene

Article abstract of DOI:10.1016/j.jorganchem.2011.07.029

Pd(OAc)₂-catalyzed aerobic alkenylation and dienylation of ferrocene with electron-poor olefins and dienes (ethyl acrylate, methyl (E)-cinnamate, diethyl fumarate and maleate, ethyl sorbate and sorbic acid) is reported. In the case of acrylate and cinnamate the reaction leads to mixtures of mono- and dialkenylated ferrocenes. In other cases the products of mono alkenylation and dienylation are formed in low yield. The relatively slow (～1 week) reaction takes place in AcOH solutions at room temperature.

Full text of DOI:10.1016/j.jorganchem.2011.07.029

Journal of Organometallic Chemistry 696 (2011) 3499e3506
Contents lists available at SciVerse ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Aerobic FujiwaraeMoritani alkenylation and dienylation of ferrocene
,
b
b
b
Micha1 Piotrowicz a, Janusz Zakrzewski a , Anna Makal , Joanna Ba˛k , Maura Malinska ,
*
ꢀ
b
ꢀ
Krzysztof Wozniak
a
ꢀ
ꢀ
Department of Organic Chemistry, Faculty of Chemistry, University of Łódz, Tamka 12, 91-403 Łódz, Poland
b Department of Chemistry, Warsaw University, Pasteura 1, 02-093 Warszawa, Poland
a r t i c l e i n f o
a b s t r a c t
Article history:
Pd(OAc)2-catalyzed aerobic alkenylation and dienylation of ferrocene with electron-poor olefins and
dienes (ethyl acrylate, methyl (E)-cinnamate, diethyl fumarate and maleate, ethyl sorbate and sorbic acid)
is reported. In the case of acrylate and cinnamate the reaction leads to mixtures of mono- and dia-
lkenylated ferrocenes. In other cases the products of mono alkenylation and dienylation are formed in
low yield. The relatively slow (w1 week) reaction takes place in AcOH solutions at room temperature.
Ó 2011 Elsevier B.V. All rights reserved.
Received 1 June 2011
Received in revised form
19 July 2011
Accepted 21 July 2011
Keywords:
Ferrocene
CeH activation
Alkenylation
FujiwaraeMoritani reaction
palladium(II) catalysis
Aerobic oxidation
1. Introduction
Pd(OAc)þ) on the arene followed by deprotonation (arene CeH
activation [4]), insertion of the olefin into the PdeC bond and
In recent two decades there has been a resurgence of interest in
the chemistry of ferrocene and its derivatives due to their growing
applications in various branches of science, ranging from materials
science (e.g. nonlinear optics) and asymmetric catalysis to
analytical chemistry, biochemistry and medicine (bio-
organometallic chemistry) [1]. This has stimulated development of
simple, efficient and selective methods of functionalization of this
readily available metallocene, based mainly on its electrophilic
substitution reactions.
Previous work in our laboratory has focused on the search of
novel electrophilic reactions of ferrocene, providing direct access
to its complex derivatives, available earlier only by more tedious,
multistep routes [2]. Continuing this research program we
recently focused our attention on the application of Pd(II)-
catalyzed reactions for functionalization of ferrocene via CeH
bond activation. The FujiwaraeMoritani dehydrogenative arene-
alkene coupling [3] seemed especially well-suited for this
purpose. This reaction involves attack of a Pd(II) electrophile (e.g.
elimination of Pd(0). The latter species should be reoxidized to
Pd(II) to sustain the catalytic cycle.
Surprisingly, up to now only little attention has been payed to
a possibility of application of this reaction in the ferrocene chem-
istry. Early reports describe only a stoichiometric coupling of
ferrocene with alkenes in the presence of Pd(II) [5]. The coupling
products were obtained in modest yields (with respect to Pd) and
there were no attempts to make this reaction catalytic.
Herein we report the first catalytic aerobic system enabling
direct alkenylation and dienylation of ferrocene with electron-poor
olefins. The main problem we have encountered in developing of
such a system is that oxidants usually used in the Fujiwar-
aeMoritani reaction for the recovery of catalytically active Pd(II)
species (e.g. quinones, hydroperoxides, peresters) [6] oxidize
ferrocene to the ferrocenium cation. However, it is known that in
the in the absence of strong acids ferrocene exhibits remarkable
resistance to dioxygen (air) [7]. Therefore, we have decided to use
air as the sole oxidant. Unfortunately, the oxidation of Pd(0) by
dioxygen is usually inefficient [8] and only a few catalytic systems
using only this oxidant have been so far reported. Such systems as
waste-free (the sole by-product is water), atom-economic [9] and
environmentally friendly are of obvious interest in the context of
“green” chemistry [10].
* Corresponding author. Tel.: þ48 42 6355 850; fax: þ48 42 6655 225.
E-mail address: janzak@uni.lodz.pl (J. Zakrzewski).
0022-328X/$ e see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2011.07.029

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M. Piotrowicz et al. / Journal of Organometallic Chemistry 696 (2011) 3499e3506
2. Results and discussion
In all cases the reaction proceeded stereoselectively yielding
exclusively (E)-isomers. The (E)-configuration of 2a and 3a was
confirmed by large values of the coupling constants between
vinylic protons (w16 Hz). For products 2b and 3b it has been
determined by X-ray diffraction(vide infra). It is worth noticing that
this configuration agrees with a syn-insertion of the olefin into the
PdeC bond in the intermediary FcPdOAc, followed by a syn-elimi-
nation of HPdOAc [3].
In contrast to acrylates, which are usually very reactive alkene
components and were frequently used in the studies of the Miz-
orokieHeck and FujiwaraeMoritani reactions, disubstituted
alkenes such as cinnamates are less reactive. They usually require
harsh reaction conditions and give rise to the formation of mixtures
of E/Z isomers. In fact, examples of stereoselective Heck reactions
with cinnamates are scarce and were developed only recently [11].
Therefore, the observed stereoselectivity of the coupling of ferro-
cene with methyl (E)-cinnamate is worth noticing.
We assume, similarly as Fujiwara and co-workers for stoichio-
metric Pd-promoted ferrocene alkenylation [5], that reactions
under study proceed via electrophilic palladation of ferrocene,
olefin insertion and elimination of “HPdOAc”.
Interestingly, disubstituted products were formed in the same
yield (20%) at the FcH to acrylate ratio 2:1 and 1:2. On the other
hand, the yield of these products increased with the catalyst
loading, which may suggest concomittant ferrocene dipalladation
occurring before insertion of the olefin into PdeC bond.
2.1. FujiwaraeMoritani coupling of ferrocene with ethyl acrylate
and methyl-(E)-cinnamate
In most published works on the FujiwaraeMoritani reactions of
arenes not containing metallation directing groups a large excess of
a liquid arene (benzene, toluene etc.), miscible with the reaction
medium was used, facilitating the first step of the reaction. This
could not be done in the case of ferrocene, which display only
a limited solubility in polar organic solvents (e.g. in acetic acid)
often used in this reaction. Therefore, we were constraint to work
with the reagents ratios closer to the stoichiometric one. In our first
attempts we used electrophilic alkenes-ethyl acrylate (1a) and
methyl (E)-cinnamate (1b) because their high reactivity in the Heck
and FujiwaraeMoritani reactions is well evidenced.
Pleasingly, we have found that ferrocene reacts in the presence
of catalytic amounts of Pd(OAc)2 with these alkenes in aerated
AcOH solutions at room temperature but the reaction is rather
sluggish (w1 week). Because of a limited solubility of ferrocene in
AcOH at the beginning of the reaction it was only partly dissolved
and we observed its gradual dissolution and formation of deep red
solutions in the course of the reaction. The reaction affords
mixtures of mono-alkenylated ferrocenes 2a,b and bis-alkenylated
products 3a,b and 4a,b (Scheme 1, Table 1).
In the absence of air (under argon) ferrocene did not react with
1a,b. On the other hand, in air at higher temperatures (70e90 ꢀC)
a fast deposition of inactive Pd black was observed and reaction
stopped giving only trace amounts of the products. This presum-
ably resulted from a faster formation of Pd(0) and its less efficient
re-oxidation due to lower solubility of dioxygen in the reaction
medium at a higher temperature.
The mono-alkenylated products 2a,b were easily isolated by
column chromatography. Preparative TLC enabled separation of
the 1,10-disubstituted products 3a,b from their homoannularly
substituted isomers 4a,b (inseparable w1:0.7 mixture of 1,2- and
1,3-isomers in the case of 4a and 1,3-isomer in the case of 4b
according to 1H NMR). Interestingly, chromatography afforded
also minor fractions (w1%), which, according to their mass
spectra, contained tri-substituted ferrocenes. However, we have
not observed formation of more substantial amounts of these
species even using six-fold excess of alkene and 20 mol% of
catalyst.
We have also attempted to obtain unsymmetric bis-alkenylated
products via reaction of 2a with methyl (E)-cinnamate under
aforementioned reaction conditions (5 mol% of catalysts). However,
unexpectedly, this attempt failed and 2a was recovered qualita-
tively. On the other hand, 2a does react, with ethyl acrylate to afford
a mixture of 3a and 4a in w20% overall yield along with 80% of
unreacted starting complex. This indicates that 2a is less active than
ferrocene, which is in keeping with the electron-withdrawing
character of the (alkoxycarbonyl)vinyl substituent, and that
methyl (E)-cinnamate is less reactive that ethyl acrylate.
2.2. FujiwaraeMoritani coupling of ferrocene with diethyl maleate
and fumarate
We next studied the reaction of ferrocene with stereoisomeric
esters of unsaturated dicarboxylic acids, diethyl maleate 5a diethyl
fumarate 5b and. Surprisingly, we found that in both cases the same
R
COOR'
Fe
2a-b
+
R
COOR'
Pd(OAc)2 / air
3a-b
R
R
COOR'
Fe
+
Fe
AcOH, rt.
1 week
R'OOC
1a-b
+
R
4a-b
R'OOC
COOR'
Fe
a
: R = H; R' = Et;
b
: R= Ph; R' = Me
R
Scheme 1. FujiwaraeMoritani alkenylation of ferrocene with ethyl acrylate (1a) and methyl-(E)-cinnamate (1b).

M. Piotrowicz et al. / Journal of Organometallic Chemistry 696 (2011) 3499e3506
3501
Table 1
FujiwaraeMoritani alkenylation and dienylation of ferrocene.
Pd(OAc)2 / air
COOR'
+
Fe
Fe
Alkene
FcH: alkene
Pd
FcH conversion Products
(%)
AcOH, rt.
1 week
(diene) (FcH: diene) (OAc)2
%
(% Yield)a,b
mola
COOR'
7a-b
1a
1a
1a
1a
1b
1b
5a
5b
7a
7b
2:1
2:1
1:2
1:2
1:2
1:6
1:2
1:2
1:2
1:2
2.5
5
5
59c
2a (35); 3a (3);4a (3)
2a (42); 3a (9);4a (3)
2a (36), 3a (6),4a (2)
2a (41), 3a (25),4a (16)
2b (25); 3b (3),4b (4)
2b (52),3b (34),4b (10)
6 (8)
6 (8)
8a (10)
8b (5)
8a-b
64c
49
a: R' = Et; b: R' = H
20
98
67
100
10
10
5
20
5
5
5
Scheme 3. FujiwaraeMoritani dienylation of ferrocene with ethyl sorbate and sorbic
acid.
2.4. Crystal structures of complexes 2b, 3b and 8b
10
10
5
Crystal structures of complexes 2b, 3b and 8b are shown in
Figs. 1e3, respectively. The most important geometrical parameters
of these molecules are collected in Tables 2 and 3.
There are two independent molecules of 2b, located in general
positions in asymmetric unit. The space group is a polar Cc in
monoclinic system. On the other hand, 3b.
a
Based on FcH.
Isolated yields.
b
c
Assuming that only a half of the amount of ferrocene can react; Reaction
conditions: FcH (1 mmol), ester and catalysts in AcOH (3 ml) stirred in air at RT for 1
week.
mono-alkenylated product 6 was formed as a red oil in modest
(10%) yield at the catalyst loading 5 mol% (Scheme 2, Table 1). Its
(E)-stereochemistry was established from the NOE effects in the 1H
NMR spectrum. No formation of disubstituted ferrocenes was
observed at the ferrocene:ester ratio 1:2. The compound 6 results
from a syn-addition of “FcPdOAc” to the thermodynamically more
stable ester 5b [12], followed by a syn-elimination of “HPdOAc”.
Formation of the same compound from 5a must involve isomeri-
zation of the kinetic product having (Z)-configuration, presumably
via elimination-readdition of the “HPdOAc” species [3] or
protonation-deprotonation of the C]C bond facilitated by stabili-
zation of the carbocationic center by the ferrocenyl group [13].
The low yield of 6 is not surprising since it is known that
disubstituted alkenes are usually less reactive in the Mizor-
okieHeck reaction than their monosubstituted congeners. More-
Crystallizes in centrosymmetric Pꢁ1 space group of the triclinic
system. One molecule of the complex is present in general position
in the asymmetric part of the unit cell. This results in two 3b
molecules per unit cell, related by the inversion center. Two inde-
pendent molecules are also found for 8b, which crystallizes in
centrosymmetric P2(1)/c space group. The most significant differ-
ence between molecules in the asymmetric unit is that the Cp ring
and lateral chain are more coplanar for 8b-I molecule in compar-
ison to the 8b-II molecule.
In all compounds the lateral chains are practically planar and
coplanar with the adjacent Cp rings revealing extensive
p-conju-
gation. In contrast, the phenyl rings in 2b and 3b are nearly
perpendicular to the plane of the Cp ligands (deviation from the
perpendicularity is larger for 3b, where the appropriate torsion
angle exceeds 100 degrees), suggesting that these rings do not
participate in the conjugation. Interestingly, the perpendicular
orientation of the phenyl rings may also be retained in solution as
indicated by comparison of the electronic spectra of 2a and 2b
over, diethyl fumarate and maleate as
p-acidic alkenes may form
relatively stable complexes with Pd(0) [14] which may hamper its
re-oxidation to Pd(II). Some such complexes were used as catalysts
in the MizorokieHeck reaction.
showing only a slight influence of the substitution of the b-vinylic
hydrogen by the phenyl group on the electronic transitions in these
molecules (364 and 469 nm for 2a and 369 and 476 nm for 2b in
chloroform).
2.3. FujiwaraeMoritani coupling of ferrocene with ethyl sorbate
and sorbic acid
Reaction of ferrocene with ethyl sorbate 7a and sorbic acid 7b
(molar ratio 1:2) afforded the dienylated ferrocenes 8a and 8b
(Scheme 3) in modest yields (10% and 5% respectively at the catalyst
loading 5 mol%). Therefore, only in the former case the reaction is
slightly catalytic (TON ¼ 2).
3. Conclusions
We have elaborated the first catalytic oxidative alkenylation and
dienylation of ferrocene with unsaturated esters using air as the
sole oxidant (“green oxidation”). Moreover, our system works at
room temperature, a condition which is still challenging in Pd-
catalyzed CeH bond activation [16]. The reactions described in
this work constitute a direct route to mono- and dialkenylated
ferrocenes and ferrocenyl-substituted dienes which may be of
interest as starting materials in syntheses of more complex ferro-
cenyl systems. Our current research is focused on improving cata-
lyst activity and selectivity, extending the scope and gaining more
detailed information on the mechanism of the reaction.
In both cases the reactions were stereoselective and afforded
exclusively the (E,E)-isomers. This configuration was deduced for
8a from NOE effects in the 1H NMR spectrum and for 8b by X-ray
diffraction (vide infra).
A product closely similar to 8a (methyl instead of ethyl ester) was
obtained in 28% yield in a stoichiometric reaction of methyl sorbate
with ferrocenylpalladium chloride [15]. This fact provides further
support for the FujiwaraeMoritani mechanism of reactions under
study.
COOEt
4. Experimental
COOEt
COOEt
Pd(OAc)2 / air
Fe
Fe
+
4.1. General remarks
AcOH, rt.
1 week
COOEt
5a: (Z); 5b (E)
Scheme 2. FujiwaraeMoritani alkenylation of ferrocenewith diethyl fumarate or maleate.
All reagents and solvents used in this work are commercially
available (SigmaeAldrich). All reactions and workups were per-
formed in air. Chromatographic separations were carried out on
Silica gel 60 (Merck, 230e400 mesh ASTM). NMR spectra were
6

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M. Piotrowicz et al. / Journal of Organometallic Chemistry 696 (2011) 3499e3506
Fig. 1. Molecular structure and labeling of atoms for two crystallographically independent molecules of 2b.
Fig. 2. Molecular structure and labeling of atoms for 3b.

M. Piotrowicz et al. / Journal of Organometallic Chemistry 696 (2011) 3499e3506
3503
Fig. 3. Molecular structure and labeling of atoms for two crystallographically independent molecules of 8b.
obtained on a Varian Gemini 200 BB (200 MHz for 1H) and Bruker
Avance (600 MHz for 1H) and referenced to internal TMS. IR spectra
were obtained on a FT-IR Nexus (Thermo Nicolet) spectrometer.
Mass spectra were recorded on a Finnigan MAT 95 spectrometer.
Elemental analysis: Found: C, 70.90; H, 4.99. C30H26FeO4 requires:
C, 71.16. H, 5.18. 4a: 1H NMR (600 MHz, CDCl3,
): 1,2-isomer: 7.76
d
(d, J ¼ 16.0 Hz, 2H), 6.14 (d, J ¼ 16.0 Hz, 2H), 4. 78 (d, J ¼ 3.0 Hz, 2H),
4.64 (t, J ¼ 3.0 Hz, 1H), 4.26 (q, J ¼ 7.2 Hz, 4H) 4.153 (s, 5H), 1.35 (t,
J ¼ 7.2 Hz, 6H). 1,3-isomer: 7.52 (d, J ¼ 16.0 Hz, 2H), 6.09 (d,
J ¼ 16.0 Hz, 2H), 4.79 (t, J ¼ 1.2 Hz, 1H), 4. 69 (d, J ¼ 1.2 Hz, 2H), 4.22
(q, J ¼ 7.2 Hz, 4H) 4.151 (s, 5H), 1.33 (t, J ¼ 7.2 Hz, 6H). IR (neat,
cmꢁ1): 1706, 1629, 1163. MS (EI, 70 eV): m/e 382 (100%, Mþ), 317
(52%, M-Cpþ). HRMS: m/e 382.08675; Calcd. For C20H22FeO4 m/e
4.2. General procedure
A suspension of ferrocene (186 mg,1 mmol), alkene or diene and
Pd(OAc)2 in acetic acid (3 ml) was stirred in air in a flask equipped
with air condenser to minimize evaporation of the solvent at r.t. In
the case of reaction with ethyl acrylate and methyl cinnamate
a slow dissolution of ferrocene was observed and after 1 week
a deeply red solution was obtained (in other cases only a partial
dissolution of ferrocene took place). The mixture was poured onto
water and extracted several times with dichloromethane. The
extracts were washed with aqueous NaHCO3, water, dried over
Na2SO4 and evaporated to dryness. Column chromatography of the
residue on silica gel afforded unreacted ferrocene (eluent: hexane),
and products (eluent: hexane-ethyl acetate 9:1). Compounds 3a,b
were separated from 4a,b (mixtures of regioisomers) by prepara-
tive TLC. In the case of the reaction of ferrocene with sorbic acid the
solvent was evaporated, the residue dissolved on dichloromethane
and extracted with aqueous NaHCO3. The product precipitated on
acidification of the aqueous layer with HCl.
382.08555. 4b (1,3-isomer): 1H NMR (600 MHz, CDCl3,
d):
7.38e7.44 (m, 6H); 7.20e7.23 (m, 4H), 6.20 (s, 2H), 4.54 (t, J ¼ 1.5 Hz,
1H), 4.41 (d, J ¼ 1.5 Hz, 2H), 4.14 (s, 5H), 3.55 (s, 6H). 13C NMR
(150 MHz, CDCl3, d): 166.0, 157.7, 138.2, 127.83, 127.81, 127.79, 113.8,
86.1, 71.8, 70.9, 67.5, 51.1. IR (neat, cmꢁ1): 1714, 1604, 1150. MS (EI,
70 eV): m/e 506 (100%, Mþ) 377 (55%, M-Cpþ). HRMS: m/e 506.1179;
Calcd. For C30H26FeO4 m/e 506.1181. 6. Yield 9%. Red oil. 1H NMR
(600 MHz, CDCl3,
d
): 5.98 (s, 1H,), 4.46 (t, J ¼ 1.8 Hz, 2H,), 4.43 (t,
J ¼ 1.8 Hz, 2H), 4.42 (q, J ¼ 7.2 Hz, 2H), 4.23 (s, 5H,), 4.19 (q,
J ¼ 7.2 Hz, 2H),1.43 (t, J ¼ 7.2 Hz, 3H),1.30 (t, J ¼ 7.2 Hz, 3H). 13C NMR
(150 MHz, CDCl3, d): 167.6, 165.1, 151.1, 112.0, 77.7, 71.0, 70.3, 67.3,
61.5, 60.5, 14.2, 14.1. Elemental analysis: Found: C, 60.65; H,
5.80.C18H20FeO4 requires: C 60.70; H. 5.66. 8a. Yield 8%. Red oil. 1H
NMR (600 MHz, CDCl3,
d
): 7.67 (dd, J1 ¼ 11.4 Hz, J2 ¼ 15.0 Hz, 1H),
6.42 (d, J ¼ 11.4 Hz, 1H), 5.86 (d, J ¼ 15.0 Hz, 1H), 4.49 (t, J ¼ 1.8 Hz,
2H), 4.35 (t, J ¼ 1.8 Hz, 2H), 4.22 (q, J ¼ 7.2 Hz, 2H), 4.11 (s, 5H), 2.21
Compounds 2a and 3a were identified by comparison of their IR
(s, 3H), 1.31 (t, J ¼ 7.2 Hz, 3H). 13C NMR (150 MHz, CDCl3,
d): 167.9,
and 1H NMR spectra with those of authentic samples [17].
2b: M.p. 113e114 ꢀC. 1H NMR (200 MHz, CDCl3,
d): 7.43 (m, 2H),
145.8, 140.8, 120.5, 118.4, 86.3, 70.0, 69.6, 66.4, 60.1, 16.2, 14.4.
Elemental analysis: Found: C, 66.55; H, 6.40.C18H20FeO2 requires C
66.69; H. 6.22. 8b. Yield 5%. Red crystals. 1H NMR (600 MHz, CDCl3):
7.29 (m, 3H), 6.29 (s, 1H), 4.41 (t, J ¼ 1.8 Hz, 2H), 4.33 (t, J ¼ 1.8 Hz,
2H), 4.19 (s, 5H), 3.59 (s, 3H). IR (KBr, cmꢁ1): 1720, 1617, 1595, 1167,
1149. MS (EI, 70 eV): m/e 346 (100%, Mþ). HRMS: m/e 346.0657;
Calcd. For C20H18FeO2 m/e 346.0656. Elemental analysis: Found: C,
69.46; H, 5.35. C20H18FeO2 requires: C, 69.34. H, 5.24. 3b: M.p.
d
7.77 (dd, J1 ¼ 11.9 Hz, J2 ¼ 14.9 Hz, 1H), 6.46 (d, J ¼ 11.9 Hz, 1H),
5.87 (d, J ¼ 14.9 Hz, 1H), 4.52 (t, J ¼ 1.6 Hz, 2H), 4.38 (t, J ¼ 1.6 Hz,
2H), 4.13 (s, 5H), 2.23 (s, 3H). 13C NMR (150 MHz, CDCl3):
d 171.8,
147.7, 143.0, 120.3, 116.9, 85.9, 70.2, 69.6, 66.6, 16.3. IR (KBr, cmꢁ1):
3433, 3091, 1672, 1597, 1416, 1316, 1296, 1268, 1160. Elemental
analysis: Found C, 64.82; H, 5.45. C16H16FeO2 requires C, 64.89;
H, 5.45.
173e174 ꢀC. 1H NMR (200 MHz, CDCl3,
d): 7.34 (m, 4H), 7.20 (m, 6H),
6.23 (s, 2H), 4.35 (t, J ¼ 1.8 Hz, 4H), 4.27 (t, J ¼ 1.8 Hz, 4H), 3.57 (s,
6H). IR (KBr, cmꢁ1): 1718, 1604, 1152. MS (EI, 70 eV): m/e 506 (100%,
Mþ). HRMS: m/e 506.1187; Calcd. For C30H26FeO4 m/e 506.1181.

3504
M. Piotrowicz et al. / Journal of Organometallic Chemistry 696 (2011) 3499e3506
Table 2
The most important geometrical parameters: bond lengths [Å], valence angles [ꢀ] and torsion angles [ꢀ] for 2b and 8b.
2b-I
2b-II
3b
Distances
Fe1 C1
Fe1 C2
Fe1 C3
Fe1 C4
Fe1 C5
Fe1 C6
Fe1 C7
Fe1 C8
Fe1 C9
Fe1 C10
Fe-Cav
Fe-Ct1
Fe-Ct2
C1 C2
2.0456
2.0310
2.0435
2.0420
2.0432
2.0482
2.0475
2.0462
2.0460
2.0502
2.044
(9)
(9)
(10)
(9)
(9)
(10)
(10)
(10)
(10)
(10)
(5)
Fe2 C21
Fe2 C22
Fe2 C23
Fe2 C24
Fe2 C25
Fe2 C26
Fe2 C27
Fe2 C28
Fe2 C29
Fe2 C30
2.0408
2.0320
2.0434
2.0462
2.0396
2.0462
2.0374
2.0409
2.0455
2.0513
2.042
(10)
(10)
(10)
(9)
Fe1 C1
Fe1 C2
Fe1 C3
Fe1 C4
Fe1 C5
Fe1 C6
Fe1 C7
Fe1 C8
Fe1 C9
Fe1 C10
2.0566
2.0694
2.0566
2.0410
2.0534
2.0548
2.0643
2.0506
2.0387
2.0550
2.054
(12)
(12)
(12)
(12)
(11)
(12)
(12)
(12)
(11)
(12)
(9)
(9)
(11)
(10)
(11)
(12)
(10)
(5)
(5)
(6)
(13)
(14)
1.639
1.651
1.4401
1.4390
(5)
(5)
(13)
(13)
1.638
1.650
1.4384
1.4354
1.659
1.656
(9)
(9)
C21 C22
C21 C25
C5 C1
C5 C4
C10 C6
C10 C9
1.4324
1.4393
1.4317
1.4378
1.426
(16)
(16)
(16)
(16)
(8)
C1 C5
C-Cav
1.427
(7)
1.424
(8)
C1 C11
1.4648
(13)
C21 C31
C31 C32
1.4681
(13)
C5 C11
C10 C21
C18 C11
C21 C28
C19 O1
C19 O2
C20 O2
C29 O3
C29 O4
C30 O4
1.4624
1.4659
1.3499
1.3489
1.2021
1.3579
1.4392
1.2022
1.3572
1.4419
(16)
(16)
(16)
(16)
(15)
(14)
(15)
(15)
(14)
(15)
C11 C12
1.3504
(14)
1.3427
(14)
O1 C13
O1 C20
O2 C13
1.3526
1.4404
1.2099
(13)
(13)
(13)
O3 C33
O3 C40
O4 C33
1.3468
1.4383
1.2121
(12)
(13)
(12)
Valence angles
Ct1-Fe-Ct2
O2 C13 O1
178.72
122.92
(9)
(9)
179,18
123,19
(11)
(10)
178.30
122.41
122.17
(11)
(11)
(11)
O4 C33 O3
O1 C19 O2
O3 C29 O4
Torsions
C2 C1 C11 C12
C14 C11 C12 C13
C11 C12 C13 O1
C12 C11 C14 C15
C1 C11 C14 C15
ꢁ3.71
ꢁ4.87
177.51
ꢁ89.66
87.34
(15)
(15)
(9)
(13)
(11)
C22 C21 C31 C32
C34 C31 C32 C33
C31 C32 C33 O3
C32 C31 C34 C35
C21 C31 C34 C35
ꢁ1.84
(15)
(15)
(9)
(12)
(11)
C4 C5 C11 C12
ꢁ4.07
ꢁ8.4
(11)
(2)
(2)
ꢁ2.54
175.46
ꢁ90.04
86.79
C19 C18 C11 C12
O1 C19 C18 C11
C18 C11 C12 C13
C5 C11 C12 C13
C9 C10 C21 C28
C22 C21 C28 C29
O3 C29 C28 C21
C28 C21 C22 C27
C10 C21 C22 C27
ꢁ173.8
ꢁ69.11
107.19
ꢁ5.88
(17)
(13)
(19)
(19)
(2)
(17)
(13)
(13)
ꢁ8.39
177.86
ꢁ70.48
106.21
146.7
C1-Ct1-Ct2-C6
3.74
(11)
1.39
(12)
4.3. X-ray structure analysis of 2b, 3b and 8b
4.4. Crystal data
Crystals of compounds 2b, 3b and 8b suitable for X-ray analyses
were obtained from layered dichloromethane-hexane. Single-
crystal X-ray measurements were performed on a BRUKER APEX II
2b: Empirical formula C20H18FeO2, Crystal system Monoclinic,
Space group Cc, Formula weight 346.19, Temp. 100(2) K, Wave-
length 0.71073 A, Unit cell dimensions:
a
b
¼
20.2616(7) Å,
¼ 107.943(2) deg.,
ULTRA
k-axis diffractometer with TXS rotating anode using MoK
a
b ¼ 8.3989(3) Å, c ¼ 19.2852(7) Å,
a
¼ 90 deg.,
radiation at 100 K. Data were collected using omega scan
measurement method, with 0.5 degrees scan width and 10 s
counting time. q angle for data collection was varied in the range of
g
¼ 90 deg., Volume 3122.24(19) Å3, Z ¼ 8, Calculated density
1.473 Mg/m3, Absorption coefficient 0.973 mmꢁ1, F(000) ¼ 1440,
Crystal size ¼ 0.22 ꢂ 0.22 ꢂ 0.17 mm, Theta range 2.11e45.29 deg.,
Limiting indices: ꢁ40 ꢃ h ꢃ 39, ꢁ16 ꢃ k ꢃ 15, ꢁ28 ꢃ l ꢃ 38,
2.5e20.00ꢀ. Data were corrected in respect to Lorentz and polari-
zation effects. Analytical absorption correction was applied using
SADABS [18]. Indexing, integration and scaling were performed
with original Bruker Apex II software [19]. The structures were
solved using direct methods and refined using SHELXL [20].
Refinement was based on F2 for all reflections. Weighted R factors
wR and all goodness-of-fit S values were based on F2. Conventional
Reflections collected/unique 64,105/19,374 [R(int)
¼
0.0359],
Completeness to theta ¼ 45.29 99.5%, Absorption correction Semi-
empirical from equivalents, Max. and min. transmission 0.849 and
0.743, Refinement method Full-matrix least-squares on F2, Data/
restraints/parameters 19,374/2/418, Goodness-of-fit on F2 0.987,
Final R indices [I > 2sigma(I)] R1 ¼ 0.0322, wR2 ¼ 0.0763, R indices
(all data) R1 ¼ 0.0384, wR2 ¼ 0.0797, Absolute structure parameter
R factors are based on F with F set to zero for negative F2. The F02
>
2
s
ðF02Þ criterion was used only for calculating R factors and is not
0.391(6), Largest diff. peak and hole 1.085 and ꢁ0.311 eÅꢁ3
.
relevant to the choice of reflections for the refinement. The R factors
based on F2 are about three times as large as those based on F. All
non-hydrogen atoms were refined anisotropically. All hydrogen
atoms were located in idealized averaged geometrical positions and
refined isotropically.
3b: Empirical formula C30H26FeO4, Crystal system Triclinic,
Space group Pꢁ1, Formula weight 506.36, Tem. 100(2) K, Wave-
length 0.71073 A, Unit cell dimensions:
b ¼ 10.3895(3) Å, c ¼ 12.3914(6) Å, a ¼ 97.566(2) deg., b ¼ 99.923(2)
a
¼
10.2696(3) Å,
deg., g ¼ 114.532(2) deg., Volume 1153.90(7) Å3, Z ¼ 2, Calculated

M. Piotrowicz et al. / Journal of Organometallic Chemistry 696 (2011) 3499e3506
3505
Table 3
accomplished at the Structural Research Laboratory of Chemistry
Department, Warsaw University, Poland. SRL has been established
with a financial support from European Regional Development
Found in the Sectoral Operational Programme "Improvement of the
Competitiveness of Enterprises, years 2004e2006" project no:
WKP_ 1/1.4.3./1/2004/72/72/165/2005/U. AM thanks for a financial
support within the Polish Ministry of Science and Higher Education
grant for PhD students number N N204 0302 33, and additional
support of the Foundation for the Polish Science e 2008 grant for
young researchers. AM, JB and KW thank the Foundation for Polish
Science for the Master subsidy.
The most important geometrical parameters: bond lengths [Å], valence angles [ꢀ]
and torsion angles [ꢀ] for 8b.
8b-I
8b-II
Distances
Fe1 C1
Fe1 C2
Fe1 C3
Fe1 C4
Fe1 C5
Fe1 C6
Fe1 C7
Fe1 C8
Fe1 C9
Fe1 C10
Fe-Cav
Fe-Ct1
Fe-Ct2
C6-C10
C9-C10
C-Cav
C10 C11
C11 C12
C11 C13
C13 C14
C14 C15
C15 C16
O1 C16
2.0377 (12) Fe(2) C(17)
2.0397 (12) Fe(2) C(18)
2.0441 (12) Fe(2) C(19)
2.0459 (12) Fe(2) C(20)
2.0400 (12) Fe(2) C(21)
2.0391 (12) Fe(2) C(22)
2.0424 (12) Fe(2) C(29)
2.0451 (12) Fe(2) C(30)
2.0362 (11) Fe(2) C(31)
2.0462 (12) Fe(2) C(32)
2.0378
2.0357
2.0400
2.0422
2.0456
2.0547
2.0416
2.0367
2.0407
2.0414
(13)
(13)
(13)
(13)
(12)
(11)
(12)
(12)
(11)
(11)
Appendix. Supplementary data
2.041
1.644
1.642
(3)
(5)
(6)
2.04164 (5)
1.643
(4)
CCDC 736149, 736150 and 769111 and contain the supplemen-
tary crystallographic data for compounds 2b, 3c, and 8b respec-
tively. These data can be obtained free of charge from the
Cambridge Crystallographic Data Centre via www.ccdc.cam.uk/
data_request/cif.
1.645
(5)
1.4330 (16) C22-C29
1.4356 (16) C22-C32
1.4327
1.4316
1,425
(16)
(16)
(8)
1.423
(8)
1.4623 (16) C22 C23
1.4984 (18) C23 C24
1.3512 (16) C23 C25
1.4415 (16) C25 C26
1.3444 (16) C26 C27
1.4635 (16) C27 C28
1.2329 (15) O3 C28
1.3185 (15) O4 C28
1.4629
1.4997
1.3534
1.4376
1.3440
1.4609
1.2315
1.3191
(15)
(16)
(15)
(15)
(16)
(16)
(15)
(14)
References
ꢁ
ꢁ
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Torsions
C9 C10 C11 C13
C12 C11 C13 C14
179.17
122.91
(11)
178.96
122.72
(96)
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C24 C23 C25 C26
C16 C15 C14 C13 ꢁ176.83
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C1 Ct1 Ct2 c10
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169.93
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1.149
mmꢁ1
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F(000)
¼
1232,
Crystal
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¼
0.0282], Completeness to
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3506
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