Iron(II) bipyridine complexes for the cross-coupling reaction of bromocyclohexane with phenylmagnesium bromide

Article abstract of DOI:10.1016/j.poly.2017.02.046

Three known iron(II) complexes bearing a bipyridine ligand, [FeCl₂(bpy)₂] (1), [FeCl₂(bpy)]₂ (2) and [FeCl₂(dmbpy)] (3) (bpy?=?2,2′-bipyridine and dmbpy?=?6,6′-dimethyl-2,2′-bipyridine) were employed for the cross-coupling reaction of bromocyclohexane (4) with phenylmagnesium bromide (5). These complexes catalyzed the cross-coupling reaction. Among the three catalysts, complex 2 acted as an effective catalyst to afford the cross-coupled product phenylcyclohexane (6) in 92% yield. The X-ray crystal structure analyses of 2 and 3 were demonstrated.

Full text of DOI:10.1016/j.poly.2017.02.046

Accepted Manuscript
Iron(II) bipyridine complexes for the cross-coupling reaction of bromocyclo-
hexane with phenylmagnesium bromide
Yutaka Matsubara, Takamichi Yamaguchi, Toru Hashimoto, Yoshitaka
Yamaguchi
PII:
S0277-5387(17)30187-0
DOI:
http://dx.doi.org/10.1016/j.poly.2017.02.046
POLY 12522
Reference:
Polyhedron
To appear in:
Received Date:
Revised Date:
Accepted Date:
17 December 2016
26 February 2017
27 February 2017
Please cite this article as: Y. Matsubara, T. Yamaguchi, T. Hashimoto, Y. Yamaguchi, Iron(II) bipyridine complexes
for the cross-coupling reaction of bromocyclohexane with phenylmagnesium bromide, Polyhedron (2017), doi:
http://dx.doi.org/10.1016/j.poly.2017.02.046
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1
Iron(II) bipyridine complexes for the cross-coupling reaction of bromocyclohexane with
phenylmagnesium bromide
Yutaka Matsubara, Takamichi Yamaguchi, Toru Hashimoto, and Yoshitaka Yamaguchi*
Department of Advanced Materials Chemistry, Graduate School of Engineering, Yokohama National
University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
Corresponding author
Tel: +81-45-339-3932; fax: +81-45-339-3932: e-mail: yyama@ynu.ac.jp
Keywords
Iron complexes; Bipyridine ligand; Cross-coupling reaction; X-ray diffraction study
Abstract
Three known iron(II) complexes bearing a bipyridine ligand, [FeCl2(bpy)2] (1), [FeCl2(bpy)]2 (2)
and [FeCl2(dmbpy)] (3) (bpy = 2,2’-bipyridine and dmbpy = 6,6’-dimethyl-2,2’-bipyridine) were
employed for the cross-coupling reaction of bromocyclohexane (4) with phenylmagnesium bromide
(5). These complexes catalyzed the cross-coupling reaction. Among the three catalysts, complex 2
acted as an effective catalyst to afford the cross-coupled product phenylcyclohexane (6) in 92% yield.
The X-ray crystal structure analyses of 2 and 3 were demonstrated.

2
1. Introduction
Bipyridines are one of the most ubiquitous classes of ligands in coordination chemistry. They are
able to bind to a wide range of metal ions and to stabilize different oxidation states. Furthermore, the
introduction of substituents on the bipyridine ring can be tunable for specific electronic and steric
properties of the metal center [1]. Therefore, the rich chemistry of bipyridine complexes has been
demonstrated in supramolecular [2], nanomaterial [3], macromolecular [4] and photophysical
chemistry [5]. Here, we turned our attention to the combination of bipyridines with iron; these iron
complexes have been subject to intense study on crystal polymorphs and their magnetic properties. For
instance, [FeCl2(bpy)] has been described as forming two polymorphs; one is an orange tetrahedral
monomer and the other is a red-rose octahedral polymer [6]. Although an X-ray diffraction study was
not performed due to the complex’s low crystallinity, based on 57Fe Mössbauer and magnetic studies, a
pentacoordinate iron(II) complex bearing terminal and bridging chloride ligands was proposed [7]. On
the other hand, iron bipyridine complexes have focused on as catalysts for carbon-carbon bond
forming reactions, e.g. atom transfer radical addition (ATRA) [8] and Ziegler-type polymerization [9].
Transition metal catalyzed cross-coupling reactions of organic halides as electrophiles with
organometallic reagents are one of the most promising procedures for synthetic organic chemistry.
Various transition metals, such as Ni, Pd and Co, have been employed as effective catalysts for these
reactions [10]. Recently iron complexes have been actively investigated as a catalysts, because iron is
a practical, ideal transition metal due to its low cost, non-toxicity and availability [11]. Although
various nitrogen, phosphorus and carbon donor ligands have been utilized in iron-catalyzed
cross-coupling reactions [12,13], to the best of our knowledge, there has been no report on an iron
bipyridine complex as a catalyst. Therefore, we were interested in the investigation of iron bipyridine
complexes on cross-coupling reactions. In this paper we investigated the cross-coupling reaction of
bromocyclohexane with phenylmagnesium bromide using the three iron(II) complexes depicted in
Chart 1.

3
2. Results and Discussion
2.1. Synthesis of iron complexes 1-3
Complex 1 was prepared according to the literature method [9b], namely the thermal
decomposition of [Fe(bpy)3]Cl2 at 80 °C under reduced pressure afforded complex 1 as a deep blue
solid. This complex obeys the 18-electron rule and shows a diamagnetic nature. Therefore, complex 1
is easily characterized by NMR spectroscopy by referring to the literature data. Complex 1 is
composed of FeCl2 and bipyridine in the ratio of 1:2 and the mutually cis positions would act as
reactive sites in an octahedral geometry [9].
As described in the introductory part, in previous studies on [FeCl2(bpy)], two polymorphs (orange
and red-rose polymorphs) were recognized. Recently, Stephens, Miller and co-workers reported that
the orange polymorph is a pentacoordinate square pyramidal iron(II) dimer, 2 as shown in Chart 1,
which was determined with synchrotron powder diffraction data [14]. We examined the direct
preparation of complex 2 by the reaction of anhydrous FeCl2 with one equivalent of bipyridine in
CH2Cl2, from which a red powder was isolated. Our attempts to grow single crystals from the red
powder were unsuccessful. In the course of our study on iron bipyridine complexes, we tried to
prepare a mixed-ligand iron complex bearing both bipyridine and N-heterocyclic carbene ligands
(Scheme 1). The reaction mixture afforded a red solid and red crystals were obtained by
recrystallization from CH2Cl2/Et2O. The X-ray diffraction study revealed that the crystal was not the

4
desired mixed-ligand complex, but the dinuclear iron bipyridine complex 2 (vide infra). Fortunately,
we carried out an X-ray diffraction study of 2. Although [FeCl2(bpy)] has been recognized as two
polymorphs, as mentioned above, our results showed that the red crystal has also a pentacoordinate
square pyramidal iron(II) dimer structure, which has the same structural properties as determined by
the synchrotron powder diffraction study [14]. At present, we have no additional evidence to explain
this result. Further investigations on the polymorphs of [FeCl2(bpy)] might be needed in the future. In
the cross-coupling reaction, the red powder was used as catalyst 2, prepared by the direct
complexation of FeCl2 and bipyridine in a molar ratio of 1:1.
Complex 3 was prepared as in the literature via the reaction of anhydrous FeCl2 with one
equivalent of 6,6’-dimethyl-2,2’-bipyridine (dmbpy) [15]. This ligand would provide steric hindrance
to prevent the coordination of a second ligand as well as the formation of chloride-bridged dimer
structure. Thus complex 3 shows a monomeric tetrahedral structure and is a paramagnetic compound.
Although the structure of complex 3 has been already determined by an X-ray diffraction study [15],
in order to confirm the formation of complex 3, we carried out an X-ray diffraction study of 3. Yellow
single crystals of 3 were easily obtained by recrystallization from CH2Cl2/hexane.
2.2. X-ray crystal structures of the iron complexes 2 and 3
The ORTEP drawings of 2 and 3 are shown in Figure 1. Selected bond lengths and angles for these
complexes are listed in Tables 1 and 2.

5
Figure 1. ORTEP drawings (upper) and -stacking conformation diagrams (bottom) of complexes 2 (left)
and 3 (right) with thermal ellipsoids of 30% probability.
Complex 2 shows a chloride-bridged dinuclear structure and each iron(II) ion is in a square
pyramidal environment. The basal Fe1-Cl1 and Fe1-Cl1* bond lengths are almost equivalent, being
2.4603(8) and 2.4602(13) Å, respectively. The apical Fe1-Cl2 (2.2612(12) Å) bond length is shorter
than the basal Fe1-Cl1 (Cl1*) bond lengths. These bond lengths show the characteristic feature
observed in d6 square pyramidal complexes [16]. The Cl1-Fe1-Cl1* bond angle is 82.55(3) °. The
Fe-N bond lengths are 2.151(2) and 2.148(4) Å, which are identical within their uncertainties and the
N1-Fe1-N2 bond angle is 79.49(12) °. The intramolecular Fe1···Fe1* distance is 3.6979(7) Å. These
structural parameters are in reasonable agreement with those of a synchrotron powder diffraction study
[14]. The bipyridine ligands show a -stacking conformation between different dinuclear complexes.
The distances between the nearest bipyridine ligands are in the range 3.417(4)-3.538(5) Å.
Baird has already reported the X-ray diffraction study of complex 3 [15]. In his report, two
polymorphs of 3 were found. These crystals showed different cell parameters and space groups,
whereas both structural parameters were very similar. In our experiment for 3, one of the polymorphs

6
was obtained. The Fe-Cl bond lengths are 2.2349(5) Å for Fe1-Cl1 and 2.2360(6) Å for Fe1-Cl2. The
Cl1-Fe1-Cl2 bond angle is 114.94(2) °. The Fe-N1 and Fe1-N2 bond lengths are 2.1134(13) and
2.1096(13) Å, respectively, and the N1-Fe1-N2 bond angle is 77.65(5) °. The structural parameters are
in good agreement with those of Baird’s report [15]. In complex 3, the bipyridine ligands prefer a
-stacking conformation between different complexes. The distances between the nearest bipyridine
ligands are in the range 3.479(2)-3.579(2) Å. These distances are consistent with the values observed
in complex 2.
Table 1. Selected bond lengths (Å) and angles (°) for 2.
Fe1-Cl1
Fe1-Cl1*
Fe1-Cl2
Fe1-N1
2.4603(8)
2.4602(13)
2.2612(12)
2.151(2)
Fe1-N2
2.148(4)
Fe1···Fe1*
3.6979(7)
Cl1-Fe1-Cl1*
Cl1-Fe1-Cl2
Cl1-Fe1-N1
Cl1-Fe1-N2
Cl1*-Fe1-Cl2
Cl1*-Fe1-N1
Cl1*-Fe1-N2
Cl2-Fe1-N1
Cl2-Fe1-N2
N1-Fe1-N2
82.55(3)
108.93(4)
145.10(8)
90.52(7)
107.39(5)
90.11(10)
143.69(8)
105.83(8)
108.57(8)
75.49(12)
97.45(4)
Fe1-Cl1-Fe1*

7
Table 2. Selected bond lengths (Å) and angles (°) for 3.
Fe1-Cl1
Fe1-Cl2
Fe1-N1
Fe1-N2
2.2349(5)
2.2360(6)
2.1134(13)
2.1096(13)
Cl1-Fe1-Cl2
Cl1-Fe1-N1
Cl1-Fe1-N2
Cl2-Fe1-N1
Cl2-Fe1-N2
N1-Fe1-N2
114.94(2)
116.59(4)
114.74(4)
114.33(4)
113.34(4)
77.65(5)
2.3. Cross-coupling reaction catalyzed by iron complexes 1-3
We prepared three iron(II) complexes, 1-3. Complex 1 has two bpy ligands in an octahedral
geometry. In complex 2, one bpy ligand coordinates to the iron center and a chloride-bridged dimeric
structure forms. Complex 3 has one dmbpy ligand bonded to the iron centre as a mononuclear
complex in a tetrahedral geometry. Next, we examined the cross-coupling reaction of
bromocyclohexane (4) with phenylmagnesium bromide (5), using the three iron(II) complexes as
catalysts. The results are summarized in Table 3.

8
Table 3. Cross-coupling reaction catalyzed by the iron complexes a
a The reaction was carried out with 0.5 mmol of 4 and 0.6 mmol of 5.
b The amount of catalyst was based on the Fe atom.
c The yields of 6 and 7 were determined by GLC analysis using undecane as an internal standard.
Yields of 6 and 7 were based on 4 and 5, respectively.
First of all, to evaluate the catalytic activity of the three iron complexes 1-3 for the cross-coupling
reaction of bromocyclohexane (4) with phenylmagnesium bromide (5), the reaction was conducted in
CPME (cyclopentyl methyl ether) at room temperature for 1 h in the presence of 5 mol% of the iron
catalyst (Entries 1-3). It was found that these complexes acted as a catalyst for the cross-coupling
reaction and that complex 2 showed the best result. Complex 2 afforded the cross-coupled product,
phenylcyclohexane (6), in 68% yield along with the formation of the homo-coupled product, biphenyl
(7), in 25% yield (Entry 2). In order to investigate the influence of solvent on the cross-coupling
reaction, the reaction was conducted in some ethereal solvents (Entries 4-6). In a THF solution, the
yield of product 6 decreased (49%) and the formation of the homo-coupled product 7 increased (36%)

9
(Entry 4). Et2O gave similar results as those in THF (Entry 5). In DME (1,2-dimethoxyethane),
product 6 was formed in 58% yield, whereas the formation of 7 increased (45%) (Entry 6). From these
results, CPME was a suitable solvent for this coupling reaction. Next, we investigated the effect of the
amount of the iron complex 2 (Entries 7-9). On decreasing the amount of complex 2, the yield of 6
increased. In the presence of 3 mol% of 2, product 6 was formed in 81% yield (Entry 8). On the other
hand, using 2.5 mol% of 2, the yield of 6 decreased (73%) (Entry 9). The reaction time was also
investigated (Entries 10 and 11). When the reaction was conducted for 2 h in the presence of 3 mol%
of 2, the yield of 6 increased (Entry 10). For 3 h, the cross-coupled product 6 was formed in 92% yield
(Entry 11). An increase in the product yield of 6 was not observed on further elongation of the reaction
time. From these results, the reaction conditions catalyzed by complex 2 were optimized as those in
Entry 11. Finally, catalytic activities of complexes 1 and 3 were reinvestigated under the optimized
reaction conditions. In the case of complex 1, product 6 was formed in 83% yield. Complex 3 afforded
product 6 in 71% yield. In comparison with the first investigations (Entries 1 and 3), the cross-coupled
product 6 increased. However, among the three iron complexes, complex 2 showed the best result for
the coupling reaction.
3. Conclusions
We investigated the cross-coupling reaction of bromocyclohexane (4) with phenylmagnesium
bromide (5) using the three iron(II) bipyridine complexes 1-3. Among these iron complexes, complex
2 was found to be an effective catalyst for the coupling reaction. In complex 2, one bpy ligand
coordinates to the iron center and a chloride-bridged dimeric structure forms. In the catalytic reaction,
we assumed that the monomeric iron-bpy species acts as an effective catalyst. Complex 1 has two bpy
ligands and in complex 3, the dmbpy ligand coordinates to the iron center. These situations would
provide steric hindrance to prevent the reaction of substrates on the iron center. Although electronic
effects at the iron center might not be ruled out, we assumed that the steric hindrance around the iron

10
center is the main reason for decreasing the catalytic activity. Further investigations on the catalytic
mechanism and the coupling reactions of various organometallic reagents with organic electrophiles
are now in progress.
4. Experimental
4.1. General procedures
All manipulations involving air- and moisture-sensitive organometallic compounds were carried
out under an atmosphere of dry nitrogen, which was purified by SICAPENT (Merck Co., Inc.), using a
standard Schlenk tube or high vacuum techniques. All solvents were distilled over appropriate drying
agents prior to use. Iron complexes 1 [9b] and 3 [15] were prepared according to literature methods. 1H
1
NMR spectra were recorded on a BRUKER DRX-300 spectrometer at ambient temperature. H NMR
chemical shifts were recorded in ppm relative to Me4Si as an internal standard. GLC was recorded on
a Shimadzu GC-17A gas chromatograph using a ULBON HR-1 capillary column (0.25 ID X 25 m,
Shinwa Chemical Industries Ltd.).
4.2. Preparation of 2 for use as a catalyst
Anhydrous FeCl2 (205.1 mg, 1.62 mmol), 2,2’-bipyridine (254.2 mg, 1.63 mmol) and CH2Cl2 (10
mL) were put in a Schlenk tube. The reaction mixture was stirred at room temperature for 18 h, and
then a red powder precipitated. After removing the mother liquor, the residual red solid was washed
with THF (10 mL, 2 times), Et2O (15 mL) and hexane (10 mL), and dried in vacuo at 80 °C to yield 2
(429.8 mg, 0.76 mmol, 94%).
4.3. Experimental procedures for the X-ray cryatallography
Single crystals of 2 were obtained by the following procedures, as shown in Scheme 1. The
reaction of FeCl2, bipyridine, NaH and 1,3-bis(trimethylphenyl)imidazolium chloride in THF afforded

11
a red solid. The red solid was recrystallized from CH2Cl2/Et2O at room temperature to grow suitable
single crystals of 2. Suitable single crystals of 3 were obtained by recrystallization from
CH2Cl2/hexane at room temperature. Single crystals were individually mounted on glass fibers.
Diffraction measurements of these complexes were made on a Rigaku Mercury 70 diffractometer
using graphite monochromated Mo-K radiation ( = 0.71073 Å). The data were collected at a
temperature of -50 ± 1 °C to a maximum 2 value of 60 °. A total of 744 oscillation images were
collected. The crystal-to-detector distance was 45.00 mm. Readout was performed in the 0.068 mm
pixel mode. Data were collected using CrystalClear (Rigaku) [17] and processed using CrysAlisPro
(Rigaku Oxford Diffraction) [18]. In the reduction of the data, an empirical absorption correction was
applied. The data were corrected for Lorentz and polarization effects.
The crystallographic data and the results of the measurements are summarized in Table 4. The
structures were solved by direct methods (SHELXT) [19] for these complexes, and expanded using
Fourier techniques. Least-square refinements were carried out using SHELXL [20]. All of the
non-hydrogen atoms were refined anisotropically. Hydrogen atoms were introduced at ideal positions
and refined using the riding model. All calculations were performed using the CrystalStructure
crystallographic software package [21].
4.4 Typical procedure for the cross-coupling reaction (Table 3, Entry 11)
Iron complex 2 (4.1 mg, 0.0072 mmol), CPME (5 mL), undecane (51.8 mg, 0.070 mL, 0.33 mmol)
and bromocyclohexane (82.0 mg, 0.062 mL, 0.5 mmol) were put in a Schlenk tube. Phenylmagnesium
bromide (0.6 mL of its 1.0 M THF solution, 0.6 mmol) was added at once to the reaction mixture.
After stirring for 3 h at room temperature, 1 M hydrochloric acid (5 mL) was added to quench the
reaction. The products were extracted with Et2O (10 mL, 5 times) and then the yields of products 6
and 7 were determined by GLC analysis using undecane as an internal standard.

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Table 4. Summary of crystal data for 2 and 3.
2
3
Empirical formula
Formula weight
Crystal color, habit
Crystal size (mm)
Crystal system
C20H16Cl4Fe2N4
C12H12Cl2FeN2
310.99
565.88
red, plate
yellow, prism
0.500 x 0.500 x 0.250
monoclinic
P21/c (No. 14)
0.150 x 0.050 x 0.050
triclinic
Space group
Lattice parameters
a (Å)
P (No. 2)
8.2171(5)
8.4313(5)
8.7480(7)
110.398(6)
105.462(6)
94.045(5)
538.47(7)
1
7.5596(3)
10.0260(3)
17.7908(7)
90.000
b (Å)
c (Å)
  (°)
  (°)
94.775(3)
90.000
 
V (Å3)
1343.73(9)
4
Z
Dc (g cm-3)
1.745
1.537
F(000)
284.00
632.00
  (Mo K) (cm-1)
Reflection measured
Independent reflections
Rint
18.570
14.959
4246
9564
2447
3020
0.0382
0.0152
No. variables
Reflection/parameter ratio
Residuals: R; Rw
Residuals: R1 [I > 2(I)]
Goodness-of-fit (GOF) on F2
136
154
17.99
19.61
0.0843; 0.0782
0.0465
0.0306; 0.0737
0.0277
1.004
1.055
 max
,
min (e Å-3)
0.38, -0.42
0.41, -0.35

13
Acknowledgements
The authors are grateful to Prof. Masatoshi Asami and Dr. Suguru Ito (Yokohama National
University (YNU)) for valuable discussions. The authors also thank Mr. Shintaro Ono (YNU) for
experimental assistance. This work was partially supported by JSPS KAKENHI Grant Number
25410063. This work was also supported by the Collaborative Research Program of Institute for
Chemical Research, Kyoto University (grant number 2016-22).
Appendix A. Supplementary material
CCDC 1502443 and 1502444 contain the supplementary crystallographic data for complexes 2 and
3. These data can be obtained free of charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html, or
from the Cambridge Crystallographic Data Center, 12 Union Road, Cambridge CB2 1EZ, UK; fax:
(+44) 1223-336-033; or e-mail: deposit@ccdc.cam.ac.uk.
References
[1] E. E. Benson, A. L. Rheingold, C. P. Kubiak, Inorg. Chem. 49 (2010) 1458-1464.
[2] B.-H. Ye, M.-L. Tong, X.-M. Chen, Coord. Chem. Rev. 249 (2005) 545-565.
[3] A. J. Fletcher, E. J. Cussen, T. J. Prior, M. J. Rosseinsky, C. J. Kepert, K. M. Thomas, J. Am.
Chem. Soc. 123 (2001) 10001-10011.
[4] U. S. Schubert, C. Eschbaumer, Angew. Chem., Int. Ed. 41 (2002) 2892-2926.
[5] B. Z. Shan, Q. Zhao, N. Goswami, D. M. Eichhorn, D. P. Rillema, Coord. Chem. Rev. 211 (2001)
117-144.
[6] H. Sato, T. Tominaga, Bull. Chem. Soc. Jpn. 49 (1976) 697-700.
[7] (a) W. M. Reiff, B. Dockum, M. A. Weber, R. B. Frankel, Inorg. Chem. 14 (1975) 800-806;
(b) F. F. Charron Jr., W. M. Reiff, Inorg. Chem. 25 (1986) 2786-2790.
[8] W. T. Eckenhoff, A. B. Biernesser, T. Pintauer, Inorg. Chim. Acta 382 (2012) 84-95.

14
[9] (a) F. Schaper, S. R. Foley, R. F. Jordan, J. Am. Chem. Soc. 126 (2004) 2114-2124;
(b) P. Yang, B. C. K. Chan, M. C. Baird, Organometallics 23 (2004) 2752-2761.
[10] Cross-coupling reactions using Ni, Pd, Co, and so on:
(a) J. Terao, N. Kambe, J. Synth. Org. Chem., Jpn. 62 (2004) 1192-1204;
(b) A. F. Littke, G. C. Fu, Angew. Chem. Int. Ed. 41 (2002) 4176-4211;
(c) J. K. Kochi, J. Organomet. Chem. 653 (2003) 11-19;
(d) H. Shinokubo, K. Oshima, Eur. J. Org. Chem. (2004) 2081-2091;
(e) G. Cahiez, A. Moyeux, Chem. Rev. 110 (2010) 1435-1462.
[11] Review for iron-catalyzed reactions:
(a) C. Bolm, J. Legros, J. L. Paih, L. Zani, Chem. Rev. 104 (2004) 6217-6254;
(b) A. Correa, O. G. Manchenõ, C. Bolm, Chem. Soc. Rev. 37 (2008) 1108-1117;
(c) S. Enthaler, K. Junge, M. Beller, Angew. Chem. Int. Ed. 47 (2008) 3317-3321;
(d) E. Nakamura, N. Yoshikai, J. Org. Chem. 75 (2010) 6061-6067.
[12] Review for cross-coupling reactions:
(a) A. Fürstner, R. Martin, Chem. Lett. 34 (2005) 624-629;
(b) A. C. Frisch, M. Beller, Angew. Chem. Int. Ed. 44 (2005) 674-688;
(c) B. D. Sherry, A. Fürstner, Acc. Chem. Res. 41 (2008) 1500-1511;
(d) A. Rudolph, M. Lautens, Angew. Chem. Int. Ed. 48 (2009) 2656-2670;
(e) W. M. Czaplik, M. Mayer, J. Cvengroš, A. J. von Wangelin, ChemSusChem. 2 (2009)
396-417.
(f) A. Guérinot, J. Cossy, Top. Curr. Chem. 374 (2016) 49.
[13] Selected papers for the iron-catalyzed cross-coupling:
(a) R. Martin, A. Fürstner, Angew. Chem., Int. Ed. 43 (2004) 3955-3957;
(b) M. Nakamura, K. Matsuo, S. Ito, E. Nakamura, J. Am. Chem. Soc. 126 (2004) 3686-3687;
(c) T. Nagano, T. Hayashi, Org. Lett. 6 (2004) 1297-1299;

15
(d) R. B. Bedford, D. W. Bruce, R. M. Frost, J. W. Goodby, M. Hird, Chem. Commun. (2004)
2822-2823;
(e) R. B. Bedford, D. W. Bruce, R. M. Frost, M. Hird, Chem. Commun. (2005) 4161-4163;
(f) R. B. Bedford, M. Betham, D. W. Bruce, A. A. Danopoulos, R. M. Frost, M. Hird, J. Org.
Chem. 71 (2006) 1104-1110;
(g) G. Cahiez, V. Habiak, C. Duplais, A. Moyeux, Angew. Chem., Int. Ed. 46 (2007) 4364-4366;
(h) R. R. Chowdhury, A. K. Crane, C. Fowler, P. Kwong, C. M. Kozak, Chem. Commun. (2008)
94-96;
(i) H.-H. Gao, C.-H. Yan, X.-P. Tao, Y. Xia, H.-M. Sun, Q. Shen, Y. Zhang, Organometallics 29
(2010) 4189-4192;
(j) A. K. Steib, T. Thaler, K. Komeyama, P. Mayer, P. Knochel, Angew. Chem., Int. Ed. 50
(2011) 3303-3307;
(k) Y. Yamaguchi, H. Ando, M. Nagaya, H. Hinago, T. Ito, M. Asami, Chem. Lett. 40 (2011)
983-985;
(l) T. Hatakeyama, Y.-i. Fujiwara, Y. Okada, T. Itoh, T. Hashimoto, S. Kawamura, K. Ogata, H.
Takaya, M. Nakamura, Chem. Lett. 40 (2011) 1030-1032;
(m) S. Meyer, C. M. Orben, S. Demeshko, S. Dechert, F. Meyer, Organometallics 30 (2011)
6692-6702;
(n) S. K. Ghorai, M. Jin, T. Hatakeyama, M. Nakamura, Org. Lett. 14 (2012) 1066-1069;
(o) Z. Mo, Q. Zhang, L. Deng, Organometallics 31 (2012) 6518-6521;
(p) G. Bauer, M. D. Wodrich, R. Scopelliti, X. Hu, Organometallics 34 (2015) 289-298;
(q) J. A. Przyojski, K. P. Veggeberg, H. D. Arman, Z. J. Tonzetich, ACS Catal. 5 (2015)
5938-5946.
[14] S. H. Lapidus, P. W. Stephens, E. Shurdha, J. G. DaSilva, J. S. Miller, Polyhedron 52 (2013)
713-718.

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[15] B. C. K. Chan, M. C. Baird, Inorg. Chim. Acta 357 (2004) 2776-2782.
[16] J. R. Gispert, Coordination Chemistry, Wiley-VCH, 2008, pp. 65-70.
[17] CrytalClear: Data Collection and Processing Software, Rigaku Corporation (1998-2014). Tokyo
196-8666, Japan.
[18] CrysAlisPro: Data Collection and Processing Software, Rigaku Corporation (2015). Tokyo
196-8666, Japan.
[19] SHELXT Version 2014/5: Sheldrick, G. M. Acta Cryst. A70 (2014) C1437.
[20] SHELXL Version2014/7: Sheldrick, G. M. Acta Cryst. A64 (2008) 112-122.
[21] CrystalStructure 4.2.2: Crystal Structure Analysis Package, Rigaku Corporation (2000-2016).
Tokyo 196-8666, Japan.

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Graphical Abstract
Synopsis
A cross-coupling reaction of bromocyclohexane with phenylmagnesium bromide catalyzed by iron(II)
bipyridine complexes was examined. The iron complex [FeCl2(2,2’-bipyridine)]2 was found to be an
effective catalyst for the cross-coupling reaction.