Synthesis of ferrocenyl aryl ethers via Cu(I)/phosphine catalyst systems

Article abstract of DOI:10.1515/znb-2014-0178

Ferrocenyl aryl ethers can be synthesized in good yields by Cu(I)/phosphine-catalyzed coupling reactions from iodoferrocene or 1,1′-dibromoferrocene and various phenols in toluene, using Cs₂CO₃ or K₃PO₄ as a base. For the first time a solid-state structure of a ferrocenyl-1,1′-diaryl ether [1,1′-di(4-tert-butylphenoxy)ferrocene] has been determined from single-crystal X-ray data. The mixed ferrocenyl aryl ether 1-(4-tert-butylphenoxy)-1′-(2,4-dimethylphenoxy)ferrocene was prepared in a two-step synthetic protocol.

Full text of DOI:10.1515/znb-2014-0178

Z. Naturforsch. 2015; 70(1)b: 65–70
GSuyidno Dt.hFreeys* ainsd SotefpfhaenrDr.oHocffemannyn l aryl ethers via
Cu(I)/phosphine catalyst systems
Abstract: Ferrocenyl aryl ethers can be synthesized in employed Ullmann-type coupling resulting in product
good yields by Cu(I)/phosphine-catalyzed coupling reac- yields of ferrocenyl phenyl ether of 10–25ꢀ%.
tions from iodoferrocene or 1,1′-dibromoferrocene and var-
ious phenols in toluene, using Cs2CO3 or K3PO4 as a base.
For the first time a solid-state structure of a ferrocenyl-
2 Results and discussion
1,1′-diaryl ether [1,1′-di(4-tert-butylphenoxy)ferrocene]
has been determined from single-crystal X-ray data. The
In a report by an der Heiden et al. [1], the high-yield syn-
mixed ferrocenyl aryl ether 1-(4-tert-butylphenoxy)-1′-(2,4-
thesis of several ferrocenyl aryl ethers was described
dimethylphenoxy)ferrocene was prepared in a two-step
starting from iodo- and 1,1′-diiodoferrocene and phenols,
synthetic protocol.
mediated by Cu(I)/2,2,6,6-tetramethylheptane-3,5-dione
(TMHD) or CuI/1,10-phenanthroline catalytic systems. The
Keywords: aryl ethers; crystal structure; ferrocene.
Cu(I)/TMHD system showed only half the activity when
using brominated ferrocenes, and a much higher catalyst
DOI 10.1515/znb-2014-0178
Received August 4, 2014; accepted August 29, 2014
loading was required. The promising results obtained in
this study with a CuI/phosphine system in toluene were
not further evaluated. As a consequence, we used a CuI/
phosphine system in toluene, a similar system to the Ven-
kataraman catalyst (CuBr(PPh3)3) [22, 23], to further evalu-
ate the potential of this coupling reaction of iodoferrocene
1 Introduction
and 1,1′-dibromoferrocene with phenols.
Ferrocenes are an important class of organometallic com-
The results for this reaction are collected in Table 1.
pounds for synthesis [1–7]. Current interest in ferrocenyl
Entries1and2differinacarbon–iodinevs.carbon–bromine
ethers lies in particular in the possibility for their use as
bond, while the same catalyst was used. The more sophis-
organometallic ligands in homogeneous catalysts [8–13].
ticated reaction using 1,1′-dibromoferrocene resulted in a
The synthetic availability of heteroatom-substituted fer-
low yield (15ꢀ%) compared with the results obtained with
rocenes is still limited because the routes for the intro-
iodoferrocene [1]. A change to a less bulky alkylphosphine
duction of heteroatoms at benzenes are not suitable for
ligand did slightly improve the yield (up to 27ꢀ%, Table 1;
ferrocenes [12, 13]. Pertinent examples of successful syn-
entry 3). In the present investigation, we have extended
theses are the amino- or hydroxyferrocenes functionalized
our previous studies and make use of different carbon–
via nucleophilic substitution with alkyl halides [14–17] or
halogen bond strengths in the variation of product forma-
the synthesis of ferrocenyl alkyl ethers via a trialkylsilyl-
tion. According to the previous publication, we changed
protected hydroxyferrocene [18, 19].
the ligand system back to arylphosphines, which provided
Presently, only very few ferrocenyl aryl ethers are
a reasonable improvement in yield using Cs2CO3 as the
known. The first synthesis of such compounds date
base (up to 86ꢀ%, Table 1; entries 4–7). A comparison of the
back to the 1960s, when Rausch [20] and Nefedova [21],
two different bases Cs2CO3 and K3PO4 showed an additional
improvement from 83 to 97ꢀ% (Table 1; entries 7–8). Nearly
identical results were also obtained for iodoferrocene in
the previous work by an der Heiden et. al., where 85 and
99ꢀ% were obtained, respectively [1]. The influence of the
ligand system and the solvent does not play any specific
role, contrary to previously published results using iodo-
ferrocene and the NMP/TMHD/toluene catalytic systems
for less sterically hindered phenols (substitution in meta
*Corresponding author: Guido D. Frey, Department für Chemie,
Lehrstuhl für Anorganische Chemie, Technische Universität
München, Lichtenbergstraße 4, 85747 Garching, Germany; and
Organometallic Chemistry, Technische Universität Darmstadt,
Alarich-Weiss-Strasse 12, 64287 Darmstadt, Germany,
Tel.: +49(0)89 289 13143, E-mail: guido.frey@ch.tum.de
Stephan D. Hoffmann: Stoe and Cie GmbH, Hilpertstrasse 10, 64295
Darmstadt, Germany
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66ꢀ ꢀG.D. Frey and S.D. Hoffmann: Ferrocenyl aryl ethers
Table 1ꢂScreening for the coupling of ferrocene halides and phenols in toluene a.
R
CuI / ligand
toluene
R
X1
X2
O
+
Fe
Fe
base
110 °C
X3
HO
R
X1 = Br, I
X3 = H,
X2 = Br, H
HO
Entry
R
Ferrocene
Ligand
Base
Yieldb (%)
Compound
1
2
4-t-Bu
FcIc
(1-Ad)2PBn 2 eq.
(1-Ad)2PBn 2 eq.
Cy2PBn 2 eq.
dppm 1 eq.
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
K3PO4
84 [1]
15
1
2
d
4-t-Bu
4-t-Bu
4-t-Bu
4-t-Bu
4-t-Bu
4-t-Bu
4-t-Bu
4-Cl
1,1′-FcBr2
1,1′-FcBr2
1,1′-FcBr2
1,1′-FcBr2
d
d
d
3
27
2
4
86
2
5
PPh2(o-i-propylphenyl) 2 eq.
P(o-tolyl)3 2 eq.
PPh3 2.5 eq.
PPh3 2.5 eq.
PPh3 3 eq.
86
2
6
1,1′-FcBr2
64
2
d
7
1,1′-FcBr2
1,1′-FcBr2
FcIc
83
2
d
8
97
2
9
Cs2CO3
Cs2CO3
K3PO4
96
3
10
11
12
13
14
15
16
17
18
19
20
21
22
23
3-t-Bu
2-t-Bu, 4-Me
2,4-t-Bu2
2,4,6-Me3
2,4,6-Me3
3,5-Me2
2-t-Bu, 4-OMe
2-NO2
2-NO2
FcIc
PPh3 3 eq.
94
4
FcIc,e
PPh3 3 eq.
27
5
FcIc,e
PPh3 3 eq.
K3PO4
23
6
FcIc
PPh3 3 eq.
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
K3PO4
37
7
d
d
1,1′-FcBr2
1,1′-FcBr2
FcIc
PPh3 3 eq.
23
8
PPh3 3 eq.
54
9
PPh3 3 eq.
(24)
10
–
d
1,1′-FcBr2
FcIc
PPh3 3 eq.
ꢀ< ꢀ5 (none)
ꢀ< ꢀ5 (none)
ꢀ< ꢀ5 (none)
ꢀ< ꢀ5 (none)
ꢀ< ꢀ5 (none)
(43)g
(56)
PPh3 3 eq.
Cs2CO3
Cs2CO3
DBU
KOt-Bu
Cs2CO3
Cs2CO3
–
2-NO2, 4-OMe
2-NO2, 4-OMe
2-NO2, 4-OMe
4-t-Bu
FcIc
(1-Ad)2PBn 2 eq.
(1-Ad)2PBn 2 eq.
Cy2PBn 2 eq.
PPh3 3 eq.
–
FcIc
–
FcIc
–
f
1,1′-FcBr2
11
12
2,4-Me2
11c
PPh3 3 eq.
aConditions: ferrocene (0.125 mmol), CuI (5 mol.ꢁ%), ligand (10–15 mol.ꢁ% according to CuI), base (0.25 mmol), Tꢁ=ꢀ110ꢁ°C, toluene. Samples
were taken after 26 h; byields determined by GC; in parentheses the isolated yield is given; cphenol (0.25 mmol); dphenol (0.35 mmol);
ereaction time was 60 h instead of 26 h; fphenol (0.125 mmol); gresults in ∼62ꢁ% yield from theory.
or para position) (comparison of Tables 1–3 in reference ferrocene species were modified. Similar unsuccessful
[1] with the present Table 1 entries 9 and 10). A dramatic results were obtained in previous work [1].
decrease in yield was only observed for ortho-substituted
Considering the obtained yields for these reactions,
phenols, regardless of whether Cs2CO3 or K3PO4 was used we found a suitable variation in starting material and side-
as the base (Table 1, entries 11–13). product rates. For example, for entries 2 and 3, we obtained
With this knowledge in hand, the less reactive between 54 and 68ꢀ% bromoferrocene and 1,1′-dibromofer-
1,1′-dibromoferrocene was tested in entry 14, resulting in rocene, ∼9ꢀ% 1,1″-biferrocene, and 6–7ꢀ% ferrocene after the
another decrease in yield (24ꢀ% by GC) compared with given reaction time. For entry 4, we found 1ꢀ% bromoferro-
the iodoferrocene reaction (37ꢀ%). If the steric hindrance cene, 3ꢀ% 1,1′-dibromoferrocene, ∼3ꢀ% 1,1″-biferrocene, and
is reduced by a meta-substitution, with 1,1′-dibromofer- 7ꢀ% ferrocene. For entry 17, where 1,1′-dibromoferrocene was
rocene, a moderate yield could also be obtained (Table 1 used, we found a 3:1 ratio of bromoferrocene: 1,1′-dibromo-
entry 15). The reaction of iodoferrocene with a deactivated ferrocene after 26 h. In contrast to entries 18–21, where the
phenol such as 4-methoxyphenol resulted in a product more reactive iodoferrocene was used, we obtained after
yield of only 24ꢀ% after column chromatography (see the 26-h reaction time mainly unreacted material (∼50–
Table 1 entry 16). Reactions with phenols containing the 60ꢀ%) and 1,1″-biferrocene and ferrocene in a ratio of ∼2:3.
strong electron-withdrawing substituent -NO2 failed com-
If only one equivalent of phenol was used in the reac-
pletely (Table 1 entries 17–21), even if the phosphine or the tion with 1,1′-dibromoferrocene (Table 1, entry 22), a yield
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G.D. Frey and S.D. Hoffmann: Ferrocenyl aryl ethersꢂ
ꢂ67
of 43ꢀ% was obtained for product 11. In an additional
attempt to prepare a mixed phenoxyferrocene, com-
pound 11 was reacted with 2,4-dimethylphenol to obtain
compound 12 in 56ꢀ% yield after workup by column
chromatography.
Crystals of 1,1′-di(4-tert-butylphenoxy)ferrocene (2)
could be obtained by slow evaporation of the solvent
(CDCl3), and their structure has been determined
(Figs. 1 and 2). The result has provided data for the
first structurally authenticated ferrocenyl diaryl ether
complex. Selected bond lengths (in Å) and angles (in deg)
are presented in the caption of Fig. 1.
The two Cp rings are rotated by 74.1(2)° against each
other, with the two ether groups pointing in opposite
directions out of the Cp planes to reduce steric hindrance.
The molecules are connected by a single intermolecular
hydrogen bond C9–H9···O2 with (H9···O2 2.51(3), H9–C9
0.97(4), C9···O2 3.398(4) Å). All other intermolecular hydro-
gen bonds establishing the three-dimensional framework
are longer than 2.76(4) Å (H5···C12 in C5–H5···C12; H5–C5
0.95(4) Å, C5···C12 3.632(5) Å).
Fig. 2ꢂdiamond [24] plot of compound 2, showing the
conformation of the two Cp rings. H atoms have been omitted for
clarity.
3 Conclusions
We present herein a simple high-yield synthesis of a
variety of different ferrocenyl aryl ethers by an Ullmann-
type coupling protocol. Using the more inexpensive
bromo- and 1,1′-dibromo-ferrocenyl precursors instead
of their iodo analogues, we have developed a more cost-
efficient method for the synthesis of ferrocenyl aryl ethers.
For the first time, a mixed 1,1′-diferrocenyl aryl ether could
be prepared via a simple synthetic protocol.
4 Experimental section
4.1 General methods
Phenols, bases, CuI, and ligands were purchased and
used as received. All reactions and experiments were per-
formed under an atmosphere of dry argon using stand-
ard Schlenk techniques. Column chromatography: Silica
MN60 (63–200 μm), TLC on Merck plates coated with silica
gel 60, F254. Gas chromatography: Perkin-Elmer Autosys-
tem with a Varian CP-SIL-8 column; ferrocene samples
were applied to the column using the sandwich technique
to obtain reproducible results. NMR spectroscopy: Spectra
were recorded at 293 K with Bruker Avance 500 (1H NMR
500 MHz, 13C NMR 125 MHz) and Bruker AC 300 (1H NMR
300 MHz, 13C NMR 75 MHz) spectrometers. 1H NMR spectra
were referenced to residual protonated impurities in the
solvent (CDCl3 7.24 ppm), 13C NMR spectra to the solvent
Fig. 1ꢂdiamond [24] plot of compound 2 in the solid state, showing
50ꢁ% probability displacement ellipsoids and the atom numbering
scheme. H atoms have been omitted for clarity. D1–Fe1 1.6549(4),
D2–Fe1 1.6565(4), C1–O1 1.412(3), C6–O2 1.397(3), C11–O1 1.398(3),
C21–O2 1.396(3), O1–C1–C6–O2 ∼74.12° (D1ꢁ=ꢀcentroid C1–C5,
D2ꢁ=ꢀcentroid C6–C10).
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ꢀꢀꢀꢁ
68ꢀ ꢀG.D. Frey and S.D. Hoffmann: Ferrocenyl aryl ethers
signal (CDCl3 77.0 ppm). Starting materials were commer- 2-tert-Butyl-4-methoxyphenoxyferrocene (10)ꢁIn a
cially available or prepared according to literature proce- Schlenk tube CuI (10 mg, 53 μmol), PPh3 (160 μmol), iodo-
dures: iodoferrocene [17, 25], 1,1′-dibromoferrocene [26, ferrocene (0.125 mmol), 2-tert-butyl-4-methoxyphenol
1
27]. For compounds 3, 4, 5, 6, 7, and 9, H and 13C NMR (45 mg, 2 eq.), and Cs2CO3 (82 mg, 2 eq.) were dissolved
data as well as Rf values were found to be identical with in toluene (8 mL), and the reaction mixture was stirred at
those reported in the literature [1].
110ꢀ°C for 26 h. After evaporation of the volatiles, the crude
product was purified by silica column chromatography
(cyclohexane-ethyl acetate). Of a light-yellow fraction, the
solvent was removed, providing 11 mg (24ꢀ%) of a yellow
4.2 General procedure for the coupling
reactions
1
solid. – Rfꢀ=ꢀ0.60 [cyclohexane-ethyl acetate (20:1)]. – H
NMR (CDCl3): δꢀ=ꢀ1.36 (s, 9H; CH3), 3.55 (m, 2H; Cp), 3.66
In a Schlenk tube CuI (1.2 mg, 6.3 μmol, 5 mol.ꢀ%), the (s, 5H; Cp), 3.83 (m, 2H, Cp), 4.20 (s, 3H, OCH3), 6.51 (s, 1H,
respective ligand (10–15 mol.ꢀ%), the respective ferroce- phenyl), 6.78 (s, 1H, phenyl), 7.18 ppm (s, 1H, phenyl H3).
nyl halide (0.125 mmol), the respective phenol (0.25–0.35
mmol), and a base (0.25 mmol) were dissolved in toluene 1-(4-tert-Butylphenoxy)-1′-bromoferrocene (11)ꢁIn a
(7.5 mL), and the reaction mixture was stirred at 110ꢀ°C for Schlenk tube CuI (100 mg, 0.53 mmol), PPh3 (1.60 mmol),
a given time (26–60 h). After evaporation of the volatiles 1,1′-dibromoferrocene (1.8 g, 5.2 mmol), 4-t-butylphenol
the crude products were purified by column chromatogra- (1.02 g, 1.3 eq.), and Cs2CO3 (1.86 g, 1.1 eq.) were dissolved
phy in cyclohexane-ethyl acetate.
in toluene (35 mL), and the reaction mixture was stirred at
110ꢀ°C for 26 h. After evaporation of the volatiles, the crude
4-tert-Butylphenoxyferrocene (1)ꢁ1H NMR (300 MHz, product was purified by silica column chromatography
CDCl3): δꢀ=ꢀ1.22 (s, 9 H, t-BuH), 3.86 (m, Jꢀ=ꢀ1.9 Hz, 2 H, (cyclohexane-ethyl acetate). Of a light-yellow fraction, the
C5H4), 4.13 (t, Jꢀ=ꢀ1.9 Hz, 2 H, C5H4), 4.19 (s, 5 H, C5H5), 6.85 solvent was removed, which resulted in 930 mg (43ꢀ%) of
(d, Jꢀ=ꢀ8.8 Hz, 2 H, C6H4), 7.21 ppm (d, Jꢀ=ꢀ8.8 Hz, 2 H, C6H4). a yellow-brownish solid. – Rfꢀ=ꢀ0.65 [cyclohexane-ethyl
–
13C NMR (75 MHz, CDCl3): δꢀ=ꢀ31.6 (CH3), 34.3 (CCH3), acetate (20:1)]. – 1H NMR (CDCl3): δꢀ=ꢀ1.22 (s, 9 H; CH3), 3.95
59.8 (C5H4), 62.9 (C5H4), 69.4 (C5H5), 116.7 (o-ArC), 126.2 (t, Jꢀ=ꢀ1.9 Hz, 4 H, Cp), 4.21 (t, Jꢀ=ꢀ1.9 Hz, 4 H, Cp), 6.87 (d,
(m-ArC), 141.6 (C(C5H4)O), 145.3 (t-Bu-ArC), 156.5 ppm Jꢀ=ꢀ8.6 Hz, 2 H, phenyl H2, H6), 7.19 ppm (d, Jꢀ=ꢀ8.6 Hz, 2 H,
(O-ArC). – MS (FAB) m/z (%)ꢀ=ꢀ334.1 (100) [M+H]+. – IR phenyl H3, H5). – 13C NMR (75 MHz, CDCl3): δꢀ=ꢀ31.7 (CH3),
(KBr): vꢀ=ꢀ2965, 2867, 1604, 1510, 1455, 1410, 1374, 1363, 34.4 (CCH3), 60.8 (C5H4), 64.2 (C5H4), 68.2, 68.8, 77.6, 117.0,
1242, 1213, 1172, 1116, 1105, 1022, 1011, 998, 930, 855, 835, 123.2, 126.2, 145.4, 156.4 ppm.
815, 718, 686, 591, 550, 528, 503 cm–1. – C20H22FeO (334.24):
calcd. C 71.87, H 6.63; found C 71.24, H 6.90.
1-(4-tert-Butylphenoxy)-1′-(2,4-dimethylphenoxy)
ferrocene (12)ꢁIn a Schlenk tube CuI (10 mg, 53 μmol),
1,1′-Di(4-tert-butylphenoxy)ferrocene (2)ꢁ1H NMR (500 PPh3 (160 μmol), compound 11 (206 mg, 0.5 mmol),
MHz, CDCl3): δꢀ=ꢀ1.22 (s, 18 H, t-BuH), 3.95 (m, Jꢀ=ꢀ2.2 Hz, 2,4-dimethylphenol (120 μL, 1 mmol), and Cs2CO3 (350
4 H, C5H4), 4.21 (t, Jꢀ=ꢀ2.2 Hz, 4 H, C5H4), 6.91 (d, Jꢀ=ꢀ8.6 Hz, mg) were dissolved in toluene (8 mL), and the reaction
4 H, C6H4), 7.23 ppm (d, Jꢀ=ꢀ8.6 Hz, 4 H, C6H4). – 13C NMR (125 mixture was stirred at 110ꢀ°C for 26 h. After evaporation
MHz, CDCl3): δꢀ=ꢀ31.6 (CH3), 34.3 (C(CH3)3), 60.8 (C5H4), 64.2 of the volatiles, the crude product was purified by silica
(C5H4), 117.0 (ArC), 126.2 (ArC), 141.7 (C(C5H4)O), 145.4 (t-Bu- column chromatography (cyclohexane – ethyl acetate). Of
ArC), 156.4 ppm (ArC). – IR (KBr): vꢀ=ꢀ2961, 2897, 2862, 1604, a light-yellow fraction, the solvent was removed, provid-
1509, 1456, 1361, 1289, 1247, 1215, 1172, 1115, 1026, 1011, 931, ing 126 mg (56ꢀ%) of a yellow solid. – Rfꢀ=ꢀ0.55 [cyclohex-
1
829, 752, 724, 686, 591, 549, 510, 503 cm–1. – C30H34FeO2·0.5 ane-ethyl acetate (20:1)]. – H NMR (300 MHz, CDCl3):
C4H8O2 (526.50): calcd. C 73.00, H 7.27; found C 72.88, H 7.53. δꢀ=ꢀ1.22 (s, 9 H, t-butyl), 2.12 (s, 3 H, CH3), 2.18 (s, 3 H, CH3),
3.84 (t, Jꢀ=ꢀ1.8 Hz, 2 H, Cp(1)), 3.94 (t, Jꢀ=ꢀ2.2 Hz, 2 H, Cp(2)),
1,1′-Di(2,4,6-trimethylphenoxy)ferrocene (8)ꢁRfꢀ=ꢀ0.57 4.14 (t, Jꢀ=ꢀ2.2 Hz, 2 H, Cp(2)), 4.19 (t, Jꢀ=ꢀ1.8 Hz, 2 H, Cp(1)),
1
[cyclohexane-ethyl acetate (20:1)]. – H NMR (500 MHz, 6.81–6.91 (m, 5 H, phenyl), 7.20 ppm (d, Jꢀ=ꢀ7.7 Hz, 2 H). – 13C
CDCl3): δꢀ=ꢀ2.18 (s, 12H, o-CH3), 2.22 (s, 6H, p-CH3), 3.83 (“t”, NMR (75 MHz, CDCl3): δꢀ=ꢀ16.5 (CH3-phenyl C2), 20.7 (CH3-
Jꢀ=ꢀ1.9 Hz, 2 H, C5H4), 4.09 (t, Jꢀ=ꢀ1.9 Hz, 4 H, C5H4), 6.78 ppm phenyl C4), 31.6 (C(CH3)3), 34.3 (C(CH3)3), 59.8 (Cp(2)), 60.8
(s, 4 H, C6H2). – 13C NMR (125 MHz, CDCl3): δꢀ=ꢀ17.0 (ArCH3), (Cp(1)), 62.9 (Cp(2)), 64.2 (Cp(1)), 116.3, 116.7, 117.0, 126.2,
20.8 (ArCH3), 59.1 (C5H4), 62.7 (C5H4), 122.6 (C(C5H4)O), 129.4, 127.2, 128.7, 131.8, 132.0, 132.6, 145.4, 150.4 (phenyl(2) C1),
134.4 (H3C-ArC), 142.0 (H3C-ArC), 154.4 ppm (O-ArC).
156.4 ppm (phenyl(1) C1).
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ꢁꢀꢀꢀ
G.D. Frey and S.D. Hoffmann: Ferrocenyl aryl ethersꢂ
ꢂ69
CCDC 1017347 contains the supplementary crystallo-
graphic data for this paper. These data can be obtained
free of charge from the Cambridge Crystallographic Data
4.3 Single-crystal X-ray structure
determination of compound 2
Crystal data and details of the structure determination are Centre via www.ccdc.cam.ac.uk/data_request/cif.
presented in Table 2. Single crystals suitable for the X-ray
diffraction study were grown from chloroform. A clear Acknowledgments: G.D.F. thanks Prof. Dr. Herbert Plenio
brown prism (0.30ꢀ×ꢀ0.20ꢀ×ꢀ0.10 mm3) was stored under per- and the Eduard-Zintl Institute of Inorganic and Physical
fluorinated ether and transferred into a Lindemann capil- Chemistry of the Technische Universität Darmstadt for
lary for data collection. Data were corrected for Lorentz, laboratory support and cooperation, Prof. Dr. Wolfgang
polarization, and, arising from the scaling procedure, for W. Schoeller and Dr. Rian D. Dewhurst for helpful discus-
latent decay and absorption effects [28]. The structure sions, and Dr. Eberhardt Herdtweck for assistance with
was solved by a combination of Direct Methods and differ- the single-crystal X-ray structure determination.
ence Fourier syntheses [29]. All nonhydrogen atoms were
refined with anisotropic displacement parameters. All
hydrogen atoms were found in the final difference Fourier
map and allowed to refine freely with isotropic displace-
References
ment parameters. Full-matrix least-squares refinements
with 434 parameters were carried out by minimizing
∑w(Fo2–Fc2)2 with the shelxl-97 [30] weighting scheme
and stopped at shift/errꢀ<ꢀ0.001.
[1] M. R. an der Heiden, G. D. Frey, H. Plenio, Organometallics
2004, 23, 3548–3551.
[2] P. D. Beer, P. A. Gale, G. Z. Chen, Coord. Chem. Rev. 1999, 186,
3–36.
[3] I. Manners, Macromol. Symp. 2003, 196, 57–62.
[4] Y. Y. Luk, N. L. Abbott, Science 2003, 301, 623–626.
[5] H. Plenio, C. Aberle, Chem. Eur. J. 2001, 7, 4438–4446.
[6] P. Štěpnička (Ed.), Ferrocenes: Ligands, Materials and
Biomolecules, John Wiley & Sons, Chichester, 2008.
[7] E. S. Phillips (Ed.), Ferrocenes: Compounds, Properties and
Applications, Nova Science Publishers, New York, 2011.
[8] T. J. Colacot, Chem. Rev. 2003, 103, 3101–3118.
[9] H.-U. Blaser, Adv. Synth. Catal. 2002, 344, 17–31.
[10] A. Togni, T. Hayashi (Eds.), Ferrocenes: Homogeneous Catalysis,
Organic Synthesis, Materials Science, VCH, Weinheim, 1995.
[11] L. X. Dai, T. Tu, S. L. You, W. P. Deng, X. L. Hou, Acc. Chem. Res.
2003, 36, 659–667.
[12] D. Schaarschmidt, H. Lang, Eur. J. Inorg. Chem. 2010, 4811–4821.
[13] H. Lang, D. Schaarschmidt. DE 10 2010 001364 B4.
[14] M. Herberhold in Ferrocenes: Homogeneous Catalysis, Organic
Synthesis, Materials Science, (Eds.: A. Togni, T. Hayashi), VCH,
Weinheim, 1995, pp. 219–279.
[15] A. Shafir, M. P. Power, G. D. Whitener, J. Arnold, Organometal-
lics 2000, 19, 3978–3982.
[16] M. Herberhold, H.-D. Brendel, A. Hofmann, B. Hofmann, W.
Milius, J. Organomet. Chem. 1998, 556, 173–187.
[17] B. Bildstein, M. Malaun, H. Kopacka, K. Wurst, M. Mitterböck,
K.-H. Ongania, G. Opromolla, G. Zanello, Organometallics
1999, 18, 4325–4336.
[18] H. Plenio, C. Aberle, Organometallics 1997, 16, 5950–5957.
[19] H. Plenio, C. Aberle, Chem. Commun. 1996, 2123–2124.
[20] M. D. Rausch, J. Org. Chem. 1961, 26, 1802–1805.
[21] V. A. Nefedov, M. N. Nefedova, Zh. Obs. Khim. 1966, 36, 122–127.
[22] R. K. Gujadhur, C. M. Bates, D. Venkataraman, Org. Lett.
2001, 3, 4315–4317.
Table 2ꢂSummary of the crystallographic data of compound 2.
Empirical formula
Molecular weight
Crystal color/shape
Crystal system
Space group
a, Å
C30H34FeO2
482.42
brown/fragment
Monoclinic
P21/c
6.2588(5)
38.0747(16)
11.6187(6)
116.005(7)
2488.4(3)
4
b, Å
c, Å
β, deg
V, Å3
Z
ρcalcd., g cm–3
μ, mm–1
1.29
0.6
Diffractometer
Wavelength; λ, Å
T, K
θ range, deg
Index ranges hkl
Oxford, Xcalibur 3 CCD
MoKα; 0.71073
150(2)
3.32–25.32
–7ꢁꢀ≤ ꢀꢁhꢁꢀ≤ ꢀꢁ4
–45ꢁꢀ≤ ꢀꢁkꢁꢀ≤ ꢀꢁ45
–13ꢁꢀ≤ ꢀꢁlꢁꢀ≤ ꢀꢁ13
14 870
Reflections integrated
Independent reflections/Rint
Observed reflections [Iꢀ>ꢀ2σ(I)]
Parameters refined
4533/0.038
4533
434
R1 (observed/all data)a
wR2 (observed/all data)b
GOFc
0.0496/0.1026
0.1026/0.1058
1.143
[23] R. K. Gujadhur, D. Venkataraman, Synth. Commun. 2001, 31,
2865–2879.
[24] K. Brandenburg, diamond (version 3.2i), Crystal and Molecular
Structure Visualization, Crystal Impact-H. Putz & K. Branden-
burg GbR, Bonn (Germany) 2012. See also: http://www.crystal-
impact.com/diamond/.
Largest diff. peak/hole, e Å–3
0.59/–0.56
2
2
2
aR1ꢁ=ꢀ∑||Fo|–|Fc||/∑|Fo|; bwR2ꢁ=ꢀ[∑w(Fo –Fc2)2/∑w(Fo )2]1/2, wꢁ=ꢀ[σ2(Fo )+
(AP)2+BP]–1, where Pꢁ=ꢀ(Max(Fo , 0)+2Fc2)/3; cGoFꢁ=ꢀ[∑w(Fo –Fc2)2/
2
2
(nobs–nparam)]1/2
.
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ꢀꢀꢀꢁ
70ꢀ ꢀG.D. Frey and S.D. Hoffmann: Ferrocenyl aryl ethers
[25] F. S. Kamounah, J. B. Christensen, J. Chem. Res. Synop. 1997, 150.
[26] T.-Y. Dong, L.-L. Lai, J. Organomet. Chem. 1996, 509, 131–134.
[27] M. S. Inkpen, S. Du, M. Driver, T. Albrecht, N. J. Long, Dalton
Trans. 2013, 42, 2813–2816.
[28] Z. Otwinowski, W. Minor in Methods in Enzymology,
Vol. 276, Macromolecular Crystallography, Part A,
(Eds.: C. W. Carter Jr, R. M. Sweet), Academic Press, New York,
1997, pp. 307–326.
[29] A. Altomare, G. Cascarano, C. Giacovazzo, A. Guagliardi,
M. C. Burla, G. Polidori, M. Camalli, J. Appl. Crystallogr.
1994, 27, 435–436.
[30] G. M. Sheldrick, Acta Crystallogr. 2008, A64, 112–122.
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