(Metallocenylphosphane)palladium dichlorides- synthesis, electrochemistry and their application in C-C coupling reactions

Article abstract of DOI:10.1002/ejic.201100842

The synthesis and characterization of a series of metallocenylphosphanes of the type PR₂Mc/Se=PR₂Mc [Mc = Fc = Fe(η⁵- C₅H₄)(η⁵-C₅H₅), R = C₆H₅ (3

Full text of DOI:10.1002/ejic.201100842

FULL PAPER
DOI: 10.1002/ejic.201100842
(Metallocenylphosphane)palladium Dichlorides – Synthesis, Electrochemistry
and Their Application in C–C Coupling Reactions
Bianca Milde,[a] Manja Lohan,[a] Claus Schreiner,[a] Tobias Rüffer,[a] and Heinrich Lang*[a]
Keywords: Ferrocene / Palladium / Phosphanes / C–C coupling / Electrochemistry
The synthesis and characterization of a series of metallocen-
[B(C6F5)4] as the supporting electrolyte. In general, the first
ylphosphanes of the type PR2Mc/Se=PR2Mc [Mc = Fc = oxidation occurs at the phosphane metallocenyl unit(s), al-
Fe(η5-C5H4)(η5-C5H5), R = C6H5 (3a/4a), 2-MeC6H4 (3b/4b),
c-C4H3O (3c/4c), tBu (3d/4d), c-C6H11 (3e/4e); Mc = Rc =
Ru(η5-C5H4)(η5-C5H5), R = C6H5 (6a/7a), 2-MeC6H4 (6b/7b),
c-C4H3O (6c/7c), c-C6H11 (6d/7d)] and their palladium com-
plexes [PdCl2(PR2Mc)2] [Mc = Fc, R = C6H5 (9a), 2-MeC6H4
(9b), c-C4H3O (9c), tBu (9d), c-C6H11 (9e); Mc = Rc, R = C6H5
(10a), 2-MeC6H4 (10b), c-C4H3O (10c), c-C6H11 (10d)] is re-
ported. The solid-state structure of 4b confirms the tetrahe-
drally distorted geometry at phosphorus with the o-tolyl
groups indicating steric congestion, which is confirmed by
1H and 13C{1H} NMR spectroscopy. Phosphanes 3, 4, and 9
were characterized by cyclic voltammetry with [N(nBu)4]-
though the appropriate Pd complexes are oxidized at more
positive potentials. Depending on the phosphane or seleno-
phosphane, follow-up reactions occur, which are discussed.
In contrast, the palladium complexes show reversible redox
behavior. UV/Vis/NIR spectroelectrochemical studies carried
out on 9b indicate an electrostatic interaction between the
two terminal ferrocenyl groups. All of the palladium com-
plexes were examined as catalysts in Heck and Suzuki C–
C cross-coupling and showed high catalytic activities. These
results can be correlated to the electronic (1J
Se) param-
31P77
eters of the selenophosphanes.
To quantify the σ donor ability of a phosphanyl group,
Introduction
the magnitude of the 31P77Se coupling constant of the cor-
The development of new ligands for palladium-catalyzed responding selenophosphane should be measured. Allen
1
31P77Se
C–C coupling reactions has accelerated over recent years and Taylor have reported that an increase in J
indi-
because new ligand structures may effect the activation of cates an increase in the s character of the phosphorus lone-
aryl–chloro bonds under mild reaction conditions with high pair orbital and as result the basicity of the phosphane de-
conversions and low catalyst loadings.[1] Hitherto, mono- creases.[6]
and bidentate alkyl-, aryl-, and ferrocenyl-functionalized
Herein we report the enrichment of the family of metall-
phosphanes, N-heterocyclic carbenes, and palladacycles ocenyl-functionalized phosphanes that feature electron-do-
have been successfully used in the synthesis of effective pal- nating or -withdrawing groups by applying straightforward
ladium catalysts.[1–4] Electron rich and/or bulky mono- and synthetic methodologies. The use of these phosphanes in
bidentate phosphanes are of particular interest,[4c,5] al- palladium-catalyzed Heck and Suzuki reactions is dis-
though it is still a challenge to predict their performance in cussed. A quantification of the electronic properties of the
homogeneous catalysis as small changes in their electronic phosphanes towards the catalytic activities has been per-
and/or spatial structure may affect the activity of the cata- formed.
lyst.[4c] This prompted us to synthesize metallocenyl-based
phosphanes of the type PR2Fc [Fc = Fe(η5-C5H4)(η5-
C5H5)] and PR2Rc [Rc = Ru(η5-C5H4)(η5-C5H5)] because
the metallocenyl entity achieves a significant increase in the
Results and Discussion
stability of the respective phosphane towards air and moist-
ure, and the ligands, R, are responsible for controlling the
electronic and steric properties.
Ligand Synthesis and Properties
[a] Chemnitz University of Technology, Faculty of Science,
Institute of Chemistry, Department of Inorganic Chemistry,
Straße der Nationen 62, 09111 Chemnitz, Germany
Fax: +49-371-531-21219
Metallocenyl-phosphanes 3a–e and 6a–d, the corre-
sponding selenophosphanes 4a–e, and 7a–d as well as their
palladium complexes 9a–e and 10a–d were prepared ac-
cording to previously reported synthetic methodologies
(Scheme 1, Reaction 1, Tables 1 and 2).[4b,6f,8]
E-mail: heinrich.lang@chemie.tu-chemnitz.de
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.201100842.
Eur. J. Inorg. Chem. 2011, 5437–5449
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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B. Milde, M. Lohan, C. Schreiner, T. Rüffer, H. Lang
FULL PAPER
(1)
Scheme 1. Synthesis of 3, 4, 6, and 7 from 1 or 5.
Table 1. Synthesis of 3a–e, 4a–e, 6a–d, and 7a–d.
All compounds were identified by elemental analysis, IR
and NMR (1H, 13C{1H}, 31P{1H}) spectroscopy, and ESI-
%
%
M
R
M
R
Yield[a]
Yield[a] TOF mass spectrometry (see Exp. Section). The electro-
chemical behavior of 3, 4, and 9 was determined.
3a
3b
3c
3d
3e
4a
4b
4c
4d
4e
Fe
Fe
Fe
Fe
Fe
Fe
Fe
Fe
Fe
Fe
C6H5
57
69
63
48
31
100
100
100
100
100
6a
6b
6c
6d
Ru
Ru
Ru
Ru
C6H5
35
36
46
42
2-MeC6H4
c-C4H3O
tBu
c-C6H11
C6H5
2-MeC6H4
c-C4H3O
tBu
2-MeC6H4
c-C4H3O
c-C6H11
Electrochemistry
7a
7b
7c
7d
Ru
Ru
Ru
Ru
C6H5
89
94
84
92
The redox properties of 3, 4, and the corresponding com-
plexes 9 were studied by cyclic voltammetry (CV), linear
sweep voltammetry (LSV, 9), square wave voltammetry
(SWV, 9), and spectroelectrochemistry (UV/Vis/NIR spec-
troscopy, 9b) in dry dichloromethane with [N(nBu)4]-
[B(C6F5)4] (0.1 molL–1) as the supporting electrolyte. This
solvent/electrolyte combination was chosen because it was
recently shown by Geiger et al.[9] that it provides almost
optimal conditions for electrochemical experiments as it
minimizes electrolyte–analyte interactions and, hence, fol-
low-up reactions. The CV studies were carried out at scan
rates of 100 mVs–1, and the data are summarized in Table 3.
All potentials are referenced to the FcH/FcH+ redox couple
as the internal standard as recommended by IUPAC.[10]
The electrochemically most studied member of the series
of phosphanes reported in this work is ferrocenyl diphenyl-
phosphane. Kotz and Nivert reported a reversible one-elec-
tron oxidation at E0 = 0.48 V (vs. SCE) when measured to
a maximum potential of 0.8 V, and irreversible oxidations
2-MeC6H4
c-C4H3O
c-C6H11
c-C6H11
[a] Based on 1 and 5 or 3 and 6.
Table 2. Synthesis of 9a–e and 10a–d.
%
%
M
R
M
R
Yield[a]
Yield[a]
9a
9b
9c
9d
9e
Fe
Fe
Fe
Fe
Fe
C6H5
90
84
77
74
81
10a Ru C6H5
83
84
86
70
2-MeC6H4
c-C4H3O
tBu
10b Ru 2-MeC6H4
10c Ru c-C4H3O
10d Ru c-C6H11
c-C6H11
[a] Based on 8.
The synthesis of the metallocenyl-phosphanes, PR2Mc
[Mc = Fc = Fe(η5-C5H4)(η5-C5H5), R = C6H5 (3a),[7] 2-
MeC6H4 (3b), c-C4H3O (3c), tBu (3d),[7] c-C6H11 (3e);[7] Mc
= Rc = Ru(η5-C5H4)(η5-C5H5), R = C6H5 (6a), 2-MeC6H4
(6b), c-C4H3O (6c), c-C6H11 (6d)], and the appropriate sele-
nophosphanes, Se=PR2Mc [Mc = Fc (4a–e), Rc (7a–d)],
was carried out by a consecutive reaction sequence
(Scheme 1). Lithiation of M(η5-C5H4I)(η5-C5H5) [M = Fe
(1), Ru (5)] and subsequent treatment with R2PCl [R =
C6H5 (2a), 2-MeC6H4 (2b), c-C4H3O (2c), tBu (2d), c-C6H11
(2e)] gave metallocenyl-phosphanes 3 and 6, which further
reacted with elemental selenium to produce the selenophos-
phanes 4 and 7, respectively (Scheme 1, Table 1).
Complexation of 3 and 6 was performed by addition to
[PdCl2(cod)] (8, cod = cyclo-1,5-octadiene) at ambient tem-
perature (Reaction 1). After work up, the orange to red col-
ored ferrocenyl complexes 9 or pale yellow ruthenocenyl
complexes 10 were isolated in 70–90% yield (Table 2).
Solid phosphanes 3 (yellow) and 6 (pale yellow) are
stable in air, and no oxidation of the phosphorus(III) center
is observed. However, it appeared that solutions containing
these molecules slowly oxidized to give the corresponding
phosphane oxides. As expected, 4, 7, 9, and 10 are air- and
moisture-stable. However, 7d shows sensitivity towards light
and slowly turns pale yellow.
Table 3. Cyclovoltammetric data (potentials vs. FcH/FcH+), scan
rate 100 mVs–1 at a glassy-carbon electrode of 1.0 mmolL–1 solu-
tions of 3 and 4 in dry dichloromethane containing 0.1 molL–1
[N(nBu)4][B(C6F5)4] as the supporting electrolyte at 25 °C.[a]
E0 (ΔEp) /V
Eox–irrev /V Ered–irrev /V
Eox–irrev /V Ered–irrev /V
3a 0.064 (0.082)
0.703
4a 0.288
–0.290
0.021
0.674
0.838
–0.449
0.713
–0.454
0.238
0.510
0.802
0.108
0.360
0.712
–0.290
0.176
0.586
0.934
1.058
3b 0.013 (0.090)
3c 0.091 (0.108)
4b 0.241
0.895
4c 0.326
1.122
3d
3e
0.022
0.188
0.806
0.023
0.207
0.815
–0.046
0.158
0.702
–0.029
0.175
0.713
4d 0.216
0.858
4e 0.270
0.706
[a] E0 = redox potential, ΔEp = difference between oxidation and
reduction potential, Eox–irrev = irreversible oxidation potential,
Ered–irrev = irreversible reduction potential.
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(Metallocenylphosphane)palladium Dichlorides
occur at higher potentials (1.5 V).[11a,11b] The first oxidation
All of the free phosphanes were converted into the corre-
process confirms the ferrocenyl oxidation, and the resulting sponding selenophosphanes to investigate their electronic
ferrocenium ion participates in an intramolecular electron properties (vide infra). Ferrocenyl-phosphane chalcogenides
transfer from the PPh2 group to iron.[11] Under our condi- are electrochemically less investigated than free phosphanes,
tions, we observed a similar behavior for all the ferrocenyl- of which phosphane sulfides and oxides are the best studied
phosphanes (Table 3). Representative CVs of 3b and 3e are and show reversible behavior.[9,12a,12b] Although electro-
shown in Figure 1. As consequence of the nature of the chemically-induced follow-up reactions are not expected be-
alkyl or aryl substituent at phosphorus, a different elec- cause of the oxidation state of +5 at phosphorus, seleno-
tronic and, hence, electrochemical behavior is expected. The phosphanes show a different behavior. We examined the
more electron-rich a compound is, the easier it is to oxidize. electrochemistry of 4a–e under the same conditions de-
This meets the expected furyl Ͻ phenyl Ͻ o-tolyl trend for scribed above (Figure 1). As expected, the selenophos-
the aromatic phosphanes, whereas aliphatic 3d and 3e show phanes are more difficult to oxidize than the corresponding
a similar electronic character and completely irreversible PIII-containing compounds 3a–e (Table 3). In all of the
behavior (Table 3).
CVs, almost irreversible oxidation events between 0.16 and
Figure 1. CVs of dichloromethane solutions containing 1.0 mmolL–1 of 3b (top, left), 4b (middle, left), and 9b (bottom, left) and 3e (top,
right), 4e (middle, right), and 9e (bottom, right) at 25 °C with [N(nBu)4][B(C6F5)4] as the supporting electrolyte at a scan rate of 100
mVs–1.
Eur. J. Inorg. Chem. 2011, 5437–5449
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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5439

B. Milde, M. Lohan, C. Schreiner, T. Rüffer, H. Lang
FULL PAPER
0.33 V that give cathodic responses between –0.67 and –0.29 molL–1) as the supporting electrolyte. This procedure al-
V are observed, which can be attributed to follow-up reac- lowed the generation of 9b+ from neutral 9b. It can be seen
tions. In addition, it is apparent that the more reversible the from Figure 2 that 9b+ does not exhibit any absorption in
oxidation processes are, the lower the intensity of the cath- the NIR range, which confirms that the positive charges
odic response is. A similar behavior was recently described were localized on the Fc+ groups in mixed-valent partially-
for diseleno-1,1Ј-bis(diphenylphosphanyl)ferrocene[12b] and oxidized intermediates (Figure 2). Nevertheless, during oxi-
seleno bi- and triferrocenyl-phenylphosphanes.[9] The corre- dation an absorption in the UV/Vis part of the spectrum at
sponding follow-up products presumably result from intra- 524 nm occurs, which is assigned to a ligand-to-metal
molecular electron transfer from the selenium-centered rad- charge transfer transition from the ligand to the ferrocen-
ical. Therefore, contributions from either the iron, phos- ium moiety.[12c–12e] The ΔE0 value of 0.126 V indicates some
phorus, or selenium radicals are expected in the monocat- electrostatic interaction between the two terminal ferrocenyl
ionic species of this series.
groups as the oxidation progresses.
However, intramolecular oxidations are inhibited when
the phosphorus atom in 3a–e is datively-bonded to palla-
dium as seen in 9a–e (Figure 1, Table 4). Surprisingly, two
reversible oxidation processes between E0 = 0.11 and 0.27
V with ΔE0 values of between 0.058 and 0.126 V were ob-
served for these ferrocenyl-phosphane palladium complexes.
This indicates that the two metallocenyls can be oxidized
separately. The electrochemical data of these complexes are
summarized in Table 4. No further redox events to indicate
follow-up reactions were observed. Compared to the non-
coordinated metallocenyl-phosphanes, the respective palla-
dium complexes are more difficult to oxidize, which can be
explained by the electron-withdrawing effect of the coordi-
nation of the phosphanes to palladium (Figure 1, Table 4).
In addition to CV measurements, LSV and SWV studies
Figure 2. UV/Vis/NIR spectra of 9b at rising potentials (–0.2 to 1.2
V vs. Ag/AgCl) at 25 °C in dichloromethane with [N(nBu)4]-
were carried out (Figure 1), which confirm the one-electron [B(C6F5)4]. Arrows indicate increasing or decreasing of absorp-
tions.
processes.
Table 4. Cyclovoltammetric data (potentials vs. FcH/FcH+), scan
rate 100 mVs–1 at a glassy-carbon electrode of 9a–e in dry dichloro-
Single-Crystal X-ray Structure Determination
methane solution (1.0 mmolL–1) with 0.1 molL–1 of [N(nBu)4]-
[B(C6F5)4] as the supporting electrolyte at 25 °C.[a]
The molecular structure of 4b was solved by single-crys-
tal X-ray structure analysis. Suitable crystals were obtained
0
0
E1 (ΔEp) /V
E2 (ΔEp) /V
ΔE0 /V
from a saturated dichloromethane solution of 4b at ambient
temperature. The ORTEP diagram, selected bond lengths,
bond angles, and torsion angles are shown in Figure 3. The
crystal and structure refinement data are presented in the
Exp. Section.
Compound 4b crystallizes in the monoclinic space group
P21/n. The structure of 4b comprises one ferrocenyl unit, in
which the two cyclopentadienyl rings are within 3° of paral-
lel orientation to each other. Two o-tolyl groups, the Fe(η5-
C5H4)(η5-C5H5) unit, and one selenium atom are bound to
9a
9b
9c
9d
9e
0.145 (0.097)
0.118 (0.072)
0.212 (0.082)
0.118 (0.094)
0.169 (0.090)
0.263 (0.099)
0.244 (0.072)
0.270 (0.080)
0.203 (0.092)
0.276 (0.088)
0.116
0.126
0.058
0.085
0.107
0
0
[a] E1 = potential of the first redox process, E2 = potential of
the second redox process, ΔEp = difference between oxidation and
reduction potential, ΔE0 = potential difference between two redox
processes.
To investigate the electrochemically generated electronic the phosphorus atom, which results in its tetrahedrally dis-
absorptions in the visible and near infrared (NIR) regions, torted geometry (Figure 3). The P–C bond lengths of
a spectroelectrochemical investigation was performed on 9b, 1.795(3) and 1.829(3) Å are representative for P–Caryl enti-
which was chosen as it shows the largest peak separation ties.[4b,6d,13,14] The P1–Se1 bond length of 2.1198(7) Å is
(ΔE0 = 0.126 V) between the first and second oxidations. characteristic of selenophosphanes (e.g. tri-o-tolylsele-
An absence of charge-transfer bands in the NIR would nophosphane)[13,14] that contain electron-donating methyl
point to electron-localized mixed-valent complexes, whereas substituents. As result, the s character of the p orbital in-
their presence would argue in favor of electron delocaliza- volved in bonding to Se is decreased (vide infra). The C–
tion. The spectroelectrochemical studies were conducted by P–C angles at P1 (Figure 3) are 103.74(12)–110.63(12)°,
the stepwise increase of the potential from –0.2 to 1.2 V which is in the range typical for tertiary selenophospha-
vs. Ag/AgCl in an optically transparent thin-layer electrode nes.[4b,6d,13,14] Notably, the Se1–H12 distance of 2.830 Å is
(OTTLE)[12f,12g] cell that contained dichloromethane solu- less than the sum of the van der Waals radii (3.10[15a]
tions of 9b (1.0 mmolL–1) and [N(nBu)4][B(C6F5)4] (0.1 3.35[15b]Å), which might be a reason for the broadened sig-
–
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Eur. J. Inorg. Chem. 2011, 5437–5449

(Metallocenylphosphane)palladium Dichlorides
Figure 3. Left: ORTEP diagram (50% probability level) of the molecular structure of 4b with the atom numbering scheme. Hydrogen
atoms are omitted for clarity. Standard uncertainties of the last significant digit(s) are shown in parenthesis (D1 = the centroid of C5H4;
D2 = the centroid of C5H5). Selected bond lengths [Å], bond angles [°], and torsion angles [°]: Fe–D1 1.673, Fe–D2 1.645, C1–P1 1.795(3),
C11–P1 1.829(3), C18–P1 1.818(3), P1–Se1 2.1198(7); C1–P1–Se1 112.30(9), C11–P1–Se1 114.04(8), C18–P1–Se1 109.92(8), C1–P1–C11
103.74(12), C1–P1–C18 105.78(12), C18–P1–C11 110.63(12), D1–Fe–D2 176.8; C16–C11–P1–Se1 163.3(2), C12–C11–P1–Se1 –20.2(2),
C23–C18–P1–Se1 –69.1(2), C5–C1–P1–Se1 –36.9(2), P1–C18–C23–C24 –6.3(4), P1–C11–C16–C17 –4.8(4). Right: Visualization of the
short intramolecular Se1–H12 contact [d(Se1···H12) = 2.830 Å].
nals in the NMR spectra (vide infra). All other structural figuration. Heteronuclear single quantum coherence and
parameters are unexceptional and correspond to those of H,H-COSY measurements were performed to completely
related compounds.[4b,6d,13,14] However, the 1H and 13C{1H} assign all of the peaks to the respective hydrogen and car-
NMR spectra of 4b and 6b show very broad resonances for bon atoms (see Supporting Information, Figure S1). The
both the C5H4 and o-tolyl protons, which indicates dynamic splitting pattern of the NMR signals reveals a C2 symmetry
behavior (Figure 4). Nevertheless, for both compounds it for 4b at low temperature in solution, which is in accord-
1
is typical that the 31P{1H} NMR signal of phosphorus(V) ance with the XRD analysis. Moreover, the H NMR sig-
displays a sharp singlet at ambient temperature. The free nals assigned to the ortho protons of the tolyl moiety shift
rotation of the phosphanyl group was reduced by cooling significantly upon cooling, which might be explained by
the NMR sample of 4b to –90 °C, which resulted in the their close proximity to the selenium atom (vide supra).
appearance of four individual signals for the protons of the
The donor properties of PR3 (R = alkyl, aryl, alkoxyl)
1
31P77Se
C5H4 moieties and eight aromatic signals of equal intensity towards selenium acceptors can be quantified by J
for both o-tolyl units (Figure 4). This observation indicates obtained from 31P{1H} NMR spectroscopy.[6] An electron-
that the o-tolyl units are not symmetrically equivalent, and withdrawing group at phosphorus increases the value of
a fast inversion of the configuration of phosphorus must 1J
Se, which is explained by the increased s character of
31P77
occur at ambient temperature, which is frozen at –90 °C on the phosphorus orbital involved in the P–Se bonding. Con-
1
31P13
C
the NMR timescale. Furthermore, the values of the J
sequently, shorter bond lengths between the phosphorus
coupling constants of both o-tolyl moieties are almost and the acceptor carbon atoms are observed. This elec-
equal, which indicates that the o-tolyl groups have no sig- tronic impact has a direct influence on the phosphorus do-
nificant influence on the spatial orientation of the P–C con- nor ability and, hence, on the electron density in the corre-
sponding transition metal complex. The absolute value of
1J
is a decisive parameter for the specific design of
31P77Se
compounds used as catalytically active species in homogen-
eous catalysis (vide infra). The 31P{1H} NMR spectroscopic
1
31P77Se
data together with the values of J
for 4a–e and 7a–d
are summarized in Table 5.
Table 5. Chemical shifts [ppm] and 1J
[Hz] values for 4a–e,
31P77Se
7a–d, and Ph3P=Se[6a] for comparison.
31P77Se
δ
1J
δ
1J
31P77Se
4a
4b
4c
4d
4e
31.8
29.4
–5.3
74.7
49.8
733
716
769
702
700
7a
7b
7c
7d
31.2
29.0
–6.8
49.2
735
718
772
704
732
Ph3P=Se[6a] 35.9
Figure 4. 1H NMR spectra of 4b between 3.5 and 9.5 ppm in
CD2Cl2 at 25 °C (top) and at –90 °C (bottom).
From Table 5 it can be seen that 4c and 7c, which contain
furyl ligands, are, as expected, the most electron-poor phos-
Eur. J. Inorg. Chem. 2011, 5437–5449
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B. Milde, M. Lohan, C. Schreiner, T. Rüffer, H. Lang
FULL PAPER
31P77
phanes as indicated by the absolute value of J
Se. The added as base and acetyl ferrocene as the internal standard
most electron-donating systems are the aliphatic t-butyl (Table 6; reaction profiles are given in Figure S2). The con-
1
versions were determined by 1H NMR spectroscopy (see
31P77Se
(4d) and cyclohexyl (4e, 7d) selenophosphanes with J
≈ 700 Hz (Table 5). The ruthenocenyl-phosphanes have Exp. Section).
slightly higher coupling constants than the isostructural
ferrocenyl derivatives, which emphasizes that the ferrocenyl-
phosphanes are somewhat better σ donors. The data sum-
marized in Table 5 indicate the suitability of the metall-
ocenyl-phosphanes as ligands in, for example, Heck and Su-
zuki reactions. Furthermore, it is possible to compare the
(2)
0
31P77Se
J
values of 4a–e with the redox potentials E1 of 9a–
It was found that 9d, which has tert-butylphosphanyl li-
gands, was the most active catalyst (Entry 4, Table 6, Figure
S2) within the series. Complexes 9b, 9c, and 9e (Entries 2,
3, and 5; Table 6) are somewhat less active, which is ex-
plained by the more electron-rich phosphane 3d providing
a greater electronic stabilization to the active catalyst 9d.
The ruthenocenyl-based catalysts 10a–d are less active than
the ferrocenyl-based complexes with conversions of 76–84%
after 25 h, which show no clear electronic dependency.
However, catalysts 9 and 10 show some benefits in homo-
geneous catalysis compared with previously reported ferro-
cenyl mono- and diphosphanes[4d] (Entries 6 and 7,
Table 6), which are (i) significantly lower catalyst loadings,
(ii) no addition of a reductant (CuI) is necessary, and (iii)
their high regioselectivity (only the E isomer was formed).
The difference to the systems used by Butler and Boyes[4d]
can be ascribed to electronic and steric factors, of which
the bis(tert-butyl) ferrocenyl-phosphane has the optimum
balance of both criteria. The fact that only one isomer was
produced can be explained by the steric congestion of the
tert-butyl groups (vide supra). This is in accordance with
the observations made by Butler and Boyes, who used palla-
dium(II) complexes of (diisopropylphosphanyl)ferrocenes,
and associated their results with the lower flexibility and
chelate effect of the sandwich compound. Nevertheless, the
ferrocenyl and ruthenocenyl-phosphanes 3 and 6 are less
active in the palladium-promoted Heck reaction than cata-
lytic systems used to date.[2f,1,1m–1o]
e, which results in a linear correlation (Figure 5). It is obvi-
ous that only molecules that feature aromatic groups on the
phosphorus atom fit this correlation, whereas the aliphatic
phosphanes differ. This is most likely attributed to the dif-
ferent hybridization and, hence, geometry of the groups at
the phosphorus atom. Therefore, it is necessary to exclu-
sively compare structurally related molecules.
0
1
31P77Se
Figure 5. Correlation of E1 and J
9c.
for 4a/9a, 4b/9b, and 4c/
Catalytic Investigations – Heck Catalysis
The reaction of iodobenzene with tert-butyl acrylate to
give E-tert-butylcinnamate (Reaction 2) was used as the
standard reaction to compare the catalytic activity of 9 and
10 with the known catalysts [PdCl2(P(iso-C3H7)2Fc)2] and
[PdCl2(disoppf)] [disoppf = 1,1Ј-bis(diisopropylphosphan-
yl)ferrocene].[4d] The reactions were performed in a mixture
Catalytic Investigations – Suzuki Catalysis
Complexes 9 and 10 were also applied to the Suzuki reac-
of toluene and acetonitrile (1:1, v/v) with a catalyst loading tion of 2-bromotoluene or 4Ј-chloroacetophenone with
of 0.2 mol-% at 80 °C for 10 and 25 h. EtN(iso-C3H7)2 was phenylboronic acid in the presence of potassium carbonate
Table 6. Heck reaction of iodobenzene with tert-butyl acrylate catalyzed by 9 and 10 (0.2 mol-%), yields with [PdCl2(P(iso-C3H7)2Fc)2]
and [PdCl2(disoppf)] are given for comparison.[a]
Entry
Compound
% Conversion[b] % Conversion[c] Entry
Compound
% Conversion[b]
% Conversion[c]
1
2
3
4
5
6
9a
9b
9c
9d
44.9
76.4
65.2
100
59.8
–
69.9
94.7
89.5
100
7
8
9
10
11
[PdCl2(disoppf)]
–
100[c]
81.0
77.1
76.4
84.3
10a
10b
10c
10d
57.1
67.0
57.7
72.6
9e
90.0
[PdCl2(P(iso-C3H7)2Fc)2]
96[a]
[a] GLC yields after heating to reflux for 24 h with a catalyst loading of 1.0 mol-%.[4d] [b] Conversion after 10 h. [c] Conversion after 25
h.
5442
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© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2011, 5437–5449

(Metallocenylphosphane)palladium Dichlorides
as a base in a mixture of 1,4-dioxane and water (2:1, v/v)
at 100 °C (Reaction 3). Acetyl ferrocene was added as the
internal standard for conversion determinations by 1H
NMR spectroscopy.
(3)
As seen from Table 7 and the reaction profiles (Figures 6
and S3), all of the complexes are active in Pd-catalyzed Su-
zuki cross-couplings (vide supra), which reflects the elec-
tronic dependency of 3 and 6, to give 2-methylbiphenyl and
4Ј-acetylbiphenyl as the only products (Figure S4). The
most active catalysts for C–Br activation are the electron-
rich ferrocenyl systems 9a, 9b, 9d, and 9e, and the rutheno-
cenyls 10b and 10d, whose reactions reached complete con-
version after 2–20 min (Figure S3). The reaction of acti-
vated 4Ј-chloroacetophenone with phenyl boronic acid re-
quires, as expected, longer conversion times and higher cat-
alyst loadings (0.5 mol-%), in which only reactions with ali-
phatic 9d and 9e reached completion within 10 min and that
of 10d after 20 min. All of the other species were signifi-
cantly less active and showed conversions below 60% after
2 h (Entries 6–8 and 19–21, Table 7, Figure 6). Further-
more, it was found that the ruthenocenyl-phosphane palla-
dium systems are somewhat less active than the iso-
structural ferrocenyls, which can be explained by the fact
that the ferrocenyl species are more electron-rich. This also
Figure 6. Reaction profiles for 9a–e (top) and 10a–d (bottom) for
the reaction of 4Ј-chloroacetophenone with phenylboronic acid and
a catalyst loading of 0.5 mol-%.
Because the Suzuki reaction strongly depends on the
electronic nature of the phosphane, we could show that a
relationship between phosphane basicity and catalytic ac-
1
31P77Se
tivity exists. The lower the value of J
and, hence, the
more basic the phosphane, the higher the catalytic activity.
is reflected by the slightly higher 1J
Se coupling constants
31P77
(vide supra, Table 5). These results are in accordance with
the general statement that electron-rich, bulky phosphanes
are suitable ligands for Suzuki C–C coupling reac-
Conclusions
The synthesis of a series of metallocenyl-phosphane pal-
tions.[4c,5a,5b] However, 9 and 10 are somewhat less active ladium dichloride complexes of the type [PdCl2(PR2Mc)2]
than currently used catalytic systems.[2e–2h,2j–2l,4e,7e]
is reported. These complexes were prepared by treatment of
Table 7. Reaction of 2-bromotoluene and 4Ј-chloroacetophenone with phenylboronic acid after 1 h with different catalyst loadings.
Eur. J. Inorg. Chem. 2011, 5437–5449
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
5443

B. Milde, M. Lohan, C. Schreiner, T. Rüffer, H. Lang
FULL PAPER
phosphanes R2PMc with [PdCl2(cod)]. CV measurements
showed that the metallocenyl-functionalized aromatic phos-
phanes are first reversibly oxidized at the metallocenyl frag-
ment when measuring to 0.8 V. The resulting ferrocenium
ion participates in intramolecular electron transfer pro-
cesses from the PR2 groups to the transition metal ion.
Irreversible oxidations occur on going to higher potentials
(1.5 V). As expected, electron-rich phosphanes are easier to
oxidize. This is verified in the series R = furyl Ͻ phenyl Ͻ
o-tolyl, however, aliphatic phosphanes show a similar elec-
tronic character and completely irreversible behavior. Ad-
ditionally, we investigated the electrochemical behavior of
the selenophosphanes 4a–e and the bis(phosphanyl)palladi-
um(II) complexes 9a–e, in which the lone pair of electrons
at phosphorus atom is part of a phosphorus–selenium or
phosphane–palladium bond. Nevertheless, as described ear-
lier,[9,12b] the selenophosphanes also show follow-up prod-
ucts, which presumably result from an intramolecular elec-
tron transfer from the selenium-centered radical. Therefore,
contributions from either the iron, phosphorus, or selenium
radicals are expected in the monocationic species. Such oxi-
dations are inhibited when the phosphorus atom is datively
bonded to palladium, as in 9a–e. As expected, the bis(phos-
phanyl) palladium complexes are more difficult to oxidize,
which can be explained by their electron-withdrawing char-
acter upon coordination of the phosphane to Pd. UV/Vis/
NIR spectroscopy revealed the absence of any NIR charge-
transfer bands, which indicate electrostatic interactions. For
classification of the σ donor ability of the phosphanes, the
corresponding selenophosphanes, Se=PR2Mc, were pre-
Experimental Section
General Methods: All reactions were carried out under an atmo-
sphere of nitrogen or argon using standard Schlenk techniques. Tol-
uene and tetrahydrofuran were purified by distillation with sodium
and sodium/benzophenone, respectively; dichloromethane was
purified by distillation with calcium hydride. Celite (purified and
annealed, Erg. B.6, Riedel-de Haën) was used for filtrations. Alu-
mina with a particle size of 90 μm (standard, Merck KGaA) or
silica with a particle size of 40–60 μm [230–400 mesh (ASTM),
Becker] was used for column chromatography.
Instrumentation: NMR spectra were recorded with a Bruker Avance
III 500 spectrometer [500.3 MHz for H, 125.7 MHz for 13C(1H),
1
and 202.5 MHz for 31P(1H) NMR spectra]. Chemical shifts are re-
ported in (parts per million) downfield from tetramethylsilane with
the solvent as the reference signal [1H NMR δ = 7.26 for CDCl3
and δ = 5.30 for CD2Cl2; 13C(1H) NMR δ = 77.16 for CDCl3 and δ
= 53.52 for CD2Cl2]. HRMS were recorded with a Bruker Daltonik
micrOTOF-QII spectrometer (ESI-TOF). Elemental analyses were
measured with a Thermo FlashAE 1112 series instrument, and
melting points of analytical pure samples were determined with a
Gallenkamp MFB 595 010 M melting point apparatus. FTIR spec-
tra were recorded with a Thermo Nicolet IR 200 spectrometer
using KBr pellets or NaCl plates.
Electrochemistry: Measurements on 1.0 mmolL–1 solutions of 3, 4,
and 9 in dry, degassed dichloromethane with 0.1 molL–1 of
[N(nBu)4][B(C6F5)4] as the supporting electrolyte were carried out
under argon at 25 °C with a Radiometer Voltalab PGZ 100 electro-
chemical workstation interfaced with a personal computer. A three
electrode cell with a Pt auxiliary electrode, a glassy carbon working
electrode (surface area 0.031 cm2), and an Ag/Ag+ (0.01 mmolL–1
[AgNO3]) reference electrode fixed on a Luggin capillary was used.
The working electrode was pretreated by polishing on a Buehler
microcloth first with 1 micron and then 1/4 micron diamond paste.
The reference electrode was constructed from a silver wire inserted
into a solution of 0.01 mmolL–1 [AgNO3] and 0.1 molL–1 [N-
(nBu)4][B(C6F5)4] in acetonitrile, in a Luggin capillary with a vicor
tip. This Luggin capillary was inserted into a second Luggin capil-
lary with vicor tip filled with a 0.1 mmolL–1 [N(nBu)4][B(C6F5)4]
solution in dichloromethane. Experiments under the same experi-
mental conditions showed that all reduction and oxidation poten-
tials were reproducible within 15 mV. Experimental potentials were
referenced against an Ag/Ag+ reference electrode but the presented
results are referenced against ferrocene as an internal standard as
required by IUPAC.[10] Data were processed on a Microsoft Excel®
worksheet to set the formal reduction potentials of the FcH/FcH+
couple to 0.0 V. Under these conditions, the FcH/FcH+ couple was
at 260 mV vs. Ag/Ag+, ΔEp = 92 mV.
pared by addition of elemental selenium.[6] High J
Se val-
31P77
ues indicate electron-poor phosphanes and hence, a lower
donor capability. Furthermore, it is possible to correlate the
0
31P77Se
J
values with the redox potential E1 of the (ferro-
cenyl-phosphane)palladium complexes, which results in a
linear correlation for the aromatic phosphanes. For the ali-
phatic tert-butyl and cyclohexyl derivatives a different be-
havior is observed, which is most probably because of the
different hybridization. The bis(metallocenylphosphane)
palladium(II) complexes were applied as catalysts in C–C
cross-coupling reactions. In the Heck reaction, iodobenzene
was treated with tert-butyl acrylate. All of the complexes
were catalytically active, and the most efficient catalyst fea-
tured tBu2PFc, which is explained by the fact that this li-
gand is bulky and electron rich. All of the palladium(II)
complexes were active in the Suzuki coupling of aryl bro-
mide and activated aryl chloride. A correlation was found
between the basicity of the phosphanes and the catalytic
activity of the corresponding complexes. The lower the
Spectroelectrochemistry: Spectroelectrochemical UV/Vis/NIR mea-
surements of a 1.0 mmolL–1 solution of 9b in dry degassed dichlo-
romethane containing 0.1 molL–1 of [N(nBu)4][B(C6F5)4] as the
supporting electrolyte were carried in an OTTLE cell[12f,12g] with a
Varian Cary 5000 spectrophotometer.
Materials: All starting materials were obtained from commercial
suppliers and used without further purification. Iodoferrocene[16]
(1), iodoruthenocene[16,17] (5), ferrocenyl-diphenylphosphane[18]
(3a), ferrocenyl-di-tert-butylphosphane[19] (3d), ferrocenyl-dicyclo-
hexylphosphane[20] (3e), [PdCl2(P(C6H5)2Fc)2][4e] (9a), [PdCl2-
(P(tBu)2Fc)2][21] (9d), chlorophosphanes (2b–e),[22–25] and
[PdCl2(cod)][26] (8) were prepared according to published pro-
1J
coupling constant and, hence, the more basic the
31P77Se
phosphane, the higher the catalytic activity. The catalysts
reported here are less active than current catalytic sys-
tems,[2,4f,7e] but show higher activity under similar reaction
conditions compared with other metallocenyl mono- and
diphosphane palladium catalysts.[4b,4c] Moreover, they are
active at lower catalyst loadings (Heck and Suzuki cataly- cedures.
sis), require no additional reductant (CuI), and show high
regioselectivity (Heck catalysis).
General Procedure for the Synthesis of Phosphanes 3 and 6: To 1 or
5 dissolved in dry tetrahydrofuran (50 mL) was added one equiva-
5444
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© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2011, 5437–5449

(Metallocenylphosphane)palladium Dichlorides
3
lent of a 2.5 m solution of nBuLi dropwise at –60 °C. After stirring
the solution for 30 min at ambient temperature, it was cooled to
–30 °C, and one equivalent of the appropriate chlorophosphane
2a–e was added dropwise. The reaction mixture was stirred for 1 h
at ambient temperature and then concentrated in vacuo. The re-
sulting residue was purified by column chromatography and dried
in vacuo.
4JHP = 1.7, JHH = 1.8 Hz, 2 H, Hβ/C5H4), 7.38–7.42 (m, 4 H, Hm/
C6H5), 7.44–7.46 (m, 2 H, Hp/C6H5), 7.70–7.74 (m, 4 H, Ho/C6H5)
ppm. 13C{1H} NMR (125.81 MHz, CDCl3): δ = 70.2 (s, C5H5),
72.0 (d, JCP = 10.0 Hz, Cβ/C5H4), 73.4 (d, JCP = 12.6 Hz, Cα/
3
2
C5H4), 74.0 (d, 1JCP = 89.2 Hz, Ci/C5H4), 128.2 (d, 2JCP = 12.6 Hz,
Co/C6H5), 131.3 (d, 4JCP = 2.9 Hz, Cp/C6H5), 132.1 (d, JCP
=
3
10.9 Hz, Cm/C6H5), 133.6 (d, JCP = 78.4 Hz, Ci/C6H5) ppm.
1
31P{1H} NMR (202.53 MHz, CDCl3):
δ
=
31.8 (1J
31P77Se
=
P(2-CH3C6H4)2Fc (3b): Using the general procedure described
above, 1 (1.0 g, 3.21 mmol) was treated with nBuLi (1.30 mL,
3.21 mmol) and chlorodi-o-tolylphosphane (2b, 0.80 g, 3.21 mmol).
The resulting residue was purified by column chromatography (col-
umn size: 3.5ϫ15 cm on silica gel) using n-hexane as eluent to give
3b as an orange solid; yield 0.88 g (2.21 mmol, 69% based on 1).
C24H23FeP (398.26): calcd. C 72.38, H 5.82; found C 72.40, H 5.94;
733.2 Hz) ppm. HRMS (ESI-TOF): calcd. for C22H19FePSe [M +
nH]+ 450.9814; found 450.9757; [M + nH + MeCN]+ 489.9923;
found 489.9812.
Se=P(2-CH3C6H4)2Fc (4b): Using the general procedure described
above, 3b (100 mg, 0.25 mmol) was treated with elemental selenium
(24 mg, 0.30 mmol) to give 4b as an orange solid; yield 119 mg
(0.25 mmol, 100% based on 3b). C24H23FePSe (477.22): calcd. C
m.p. 168 °C. IR (KBr): ν = 752 (s, =C–H, o-disubst. benzene), 1465
˜
(m, P–C), 1585/1623 (w, C=C), 2845/2908/2965 (w, C–H), 3003/
60.40, H 4.86; found C 60.49, H 5.34. IR (KBr): ν = 560/575 (s,
˜
3041 (w, =C–H) cm–1. 1H NMR (500.30 MHz, CDCl3): δ = 2.56
P=Se), 761 (s, =C–H, o-disubst. benzene), 1449 (m, P–C), 1635 (m,
C=C), 2857/2917/2965 (w, C–H), 3002/3034/3088 (w, =C–H) cm–1.
1H NMR (500.30 MHz, CD2Cl2, –90 °C): δ = 1.70 (s, 3 H, CH3),
1.99 (s, 3 H, CH3), 3.88 (m, 1 H, Hβ/C5H4), 4.07 (s, 5 H, C5H5),
4.40 (m, 1 H, Hα/C5H4), 4.58 (m, 1 H, Hβ/C5H4), 4.82 (m, 1 H, Hα/
3
3
(s, 6 H, CH3), 4.10 (s, 5 H, C5H5), 4.19 (dpt, JHP = 1.8, JHH
=
1.8 Hz, 2 H, Hα/C5H4), 4.44 (pt, JHH = 1.8 Hz, 2 H, Hβ/C5H4),
7.10 (m, 4 H, Ho/C6H4), 7.18–7.25 (m, 6 H, Hm,p/C6H4) ppm.
13C{1H} NMR (125.81 MHz, CDCl3): δ = 21.4 (d, 3JCP = 21.8 Hz,
3
CH3), 69.1 (s, C5H5), 70.9 (d, JCP = 4.2 Hz, Cβ/C5H4), 73.4 (d,
3
C5H4), 7.00 (t, JHH = 7.6 Hz, 1 H, Ho/C6H4), 7.03 (t, JHH
=
3
3
2JCP = 15.3 Hz, Cα/C5H4), 75.8 (d, JCP = 6.0 Hz, Ci/C5H4), 125.7
1
6.9 Hz, 2 H, Hm/C6H4), 7.06 (t, JHH = 6.9 Hz, 1 H, Hm/C6H4),
3
3
(s, Cp/C6H4), 128.5 (s, Cm/C6H4), 129.9 (d, JCP = 5.2 Hz, Cm/
7.14 (t, JHH = 6.1 Hz, 1 H, Hm/C6H4), 7.23 (t, JHH = 7.2 Hz, 1
3
3
C6H4), 133.5 (s, Co/C6H4), 137.9 (d, JCP = 10.8 Hz, Ci/C6H4),
1
H, Hp/C6H4), 7.47 (t, JHH = 7.2 Hz, 1 H, Hp/C6H4), 7.52 (t, JHH
3
3
2
141.7 (d, JCP
=
26.3 Hz, Co/C6H4) ppm. 31P{1H} NMR
= 7.4 Hz, 1 H, Hm/C6H4), 8.82 (dd, JHP = 18.2, JHH = 7.5 Hz, 1
3
3
H, Ho/C6H4) ppm. 13C{1H} NMR (125.81 MHz, CD2Cl2, –90 °C):
(202.53 MHz, CDCl3): δ = –36.4 (s) ppm. HRMS (ESI-TOF):
calcd. for C24H23FeP [M]+ 398.0882; found 398.0836.
3
3
δ = 19.9 (d, JCP = 6.1 Hz, CH3), 22.0 (d, JCP = 3.5 Hz, CH3),
69.6 (s, C5H5), 71.2 (d, JCP = 9.1 Hz, Cα/C5H4), 71.5 (d, JCP
=
2
3
P(c-C4H3O)2Fc (3c): Using the general procedure described above,
1 (1.0 g, 3.21 mmol) was treated with nBuLi (1.30 mL, 3.21 mmol)
and chlorodifurylphosphane (2c, 0.64 g, 3.21 mmol). The resulting
residue was purified by column chromatography on silica gel (col-
umn size: 3.5ϫ15 cm) using n-hexane as eluent to give 3c as an
orange solid; yield 0.71 g (2.02 mmol, 63% based on 1).
C18H15FeO2P (350.13): calcd. C 61.75, H 4.32; found C 61.37, H
5.5 Hz, Cβ/C5H4), 71.6 (d, JCP = 5.4 Hz, Cβ/C5H4), 72.2 (d, JCP
3
1
= 90.1 Hz, Ci/C5H4), 74.5 (d, JCP = 14.0 Hz, Cα/C5H4), 125.4 (d,
2
3JCP = 12.2 Hz, Cm/C6H4), 125.6 (d, JCP = 72.2 Hz, Ci/C6H4),
1
126.0 (d, JCP = 14.1 Hz, Cm/C6H4), 128.8 (d, JCP = 10.5 Hz, Co/
3
2
C6H4), 130.2 (d, JCP = 2.0 Hz, Cp/C6H4), 130.6 (d, JCP = 9.9 Hz,
4
3
Cm/C6H4), 130.9 (d, JCP = 10.5 Hz, Cm/C6H4), 131.3 (d, JCP
=
3
4
2.7 Hz, Cp/C6H4), 133.6 (d, JCP = 77.8 Hz, Ci/C6H4), 135.1 (d,
2JCP = 17.0 Hz, Co/C6H4), 138.6 (d, 2JCP = 6.4 Hz, Co/C6H4), 138.9
1
4.32; m.p. 115 °C. IR (KBr): ν = 1009 (s, C–O), 1459 (m, P–C),
˜
1550/1560/1638/1654 (w, C=C), 3078/3125/3147 (w, =C–H) cm–1.
(d, JCP = 10.4 Hz, Co/C6H4) ppm. 31P{1H} NMR (202.53 MHz,
2
1H NMR (500.30 MHz, CDCl3): δ = 4.04 (s, 5 H, C5H5), 4.35 (pt,
CDCl3): δ = 29.4 (1J
= 715.5 Hz) ppm. HRMS (ESI-TOF):
31P77Se
3
3
3JHH = 1.5 Hz, Hβ/C5H4), 4.44 (dpt, JHP = 1.9, JHH = 1.8 Hz,
calcd. for C24H23FePSe [M]+ 478.0049; found 478.0004;
Hα/C5H4), 6.40 (dt, JHP = 1.6, JHH = 3.2, JHH = 1.6 Hz, 2 H,
H4/C4H3O), 6.69 (m, 2 H, H3/C4H3O), 7.64 (m, 2 H, H5/C4H3O)
ppm. 13C{1H} NMR (125.81 MHz, CDCl3): δ = 69.2 (s, C5H5),
70.9 (d, 3JCP = 5.4 Hz, Cβ/C5H4), 72.5 (d, 1JCP = 5.1 Hz, Ci/C5H4),
4
3
3
[M + nK]+ 516.9685; found 516.9624.
Se=P(c-C4H3O)2Fc (4c): Using the general procedure described
above, 3c (100 mg, 0.29 mmol) was treated with selenium (26 mg,
0.34 mmol) to give 4c as an orange solid; yield 124 g (0.29 mmol,
100% based on 3c). C18H15FeO2PSe (429.09): calcd. C 50.38, H
73.7 (d, JCP = 18.3 Hz, Cα/C5H4), 110.6 (d, JCP = 6.2 Hz, C4/
2
3
C4H3O), 119.8 (d, JCP = 23.6 Hz, C3/C4H3O), 146.7 (d, JCP
=
2
3
2.4 Hz, C5/C4H3O), 152.6 (d, JCP = 8.3 Hz, C2/C4H3O) ppm.
31P{1H} NMR (202.53 MHz, CDCl3): δ = –64.4 (s) ppm. HRMS
(ESI-TOF): calcd. for C18H15FeO2P [M]+ 350.0154; found
350.0116.
1
3.52; found C 50.53, H 3.48; m.p. 80 °C. IR (KBr): ν = 577 (m,
˜
P=Se), 1005 (m, C–O), 1458 (w, P–C), 3080/3105/3119 (w, =C–H)
cm–1. 1H NMR (500.30 MHz, CDCl3): δ = 4.17 (s, 5 H, C5H5),
4.51 (dpt, 4JHP = 1.8, 3JHH = 1.8 Hz, 2 H, Hβ/C5H4), 4.60 (pt, 3JHP
= 2.3, JHH = 2.1 Hz, 2 H, Hα/C5H4), 6.49 (dpt, JHP = 1.7, JHH
3
4
3
General Procedure for the Synthesis of Selenophosphanes 4 and 7:
To a toluene solution (20 mL) of 3 or 6 (100 mg) was added 1.2
equivalents of elemental selenium in a single portion, and the reac-
tion mixture was stirred for 1 h at 100 °C. After cooling to ambient
temperature, the reaction mixture was filtered through a pad of
Celite. The filtrate was dried under vacuum.
= 3.4, JHH = 1.6 Hz, 2 H, H4/C4H3O), 7.11 (m, 2 H, H3/C4H3O),
3
7.71 (m, 2 H, H5/C3H4O) ppm. 13C{1H} NMR (125.81 MHz,
CDCl3): δ = 70.4 (s, C5H5), 72.1 (d, 3JCP = 11.1 Hz, Cβ/C5H4), 73.1
(d, 2JCP = 14.5 Hz, Cα/C5H4), 111.2 (d, JCP = 9.1 Hz, C4/C4H3O),
3
122.2 (d, 2JCP = 21.8 Hz, C3/C4H3O), 147.4 (d, 1JCP = 114.3 Hz, C2/
C4H3O), 148.3 (d, JCP = 7.1 Hz, C5/C4H3O) ppm. 31P{1H} NMR
4
Se=P(C6H5)2Fc (4a): The reaction of 3a (100 mg, 0.27 mmol) with
elemental selenium (26 mg, 0.33 mmol) gave 4a as an orange solid;
yield 120 mg (0.27 mmol, 100% based on 3a). C22H19FePSe
(449.17): calcd. C 58.83, H 4.26; found C 58.90, H 4.28. IR (KBr):
(202.53 MHz, CDCl3): δ = –5.3 (1J
Se = 769.3 Hz) ppm. HRMS
31P77
(ESI-TOF): calcd. for C18H15FeO2PSe [M + nH]+ 430.9388; found
430.9399.
ν = 572 (s, P=Se), 1434 (m, P–C), 1638 (m, C=C), 3071 (w, =C– Se=P(tBu)2Fc (4d): Using the general procedure described above,
˜
H) cm–1. 1H NMR (500.30 MHz, CDCl3): δ = 4.16 (s, 5 H, C5H5),
3d (100 mg, 0.30 mmol) was treated with selenium (28 mg,
0.36 mmol) to give 4d as an orange solid; yield 122 g (0.30 mmol,
3
3
4.45 (dpt, JHP = 2.1, JHH = 1.9 Hz, 2 H, Hα/C5H4), 4.52 (dpt,
Eur. J. Inorg. Chem. 2011, 5437–5449
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
5445

B. Milde, M. Lohan, C. Schreiner, T. Rüffer, H. Lang
FULL PAPER
100% based on 3d). C18H27FePSe (409.19): calcd. C 52.83, H 6.65; 4.53 (dpt, 3JHP = 1.6, 3JHH = 1.6 Hz, 2 H, Hα/C5H4), 4.74 (pt, 3JHH
found C 52.81, H 6.81; m.p. 145 °C. IR (KBr): ν = 565 (m, P=Se),
= 1.6 Hz, 2 H, Hβ/C5H4), 7.06–7.2 (m, 8 H, C6H4) ppm. 13C{1H}
NMR (125.81 MHz, CDCl3): δ = 21.4 (d, JCP = 21.9 Hz, CH3),
˜
2
1456 (P–C), 2867/2899/2968/2951/2988 (m, C–H), 3085 (w, =C–H)
cm–1. 1H NMR (500.30 MHz, CDCl3): δ = 1.39 [d, 3JHP = 15.4 Hz,
71.4 (s, C5H5), 72.7 (d, JCP = 3.6 Hz, Cβ/C5H4), 75.7 (d, JCP
=
3
2
4
3
18 H, C(CH3)3], 4.32 (s, 5 H, C5H5), 4.47 (dpt, JHP = 1.6, JHH
=
16.9 Hz, Cα/C5H4), 125.7 (s, Cp/C6H4), 128.5 (s, Cm/C6H4), 129.9
1.5 Hz, 2 H, Hβ/C5H4), 4.59 (dpt, JHP = 1.7, JHH = 1.5 Hz, 2 H, (d, JCP = 4.8 Hz, Cm/C6H4), 133.3 (s, Co/C6H4), 138.0 (d, JCP
=
3
3
3
1
Hα/C5H4) ppm. 13C{1H} NMR (125.81 MHz, CDCl3): δ = 28.9 [d,
10.8 Hz, Ci/C6H4), 141.8 (d, JCP = 26.4 Hz, Co/C6H4) ppm.
2
2JCP = 2.0 Hz, C(CH3)3], 38.3 [d, JCP = 36.2 Hz, C(CH3)3], 70.3 31P{1H} NMR (202.53 MHz, CDCl3): δ = –36.1 (s) ppm.
(d, 3JCP = 8.2 Hz, Cβ/C5H4), 70.7 (s, C5H5), 73.8 (d, 2JCP = 9.1 Hz,
1
P(c-C4H3O)2Rc (6c): Using the general procedure described above,
5 (2.0 g, 5.5 mmol) was treated with nBuLi (2.2 mL, 3.21 mmol)
and chlorodifurylphosphane (2c, 1.10 g, 5.5 mmol). The resulting
residue was purified by column chromatography on ALOX (col-
umn size: 2.5ϫ30 cm) using n-hexane/diethyl ether (5:1, v:v) as elu-
ent. Phosphane 6a was obtained as a pale yellow solid; yield 1.0 g
Cα/C5H4), 74.6 (d, JCP = 64.1 Hz, Ci/C5H4) ppm. 31P{1H} NMR
1
(202.53 MHz, CDCl3): δ = 74.7 (1J
Se = 701.7 Hz) ppm. HRMS
31P77
(ESI-TOF): calcd. for C18H27FePSe [M]+ 410.0361; found
410.0312.
Se=P(c-C6H11)2Fc (4e): Using the general procedure described
above, 3e (100 mg, 0.26 mmol) was treated with selenium (24 mg, (2.53 mmol, 46% based on 5). C18H15O2PRu (395.35): calcd. C
0.31 mmol) to give 4e as an orange solid; yield 119 mg (0.26 mmol,
100% based on 3e). C22H31FePSe (461.26): calcd. C 57.29, H 6.77;
54.68, H 3.82; found C 54.33, H 3.84; m.p. 116 °C (dec.). IR (KBr):
ν = 1008 (m, C–O), 1458 (w, P–C), 3100 (m, =C–H) cm–1. 1H NMR
˜
3
found C 57.40, H 6.99; m.p. 116 °C. IR (NaCl): ν = 531/551 (m,
(500.30 MHz, CDCl3): δ = 4.41 (s, 5 H, C5H5), 4.69 (pt, JHH
=
˜
P=Se), 1453 (m, P–C), 2853/2930 (s, C–H), 3076/3097 (w, =C–H) 1.6 Hz, 2 H, Hβ/C5H4), 4.85 (dpt, JHP = 1.7, JHH = 1.6 Hz, 2 H,
3
3
cm–1. 1H NMR (500.30 MHz, CDCl3): δ = 1.14–1.21 (m, 2 H, Hα/C5H4), 6.38 (dt, JHP = 1.6, JHH = 3.2, JHH = 1.6 Hz, 2 H,
4
3
3
C6H11), 1.23–1.31 (m, 6 H, C6H11), 1.33–1.40 (m, 2 H, C6H11), H4/C4H3O), 6.67 (m, 2 H, H3/C4H3O), 7.61 (m, 2 H, H5/C4H3O)
1.66–1.69 (m, 2 H, C6H11), 1.81–1.86 (m, 4 H, C6H11), 1.97–2.03
ppm. 13C{1H} NMR (125.81 MHz, CDCl3): δ = 71.5 (s, C5H5),
3
3
3
2
(m, 6 H, C6H11), 4.32 (s, 5 H, C5H5), 4.41 (dpt, JHP = 1.8, JHH
72.8 (d, JCP = 5.0 Hz, Cβ/C5H4), 76.0 (d, JCP = 19.9 Hz, Cα/
= 1.6 Hz, Hα/C5H4), 4.43 (dpt, JHP = 1.7, JHH = 1.6 Hz, Hβ/
C5H4), 110.6 (d, JCP = 6.2 Hz, C4/C4H3O), 119.5 (d, JCP
=
4
3
3
2
C5H4) ppm. 13C{1H} NMR (125.81 MHz, CDCl3): δ = 26.0 (d, JCP 23.9 Hz, C3/C4H3O), 146.5 (d, JCP = 1.9 Hz, C5/C4H3O), 153.0
4
1
= 1.4 Hz, C6H11), 26.4 (d, JCP = 1.6 Hz, C6H11), 26.6 (d, JCP
2.8 Hz, C6H11), 26.7 (d, JCP = 1.8 Hz, C6H11), 27.4 (d, JCP
=
=
=
(d, JCP = 8.1 Hz, C2/C4H3O) ppm. 31P{1H} NMR (202.53 MHz,
CDCl3): δ = –65.2 (s) ppm.
1
3
3.2 Hz, C6H11), 37.4 (d, JCP = 44.9 Hz, C6H11), 70.5 (d, JCP
P(c-C6H11)2Rc (6d): Using the general procedure described above,
5 (2.0 g, 5.5 mmol) was treated with nBuLi (2.2 mL, 3.21 mmol)
and chlorodicyclohexylphosphane (2d, 1.28 g, 5.5 mmol). The re-
sulting residue was purified by column chromatography on ALOX
(column size: 2.5ϫ30 cm) using n-hexane/diethyl ether (5:1, v:v) as
eluent. Please note that 6d could not be completely separated from
free ruthenocene and was used without additional purification in
2
8.9 Hz, Cβ/C5H4), 70.5 (s, C5H5), 72.2 (d, JCP = 10.0 Hz, Cα/
1
C5H4), 72.6 (d, JCP = 71.0 Hz, Ci/C5H4) ppm. 31P{1H} NMR
(202.53 MHz, CDCl3): δ = 49.8 (1J
= 699.9 Hz) ppm. HRMS
31P77Se
(ESI-TOF): calcd. for C22H31FePSe [M + nH]+ 463.0743; found
463.0753; calcd. for C22H31FePSeCH3CN [M + nH]+ 502.0843;
found 502.0862.
1
P(C6H5)2Rc (6a): Using the general procedure described above, 5
(2.0 g, 5.5 mmol) was treated with nBuLi (2.20 mL, 3.21 mmol) and
chlorodiphenylphosphane (2a, 1.21 g, 5.5 mmol). The resulting res-
idue was purified by column chromatography on ALOX (column
size: 2.5ϫ30 cm) using n-hexane/diethyl ether (5:1, v:v) as eluent.
Phosphane 6a was obtained as a pale yellow solid; yield 0.80 g
(1.92 mmol, 35% based on 5). C22H19PRu (415.43): calcd. C 63.61,
further reactions. C22H31PRu (427.53): C 61.81, H 7.31. H NMR
(500.30 MHz, CDCl3): δ = 1.18–1.27 (m, 10 H, C6H11), 1.62–1.88
(m, 10 H, C6H11), 1.81–1.84 (m, 2 H, C6H11), 4.45 (s, 5 H, C5H5),
3
4.48 (m, 2 H, C5H4), 4.56 (pt, JHH = 1.5 Hz, 2 H, C5H4) ppm.
13C{1H} NMR (125.81 MHz, CDCl3): δ = 26.6 (s, C6H11), 27.4 (d,
JCP = 8.3 Hz, C6H11), 27.5 (d, JCP = 11.2 Hz, C6H11), 30.3 (d, JCP
1
= 2.5 Hz, C6H11), 30.4 (d, JCP = 7.5 Hz, C6H11), 33.8 (d, JCP
=
3
H 4.61; found C 63.55, H 4.62; m.p. 128 °C. IR (KBr): ν = 1432 (m,
11.2 Hz, C1/C6H11), 70.2 [s, Ru(η5-C5H5)2], 71.4 (d, JCP = 2.6 Hz,
˜
1
2
P–C), 1477/1652 (w, C=C), 3047/3067 (w, =C–H) cm–1. H NMR Cβ/C5H4), 71.6 (s, C5H5), 74.4 (d, JCP = 12.7 Hz, Cα/C5H4), 77.3
3
(500.30 MHz, CDCl3): δ = 4.45 (s, 5 H, C5H5), 4.49 (dpt, JHP
=
(Ci/C5H4*) ppm. 31P{1H} NMR (202.53 MHz, CDCl3): δ = –7.1
(s) ppm. HRMS (ESI-TOF): calcd. for C22H21PRu [M + nH]+
1.7, JHH = 1.6 Hz, 2 H, Hα/C5H4), 4.71 (pt, JHH = 1.6 Hz, 2 H,
3
3
Hβ/C5H4), 7.30–7.33 (m, 6 H, Hm,p/C6H5), 7.36–7.39 (m, 4 H, Ho/ 429.1278; found 429.1286, calcd. for C10H10Ru [M + nH]+
C6H5) ppm. 13C{1H} NMR (125.81 MHz CDCl3): δ = 71.5 (s,
232.9897; found 232.9901. * signal concealed by CDCl3.
C5H5), 72.7 (d, JCP = 3.8 Hz, Cβ/C5H4), 75.3 (d, JCP = 16.4 Hz,
3
2
Se=P(C6H5)2Rc (7a): Using the general procedure described above,
the reaction of 5a (100 mg, 0.22 mmol) with selenium (22 mg,
0.28 mmol) gave 7a as a pale red solid; yield 105 mg (0.21 mmol,
89% based on 5a). C22H19PRuSe·0.25Et2O (494.39): calcd. C 53.85,
Cα/C5H4), 79.9 (d, 1JCP = 8.8 Hz, Ci/C5H4), 128.1 (d, 3JCP = 6.3 Hz,
Cm/C6H5), 128.4 (s, Cp/C6H5), 133.4 (d, JCP = 18.9 Hz, Co/C6H5),
2
1
139.4 (d, JCP
=
8.8 Hz, Ci/C6H5) ppm. 31P{1H} NMR
(202.53 MHz, CDCl3): δ = –16.0 (s) ppm.
H 4.22; found C 53.87, H 4.15; m.p. 179 °C. IR (KBr): ν = 534/
˜
P(2-CH3C6H4)2Rc (6b): Using the general procedure described
above, 5 (2.0 g, 5.5 mmol) was treated with nBuLi (2.2 mL, (500.30 MHz, CDCl3): δ = 1.21 [t, JHH = 7.0 Hz, (CH3CH2)2O],
545 (m, P=Se), 1449 (m, P–C), 1476 (m, C=C) cm–1. 1H NMR
3
3
3.21 mmol) and chlorodi-o-tolylphosphane (2b, 1.36 g, 5.5 mmol).
The resulting residue was purified by column chromatography on
ALOX (column size: 2.5ϫ30 cm) using n-hexane/diethyl ether (5:1,
v:v) as eluent. Compound 6a was obtained as a pale yellow solid;
yield 0.90 g (2.02 mmol, 36% based on 5). C24H23PRu (443.48):
calcd. C 65.00, H 5.27; found C 64.71, H 5.32; m.p. 127 °C. IR
3.43 [q, JHH = 7.0 Hz, (CH3CH2)2O], 4.45 (s, 5 H, C5H5), 4.68
3
3
4
(dpt, JHP = 1.9, JHH = 1.7 Hz, 2 H, Hα/C5H4), 4.74 (dpt, JHP
=
1.6, JHH = 1.7 Hz, 2 H, Hβ/C5H4), 7.32–7.4 (m, 6 H, Hm,p/C6H5),
7.64–7.69 (m, 4 H, Ho/C6H5) ppm. 13C{1H} NMR (125.81 MHz,
CDCl3): δ = 15.2 [s, (CH3CH2)2O], 65.9 [(CH3CH2)2O], 73.0 (s,
3
C5H5), 73.7 (d, JCP = 9.2 Hz, Cβ/C5H4), 75.4 (d, JCP = 13.3 Hz,
3
2
(KBr): ν = 1432 (m, P–C), 1477 (w, C=C) cm–1. 1H NMR
Cα/C5H4), 79.2 (d, JCP = 86.1 Hz, Ci/C5H4), 128.2 (d, JCP
=
1
2
˜
(500.30 MHz, CDCl3): δ = 2.43 (s, 6 H, CH3), 4.44 (s, 5 H, C5H5), 12.5 Hz, Co/C6H5), 131.4 (d, JCP = 2.8 Hz, Cp/C6H5), 132.3 (d,
4
5446
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© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2011, 5437–5449

(Metallocenylphosphane)palladium Dichlorides
3JCP = 10.9 Hz, Cm/C6H5), 133.7 (d, 1JCP = 78.8 Hz, Ci/C6H5) ppm. ethyl ether (5ϫ5 mL). After drying the residue under vacuum, the
31P{1H} NMR (202.53 MHz, CDCl3):
735.2 Hz) ppm.
δ
=
31.2 (1J
=
complexes were obtained as yellow or red solids.
31P77Se
[PdCl2(P(2-CH3C6H4)2Fc)2] (9b): Following the general procedure
described above, 3b (0.5 g, 1.26 mmol) was treated with 8 (0.18 g,
0.63 mmol) to give 9b as an air-stable red solid; yield 0.52 g
(0.53 mmol, 84% based on 8). C48H46Cl2Fe2P2Pd·2/3CH2Cl2
(1030.46): calcd. C 56.72, H 4.63; found C 56.23, H 4.64; m.p.
Se=P(2-CH3C6H4)2Rc (7b): According to the general procedure de-
scribed earlier, 5b (100 mg, 0.23 mmol) was treated with selenium
(21 mg, 0.27 mmol) to give 7b as a colorless solid; yield 110 mg
(0.21 mmol, 94% based on 5b). C24H23PRuSe·0.5Et2O (522.44):
calcd. C 55.81, H 5.04; found C 55.91, H 4.94; m.p. 200 °C (dec.).
210 °C (dec.). IR (KBr): ν = 754 (s, =C–H, o-disubst. benzene),
˜
IR (KBr): ν = 571 (m, P=Se), 1453 (m, P–C), 1559 (m, C=C) cm–1. 1449 (m, P–C), 1561/1638/1655 (m, C=C), 2928/2969 (w, C–H),
˜
1H NMR (500.30 MHz, CDCl3): δ = 1.21 [t, JHH = 7.0 Hz,
3053 (w, =C–H) cm–1. H NMR (500.30 MHz, CD2Cl2): δ = 2.39
3
1
3
3
(CH3CH2)2O], 2.05 (s, 6 H, CH3), 3.43 [q, JHH = 7.0 Hz, (s, 12 H, CH3), 4.23 (s, 10 H, C5H5), 4.51 (pt, JHH = 1.7 Hz, 4 H,
(CH3CH2)2O], 4.52 (s, 5 H, C5H5), 4.84 (m, 4 H, Hα,β/C5H4), 7.10– C5H4), 4.68 (m, 4 H, C5H4), 5.29 (s, CH2Cl2), 7.16–7.19 (m, 8 H,
7.13 (m, 2 H, C6H4), 7.35–7.37 (m, 4 H, C6H4), 7.9–8.4 (m, 2 H,
C6H4) ppm. 13C{1H} NMR (125.81 MHz, CDCl3): δ = 15.2 [s,
(CH3CH2)2O], 22.0 (d, 3JCP = 3.9 Hz, CH3), 65.9 [s, (CH3CH2)2O],
73.2 (s, C5H5), 73.6 (d, 2JCP = 9.1 Hz, Cα/C5H4), 74.7 (m, Cβ/C5H4),
C6H4), 7.32–7.35 (m, 4 H, C6H4), 7.85–7.89 (m, 4 H, C6H4) ppm.
13C{1H} NMR (125.81 MHz, CD2Cl2): δ = 23.9 (pt, 3JCP = 3.4 Hz,
CH3), 53.5 (s, CH2Cl2), 70.9 (s, C5H5), 71.1 (pt, 3JCP = 4.0 Hz, Cβ/
2
C5H4), 77.4 (pt, JCP = 6.4 Hz, Cα/C5H4), 125.0 (pt, JCP = 5.0 Hz,
80.3 (d, JCP = 85.4 Hz, Ci/C5H4), 126.4 (d, JCP = 13.4 Hz, Co/
C6H4), 130.4 (s, Cp/C6H4), 131.1 (pt, JCP = 4.2 Hz, C6H4), 134.9
1
2
C6H4), 131.5 (d, 4JCP = 2.4 Hz, Cp/C6H4), 131.7 (d, 3JCP = 10.3 Hz, (pt, JCP = 5.7 Hz, C6H4), 142.7 (pt, JCP = 5.3 Hz, C6H4) ppm.
1
Cm/C6H4), 140.1 (d, JCP = 9.2 Hz, Ci/C6H4) ppm. 31P{1H} NMR 31P{1H} NMR (202.53 MHz, CD2Cl2): δ = 13.9 (s) ppm. HRMS
(202.53 MHz, CDCl3): δ = 29.0 (1J
= 717.5 Hz) ppm.
(ESI-TOF): calcd. for C48H46Fe2P2PdCl2 [M – Cl]+ 937.0510;
31P77Se
found 937.0464; [M + nH – 2Cl]+ 901.0746; found 901.0699.
Se=P(c-C4H3O)2Rc (7c): Using the general procedure described
above, the reaction of 5c (100 mg, 0.25 mmol) with selenium
(24 mg, 0.30 mmol) gave 7c as a pale red solid; yield 100 mg
(0.21 mmol, 84% based on 5c). C18H15O2PRuSe (474.30): calcd. C
[PdCl2(P(c-C4H3O)2Fc)2] (9c): Following the general procedure de-
scribed above, 3c (0.5 g, 1.43 mmol) was treated with 8 (0.20 g,
0.70 mmol) to give 9c as an air-stable red solid; yield 0.47 g
(0.54 mmol, 77% based on 8). C36H30Cl2Fe2O4P2Pd·1/3 CH2Cl2
45.58, H 3.19; found C 45.45, H 3.20; m.p. 242 °C. IR (KBr): ν =
˜
549/570 (m, P=Se), 1013 (m, C–O), 1457 (w, P–C), 1556 (m, C=C), (905.90): calcd. C 48.17, H 3.41; found C 48.65, H 3.45; m.p. 242 °C
1
3097 (m, =C–H) cm–1. H NMR (500.30 MHz, CDCl3): δ = 4.51 (dec.). IR (KBr): ν = 1005/1010 (s, C–O), 1457 (w, P–C), 1654 (w,
˜
(s, 5 H, C5H5), 4.81 (dpt, JHP = 1.6, JHH = 1.5 Hz, 2 H, Hβ/ C=C), 3047/3127/3152 (w, =C–H) cm–1. 1H NMR (500.30 MHz,
3
3
C5H4), 5.06 (dpt, JHP = 2.0, JHH = 1.8 Hz, 2 H, Hα/C4H5), 6.48
CD2Cl2): δ = 4.43 (s, 10 H, C5H5), 4.50 (pt, JHH = 1.8 Hz, 4 H,
3
3
3
(dpt, 4JHP = 1.7, 3JHH = 3.4, 3JHH = 1.7 Hz, 2 H, H4/C4H3O), 7.12
C5H4), 4.74 (m, 4 H, C5H4), 5.30 (s, CH2Cl2), 6.50 (m, 4 H, H4/
C4H3O), 7.00 (m, 4 H, H3/C4H3O), 7.75 (m, 4 H, H5/C4H3O) ppm.
13C{1H} NMR (125.81 MHz, CD2Cl2): δ = 53.5 (s, CH2Cl2), 70.5
(m, 2 H, H3/C4H3O), 7.68 (m, 2 H, H5/C3H4O) ppm. 13C{1H}
3
NMR (125.81 MHz, CDCl3): δ = 72.9 (s, C5H5), 73.7 (d, JCP
=
10.7 Hz, Cβ/C5H4), 74.8 (d, 2JCP = 15.5 Hz, Cα/C5H4), 75.9 (d, 1JCP
= 98.0 Hz, Ci/C5H4), 111.1 (d, 3JCP = 9.2 Hz, C4/C4H3O), 122.0 (d,
(s, C5H5), 71.9 (pt, JCP = 4.5 Hz, Cβ/C5H4), 74.7 (pt, JCP
=
3
2
7.4 Hz, Cα/C5H4), 110.9 (pt, JCP = 3.4 Hz, C4/C4H3O), 123.3 (m,
3
2JCP = 21.9 Hz, C3/C4H3O), 147.3 (d, 1JCP = 114.7 Hz, C2/C4H3O), C3/C4H3O), 147.8 (pt, JCP = 3.1 Hz, C5/C4H3O) ppm. 31P{1H}
4
4
148.2 (d, JCP
=
7.1 Hz, C5/C4H3O) ppm. 31P{1H} NMR NMR (202.53 MHz, CD2Cl2): δ = –14.0 (s) ppm. HRMS (ESI-
(202.53 MHz, CDCl3): δ = –6.8 (1J
= 772 Hz) ppm.
TOF): calcd. for C36H30Cl2Fe2O4P2Pd [M – Cl]+ 840.9051; found
840.9041, [M – C18H15FeO2P – Cl]+ 492.8880; found 492.8847.
31P77Se
Se=P(c-C6H11)2Rc (7d): According to the general procedure de-
scribed above, 5d (100 mg, 0.26 mmol) was treated with selenium
(22 mg, 0.28 mmol) to give 7d as a colorless solid. C22H31PRuSe
(506.49): calcd. C 52.17, H 6.17; found C 53.33, H 6.29. Please note
that the results of the elemental analysis deviate from the calculated
values due to the light sensitivity and, therefore, decomposition of
[PdCl2(P(c-C6H11)2Fc)2] (9e): According to the general procedure
described earlier, 3e (0.5 g, 1.31 mmol) was treated with 8 (0.18 g,
0.63 mmol) to give 9e as an air-stable red solid; yield 0.48 g
(0.51 mmol, 81% based on 8). C44H62Cl2Fe2P2Pd·1/2 Et2O
(978.68): C 56.44; H 6.90; found C 56.70; H 6.78; m.p. 253 °C
this compound. IR (KBr): ν = 549 (m, P=Se), 1453 (w, P–C), 1556
(dec.). IR (KBr): ν = 1433/1436 (m, P–C), 2857/2926/2979 (w, C–
˜
˜
(m, C=C), 3097 (m, =C–H) cm–1. 1H NMR (500.30 MHz, CDCl3): H), 3038/3050/3088 (w, =C–H) cm–1. 1H NMR (500.30 MHz,
δ = 1.15–1.41 (m, 10 H, C6H11), 1.66–1.69 (m, 2 H, C6H11), 1.79– CD2Cl2): δ = 1.27–1.31 [m, 12 H, C6H11 + (CH3CH2)2O], 1.69–
1.86 (m, 4 H, C6H11), 1.96–2.02 (m, 6 H, C6H11), 4.63 (s, 5 H,
1.78 (m, 20 H, C6H11), 2.08–2.10 (m, 4 H, C6H11), 2.33–2.55 (m, 4
3
C5H5), 4.74 (m, 2 H, C5H4), 4.76 (dpt, JHP = 1.6, JHH = 1.5 Hz, 2 H, C6H11), 2.56–2.61 (m, 4 H, H1/C6H11), 3.48 [q, JHH = 7.0 Hz,
H, C5H4) ppm. 13C{1H} NMR (125.81 MHz, CDCl3): δ = 26.0 (d, (CH3CH2)2O], 4.36 (s, 10 H, C5H5), 4.41 (m, 4 H, C5H4), 4.71 (m,
JCP = 1.4 Hz, C6H11), 26.4 (d, JCP = 1.6 Hz, C6H11), 26.6 (d, JCP
= 4.5 Hz, C6H11), 26.7 (d, JCP = 3.7 Hz, C6H11), 27.6 (d, JCP
4 H, C5H4) ppm. 13C{1H} NMR (125.81 MHz, CD2Cl2): δ = 15.4
2
=
[s, (CH3CH2)2O], 26.5 (s, C6/C6H11), 27.6 (pt, JCP = 5.5 Hz, C2/3
/
1
3
2
3.3 Hz, C6H11), 37.3 (d, JCP = 44.7 Hz, C1/C6H11), 72.4 (d, JCP C6H11), 27.8 (pt, JCP = 6.3 Hz, C2/3/C6H11), 28.9 (s, C4/5/C6H11),
= 8.0 Hz, Cβ/C5H4), 73.1 (s, C5H5), 74.3 (d, JCP = 10.8 Hz, Cα/
30.2 (s, C4/5/C6H11), 36.9 (pt, JCP = 11.7 Hz, C1/C6H11), 65.9 [s,
2
1
C5H4), 76.7 (d, JCP = 68.0 Hz, Ci/C5H4) ppm. 31P{1H} NMR
(CH3CH2)2O], 70.1 (pt, JCP = 3.4 Hz, Cβ/C5H4), 70.2 (s, C5H5),
1
3
(202.53 MHz, CDCl3): δ = 49.2 (1J
= 704 Hz) ppm. HRMS 72.1 (pt, JCP = 20.0 Hz, Ci/C5H4), 75.0 (pt, JCP = 5.3 Hz, Cα/
1
2
31P77Se
(ESI-TOF): calcd. for C22H31PRuSe [M + nH]+ 509.0455; found
C5H4) ppm. 31P{1H} NMR (202.53 MHz, CDCl3): δ = 18.0 (s)
ppm. HRMS (ESI-TOF): calcd. for C44H62Cl2Fe2P2Pd [M + nH –
C22H31FePCl2]+ 487.0475; found 487.0413.
509.0378.
General Procedure for the Synthesis of Palladium Complexes 9a–e
and 10a–d: Phosphane 3 or 6 (0.5 g) and [PdCl2(cod)] (8, 0.5 equiv.)
were dissolved in dry dichloromethane (40 mL). This solution was
stirred for 2 h at ambient temperature. All of the volatile materials
were removed under vacuum, and the residue was washed with di-
[PdCl2(P(C6H5)2Rc)2] (10a): Following the synthetic methodology
described above, 6a (0.5 g, 1.20 mmol) was treated with 8 (0.17 g,
0.60 mmol) to give 10a as an air-stable yellow solid; yield 0.50 g
(0.50 mmol, 83% based on 8). C44H38Cl2P2PdRu2·1/3 CH2Cl2
Eur. J. Inorg. Chem. 2011, 5437–5449
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
5447

B. Milde, M. Lohan, C. Schreiner, T. Rüffer, H. Lang
FULL PAPER
(1008.19): C 51.37, H 3.76; found C 51.41, H 3.83; m.p. 164 °C
3
11.8 Hz, C1/C6H11), 72.0 (pt, JCP = 3.0 Hz, Cβ/C5H4), 72.6 (s,
1
2
(dec.). IR (KBr): ν = 1437 (w, P–C), 1481 (m, C=C) cm–1. 1H NMR C5H5), 75.2 (pt, JCP = 19.0 Hz, Ci/C5H4), 77.0 (pt, JCP = 5.6 Hz,
˜
(500.30 MHz, CDCl3): δ = 4.81 (m, 4 H, C5H4), 4.84 (m, 10 H, Cα/C5H4) ppm. 31P{1H} NMR (202.53 MHz, CDCl3): δ = 16.4 (s)
C5H5), 4.95 (m, 4 H, C5H4), 5.30 (s, CH2Cl2), 7.36–7.47 (m, 12
ppm. HRMS (ESI-TOF): calcd. for C44H62ClP2PdRu2 [M]+
H, Hm,p/C6H5), 7.63–7.67 (m, 8 H, Ho/C6H5) ppm. 13C{1H} NMR 977.1156; found 997.1156.
(125.81 MHz, CDCl3): δ = 53.5 (s, CH2Cl2), 72.9 (s, C5H5), 73.3
General Procedure for the Heck Reaction: Iodobenzene (612 mg,
(m, C5H4), 77.5 (m, C5H4), 127.7 (pt, JCP = 4.9 Hz, Cm/C6H5),
3
3.0 mmol), t-butyl acrylate (397 mg, 3.1 mmol), EtN(iso-C3H7)2
(452 mg, 3.5 mmol), and acetyl ferrocene (114 mg, 0.5 mmol) were
dissolved in toluene/acetonitrile (15 mL, 1:1, v:v) with 0.2 mol-%
of the catalyst (9a–e or 10a–d). The reaction mixture was stirred at
80 °C and samples (1 mL) were taken every hour. The samples were
chomatographed on silica gel with diethyl ether as eluent. All vola-
130.4 [s, Cp/(C6H5)], 131.5 (pt, 1JCP = 25.3 Hz, Ci/C6H5), 134.3 (pt,
2JCP = 5.9 Hz, Co/C6H5) ppm. 31P{1H} NMR (202.53 MHz,
CDCl3):
δ = 14.8 (s) ppm. HRMS (ESI-TOF): calcd. for
C44H38ClP2PdRu2 [M]+ 972.9278; found 972.9249, calcd. for
C22H19ClPRu [M]+ 450.9954; found 450.9926.
1
tiles were evaporated, and the conversions were determined by H
[PdCl2(P(2-CH3C6H4)2Rc)2] (10b): Following the synthetic pro-
cedure described above, 6b (0.5 g, 1.13 mmol) was treated with 8
(0.16 g, 0.56 mmol) to give 10b as an air-stable yellow solid; yield
0.50 mg (0.47 mmol, 84% based on 8). C48H46Cl2P2PdRu2·1/
2CH2Cl2 (1064.29): C 52.58, H 4.36; found C 52.36, H 4.39; m.p.
NMR spectroscopy.
General Procedure for the Suzuki Reaction: 2-Bromotoluene
(500 mg, 2.92 mmol) or 4Ј-chloroacetophenone (464 mg,
3.00 mmol), phenylboronic acid (470 mg, 3.85 mmol), potassium
carbonate (1.21 g, 8.76 mmol), and acetyl ferrocene (114 mg,
0.50 mmol) were dissolved in 1,4-dioxane/water (12 mL, 2:1, v:v).
After addition of 0.1 mol-%, 0.25 mol-% (reaction of 2-bromotolu-
ene) or 0.5 mol-% (reaction of 4Ј-chloroacetophenone) of the cata-
lyst (9a–e or 10a–d), the reaction mixture was stirred for 1 h at
100 °C. Samples of 1 mL were taken after 2.5, 5, 10, 20, 30, and
60 min and chromatographed on silica gel with diethyl ether as elu-
ent. All volatiles were evaporated under reduced pressure, and the
250 °C (dec.). IR (KBr): ν = 1448 (w, P–C), 1559 (m, C=C) cm–1.
˜
1H NMR (500.30 MHz, CDCl3): δ = 2.69 (s, 12 H, CH3), 4.66 (s,
3
10 H, C5H5), 4.79 (m, 4 H, C5H4), 5.00 (pt, JHH = 1.6 Hz, 4 H,
C5H4), 5.30 (s, CH2Cl2), 7.12–7.15 (m, 4 H, C6H4), 7.21–7.23 (m,
4 H, C6H4), 7.34–7.37 (m, 4 H, C6H4), 7.57–7.61 (m, 4 H, C6H4)
ppm. 13C{1H} NMR (125.81 MHz, CDCl3): δ = 24.3 (pt, JCP
=
3
3.3 Hz, CH3), 53.5 (CH2Cl2), 72.9 (pt, JCP = 3.6 Hz, Cβ/C5H4),
3
1
2
73.5 (s, C5H5), 77.8 (pt, JCP = 25.5 Hz, Ci/C5H4), 79.3 (pt, JCP
=
6.8 Hz, Cα/C5H4), 125.0 (pt, JCP = 5.2 Hz, C6H4), 130.4 (s, C6H4),
130.6 (pt, 1JCP = 24.0 Hz, Ci/C6H4), 131.1 (pt, JCP = 3.8 Hz, C6H4),
135.2 (pt, JCP = 5.7 Hz, C6H4), 142.6 (pt, JCP = 5.3 Hz, C6H4)
ppm. 31P{1H} NMR (202.53 MHz, CDCl3): δ = 16.2 (s) ppm.
HRMS (ESI-TOF): calcd. for C48H46ClP2PdRu2 [M]+ 1028.9906;
found 1028.9891, calcd. for C48H46P2PdRu2 [M]+ 994.02; found
994.0216, calcd. for C24H23PPdClRu [M]+ 584.9309; found
584.9286, calcd. for C24H23PPdRu [M + nH]+ 548.9547; found
548.9517.
1
conversions were determined by H NMR spectroscopy.
Crystal Data for 4b: C24H23FePSe, Mr = 477.20 gmol–1, mono-
clinic, P21/n, λ = 0.71073 Å, a = 15.7844(4) Å, b = 7.4393(2) Å, c
= 17.6781(5) Å, β = 90.127(2)°, V = 2075.84(10) Å3, Z = 4, ρcalcd
= 1.527 mgm–3, μ = 2.563 mm–1, T = 298(2) K, Θ range = 3.03–
26.00°, reflections collected: 10904, independent: 4054 (Rint
=
0.0321), R1 = 0.0297, wR2 = 0.0647 [IϾ2σ(I)]. Single crystals of
4b were obtained from a saturated dichloromethane solution of 4b
at 298 K. Data were collected with an Oxford Gemini S dif-
fractometer, with graphite monochromated Mo-Kα radiation (λ =
0.71073 Å). The structure was solved by direct methods and refined
by full-matrix least-squares procedures on F2.[27]
[PdCl2(P(c-C4H3O)2Rc)2] (10c): Following the synthetic procedure
described above, the reaction of 6c (0.5 g, 1.26 mmol) with 8
(0.18 g, 0.63 mmol) gave 10c as an air-stable yellow solid; yield
0.52 g (0.54 mmol, 86% based on 8). C36H30Cl2O4P2PdRu2
(968.03): C 44.67, H 3.12; found C 44.63, H 3.13; m.p. 242 °C. IR
CCDC-834561 contains the supplementary crystallographic data
for this paper. These data can be obtained free of charge from The
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
(KBr): ν = 1024 (w, C–O), 1454 (w, P–C), 1536 (m, C=C) cm–1. 1H
˜
NMR (500.30 MHz, CDCl3): δ = 4.75 (s, 10 H, C5H5), 4.79 (pt,
3JHH = 1.7 Hz, 4 H, C5H4), 5.13 (m, 4 H, C5H4), 6.45 (m, 4 H, H4/
C4H3O), 7.08 (m, 4 H, H3/C4H3O), 7.67 (m, 4 H, H5/C4H3O) ppm.
13C{1H} NMR (125.81 MHz, CDCl3): δ = 73.0 (s, C5H5), 73.5 (pt,
Supporting Information (see footnote on the first page of this arti-
cle): NMR spectra and reaction profiles are given.
3JCP = 4.2 Hz, Cβ/C5H4), 76.5 (pt, JCP = 7.5 Hz, Cα/C5H4), 110.9
2
3
2
(pt, JCP = 3.5 Hz, C4/C4H3O), 123.4 (pt, JCP = 9.2 Hz, C3/
Acknowledgments
1
4
C4H3O), 144.59 (pt, JCP = 39.2 Hz, C2/C4H3O), 147.6 (pt, JCP
=
2.8 Hz, C5/C4H3O) ppm. 31P{1H} NMR (202.53 MHz, CDCl3): δ
We are grateful to the Deutsche Forschungsgemeinschaft (DFG)
and the Fonds der Chemischen Industrie (FCI) for generous finan-
cial support.
= –15.0 (s) ppm.
[PdCl2(P(c-C6H11)2Rc)2] (10d): Following the synthetic procedure
described earlier, 6d (0.5 g, 1.17 mmol) was treated with 8 (0.16 g,
0.56 mmol) to give 10d as an air-stable red solid; yield 0.40 g
(0.39 mmol, 70% based on 8). C44H62Cl2P2PdRu2 (1032.38): C
51.19, H 6.05; found C 51.19, H 5.92; m.p. 180 °C (dec.). IR (KBr):
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www.eurjic.org
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2011, 5437–5449

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