O-diarylphosphinoferrocene sulfonate palladium systems for nonalternating ethene-carbon monoxide copolymerization

Article abstract of DOI:10.1021/om200628r

A series of ferrocene-derived o-diarylphosphino/sulfonate ligands were prepared. Treatment of the o-diphenylphosphinoferrocene sulfonic acid (2a) with (allyl)PdCl dimer and sodium carbonate as the base gave the corresponding chelate (Fc-O,P)Pd(π-allyl) co

Full text of DOI:10.1021/om200628r

ARTICLE
pubs.acs.org/Organometallics
o-Diarylphosphinoferrocene Sulfonate Palladium Systems for
Nonalternating EtheneÀCarbon Monoxide Copolymerization
Chao Chen,† Timo M. J. Anselment,‡ Roland Fr€ohlich,†,§ Bernhard Rieger,‡ Gerald Kehr,† and
Gerhard Erker*,†
†Organisch-Chemisches Institut der Universit€at M€unster, Corrensstrasse 40, 48149 M€unster, Germany
‡WACKER-Lehrstuhl f€ur Makromolekulare Chemie, Technische Universit€at M€unchen, Lichtenbergstraße 4,
85747 Garching bei M€unchen, Germany
S Supporting Information
b
ABSTRACT: A series of ferrocene-derived o-diarylphosphino/sulfonate ligands
were prepared. Treatment of the o-diphenylphosphinoferrocene sulfonic acid (2a)
with (allyl)PdCl dimer and sodium carbonate as the base gave the corresponding
chelate (Fc-O,P)Pd(π-allyl) complex 7a (as a mixture of two isomers). In the
presence of pyridine instead of Na2CO3 the analogous reaction yielded the square-planar (Fc-O,P)Pd(Cl)pyridine complex 8a.
Both systems were characterized by X-ray diffraction. Reaction of the series of three differently ÀP(aryl)2-substituted (Fc-O,P)H
ligands with PdMe2(tmeda) gave the respective (Fc-O,P)PdMe(pyridine) derivatives (11). All three examples 11a,b,c and
one precursor complex, [(Fc-O,P)PdMe]2(tmeda) (10a), were characterized by X-ray diffraction. The ligand system o-bis-
(o-anisyl)phosphinoferrocene sulfonic acid (2b) formed an active catalyst for ethene/CO nonalternating copolymerization upon
treatment with Pd(OAc)2 in methanol. Up to ca. 25% extra ethene incorporation was obtained at an ethene/CO partial pressure
ratio of ca. 10:1. This catalyst system and its equivalent derived from the preformed (Fc-O,P)PdMe(pyridine) precursor complex
(11b) showed reasonable catalyst activities under these conditions.
’ INTRODUCTION
that an ethene/CO copolymer with up to 20% “extra ethylene”
units could be formed with neutral Pd(II) catalyst systems
derived from the o-diarylphosphinobenzene sulfonate ligand
family.12,13 The bis(o-anisyl)phosphino derivate (1) is a promi-
nent example (see Chart 1). Ziegler had identified (by DFT
calculation) the ability of these systems to allow reversibility
of the CO-insertion step to some extent, thereby opening the
pathway of multiple consecutive ethene insertions during the
polymerization process.14 Sen et al. later showed that copolymers
of almost any ethene/CO ratio could be formed by carefully
controlling the specific reaction conditions of the polymerization
process, but that a decreasing CO content was achieved at the
“prize” of an enormous decrease of the actual polymerization
rate.15
We recently introduced some novel [3]ferrocenophane-de-
rived bis-phosphine chelate ligands. These made very effective Pd
catalysts for alt-ethene/CO and for active and highly selective alt-
propene/CO copolymer formation.16,17 Therefore, it was tempt-
ing to extend the use of novel ferrocene-based ligand systems
to the neutral phosphino/sulfonate ligand derived Pd systems.
We will here describe the synthesis of a variety of such diaryl-
phosphinoferrocene sulfonate ligands (2, see Chart 1), their Pd
coordination chemistry, and the successful use of a selected
example in catalytic nonalternating ethene/carbon monoxide
copolymer formation.
Homogeneous ZieglerÀNatta olefin polymerization catalysis
has made some remarkable development in recent decades. A
variety of very active and often very selective catalysts were
described for the production of various types of 1-alkene-derived
polymers and copolymers with catalyst types ranging from selec-
tively designed group 4 metallocenes1 to Cp/amido complexes2
of the early transition metals all the way to remarkably well
performing “non-metallocene” systems of some late transition
metals.3
Copolymerization of ethene with polar olefinic monomers had
been difficult initially,4 but meanwhile truly remarkable progress
has been achieved combining C2H4 with acrylates, metacrylates,
(even) acrylonitrile, and other related alkenes bearing reactive
functional groups.5À9 Ethene/carbon monoxide copolymeriza-
tion is a slightly different case. Seminal work by Drent had shown
that cationic chelate bis-phosphine palladium systems produce a
strictly alternating “polyketone” (i.e., alt-ethene/CO) with high
activities.10 The mechanism of its formation is well understood
from the work of a great number of research groups.11 The alt-
ethene/CO copolymer formed at this catalyst type has a high
melting point, and it is hard to process. Introducing a more than
50% share of the ethylene monomer into the polymer would
greatly improve the polymer properties and processability, but
achieving substantial deviations from the strictly alternating
ethene (or 1-alkene)/CO copolymer formation was difficult
initially. A solution was proposed by Drent et al., who showed
Received: July 12, 2011
Published: September 09, 2011
§ X-ray crystal structure analyses.
r
2011 American Chemical Society
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Organometallics
ARTICLE
’ RESULTS AND DISCUSSION
treatment of the toluidinium salt (3) with n-butyl lithium in THF
to yield the corresponding lithium salt (4; see Scheme 1).
The ferrocene sulfonate lithium salt 4 then underwent a clean
ortho-directed metalation reaction upon treatment with an addi-
tional molar equivalent of n-butyl lithium to generate the reagent
5.20 The in situ generated dilithio ferrocene sulfonate reagent (5)
was quenched by adding a slight excess of the diarylchlorophos-
phines 6(a,b,c) followed by acidification to give the correspond-
ing o-diarylphosphinoferrocene sulfonic acids 2a, 2b, and 2c,
respectively. These ligand systems were not further purified but
used for the subsequent reactions as they were obtained. How-
ever, we monitored their 31P NMR resonances [e.g., 2b: δ À44.2
in d6-DMSO].
Our synthesis was carried out starting with ferrocene substitu-
tion along the lines introduced by Pauson et al.18 and Schl€ogl
et al.,19 respectively. Electrophilic “aromatic” substitution of
ferrocene with chlorosulfonic acid was followed by treatment
with p-toluidine to give the toluidinium ferrocene sulfonate salt
(3), thereby avoiding the problematic isolated free ferrocene
sulfonic acid stage. Cation exchange was then carried out by
Chart 1
Scheme 1
Figure 2. View of the molecular structure of the anti-(Fc-O,P)Pd-
(π-allyl) complex 7a.
Figure 1. 1H NMR spectra (CD2Cl2, 500 MHz, 193 K) of the isomeric mixture of 7a (top). 1D-TOCSY experiments: Irradiation (*) at the methine
proton of the respective π-allyl ligands of both isomers of 7a [δ1H = 6.00 (major isomer) and δ1H = 5.69 (minor isomer)].
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Compound 2a [“(Fc-O,P)H”] was treated with the (allyl)-
PdCl dimer reagent under two different reaction conditions. First
we added sodium carbonate as a base. This reaction led to the
formation of the (Fc-O,P)Pd(π-allyl) complex 7a. It was isolated
in a total yield of ca. 40% as a mixture of two isomers. These can
be described tentatively as the syn- and anti-π-allyl Pd(Fc-O,P)
substituent and the ÀPPh2 group at the ferrocene nucleus. The
Pd atom is coordinated to the sulfonate oxygen and the
phosphorus atom. The allyl ligand is bonded in the η3-mode.
In the depicted isomer the internal allyl CH group is oriented
away from the ferrocene center (i.e., the 7a-anti isomer).
When the reaction of the ferrocene-derived (Fc-O,P) ligand
system 2a with [Pd(allyl)Cl]2 was carried out in the presence of
pyridine instead of the sodium carbonate base, we obtained the
product 8a, which was isolated in ca. 50% yield. The X-ray
crystal structure analysis (see Figure 3) revealed that the (Fc-O,
P) ligand (2a) was bonded in the usual cis fashion to palladium
and that the Pd center carried a chloride ligand and pyridine
bonded to it in a square-planar coordination geometry. The
pyridine ligand was found positioned trans to the phosphine
and, consequently, chloride was found trans to the sulfo-
nate oxygen atom (see Figure 3 for selected bond lengths and
angles).
1
diastereoisomers 7a(A,B). Each features the typical H/13C
NMR signals of a chiral (racemic) Pd(π-allyl) complex (see
Figure 1). In solution they were found in a 1:0.3 molar ratio.
Single crystals of the product 7a were obtained from pentane/
CH2Cl2 by the diffusion method. The X-ray crystal structure
analysis shows two crystallographically independent chemically
identical molecules in the unit cell. The structure of 7a, depic-
À
ted in Figure 2, shows the ortho attachment of the ÀSO3
Table 1. Selected Bond Lengths (Å) and Angles (deg) of the
Pair of Crystallographically Independent 7a(A,B) Molecules
in the Crystal
In solution, complex 8a features a 1H NMR Cp singlet [δ 4.30,
s, 5H (13C: δ 72.8)] and three separate 1H NMR signals of the
remaining ferrocene C5H3[S][P] moiety (δ 5.18, 4.47, 3.96). We
monitored the signals of a ÀPPh2 substituent (31P NMR: δ 12.5)
and the NMR resonances of the Pd-coordinated pyridine ligand
[1H NMR: δ 8.90 (o), 7.92 (p), 7.52 (m)].
A
B
PdÀO
2.127(3)
2.281(1)
2.101(5)
2.165(5)
2.230(5)
1.408(8)
1.365(8)
2.129(3)
2.283(1)
2.097(5)
2.156(5)
2.218(5)
1.396(8)
1.369(9)
PdÀP
We next reacted each of the ferrocene-O,P chelate ligand
systems 2(a,b,c) with the (tmeda)PdMe2 reagent (9).21 A typical
example is the reaction of 2a with 9, which gave the product 10a.
It was isolated in close to 50% yield. Compound 10a was
characterized by C,H,N elemental analysis and by X-ray diffrac-
tion before it was used for the subsequent amine displacement
reaction with pyridine (see below). In the crystal, complex
10a was shown to be a dimer, featuring a kN,kN-bridging
tetramethylethylenediamine ligand. The kN-amino ligands are
oriented trans to phosphorus at each square-planar coordinated
Pd atom. The structure of complex 10a is depicted in the
Supporting Information.
PdÀC(31)
PdÀC(32)
PdÀC(33)
C(31)ÀC(32)
C(32)ÀC(33)
The Pd complex 10a was then subjected to the amine
exchange reaction. Treatment with pyridine for 2 h at ambient
conditions gave the monomeric (Fc-O,P)Pd(CH3)(pyridine)
complex 11a, which was isolated from the reaction mixture in
close to 50% yield (see Scheme 3). The chelate diarylphos-
phinoferrocene sulfonate ligands 2b and 2c were reacted analo-
gously with the (tmeda)PdMe2 reagent (9); only in these cases
we did not isolate the respective intermediates (10b, 10c) but
subjected them after in situ formation directly to the exchange
reaction with pyridine. We isolated the respective products (11b,
11c) in yields of 38% and 61%, respectively. All three products
(11a,b,c) were characterized spectroscopically, by C,H,N ele-
mental analysis, and by X-ray diffraction. As a typical example
complex 11b features a broad 1H NMR singlet at δ 0.51 of the
[Pd]-CH3 group [13C NMR feature at δ 0.40] and the signals
of a pair of diastereotopic o-anisyl groups at phosphorus (OCH3,
1H NMR: δ 3.54, 3.72; 31P NMR resonance at δ 20.0) and
kN pyridine ligand 1H NMR signals at δ 8.89 (o), 7.89 (p), and
7.52 (m).
Figure 3. View of the molecular structure of complex 8a. Selected bond
lengths (Å) and angles (deg): PdÀO(1) 2.066(2), PdÀCl(1) 2.261(1),
PdÀN(31) 2.137(3), PdÀP(1) 2.247(1), Cl(1)ÀPdÀN(31) 91.3(1),
Cl(1)ÀPdÀO(1) 179.3(1), N(31)ÀPdÀO(1) 88.2(1), Cl(1)ÀPdÀ
P(1) 85.2(1), N(31)ÀPdÀP(1) 175.1(1), O(1)ÀPdÀP(1) 95.3(1),
S(1)ÀO(1)ÀPd 119.6(2).
Scheme 2
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ARTICLE
Scheme 3
Figure 6. Molecular structure of the (Fc-O,P)PdMe(pyridine) complex
11c.
Figure 4. Molecular structure of the Pd complex 11a.
Table 2. Selected Bond Lengths (Å) and Angles (deg) of the
New (Fc-O,P)PdCH3(pyridine) Complexes 11(a,b,c) and
(for comparison) of 1215 (see Chart 2)
11a
11b
11c
12
PdÀO
2.179(5)
2.038(8)
2.126(6)
2.228(2)
89.5(3)
2.161(2)
2.033(3)
2.114(2)
2.234(1)
92.0(1)
2.158(2)
2.021(3)
2.118(2)
2.205(1)
90.8(1)
2.165(3)
2.027(5)
2.108(3)
2.232(1)
90.8(2)
PdÀC(Me)
PdÀN(Py)
PdÀP
C(Me)ÀPdÀN(Py)
C(Me)ÀPdÀO(1)
N(Py)ÀPdÀO(1)
C(Me)ÀPdÀP(1)
N(Py)ÀPdÀP(1)
O(1)ÀPdÀP(1)
S(1)ÀO(1)ÀPd
175.5(3)
86.5(2)
176.4(1)
85.4(1)
175.4(1)
85.8(1)
175.0(2)
84.9(1)
87.6(3)
86.9(1)
86.7(1)
90.0(1)
176.9(2)
96.3(1)
177.4(1)
95.6(1)
176.5(1)
96.9(1)
172.7(1)
94.6(1)
116.9(3)
117.3(1)
124.3(1)
122.4(2)
shows a molecular structure in the crystal that features the pair of
ÀSO3À and ÀP(anisyl)2 substituents at the ferrocene backbone
(see Figure 5). The characteristic bonding parameters around the
square-planar Pd coordination sphere of 11b and the ferrocene-
free reference compound 12 are quite similar (see Table 2); only
the C(Me)ÀPdÀP and the SÀOÀPd angles in 11b are slightly
smaller than in 12, and the NÀPdÀP angle in 11b is enlarged by
ca. 5° relative to this reference.
Figure 5. View of the molecular structure of complex 11b.
The molecular structures of compounds 11a, 11b, and 11c are
depicted in Figures 4, 5, and 6. Selected structural data of these
(Fc-O,P)PdCH3(pyridine) systems are listed in Table 2, which
also contains the data of the parent benzene derivate (12)15 for a
comparison (see Chart 2). As a typical example, complex 11b
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’ POLYMERIZATION REACTIONS
We also employed the preformed (Fc-O,P)PdMe(pyridine)
system 11b for the catalyst generation in methanol at elevated
temperature. This system performed similarly in ethene/CO
nonalternating copolymerization (see Table 4) to the in situ
formed catalyst (see above). At an ethene/CO partial pressure
ratio of 50/5 we obtained a nonalternating copolymer that
contained slightly more than 25% extra ethene insertions.
Addition of B(C6F5)3 as a Lewis acid activator component
resulted in a marked increase in catalyst activity but at the
expense of some reduction of the extra ethylene insertion
amount (see Table 4). As expected the melting points (1st dsc
cycle) were found to decrease markedly with increasing extra
ethene insertion.13,15b
Ethene/CO copolymerization reactions were carried out
in methanol with either the preformed Pd complex or by
preparing the active Pd complex in situ by treatment of the
respective ligand system 2 with Pd-acetate. In some cases
activation by added Lewis acids was probed (see below).
Orientating experiments showed that under these conditions
the catalysts derived from the diphenylphosphino-substi-
tuted (Fc-O,P)H ligand (2a) showed only a moderate reac-
tivity and the 2c-derived system was catalytically inactive.
Therefore, we concentrated on the use of the bis(o-anisyl)-
phosphino-substituted (Fc-O,P)H (2b)-derived catalyst sys-
tems. As can be seen from Table 3, the catalyst generated in situ
from the ligand system 2b and Pd(OAc)2 in methanol tested
under the typical “Drent conditions” (30 bar ethene and 20 bar
CO partial pressure)12 was active but produced only a close to
perfectly alternating ethene/CO copolymer. Therefore, we
changed the ethene/CO partial pressure ratio in steps to
eventually 60/5. This resulted in a reduced catalyst activity, as
expected, but the resulting system was still reasonably active. It
produced an ethene/CO copolymer that contained substantial
amounts of nonalternating sections. The amount of “extra”
ethene insertions amounted to ca. 25 mol %. The addition of
the Lewis acid activator BF3 resulted in a small activity increase
going along with only a slight decrease in extra ethene insertions
(see Table 3, entry 5). From the 13C NMR spectra of the polymer
samples (measured in a hexafluoro-2-propanol/d6-benzene
mixture) we could identify the formation of single, double, and
potentially triple additional ethene insertion sequences12,13 (see
Scheme 4 and Figure 6).
’ CONCLUSIONS
The o-diarylphosphinoferrocene sulfonates (2) are the orga-
nometallic analogues of the organic benzene-derived chelate
ligand systems 1. The systems 2 can be prepared by a straightfor-
ward synthetic route and form the basis for the preparation of the
corresponding neutral Pd(II) chelate complexes 7, 8, 10, and 11,
respectively. The bis(o-anisyl)phosphino derivatives are active
catalysts for ethene/CO copolymerization. At relatively low
ethene/CO ratios they produce nearly alternating ethene/CO
copolymers, but at a ca. 10:1 ethene/CO partial pressure ratio
substantially nonalternating copolymers were obtained. Of
course, the overall catalyst activities decreased with decreasing
CO partial pressure,15 but the resulting activities were still quite
remarkable. So, in principle, the new ferrocene-based chelate
phosphino/sulfonate catalyst systems (derived from 2) behaved
qualitatively similar to the systems derived from the purely
organic ligands 1. The ferrocene moiety offers quite a variety
of possibilities for electronic variation of catalyst systems derived
from such chelate ligands. This lets us hope that the described
systems are a good start for developing advanced catalyst systems
on a ferrocene derivative basis.
Chart 2
’ EXPERIMENTAL SECTION
General Procedures. All experiments were carried out under a dry
argon atmosphere using standard Schlenk techniques or in a glovebox.
Table 3. Ethene/CO Copolymerization at the Catalyst Systems in Situ Prepared from the (Fc-O,P)H Ligand 2ba
entry
1
2
3
4
5
6
catalyst
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
10
Pd(OTfa)2
loading(μmol) [Pd]
loading(μmol) [2b]
additive
10
10
10
10
10
10
10
10
10
10
10
BF3
10
loading (μL)
loading (μmol)
p(C2H4) (bar)
p(CO) (bar)
T (°C)
50
30
50
50
60
60
30
5
5
5
5
5
20
110
220
22
110
280
28
90
110
210
21
110
270
27
110
750
75
yield (mg)
activityb
180
18
extra insertion
Mp(dsc)c [°C]
5%
220
12%
206
12%
199
25%
171
23%
182
1%
242
a In methanol solution, 1 h reaction time. b g (polymer) Â mmol[Pd]À1 Â hÀ1. c Values from the first heating cycle.
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Solvents (including deuterated solvents used for NMR) were dried and
distilled prior to use. 1H, 13C, and 31P NMR spectra were recorded on a
300, 500, or 600 MHz spectrometer at ambient temperature unless
otherwise stated. Chemical shifts are given in ppm relative to solvents
(1H and 13C) or to phosphoric acid (85%) as an external standard.
Coupling constants are in Hz. Elemental analysis data were recorded
on a Foss-Heraeus CHNO-Rapid. The starting materials di(o-anisyl)-
Scheme 4
phosphine chloride6a and Pd(tmeda)Me2 were prepared according
21
to the reported or modified procedure or purchased from Alfa Aeser
and Strem.
X-ray single-crystal structure analysis. Data sets were collected with a
Nonius KappaCCD diffractometer, equipped with a rotating anode
generator. Programs used: data collection COLLECT (Nonius B.V.,
1998), data reduction Denzo-SMN (Z. Otwinowski, W. Minor, Methods
Figure 7. 13C{1H} NMR (75 MHz, 294 K) spectrum of the ethylene section of the nonalternating copolymer formed at the 2b/Pd catalyst (entry 5 in
Table 3).
Table 4. Nonalternating Ethene/CO Copolymerization with the Catalyst Derived from the Preformed 11b (Fc-O,P)PdMe-
(pyridine) Systema
entry
1
2
3
4
5
6
7
loading (μmol) [Pd]
LAb additive
loading (mg) [LA]
loading (μmol) [LA]
p(C2H4) (bar)
p(CO) (bar)
T (°C)
10
10
10
10
10
10
10
B(C6F5)3
11
B(C6F5)3
11
B(C6F5)3
11
20
20
20
30
30
30
30
50
50
40
20
20
5
5
5
5
10
110
1
110
1
110
1
110
1
110
1
110
1
110
1
t (h)
yield (mg)
activity c
740
74
1590
159
1%
250
25
360
36
180
18
320
32
420
42
extra insertion
Mp(dsc)d [°C]
3%
15%
10%
27%
17%
170
8%
207
233
242
178
197
167
a In CH2Cl2 solution. b LA: Lewis acid. c g (polymer) Â mmol[Pd]À1 Â hÀ1. d Values from the first heating cycle.
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Enzymol. 1997, 276, 307À326), absorption correction SORTAV (R. H.
Blessing, Acta Crystallogr. 1995, A51, 33À37; R. H. Blessing, J. Appl.
Crystallogr. 1997, 30, 421À426) and Denzo (Z. Otwinowski, D. Borek,
W. Majewski, W. Minor, Acta Crystallogr. 2003, A59, 228À234), struc-
ture solution SHELXS-97 (G. M. Sheldrick, Acta Crystallogr. 1990, A46,
467À473), structure refinement SHELXL-97 (G. M. Sheldrick, Acta
Crystallogr. 2008, A64, 112À122), graphics XP (BrukerAXS, 2000).
Graphics show the thermal ellipsoids with 50% probability. R values are
given for the observed reflections; wR2 values for all reflections.
Preparation of Lithium Ferrocene Sulfonate 3. Preparation of
toluidinium ferrocene sulfonate:19 Ferrocene (20 g, 108 mmol) was sus-
pended in acetic anhydride (120 mL) under argon and cooled to 0 °C.
Then chlorosulfonic acid was added dropwise over 15 min. After the
addition was completed, the mixture was stirred at room temperature for
24 h. The resulting green solution was carefully added to 600 mL of
ice. After quenched, the solution was filtered. p-Toluidine (12.2 g,
114 mmol) was dissolved in 50 mL of water and concentrated HCl
(about 9.0 mL). The two solutions above were cooled to 0 °C and mixed
together. A lot of solid was generated. The solid was filtered, pressed,
and washed with cooled water (0 °C, 50 mL Â 2) and ether (0 °C,
50 mL Â 2). The solid was collected and dried under vacuum. The
product was obtained as a yellow solid (37 g, 92%). The product was
further purified by recrystallization from ethanol. Lithium ferrocene sulfo-
nate 3: Toluidinium ferrocene sulfonate (11.2 g, 30.0 mmol) was
weighted into a Schlenk tube. The vessel was evacuated and recharged
with argon. The cycle was made three times before THF (200 mL) was
added under Ar. The suspension was cooled to 0 °C, and n-BuLi (1.6 M
in hexane, 19 mL, 30.4 mmol) was added dropwise. After the addition
was completed, the reaction was allowed to warm to room temperature
and stirred overnight. The yellow mixture was filtered under Ar, and the
solid was washed with THF (50 mL), dried, and collected in a glovebox.
About 10.3 g of product was obtained, and the yield was quantitative.
Preparation of Ligand 2a. Lithium ferrocene sulfonate (1.73 g,
6.3 mmol) was suspended in dry THF (50 mL) under Ar and cooled to
0 °C with an ice bath. Then n-BuLi (1.6 M in hexane, 5 mL, 8.0 mmol)
was added dropwise. The resulting red solution was stirred for 5.0 h at
0 °C before it was quenched by ClPPh2 (1.7 mL, 8.0 mmol). The mix-
ture was stirred for a further 14 h at room temperature. A 20 mL amount
of water and 20 mL of brine were added in one portion to quench the
reaction. The organic layer was separated and acidified by 1.5 mL of
concentrated HCl in 30 mL of water. The aqueous phase was separated
and extracted with THF (30 mL). The organic phases were combined,
dried over MgSO4 quickly, and filtered. The filtrate was evaporated to
dryness under vacuum. The residue was dispersed with acetone (10 mL)
with the assistance of ultrasonic bath. The solution was filtered, and
the solid was collected. The product was obtained as a yellow solid
(1.0 g, 44%) and was not further purified. 31P NMR (d6-DMSO, 300 K):
δ À18.8.
was warmed to RT and stirred overnight. The reaction was quenched
with water (50 mL). The pentane solution was separated. The aqueous
phase with lots of solid was extracted with dichloromethane (2 Â
50 mL). The organic phases were combined, dried over MgSO4, and
filtered. The filtrate was rotatory evaporated to dryness. The residue was
purified by recrystallization from hexane to give di(o-anisyl)-di-
(isopropyl)amido phosphine as a white solid (10.4 g, 60%). The solid
was suspended in ether (200 mL) under Ar and cooled to 0 °C. Then
HCl etheral solution (2 M, 60 mmol) was added and caused a white
precipitation. The suspension was reacted for 12 h at RT and heated to
reflux for 1 h. The mixture was filtered, and the solid was washed with
ether (200 mL). The ether solution was evaporated to dryness under
vacuum, and the product was collected as white solid in a glovebox
(7.32 g, 87%). The product, di(o-anisyl)phosphine chloride, could be
purified by recrystallization from toluene if necessary. Preparation of
ligand 2b: Lithium ferrocene sulfonate (2.73 g, 10 mmol) was suspended
in dry THF (60 mL) under Ar and cooled to 0 °C with an ice bath. Then
n-BuLi (1.6 M in hexane, 9.5 mL, 15 mmol) was added dropwise. The
resulting red solution was stirred for 5 h at 0 °C before it was quenched
by ClPAn2 (4.3 g, 15 mmol, dissolved in 20 mL of THF under argon).
The mixture was stirred for a further 14 h at room temperature.
Sometimes, the mixture should be filtered if some precipitation was
produced before being quenched. Then 30 mL of water and 30 mL of
brine were added in one portion to quench the reaction. The organic
layer was separated and acidified by 2 mL of concentrated HCl in 30 mL
of water. The aqueous phase was separated and extracted with THF (2 Â
30 mL). The organic phases were combined, dried over MgSO4 quickly,
and filtered. The filtrate was evaporated to dryness under vacuum. The
residue was dispersed with acetone (10 mL) with the assistance of an
ultrasonic bath. The solution was filtered, and the solid was collected.
The product was obtained as a yellow solid (2.0 g, 40%) and was not
further purified. 31P NMR (d6-DMSO, 300 K): δ À44.2.
Preparation of Ligand 2c. Preparation of POPCl [2,8-dimethyl-10-
chlorophenoxaphosphine]:23 Ditolyl ether (11.9 g, 60 mmol) and AlCl3
(10.7 g, 80 mmol) were dissolved in PCl3 (40 mL) under argon. The
mixture was heated to reflux (ca. 80 °C) for 8 h. Then the mixture was
cooled to RT, and execess PCl3 was removed under vacuum. To the
residue was added toluene (80 mL), and the suspension was stirred
thoroughly at 0 °C. Then pyridine was slowly added to produce much
solid. After the suspension was stirred for 1 h at room temperature,
the solid was filtered off and washed with toluene (50 mL) twice. The
toluene solution was combined and evaporated under vacuum. Then
60 mL of toluene was added, and the mixture was heated to reflux.
The solution was slowly cooled and kept at À20 °C overnight to give
POPCl as a white solid (10.53 g, 74%). Preparation of ligand 2c: Lithium
ferrocene sulfonate (2.73 g, 10 mmol) was suspended in dry THF
(60 mL) under Ar and cooled to 0 °C with an ice bath. Then t-BuLi (1.6
M in hexane, 10 mL, 16 mmol) was added dropwise. The resulting red
solution was stirred overnight at at room temperature. The reaction was
quenched with POPCl (3.15 g, 12 mmol) at 0 °C. The mixture was
stirred overnight at room temperature. Then 2.0 mL of concentrated
HCl was added followed by 25 mL of water and 25 mL of brine. The
aqueous phase was separated and extracted with THF (2 Â 20 mL). The
organic phases were combined, dried over MgSO4 quickly, and filtered.
The filtrate was evaporated to dryness under vacuum. The residue
was dispersed with dichloromethane (20 mL) with the assistance of an
ultrasonic bath. The solution was filtered, and the solid was collected.
The product was obtained as a yellow solid (0.86 g, 17%) and was not
further purified.
Preparation of Ligand 2b. Preparation of dichloro[di(isopropyl)-
amido]phosphine:22 PCl3 (12.5 mL, 145 mmol) was dissolved in ether
(125 mL) and cooled to 0 °C. Di(isopropyl)amine (37.5 mL, 195
mmol) was slowly added. Then the resulting suspension was allowed to
react overnight at RT before it was filtered under Ar. The white solid was
washed with ether (2 Â 50 mL). The ether solution was combined and
evaporated under vacuum. The residue was transferred into a flask via
syringe for distillation. The product was obtained as a colorless liquid
and slowly crystallized while stored (15.2 mL, 69%). Preparation of
chlorodi(o-anisyl)phosphine: Anisole (10.8 mL, 100 mmol) and TMEDA
(15.0 mL, 100 mmol) were dissolved in pentane (120 mL) under
argon and cooled to À78 °C. Then n-BuLi (1.6 M in hexane, 64 mL,
102 mmol) was added dropwise. After the addition was completed,
the resulting suspension was slowly warmed to RT and stirred for 24 h.
Then it was cooled to À78 °C again, and dichloro[di(isopropyl)-
amido]phosphine (7.1 mL, 50 mmol) was slowly added. The mixture
Preparation of Complex 7a. Ligand 2a (225 mg, 0.5 mmol) was
suspended in CH2Cl2 (5 mL) and treated with Na2CO3 (210 mg,
2.0 mmol) for 0.5 h. AllylPdCl dimer (90 mg, 0.5 mmol) was added. The
mixture was stirred overnight and filtered. The solid was washed with
CH2Cl2 (5 mL Â 2). The solution was combined, layered with ether
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Organometallics
ARTICLE
(20 mL), and filtered. The product was obtained as a red solid (122 mg,
39%). Anal. Calcd for for C25.5H24ClFeO3PPdS: C 47.91, H 3.78.
Found: C 48.79, H 3.97.
V = 2843.8(1) Å3, Dcalcd = 1.652 g cmÀ3, μ = 1.400 mmÀ1, empirical
absorption correction (0.640 e T e 0.933), Z = 4, λ = 0.71073 Å,
T = 223 K, ω and j scans, 17 847 reflections collected ((h, (k, (l),
[(sin θ)/λ] = 0.66 ÅÀ1, 6772 independent (Rint = 0.055) and 4717
observed reflections [I g 2σ(I)], 358 refined parameters, R = 0.043,
Major product (78%): 1H NMR (500 MHz, CD2Cl2, 193 K): δ 7.60
(m, 2H, p-Phb), 7.56 (m, 2H, o-Phb), 7.53 (m, 2H, m-Phb), 7.39 (m, 2H,
p-Pha), 7.35 (m, 2H, m-Pha), 7.15 (m, 2H, o-Pha), 6.00 (m, 1H, dCH),
wR2 = 0.104, max. residual electron density 0.80 (À0.78) e ÅÀ3
,
b
5.08 (br, 1H, 5-H), 5.01 (m, 1H, dCH2 ), 4.44 (m, 1H, 4-H), 4.04 (s,
hydrogen atoms calculated and refined as riding atoms.
b
5H, Cp), 3.99 (m, 1H, dCH2 ), 3.93 (br, 1H, 3-H), 3.72 (br d, J = 6.5
Preparation of Complex 11a. Ligand 2a (225 mg, 0.5 mmol)
was suspended in THF (10 mL), and Pd(tmeda)Me2 (128 mg, 0.5
mmol) was added at 0 °C. After 5 min the emission of gas ceased and the
suspension turned clear. The solution was stirred overnight, and much
precipitation was produced again. The solid could be collected via
filtration and was characterized as the tmeda-bridged dimer of the Pd
complex 10a (170 mg, 52%). Pyridine (1 mL, excess) was added to the
former suspension, giving a solution. After 2 h the mixture was filtered
and the residue was washed with dichloromethane (5 mL). The organic
phases were combined and deposited with ether (200 mL). Then it was
filtered, and the filtrate was kept at À32 °C for 2 days. The crystalline
product 11a was collected via filtration (160 mg, 49%).
Compound 10a was characterized only by elemental analysis and
X-ray crystal structure analysis. Single crystals suitable for the X-ray
crystal structure analysis were obtained by slow diffusion of pentane into
a solution of 10 and CH2Cl2. Anal. Calcd for C52H58Fe2N2O6P2Pd2S2:
C 49.66, H 4.65, N 2.23. Found: C 49.54, H 4.49, N 2.09.
a
a
Hz, 1H, dCH2 ), 2.65 (br d, J = 11.9 Hz, 1H, =CH2 ). 13C{1H} NMR
(126 MHz, CD2Cl2, 298 K): δ 134.1 (d, 2JPC = 14.7 Hz, o-Phb), 133.0 (d,
1JPC = 46.2 Hz, i-Pha), 131.6 (br, p-Phb), 131.1 (d, JPC = 12.1 Hz,
2
o-Pha), 130.7 (d, JPC = 52.7 Hz, i-Phb), 129.8 (br, p-Pha), 128.6 (d,
1
3JPC = 11.2 Hz, m-Phb), 128.3 (d, JPC = 11.2 Hz, m-Pha), 119.5 (m,
3
dCH), 96.3 (d, 2JPC = 17.8 Hz, 1-C), 84.7 (d, J = 27.2 Hz, dCH2 ), 73.3
b
(m, 3,5-C), 70.7 (d, J = 5.0 Hz, 4-C), 71.4 (Cp), 67.9 (d, 1JPC = 50.2 Hz,
a
2-C), 51.3 (dCH2 ). 31P{1H} NMR (202 MHz, CD2Cl2, 193 K): δ 13.8
(ν1/2 ≈ 2 Hz). Minor product (22%): 1H NMR (500 MHz, CD2Cl2, 193
K): δ 7.68 (m, 2H, p-Phb), 7.56 (m, 2H, m-Phb), 7.53 (m, 2H, o-Phb),
7.39 (m, 2H, p-Pha), 7.35 (m, 2H, m-Pha), 7.15 (m, 2H, o-Pha), 5.69 (m,
b
1H, dCH), 5.08 (br, 1H, 5-C), 4.99 (m, 1H, dCH2 ), 4.44 (m, 1H,
b
4-C), 4.19 (s, 5H, Cp), 4.15 (m, 1H, dCH2 ), 3.86 (br, 1H, 3-C), 3.57
(br m, 1H, dCH2 ), 2.94 (br d, J = 11.9 Hz, 1H, dCH2 ). 13C{1H}
NMR (126 MHz, CD2Cl2, 298 K): δ [selected resonances] 119.5
a
a
b
a
(m, dCH), 84.5 (d, J = 28.8 Hz, dCH2 ), 71.6 (Cp), 49.2 (dCH2 ).
31P{1H} NMR (202 MHz, CD2Cl2, 193 K): δ 14.6 (ν1/2 ≈ 2 Hz).
Single crystals suitable for the X-ray crystal structure analysis were
obtained by slow diffusion of pentane into a solution of 7a and CH2Cl2.
X-ray crystal structure analysis for 10a 2CH2Cl2: formula C52H58Fe2-
3
N2O6P2Pd2S2 2CH2Cl2, M = 1427.42, yellow crystal 0.50 Â 0.10 Â
3
0.05 mm, monoclinic, space group P21/n (No. 14), a = 12.0508(2) Å,
b = 11.6611(2) Å, c = 24.0288(7) Å, β = 99.615(1)°, V = 3329.23(13) Å3,
Dcalcd = 1.424 g cmÀ3, μ = 1.273 mmÀ1, empirical absorption correction
(0.569 e T e 0.939), Z = 2, λ = 0.71073 Å, T = 223 K, ω and j scans,
21 179 reflections collected ((h, (k, (l), [(sin θ)/λ] = 0.66 ÅÀ1, 7953
independent (Rint = 0.067) and 5423 observed reflections [I g 2σ(I)],
355 refined parameters, R = 0.064, wR2 = 0.223, max. residual electron
density 1.70 (À0.73) e ÅÀ3, hydrogen atoms calculated and refined as
riding atoms.
X-ray crystal structure analysis for 7a 0.5 CH2Cl2: formula C25H23-
3
FeO3PPdS 1/2CH2Cl2, M = 639.18, yellow crystal 0.30 Â 0.10 Â
3
0.05 mm, triclinic, space group P1 (No. 2), a = 10.9418(2) Å, b =
14.3677(2) Å, c = 16.6363(3) Å, α = 90.136(1)°, β = 94.013(1)°, γ =
108.473(1)°, V = 2473.69(7) Å3, Dcalcd = 1.716 g cmÀ3, μ = 1.597
mmÀ1, empirical absorption correction (0.646 e T e 0.924), Z = 4, λ =
0.71073 Å, T = 223 K, ω and j scans, 22 713 reflections collected ((h,
(k, (l), [(sin θ)/λ] = 0.66 ÅÀ1, 11 621 independent (Rint = 0.044) and
10 441 observed reflections [I g 2σ(I)], 604 refined parameters, R =
Compound 11a: Anal. Calcd for C28H26FeNO3PPdS: C 51.75, H
0.049, wR2 = 0.121, max. residual electron density 1.24 (À1.08) e ÅÀ3
hydrogen atoms calculated and refined as riding atoms.
,
1
4.03, N 2.16. Found: C 51.79, H 4.33, N 2.15. H NMR (500 MHz,
CD2Cl2, 298 K): δ 8.83 (m, 2H, o-Py), 8.00 (m, 2H, o-Pha), 7.92 (m, 1H,
p-Py), 7.65 (m, 1H, p-Pha), 7.62 (m, 2H, m-Pha), 7.54 (m, 2H, m-Py),
7.44 (m, 1H, o-Phb), 7.42 (m, 1H, p-Phb), 7.37 (m, 2H, m-Phb), 5.09 (m,
1H, 5-H), 4.40 (m, 1H, 4-H), 4.21 (s, 5H, Cp), 3.90 (m, 1H, 3-H), 0.67
(d, 3JPH = 2.6 Hz, 3H, PdCH3). 13C{1H} NMR (126 MHz, CD2Cl2, 298
K): δ 150.7 (o-Py), 138.9 (p-Py), 135.8 (d, 2JPC = 13.0 Hz, o-Pha), 133.6
(d, 1JPC = 52.2 Hz, i-Phb), 132.5 (d, 2JPC = 10.8 Hz, o-Phb), 132.1 (d,
Preparation of Complex 8a. Ligand 2a (225 mg, 0.5 mmol) was
suspended in CH2Cl2 (10 mL) and treated with pyridine (10 mL) for
1 h. AllylPdCl dimer (90 mg, 0.5 mmol) was added. The mixture was
stirred overnight and filtered. The solution was deposited with ether
(20 mL) and filtered. Then the solution was slowly evaporated to give
the product (175 mg, 52%). Anal. Calcd for C27H23ClFeNO3PPdS: C
48.33, H 3.89, N 1.94. Found: C 48.51, H 3.74, N 1.61. 1H NMR (500
MHz, CD2Cl2, 298 K): δ 8.90 (d, 3JHH = 4.7 Hz, 2H, o-Py), 8.14 (m, 2H,
o-Pha), 7.92 (t, 3JHH = 7.6 Hz, 1H, p-Py), 7.70 (m, 1H, p-Pha), 7.63 (m,
2H, 2H, m-Pha), 7.61 (m, 2H, 2H, o-Phb), 7.52 (m, 2H, m-Py), 7.52 (m,
1H, p-Phb), 7.39 (m, 1H, m-Phb), 5.18 (m, 1H, 5-H), 4.47 (m, 1H, 4-H),
4.30 (s, 5H, Cp), 3.96 (m, 1H, 1H, 3-H). 13C{1H} NMR (126 MHz,
CD2Cl2, 298 K): δ 150.2 (o-Py), 139.5 (p-Py), 135.5 (d, 2JPC = 11.4 Hz,
o-Pha), 133.6 (d, 2JPC = 10.2 Hz, o-Phb), 132.6 (d, 4JPC = 2.8 Hz, p-Pha),
131.7 (d, 4JPC = 3.2 Hz, p-Phb), 130.8 (d, 1JPC = 58.7 Hz, i-Phb), 128.7
(d, 3JPC = 10.3 Hz, m-Phb), 128.6 (d, 3JPC = 10.7 Hz, m-Pha),128.4 (d,
1JPC = 69.1 Hz, i-Pha), 125.4 (m-Py), 96.5 (d, 2JPC = 15.3 Hz, 1-C), 73.9
(d, 3JPC = 1.7 Hz, 3-C), 73.4 (d, 3JPC = 6.6 Hz, 5-C), 72.8 (Cp), 72.1 (d,
3JPC = 6.7 Hz, 4-C), 69.4 (d, 1JPC = 60.1 Hz, 2-C). 31P{1H} NMR (202
MHz, CD2Cl2, 298 K): δ 12.5 (ν1/2 ≈ 5 Hz).
4JPC = 2.6 Hz, p-Pha), 130.5 (d, 4JPC = 2.5 Hz, p-Phb), 129.7 (d, 1JPC
=
60.1 Hz, i-Pha), 128.9 (d, 3JPC = 11.3 Hz, m-Pha), 128.7 (d, 3JPC = 10.5
Hz, m-Phb), 125.6 (m-Py), 98.6 (d, 2JPC = 17.2 Hz, 1-C), 73.4 (d, 3JPC
=
6.5 Hz, 5-C), 73.3 (d, 2JPC = 1.1 Hz, 3-C), 72.4 (Cp), 71.4 (d, 3JPC = 6.0
Hz, 4-C), 70.9 (d, 1JPC = 55.1 Hz, 2-C), 0.40 (d, 2JPC = 6.5 Hz, PdCH3).
31P{1H} NMR (202 MHz, CD2Cl2, 298 K): δ 24.1 (ν1/2 ≈ 2 Hz).
Single crystals suitable for X-ray crystal structure analysis were
obtained by slow diffusion of pentane into a solution of 11a and CH2Cl2.
X-ray crystal structure analysis for 11a CH2Cl2: formula C28H26Fe-
3
NO3PPdS CH2Cl2, M = 734.70, yellow crystal 0.20 Â 0.15 Â 0.05 mm,
3
monoclinic, space groupP21/c (No. 14), a = 17.8906(7) Å, b = 9.3517(5)
Å, c = 17.9434(8) Å, β = 102.814(2)°, V = 2927.3(2) Å3, Dcalcd = 1.667
g cmÀ3, μ = 1.451 mmÀ1, empirical absorption correction (0.760 e T e
0.931), Z = 4, λ = 0.71073 Å, T = 223 K, ω and j scans, 19 908 reflections
collected ((h, (k, (l), [(sin θ)/λ] = 0.66 ÅÀ1, 6629 independent
(Rint = 0.054) and 4831 observed reflections [I g 2σ(I)], 346 refined
parameters, R = 0.077, wR2 = 0.191, max. residual electron density 1.32
(À1.27) e ÅÀ3, hydrogen atoms calculated and refined as riding atoms.
Preparation of the Complex 11b. Ligand 2b (512 mg, 1.0
mmol) was suspended in THF (10 mL), and Pd(tmeda)Me2 (256 mg,
Single crystals suitable for the X-ray crystal structure analysis were
obtained by slow diffusion of ether into a solution of 8 and CH2Cl2.
X-ray crystal structure analysis of 8 0.5Et2O: formula C27H23Fe-
3
NO3PPdS 1/2 C4H10O, M = 707.25, yellow-organge crystal 0.35 Â
3
0.30 Â 0.05 mm, monoclinic, space group P21/c (No. 14), a =
17.2424(3) Å, b = 9.4608(2)Å, c = 17.4506(3) Å, β = 92.582 (1)°,
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1.0 mmol) was added at 0 °C. The suspension was stirred overnight, and
then pyridine (1.2 mL, excess) was added to cause some solid to get
dissolved. After 2 h the mixture was filtered, and the solid was washed
with dichloromethane (5 mL). The organic phases were combined, and
the product was precipitated with pentane (200 mL). Then it was
filtered, and the filtrate was kept at À32 °C for 2 days. The crystalline
product was collected by filtration (266 mg, 38%). Anal. Calcd for
C30H30FeNO5PPdS: C 50.76, H 4.26, N 1.97. Found: C 50.39, H 4.07,
N 1.82. 1H NMR (500 MHz, CD2Cl2, 298 K): δ 8.89 (m, 2H, o-Py), 8.73
(br, 1H, 6-Ara), 7.89 (m, 1H, p-Py), 7.63 (m, 1H, 4-Ara), 7.52 (m, 2H,
m-Py), 7.35 (m, 1H, 4-Arb), 7.23 (m, 1H, 5-Ara), 7.09 (m, 1H, 3-Ara),
7.06 (m, 1H, 6-Arb), 6.87 (m, 1H, 5-Arb), 6.84 (m, 1H, 3-Arb), 4.97 (m,
1H, 5-H), 4.34 (m, 1H, 4-H), 4.32 (br, 1H, 3-H), 4.04 (s, 5H, Cp), 3.72
3JPC = 6.6 Hz, 5-C), 72.1 (Cp), 72.1 (3-C), 70.9 (d, 3JPC = 6.3 Hz, 4-C),
2
20.9 (2-MePOP), 20.8 (8-MePOP), 0.93 (d, JPC = 6.3 Hz, PdCH3).
31P{1H} NMR (162 MHz, CD2Cl2, 298 K): δ À10.7 (ν1/2 ≈ 3 Hz).
Single crystals suitable for X-ray crystal structure analysis were
obtained by slow diffusion of pentane into a solution of 11c and CH2Cl2.
X-ray crystal structure analysis for 11c CH2Cl2: formula C30H28Fe-
3
NO4PPdS CH2Cl2, M = 776.74, yellow crystal 0.30 Â 0.15 Â 0.10 mm,
3
triclinic, space group P1 (No. 2), a = 10.2911(2) Å, b = 11.3479(2) Å,
c = 15.2349(3) Å, α = 71.626(1)°, β = 72.345 (1)°, γ = 71.369(1)°, V =
1558.86 (5) Å3, Dcalcd = 1.655 g cmÀ3, μ = 1.369 mmÀ1, empirical
absorption correction (0.684 e T e 0.875), Z = 2, λ = 0.71073 Å,
T = 223 K, ω and j scans, 16 046 reflections collected ((h, (k, (l),
[(sin θ)/λ] = 0.66 ÅÀ1, 7381 independent (Rint = 0.048) and 6108
observed reflections [I g 2σ(I)], 404 refined parameters, R = 0.037,
wR2 = 0.096, max. residual electron density 0.71 (À1.06) e ÅÀ3, hydrogen
atoms calculated and refined as riding atoms.
a
b
(br, 3H, OCH3 ), 3.54 (br, 3H, OCH3 ), 0.51 (br, 3H, PdCH3).
13C{1H} NMR (126 MHz, CD2Cl2, 298 K): δ 161.4 (br d, 2JPC = 0.9
Hz, 2-Ara), 160.0 (d, 2JPC = 4.5 Hz, 2-Arb), 150.9 (o-Py), 140.7 (br d,
4
2JPC = 24.0 Hz, 6-Ara), 138.6 (p-Py), 133.8 (d, JPC = 0.9 Hz, 4-Ara),
In Situ Copolymerizations. In a typical reaction, 10 μmol
(2.3 mg) of Pd(OAc)2, 10 μmol of ligand 2b, and 25 mL of MeOH
were transferred to a 100 mL (Roth) or 250 mL stainless steel autoclave.
The autoclave was quickly closed and purged with argon and then
charged with ethylene until a pressure of 30 bar was reached. Subse-
quently, CO was introduced to reach the respective pressure, e.g., 50 bar
(C2H4:CO ≈ 30:20). After the solution was completely saturated with
gas (15 min), the 100 or 250 mL autoclave was heated using a mantel for
the indicated time (usually 1 h). After this time the cooled contents were
filtered and the solid was washed with methanol (50 mL) and dried
overnight.
Copolymerization Using 11b. In a typical reaction, 10 μmol of
complex 11b and 25 mL of dichloromethane were transferred to a
100 mL (Roth) or 250 mL stainless steel autoclave. The autoclave was
quickly closed and purged with argon and then charged with ethylene
until a pressure of 30 bar was reached. Subsequently, CO was introduced
to reach the respective pressure, e.g., of 50 bar (C2H4:CO ≈ 30:20).
After the solution was completely saturated with gas (15 min), the 100 or
250 mL autoclave was heated using a mantel for the indicated time.
Afterward the cooled contents were deposited with methanol (50 mL),
filtered, washed with methanol (50 mL), and dried overnight.
133.4 (d, 2JPC = 7.0 Hz, 6-Arb), 131.6 (d, 4JPC = 1.5 Hz, 4-Arb), 125.4 (m-
Py), 121.7 (br d, 1JPC = 57.8 Hz, 1-Arb), 120.9 (d, 3JPC = 13.4 Hz, 5-Ara),
3
1
120.3 (br d, JPC = 10.2 Hz, 5-Arb), 118.8 (d, JPC = 57.2 Hz, 1-Ara),
111.4 (d, 3JPC = 4.2 Hz, 3-Ara), 111.3 (br, 3-Arb), 98.0 (d, 2JPC = 18.8 Hz,
1-C), 74.3 (d, 2JPC = 1.0 Hz, 3-C), 73.8 (br d, 1JPC = 56.2 Hz, 2-C), 72.1
(Cp), 71.9 (d, 3JPC = 6.7 Hz, 5-C), 70.8 (d, 3JPC = 6.3 Hz, 4-C), 55.4 (br,
b
a
OCH3 ), 55.3 (OCH3 ), 0.40 (PdCH3). 31P{1H} NMR (202 MHz,
CD2Cl2, 298 K): δ 20.0 (ν1/2 ≈ 150 Hz).
Single crystals suitable for the X-ray crystal structure analysis were
obtained by slow diffusion of pentane into a solution of 11b and CH2Cl2.
X-ray crystal structure analysis for 11b: formula C30H30FeNO5PPdS,
M = 709.83, organge crystal 0.50 Â 0.30 Â 0.15 mm, monoclinic, space
group P21/c (No. 14), a = 14.5221(2) Å, b = 10.9631(2) Å, c =
18.2341(3) Å, β = 97.508(1)°, V = 2878.11(8) Å3, Dcalcd = 1.638
g cmÀ3, μ = 1.298 mmÀ1, empirical absorption correction (0.563 e T e
0.829), Z = 4, λ = 0.71073 Å, T = 223 K, ω and j scans, 26 492
reflections collected ((h, (k, (l), [(sin θ)/λ] = 0.66 ÅÀ1, 6897
independent (Rint = 0.042) and 5703 observed reflections [I g 2σ(I)],
364 refined parameters, R = 0.029, wR2 = 0.078, max. residual electron
density 0.59 (À0.62) e ÅÀ3, hydrogen atoms calculated and refined as
riding atoms.
’ ASSOCIATED CONTENT
Preparation of Complex 11c. Ligand 2c (248 mg, 0.5 mmol) was
suspended in CH2Cl2 (5 mL), and Pd(tmeda)Me2 (126 mg, 0.5 mmol)
was added at 0 °C. The suspension turned clear initially and formed a
suspension again in 0.5 h. Then pyridine (1 mL, excess) was added to
cause some solid to dissolve. After 2 h the mixture was filtered and the
solid was washed with dichloromethane (5 mL). The organic phases
were combined and deposited with ether (90 mL). Then it was filtered,
and the filtrate was kept at À32 °C for 2 days. The crystalline product
was collected by filtration (236 mg, 61%). Anal. Calcd for C30H28Fe-
S
Supporting Information. Text and figures giving further
b
experimental and spectroscopic details and crystallographic data
(CIF files) for 7a, 8a, 10, and 11aÀc. This material is available
free of charge via the Internet at http://pubs.acs.org.
’ AUTHOR INFORMATION
Corresponding Author
*E-mail: erker@uni-muenster.de.
NO4PPdS 0.5CH2Cl2: C 49.89, H 3.98, N 1.91. Found: C 50.34, H
3
1
3.79, N 1.98. H NMR (600 MHz, CD2Cl2, 298 K): δ 8.93 (m, 2H,
o-Py), 8.14 (dm, 3JPH = 15.5 Hz, 1H, 9-POP), 8.07 (dm, 3JPH = 15.2 Hz,
1H, 1-POP), 7.97 (m, 1H, p-Py), 7.60 (m, 2H, m-Py), 7.48 (dm, 3JHH
=
’ ACKNOWLEDGMENT
8.4 Hz, 1H, 3-POP), 7.29 (dd, 3JHH = 8.5 Hz, 4JPH = 3.9 Hz, 1H, 4-POP),
7.25 (dm, 3JHH = 8.2 Hz, 1H, 7-POP), 7.08 (dd, 3JHH = 8.2 Hz, 4JPH
=
Financial support from the Deutsche Forschungsgemeinschaft
is gratefully acknowledged.
3.9 Hz, 1H, 6-POP), 4.89 (br m, 1H, 5-H), 4.31 (s, 5H, Cp), 4.19 (br t,
3JHH = 2.5 Hz, 1H, 4-H), 3.68 (br m, 1H, 3-H), 2.54 (s, 3H, 2-MePOP),
2.35 (s, 3H, 8-MePOP), 0.55 (d, 3JPH = 3.5 Hz, 1H, PdCH3). 13C{1H}
NMR (151 MHz, CD2Cl2, 298 K): δ 155.3 (d, 2JPC = 1.3 Hz, 4a-POP),
153.0 (d, 2JPC = 1.4 Hz, 5a-POP), 150.6 (o-Py), 139.0 (p-Py), 135.9 (d,
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