Synthesis of fluoroalkyl palladium and nickel complexes via decarbonylation of acylmetal species

Article abstract of DOI:10.1021/om500535x

The synthesis and characterization of a series of fluoroalkyl palladium(II) and nickel(II) complexes via decarbonylation of the corresponding acylmetal species is reported. At palladium(II), labile supporting ligands such as tri-o-tolylphosphine are required to achieve decarbonylation within 30 min at 85 °C. In contrast, decarbonylation at (PPh₃)₂Ni(C(O) R_F)(OCOR_F) (R_F = fluoroalkyl) complexes proceeds rapidly at or below room temperature.

Full text of DOI:10.1021/om500535x

Article
pubs.acs.org/Organometallics
Synthesis of Fluoroalkyl Palladium and Nickel Complexes via
Decarbonylation of Acylmetal Species
Ansis Maleckis and Melanie S. Sanford*
Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor Michigan 48109, United States
S
* Supporting Information
ABSTRACT: The synthesis and characterization of a series of
fluoroalkyl palladium(II) and nickel(II) complexes via decar-
bonylation of the corresponding acylmetal species is reported.
At palladium(II), labile supporting ligands such as tri-o-
tolylphosphine are required to achieve decarbonylation within
30 min at 85 °C. In contrast, decarbonylation at (PPh3)2Ni-
(C(O)RF)(OCORF) (RF = fluoroalkyl) complexes proceeds
rapidly at or below room temperature.
reactions between transmetalating reagents (e.g., aryl zincs, aryl
stannanes, or aryl boron reagents) and electrophilic fluorinated
anhydrides and esters occur at elevated temperatures. Second,
slow CO deinsertion relative to transmetalation can lead to
acetylation of the aryl group instead of the targeted
INTRODUCTION
■
Efficient and functional group tolerant trifluoromethylation
methods would provide valuable approaches for fine-tuning the
pharmacokinetics, metabolic stability, and bioavailability of
biologically active molecules. Transition-metal catalysis is an
attractive and widely studied approach for the late-stage
fluoroalkylation of complex organic molecules.1,2 However,
most of the fluoroalkyl (RF) sources employed in transition-
metal-catalyzed fluoroalkyl cross-coupling reactions (e.g., RFI,
RFSiMe3, RFSiEt3, RFH, Togni reagent, Umemoto reagent) are
expensive, toxic, and/or volatile. In contrast, fluoroalkyl
carboxylic acid derivatives are relatively inexpensive, safe, and
easy-to-handle alternatives. Despite these advantages, current
decarboxylative fluoroalkylation reactions with, for example,
trifluoroacetate salts remain impractical due to the require-
ments for superstoichiometric quantities of transition-metal
reagents and forcing conditions (often ≥150 °C).1,3,4 We
recently proposed an alternative approach involving metal-
catalyzed decarbonylative fluoroalkylation with fluorinated
anhydrides or fluorinated esters as RF donors.5 Our proposed
catalytic cycle for fluoroalkylation with these reagents has four
steps: (1) oxidative addition of the anhydride or ester to LnPd0
to generate LnPdII(C(O)RF)(OR), (2) CO deinsertion from
LnPdII(C(O)RF)(OR) leading to LnPdII(RF)(OR), (3) aryl
group transfer to PdII via transmetalation or C−H activation,
and (4) aryl−RF bond-forming reductive elimination2g,6 to
release the fluoroalkylated product and return LnPd0 to the
catalytic cycle. We previously demonstrated the feasibility of
each elementary step of this proposed cycle at Pd model
complexes supported by the RuPhos ligand.2g,7 This inves-
tigation revealed that CO deinsertion at PdII is a particularly
challenging transformation. For example, to achieve full
conversion, the complex (RuPhos)Pd(C(O)CF3)(OC(O)CF3)
had to be heated for 1.5 h in refluxing benzene.
fluoroalkylation reaction. For example, a high-yielding Pd0/II
-
catalyzed trifluoroacetylation of arylboronic acids with phenyl-
trifluoroacetate has been reported and presumably proceeds via
this pathway.8
In the current paper, we describe two approaches for
accelerating this critical CO deinsertion step. The first involves
the synthesis of PdII perfluoroacyl complexes containing labile
supporting ligands, with the hypothesis that such ligands should
facilitate the generation of coordinatively unsaturated Pd
intermediates necessary for rapid CO deinsertion.9,10 In
addition, we explore CO deinsertion from analogous fluoroacyl
NiII complexes.11 This second approach is predicated on
literature reports suggesting that decarbonylation is often more
facile at first-row metal centers in comparison to their second-
and third-row analogues.12−16 We demonstrate herein the
feasibility of CO deinsertion at a variety of MII−C(O)RF
complexes (M = Ni, Pd). Furthermore, we show that changing
the supporting ligand and/or the metal center can have a
dramatic impact on the rates of these reactions.
RESULTS AND DISCUSSION
■
Accelerating CO Deinsertion via Modification of the
Supporting Ligands at PdII−C(O)RF Complexes. CO
insertion/deinsertion is generally accepted to proceed via a
three-center transition state (eqs 1 and 2).17 In principle, CO
insertion/deinsertion via a pentacoordinate PdII transition state
such as 1 is feasible, but it is expected to be a high-energy
pathway (eq 1).18 CO insertion/deinsertion via a tetracoordi-
nate Pd transition state such as 2 is, in general, a much more
The challenges associated with the CO deinsertion step are a
major hindrance to the development of the envisioned catalytic
fluoroalkylation reaction for several reasons. First, background
Received: May 19, 2014
© XXXX American Chemical Society
A
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crystalline solid that was fully characterized using 1D and 2D
NMR spectroscopic techniques. The 19F NMR spectrum of 5
exhibits two characteristic resonances in a 1:1 integral ratio, a
doublet of doublets at −27 ppm (3JF−P = 66 and 26 Hz) and a
singlet at −75 ppm. In addition, the 31P NMR spectrum of 5
3
shows an apparent quintet at 57 ppm (2JP−P ≈ JP−F ≈ 26 Hz)
and a quartet of doublets at 44 ppm (3JP−F = 66 Hz and 2JP−P
27 Hz) in a 1:1 integral ratio. The observed multiplicities and
coupling constants are characteristic of square-planar cis-
bis(phosphine) Pd−CF3 adducts.20
As discussed above, we hypothesize that phosphine
dissociation is required for CO deinsertion to occur efficiently
at these PdII complexes. Consistent with this proposal, the
addition of 3 equiv of exogeneous P(o-Tol)3 greatly inhibited
decarbonylation at 3. For example, after benzene solutions of 3
were refluxed for 3 h in the presence of 3 equiv of P(o-Tol)3,
the starting material (3) could be recovered in 63% yield.
In addition, complex 6, which contains smaller PPh3 ligands,
undergoes decarbonylation at a much slower rate than 3 (eq 5).
=
facile process for PdII complexes (eq 2).18 However, the
pathway depicted in eq 2 requires pre-equilibrium dissociation
of a spectator ligand (L), which could potentially become the
limiting step of the overall transformation.
We envisioned that the use of a labile monodentate
supporting ligand (L) should lead to a high equilibrium
concentration of a coordinatively unsaturated tricoordinate PdII
intermediate and thus accelerate the rate of decarbonylation via
the pathway shown in eq 2. On the basis of this reasoning, our
initial investigations focused on complexes bearing the sterically
bulky ligand P(o-Tol)3. The treatment of Pd[P(o-Tol)3]2 with
trifluoroacetic anhydride in THF at room temperature afforded
the PdII oxidative addition product 3 in 91% isolated yield (eq
For instance, heating 6 to 85 °C for 3 h resulted in only ∼30%
conversion to the decarbonylated product 7, as detected by
NMR analysis of the crude reaction mixture.21 The slower rate
of decarbonylation from 6 versus 3 is proposed to be due to the
smaller size of PPh3 versus P(o-Tol)3, which renders the former
ligand significantly less labile.
3). Isolated samples of 3 were analytically pure; however, the
19F and 31P NMR spectra of this complex appear broad at room
temperature, likely due to reversible dissociation of the
phosphine ligand and/or conformational dynamics of bulky
ligands around the sterically congested Pd center.
We next examined the scope of perfluoroalkyl (RF) groups
that can participate in decarbonylation at palladium(II) P(o-
Tol)3 complexes. A series of PdII(RF)(OC(O)RF) complexes
were prepared via a one-pot procedure involving (1) reaction of
Pd0[P(o-Tol)3]2 with the corresponding carboxylic anhydride at
room temperature for 20 min, (2) removal of solvent and
dissolution of the crude [P(o-Tol)3]2Pd(C(O)RF)(OC(O)RF)
in benzene, and (3) heating the resulting benzene solution to
reflux for 30 min. Finally, to facilitate purification and
characterization, the in situ generated [P(o-Tol)3]2Pd(RF)-
(OC(O)RF) complexes were reacted with dppe to form the
more stable bidentate phosphine adducts (Table 1).22 This
procedure worked well to provide the perfluoroethyl and
perfluoropropyl derivatives 8 and 9 in 87% and 50% isolated
yields, respectively. In addition, the difluoromethyl complex 11
was prepared via a slight modification of the standard
procedure. In this case, substitution of the carboxylate ligand
of (dppe)Pd(CF2H)(OC(O)CF2H) (10) for chloride (via
reaction of 10 with NaCl) was necessary to obtain a stable
product. In contrast, cyclic fluorinated anhydrides provided
poor results. Product 13 was obtained in only 16% isolated
yield; furthermore, attempts to prepare 12 under our standard
conditions yielded no detectable product.
Decarbonylation at complex 3 was next investigated.
Consistent with our hypothesis, this transformation proceeded
to form PdII trifluoromethyl complex 4 quantitatively within
just 30 min in refluxing benzene (eq 3). For comparison, the
corresponding Ruphos complex (RuPhos)Pd(C(O)CF3)(OC-
(O)CF3) underwent significantly slower decarbonylation (i.e.,
the reaction took 1.5 h to reach completion under analogous
conditions).5 Analytically pure samples of 4 were isolated in
67% yield by recrystallization from diisopropyl ether. The
room-temperature 19F and 31P NMR spectra of 4 show broad
resonances. A VT-NMR study of complex 4 revealed that both
ligand dissociation and conformational dynamics contribute to
the broadness of NMR spectra at room temperature. At −50
°C, several previously broad resonances in the 19F NMR
spectrum resolved into sharp triplets, while other broad
resonances resolved into doublets. We assign the triplets in
the 19F NMR spectrum to conformational isomers of the bis-
phosphine complex 4, while the doublets are assigned to the
corresponding monophosphine species. The ligand dissociation
is also supported by the fact that a signal for free P(o-Tol)3 is
observed in the 31P{1H} NMR spectrum of 4 at both 25 and
−50 °C.19
To facilitate complete NMR characterization, complex 4 was
treated with 1,2-bis(diphenylphosphino)ethane (dppe) (eq 4).
Ligand exchange proceeded within 5 min at room temperature
to afford complex 5 in 96% yield as an analytically pure
Accelerating CO Deinsertion via Substitution of PdII
for NiII. We next turned our attention to decarbonylation
reactions at analogous NiII fluoroacyl complexes. As detailed in
the Introduction, literature reports led us to hypothesize that
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within 1 min at room temperature (eq 6).24 Complex 15 was
Table 1. Perfluoroalkyl Palladium(II) Complexes Prepared
via Decarbonylation from [P(o-
Tol)3]2Pd(C(O)RF)(OC(O)RF)
characterized via 1D and 2D NMR spectroscopy. The
3
observation of JF−P coupling in both the 19F and 31P NMR
spectra of 15 strongly supports the proposed structure.
Specifically, the 19F NMR spectrum of 15 contains a doublet
of doublets at −29 ppm (3JF−P = 43 and 10 Hz) and a singlet at
−75 ppm in a 1:1 integral ratio. In addition, the 31P NMR
spectrum of 15 shows an apparent quintet at 45 ppm (2JP−P
≈
3JP−F ≈ 45 Hz) as well as a doublet of quartets at 56 ppm (2JP−P
3
= 46 Hz and JP−F = 10 Hz) in a 1:1 integral ratio.
We next investigated decarbonylation of other fluoroacyl
ligands at nickel(II) triphenylphosphine complexes. A con-
venient one-pot procedure was developed involving (1)
treatment of Ni(COD)2 with 2 equiv of PPh3, (2) addition
of the corresponding anhydride or acyl chloride, and (3)
trapping with dppe to facilitate purification and characterization
of the NiII perfluoroalkyl products.25 This approach proved
successful for the preparation of a series of NiII perfluoroalkyl
adducts (Table 2). For example, when higher analogues of
Table 2. Perfluoroalkyl Nickel(II) Complexes Prepared via
Decarbonylation from in Situ Generated
(PPh3)2Ni(C(O)RF)(X)
these transformations should be faster at a first-row transition-
metal center.12−16 Our initial experiments focused on PPh3 as a
simple and readily available supporting ligand for Ni. This
ligand also enabled straightforward comparison to the
analogous PPh3 palladium complex 6. The treatment of
Ni(COD)2 with 2 equiv of PPh3 followed by 1.5 equiv of
trifluoroacetic anhydride (TFAA) produced the decarbon-
ylation product 14 directly in 70% isolated yield (eq 6).
Importantly, the initial reaction temperature was −78 °C, and
the reaction mixture was warmed to 25 °C over 20 min. While
the exact temperature at which decarbonylation occurs has
proven difficult to pinpoint, these results clearly show that
decarbonylation at NiII proceeds rapidly at or below room
temperature. This represents a striking contrast to (and
improvement over) the corresponding palladium system,
complex 6. We hypothesize that this reaction is facile because
tetracoordinate NiII centers can easily expand their coordina-
tion number to 5.23 As such, decarbonylation should be able to
proceed without dissociation of a phosphine ligand. Consistent
with this proposal, exogenous phosphine does not appear to
inhibit decarbonylation in this system.
TFAA were used, the corresponding products 16 and 17 were
isolated in 48% and 52% yields, respectively. Cyclic carboxylic
anhydrides afforded 18 and 19 in 52% and 36% isolated yields.
Notably, the PdII analogue of 18 was not accessible via the
decarbonylation procedure above. Finally, the use of acid
chlorides in place of anhydrides afforded the corresponding NiII
perfluoroalkyl chloride complexes 20 and 21 in 47% and 65%
isolated yields. Importantly, for all of the complexes 16−21, the
moderate isolated yields are not due to the formation of side
products; instead, they are the result of material losses during
isolation and purification.
Reactivity of Fluoroalkyl Nickel and Palladium
Complexes with Transmetalating Reagents. The next
step of our proposed catalytic cycle for arene trifluoromethy-
lation involves transmetalation from an aryl organometallic
reagent.5 As such, we have also conducted preliminary
investigations to assess the viability of this transformation at
representative PdII and NiII perfluoroalkyl species. We first
probed the reaction of PdII trifluoromethyl complex 4 and NiII
trifluoromethyl complex 14 with phenyllithium, phenylmagne-
sium bromide, and diphenylzinc. As shown in eq 7, all of these
Complex 14 was characterized via NMR and IR spectroscopy
as well as by elemental analysis. The 19F NMR spectrum of 14
exhibits two characteristic resonances at −20 and −75 ppm in a
1:1 integral ratio, while the 31P NMR spectrum contains a
single resonance at 40 ppm. Peaks in both the 19F and 31P
3
NMR spectra of 14 are broad, and JF−P coupling is not
resolved in the temperature range from −55 to +25 °C. This
suggests that complex 14 is fluxional. The treatment of 14 with
1.05 equiv of 1,2-bis(diphenylphosphino)ethane (dppe)
resulted in rapid ligand exchange to afford 15 in 95% yield
C
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typically at or below room temperature. This is likely because
decarbonylation at nickel can proceed without ligand
dissociation via a pentacoordinate transition state. These
studies implicate Ni-based systems as highly attractive targets
for achieving catalytic decarbonylative trifluoromethylation
reactions.26 As such, current efforts in our group are focused
on strategies to achieve both transmetalation and aryl−CF3
bond-forming reductive elimination at Ni centers.
transformations afforded an inseparable mixture of inorganic
products, along with large amounts of biphenyl. It has been
reported previously that complexes of the general structure
(P)2M(CF3)(aryl) (M = Pd, Ni, (P)2 = bidentate phosphine)
decompose with concomitant release of the corresponding
biaryl.6,26 Thus, it is possible that the desired aryl nickel and
palladium species are generated in our transformation but then
undergo rapid decomposition.
We hypothesized that the bidentate dppe ligand would
stabilize the desired transmetalation products by limiting
disproportionative decomposition to form biphenyl. Indeed,
the treatment of dppe complexes 5, 8, and 9 with diphenylzinc
afforded the targeted (dppe)PdII(RF)(Ph) products 22−24 in
high isolated yields (eq 8). Complexes 22−24 are stable under
EXPERIMENTAL SECTION
■
General Procedures. All syntheses were conducted under
nitrogen unless otherwise stated. All reagents were purchased from
commercial sources and used as received. Pd[P(o-Tol)3]2 was
prepared via a literature procedure.29 Tetrahydrofuran, dichloro-
methane, and diethyl ether were purified using a solvent purification
system consisting of a copper catalyst, activated alumina, and
molecular sieves. 1H, 19F, and 13C chemical shifts are reported in
parts per million (ppm) relative to TMS, with the residual solvent peak
used as an internal reference. Elemental analyses were performed by
Atlantic Microlab, Inc.
Preparation of (P(o-Tol)3)2Pd(C(O)CF3)(OC(O)CF3) (3). A
Schlenk flask was charged with a stirbar and Pd[P(o-Tol)3]2 (4.00 g,
6.92 mmol). The flask was sealed, placed under vacuum, and then
refilled with nitrogen. The flask was evacuated and refilled with
nitrogen three more times. Dry THF (100 mL) was added via cannula.
Trifluoroacetic anhydride (TFAA; 1.13 mL, 8 mmol) was then added
dropwise over a period of 10 min. The resulting solution was stirred at
room temperature for 20 min and then filtered through a pad of Celite.
The volatiles were removed under reduced pressure. The residue was
suspended in diethyl ether (100 mL), and the product slowly
crystallized over a period of 4 h at room temperature. The crystals
were collected, washed with several portions of diethyl ether, and then
dried under vacuum. The product was obtained as a white solid (5.08
ambient conditions, and their structures were confirmed by
NMR spectroscopy and elemental analysis. Preliminary studies
suggest that these PdII complexes are unreactive toward aryl−
RF bond-forming reductive elimination, as would be expected
on the basis of Grushin’s prior studies of complex 22.27
Notably, the reaction of NiII dppe complex 15 with
diphenylzinc under analogous conditions afforded an insepa-
rable mixture of inorganic products.
We also found that dimethylzinc is an appropriate trans-
metalating reagent for PdII complex 5.28 Treatment of 5 with
Zn(CH3)2 in anhydrous THF resulted in the formation of air-
stable complex 26 in 80% isolated yield (eq 9).
1
g, 91% yield). Both H NMR spectroscopic analysis and elemental
analysis show the presence of 1 equiv of cocrystallized diethyl ether
that could not be removed even after prolonged drying under vacuum.
The cocrystallized diethyl ether was taken into account when the
1
reaction yield was calculated. The H, 19F, and 31P NMR spectra of 3
show very broad resonances. Additionally, the 31P NMR spectrum of 3
1
contains a singlet at −29.6 ppm, corresponding to free P(o-Tol)3. H
NMR (CDCl3 at 23 °C): δ 10.0−6.0 (br s, 24H), 4.0−1.0 (br s, 18H),
3.48 (q, J = 7.1 Hz, 4H, diethyl ether), 1.21 (t, J = 7.1 Hz, 6H, diethyl
ether). 19F NMR (CDCl3 at 23 °C): δ −73.2 (br, 3F), −74.8 (br, 3F).
31P{1H} NMR (CDCl3 at 23 °C): δ 20.5−6.7 (brs). IR (ATR, cm−1):
3058 (w), 2973 (m), 1700 (s), 1677 (s), 1590 (m), 1566 (m), 1444
(s), 1405 (s), 1381 (m), 1279 (m), 1231 (m), 1191 (s). Anal. Calcd
for PdC46H42F6O3P2·C2H5OC2H5: C, 60.10; H, 5.24; F, 11.41. Found:
C, 60.03; H, 5.32; F, 11.69.
Preparation of (P(o-Tol)3)2Pd(CF3)(OC(O)CF3) (4). (P(o-
Tol)3)2Pd(COCF3)(OCOCF3) (3; 2.50 g, 2.70 mmol) was dissolved
in benzene (150 mL), and the resulting solution was heated at reflux
for 1 h. The reaction mixture was then filtered through a pad of Celite,
and the volatiles were removed under reduced pressure. The residue
was then dissolved in diisopropyl ether (150 mL). This solution was
allowed to stand for 4 h, during which time the product crystallized.
The crystals were collected, washed with several portions of
diisopropyl ether, and dried under vacuum to afford 4 as a yellow
CONCLUSIONS
■
This report describes the synthesis and characterization of a
series of fluoroalkyl palladium and nickel complexes via
decarbonylation of the corresponding acylmetal species. At
PdII, the decarbonylation reaction is accelerated by the presence
of the sterically large ligand P(o-Tol)3. For example, complete
decarbonylative decomposition of [P(o-Tol)3]2Pd(C(O)CF3)-
(OCOCF3) was achieved within 30 min in refluxing benzene.
The rate of this reaction is much faster than that at PdII
complexes containing the smaller PPh3 ligand or the hemilabile
bidentate RuPhos ligand. The accessibility of three-coordinate
PdII intermediates via ligand dissociation is proposed to be
crucial for these transformations. In contrast, analogous NiII
complexes of the general structure (PPh3)2Ni(C(O)RF)-
(OCORF) decarbonylate under much milder conditions,
1
solid (1.82 g, 67% yield). Both H NMR spectroscopic analysis and
elemental analysis show the presence of 1 equiv of cocrystallized
diisopropyl ether that could not be removed even after prolonged
drying under vacuum. The cocrystallized diisopropyl ether was taken
1
into account when the reaction yield was calculated. The H, 19F, and
31P NMR spectra of 4 show very broad resonances. Additionally, the
31P NMR spectrum of 4 contains a singlet at −29.6 ppm,
corresponding to free P(o-Tol)3. NMR spectra for 4 are provided in
the Supporting Information. IR (ATR, cm−1): 3059 (w), 2968 (m),
2870 (w), 1698 (s), 1591 (m), 1566 (m), 1445 (s), 1405 (m), 1380
(m), 1281 (m), 1190 (s). FAB MS (m/z): [M − CF3COO]+ calcd for
D
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C43H42F3P2Pd 783.2, found 783.5. Anal. Calcd for PdC45H42F6O2P2·
C3H7OC3H7: C, 61.29; H, 5.65; F, 11.41. Found: C, 61.04; H, 5.34; F,
11.50.
with a stirbar and Pd[P(o-Tol)3]2 (2.00 g, 3.46 mmol). The flask was
sealed, placed under vacuum, and then refilled with nitrogen. The flask
was evacuated and refilled with nitrogen three more times. Dry THF
(100 mL) was added via cannula. The corresponding anhydride (5.0
mmol) was then added dropwise over a period of 5 min. The resulting
solution was stirred at room temperature for 20 min and was then
filtered through a pad of Celite. The volatiles were removed under
reduced pressure, and the resulting residue was taken up in benzene
(150 mL) and heated at reflux for ∼30 min, during which time the
color changed from yellow to deep red and then back to yellow. The
benzene solution was cooled to room temperature, and dppe (1.35 g,
3.4 mmol) was added. The reaction mixture was filtered through a pad
of Celite, and benzene was removed under reduced pressure. The
residue was dissolved in diisopropyl ether (100 mL), and the product
slowly crystallized over ∼4 h. The crystals were collected, washed with
several portions of diisopropyl ether, and dried under vacuum.
Samples for elemental analysis were generally recrystallized three
additional times from dichloromethane/diisopropyl ether.
Preparation of (dppe)Pd(CF3)(OC(O)CF3) (5). (P(o-Tol)3)2Pd-
(CF3)(OCOCF3)·C3H7OC3H7 (4; 250 mg, 0.25 mmol) and 1,2-
bis(diphenylphosphino)ethane (dppe; 115 mg, 0.29 mmol) were
dissolved in dichloromethane (7 mL). The reaction mixture was
stirred at room temperature for 5 min, and it was then filtered through
a pad of Celite. Diisopropyl ether was slowly added to the solution
until the product started to crystallize. The mixture was cooled to 5 °C
for 4 h, to promote crystallization. The crystalline product was then
collected, washed with several portions of diisopropyl ether, and dried
under reduced pressure to afford 5 as a white solid (154 mg, 90%
yield). Samples for elemental analysis were recrystallized an additional
three times from dichloromethane/diisopropyl ether. 1H NMR
(CD2Cl2 at 25 °C): δ 7.87−7.80 (m, 4H), 7.77−7.71 (m, 4H),
7.66−7.61 (m, m, 2H) 7.60−7.49 (m, 10H), 2.51−2.42 (m, 2H),
2.28−2.18 (m, 2H). 13C{1H} NMR (CD2Cl2 at 25 °C): δ 160.73 (q,
1
2
2JC−F = 36.1 Hz), 136.15 (qdd, JC−F = 381.47 Hz, JC−P = 215.9 and
Preparation of (dppe)Pd(C2F5)(OC(O)C2F5) (8). Complex 8 was
1
3
3
obtained via general procedure 1 (white solid, 1.92 g, 87% yield). H
8.9 Hz), 133.50 (d, JC−P = 11.6 Hz), 133.08 (d, JC−P = 11.6 Hz),
132.39 (d, 4JC−P = 2.7 Hz), 131.89 (d, 4JC−P = 2.7 Hz), 129.36−129.16
NMR (CD2Cl2 at 25 °C): δ 7.85−7.79 (m, 4H), 7.74−7.69 (m, 4H),
7.66−7.61 (m, 2H), 7.60−7.50 (m, 10H), 2.43−2.34 (m, 2H), 2.24−
2.14 (m, 2H). 13C{1H} NMR (CD2Cl2 at 25 °C; resonances of
fluoroalkyl groups are assigned from the 19F/13C HSQC spectrum): δ
1
1
(two overlapping d), 127.92 (d, JC−P = 40.9 Hz), 127.24 (d, JC−P
=
1
4
55.2 Hz), 116.22 (qd, JC−F = 290.9 Hz, JC−P = 7.5 Hz), 30.61 (dd,
1JC−P = 36.8 Hz, 2JC−P = 18.4 Hz), 23.66 (dd, 1JC−P = 30.0 Hz, 2JC−P
=
2
3
8.2 Hz). 19F NMR (CD2Cl2 at 25 °C): δ −26.6 (dd, 3JF−P = 66 and 27
160.85 (t, JC−F = 25.2 Hz), 133.62 (d, JC−P = 11.6 Hz), 133.28 (d,
3JC−P = 11.6 Hz), 132.31 (d, JC−P = 2.7 Hz), 131.88 (d, JC−P = 2.7
4
4
Hz, 3F), −74.6 (s, 3F). 31P{1H} NMR (CD2Cl2 at 25 °C): δ 56.6
2
3
3
Hz), 129.68 (m, Pd-CF2), 129.24−129.07 (two overlapping d), 127.67
(apparent quin, JP−P = JP−F = 26 Hz, 1P), 44.0 (qd, JP−F = 66 Hz,
2JP−P = 28 Hz, 1P). 19F/13C HSQC NMR (CD2Cl2 at 25 °C): δF/δC
−74.6/116.3 (peak corresponding to the Pd-CF3 group was not
observed in 19F/13C HSQC. However, the Pd-CF3 group was observed
1
1
(d, JC−P = 42.2 Hz), 127.27 (d, JC−P = 54.5 Hz), 121.15 (m, CF3),
1
2
118.50 (qt, JC−F = 286.1 Hz, JC−F = 35.4 Hz, CF3) 106.56 (m, CO-
CF2−), 30.48 (dd, 1JC−P = 36.1 Hz, 2JC−P = 17.7 Hz), 24.28 (dd, 1JC−P
= 29.3 Hz, 2JC−P = 8.9 Hz). 19F NMR (CD2Cl2 at 25 °C): δ −81.5 (s,
in 19F/13C HMBC as a J artifact). 19F/13C HMBC NMR (CD2Cl2 at
1
3
25 °C): δF/δC −26.6/136.3 (1J correlation), −74.6/116.4 (1J
correlation), −74.6/160.8. IR (ATR, cm−1): 3068 (w), 2976 (w),
1682 (s), 1486 (m), 1436 (s), 1418 (m), 1314 (m), 1182 (s), 1136
(s), 1082 (s). HRMS electrospray (m/z): [M − OCOCF3]+ calcd for
C27H24F3P2Pd 573.0335, found 573.0348; [M − CO2CF3 + CH3CN]+
calcd for C29H27F3NP2Pd 614.0600, found 614.0610. Anal. Calcd for
PdC29H24F6O2P2: C, 50.71; H, 3.52; F, 16.60. Found: C, 50.46; H,
3.59; F, 16.37.
3F), −83.5 (s, 3F), −96.6 (dd, JF−P = 40 and 32 Hz, 2F), −119.6 (s,
2F). 31P{1H} NMR (CD2Cl2 at 25 °C): δ 55.9 (td, 3JP−F = 32 Hz, 2JP−P
3
2
4
= 27 Hz, 1P), 44.1 (tdq, JP−F = 39 Hz, JP−P = 26 Hz, JP−F = 3 Hz,
1P). 19F/13C HSQC NMR (CD2Cl2 at 25 °C): δF/δC −81.6/121.2,
−83.6/118.5, −96.7/129.7, −119.7/106.6. 19F/13C HMBC NMR
(CD2Cl2 at 25 °C): δF/δC −81.6/121.2 (1J correlation), −81.6/129.7,
−83.6/106.6, −83.6/118.5 (1J correlation), −96.7/121.2, −119.7/
118.5, −119.7/160.9. IR (ATR, cm−1): 3066 (w), 1693 (s), 1485 (w),
1437 (s), 1386 (m), 1319 (s), 1300 (s), 1226 (m), 1150 (s), 1104 (s).
HRMS electrospray (m/z): [M − OCOC2F5]+ calcd for
Preparation of (PPh3)2Pd(C(O)CF3)(OC(O)CF3) (6). A Schlenk
flask was charged with a stirbar and (PPh3)4Pd (8.00 g, 6.92 mmol).
The flask was sealed, placed under vacuum, and then refilled with
nitrogen. The flask was evacuated and refilled with nitrogen three
more times. Dry THF (250 mL) was added via cannula. Trifluoro-
acetic anhydride (TFAA; 3.40 mL, 24.0 mmol) was then added
dropwise over a period of 10 min. The resulting solution was stirred at
room temperature for 20 min, and then the volatiles were removed
under reduced pressure. The resulting white crystalline residue was
suspended in EtOAc (100 mL), collected via filtration, washed with
several portions of EtOAc, and dried under vacuum to afford the
C28H24F5P2Pd 623.0303, found 623.0312; [M − CO2C2F5
+
CH3CN]+ calcd for C30H27F5NP2Pd 664.0568, found 664.0575.
Anal. Calcd for PdC31H24F10O2P2: C, 47.32; H, 3.07; F, 24.14.
Found: C, 47.08; H, 3.02; F, 24.05.
Preparation of (dppe)Pd(C3F7)(OC(O)C3F7) (9). Complex 9 was
1
obtained via general procedure 1 (white solid, 1.12 g, 50% yield). H
NMR (CDCl3 at 25 °C): δ 7.82−7.76 (m, 4H), 7.73−7.68 (m, 4H),
7.60−7.46 (m, 12H), 2.38−2.26 (m, 2H), 2.19−2.08 (m, 2H).
13C{1H} NMR (CDCl3 at 25 °C; resonances of fluoroalkyl groups are
assigned from the 19F/13C HSQC spectrum): δ 161.15 (t, 3JC−F = 25.9
1
product as a white solid (5.23 g, 90% yield). H NMR (CDCl3 at 25
3
Hz), 133.66 (d, JC−P = 12.3 Hz), 132.59 (m, Pd-CF2−), 133.27 (d,
°C): δ 7.64−7.58 (m, 12H), 7.49−7.44 (m, 6H), 7.44−7.38 (m, 12H).
4
4
3JC−P = 11.6 Hz), 132.25 (d, JC−P = 2.7 Hz), 131.88 (d, JC−P = 2.7
2
13C{1H} NMR (CDCl3 at 25 °C): δ 219.54 (q, JC−F = 38.2 Hz),
2
2
2
2
Hz), 129.26 (d, JC−P = 10.2 Hz), 129.14 (d, JC−P = 11.6 Hz),
127.70−127.27 (two overlapping d), 118.51 (m, −CF3), 117.85 (m,
−CF3), 110.87 (m, −CF2-), 108.47 (m, −CF2-), 108.41 (m, −CF2-),
30.20 (dd, JC−P = 36.1 Hz, JC−P = 17.7 Hz), 24.17 (dd, JC−P = 29.3
Hz, 2JC−P = 8.9 Hz). 19F NMR (CDCl3 at 25 °C): δ −80.3 (t, 3JF−F = 8
Hz, 3F), −80.8 (t, 3JF−F = 8 Hz, 3F), −93.3 (m, 2F), −116.5 (q, 3JF−F
= 10 Hz, 2F), −120.4 (s, 2F), −127.0 (s, 2F). 31P{1H} NMR (CDCl3
159.69 (q, JC−F = 36.2 Hz), 134.39 (t, JC−P = 6.9 Hz), 131.0 (two
overlapping t), 128.55 (t, 3JC−P = 4.9 Hz), 128.54 (t, 1JC−P = 23.5 Hz),
1
1
3
115.51 (q, JC−F = 291.5 Hz), 111.65 (qt, JC−F = 301.3 Hz, JC−P
=
1
2
1
16.6 Hz). 19F NMR (CDCl3 at 25 °C): δ −75.0 (s, 3F), −75.5 (s, 3F).
31P{1H} NMR (CDCl3 at 25 °C): δ 17.5 (s). 19F/13C HSQC NMR
(CDCl3 at 25 °C): δF/ δC −75.1/111.8, −75.6/115.7. 19F/13C HMBC
NMR (CDCl3 at 25 °C): δF/δC −75.0/219.5, −75.6/111.8 (1J
correlation), −75.5/159.7, −75.5/115.5 (1J correlation). IR (ATR,
cm−1): 3059 (w), 1752 (w), 1684 (s), 1665 (s), 1481 (s), 1436 (s),
1422 (s), 1229 (s), 1177 (s), 1136 (s), 1095 (s). FAB MS (m/z): [M
− CF3COO]+ calcd for C38H30F3OP2Pd, 727.1; found 727.5;
[(PPh3)2PdCF3]+ calcd for C37H30F3P2Pd, 699.1, found, 699.5. Anal.
Calcd for PdC40H30F6O3P2: C, 57.12; H, 3.60; F, 13.55, found C,
57.09; H, 3.70; F, 13.66.
2
3
at 25 °C): δ 55.9 (apparent q, JP−P = JP−F = 28 Hz, 1P), 44.1 (td,
3JP−F = 40 Hz, 2JP−P = 28 Hz, 1P). 19F/13C HSQC NMR (CDCl3 at 25
°C): δF/δC −80.4/118.5, −80.9/117.9, −93.4/132.6, −116.6/108.5,
−120.5/110.9, −127.1/108.4. 19F/13C HMBC NMR (CDCl3 at 25
°C): δF/δC −80.4/110.9, −80.9/108.5, −116.6/108.5, −116.6/161.5,
−120.5/110.9 (1J correlation), −120.5/118.5, −127.1/108.5, −127.1/
117.9. IR (ATR, cm−1): 3065 (w), 1494 (s), 1486 (m), 1438 (s), 1384
(m), 1331 (s), 1210 (s), 1175 (s). HRMS electrospray (m/z): [M −
OCOC3F7]+ calcd for C29H24F7P2Pd 673.0271, found 673.0278; [M −
General Procedure 1. Preparation of dppe-Supported
Perfluoroalkyl Palladium Complexes. A Schlenk flask was charged
E
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Organometallics
Article
CO2C3F7 + CH3CN]+ calcd for C31H27F7NP2Pd 714.0536, found
714.0540. Anal. Calcd for PdC33H24F14O2P2: C, 44.69; H, 2.73; F,
29.99. Found: C, 44.76; H, 2.74; F, 29.91.
1436 (s), 1374 (m), 1276 (m), 1222 (m), 1161 (s), 1104 (s), 1056
(s), 992 (s). HRMS electrospray (m/z): [M + H]+ calcd for
C30H25F6O2P2Pd 699.0263, found 699.0262.
Preparation of (PPh3)2Ni(CF3)(OC(O)CF3) (14). In a nitrogen-
filled glovebox, a Schlenk flask was charged with a stirbar,
triphenylphosphine (4.20 g, 16 mmol), and Ni(COD)2 (2.00 g, 7.27
mmol). The flask was sealed with a septum and then removed from
the glovebox. Dry THF (150 mL) was added via cannula, and the
resulting dark red mixture was stirred at 25 °C for 15 min. The
solution was then cooled to −78 °C, and trifluoroacetic anhydride
(TFAA) (1.70 mL, 12 mmol) was added dropwise. The solution was
slowly warmed to room temperature over ∼20 min, and volatiles were
then removed under reduced pressure via the side arm of the reaction
flask. Diethyl ether (200 mL) was added to the residue, and the
product precipitated in the form of yellow crystals. The product was
collected, washed with several portions of diethyl ether, and dried
under vacuum to afford 14 as a yellow crystalline powder (4.04 g, 70%
yield). 1H NMR (CDCl3 at 23 °C): δ 7.90−7.78 (m, 12H), 7.52−7.37
(m, 18H). 13C{H} NMR (CDCl3 at 23 °C): δ 160.11 (q, 2JC−F = 37.5
Hz), 134.39 (br s), 130.49 (br s), 130.07 (br s), 128.40 (br s), 123.28
Preparation of (dppe)Pd(CHF2)(Cl) (11). A Schlenk flask was
charged with a stirbar and Pd[P(o-Tol)3]2 (2.00 g, 3.46 mmol). The
flask was sealed, placed under vacuum, and then refilled with nitrogen.
The flask was evacuated and refilled with nitrogen three more times.
Dry THF (100 mL) was added via cannula. Difluoroacetic anhydride
(4.0 mmol, 0.89 mL) was then added dropwise over a period of 5 min.
The resulting solution was stirred at room temperature for 20 min and
then filtered through a pad of Celite. The volatiles were removed
under reduced pressure, and the residue was taken up in benzene (150
mL) and heated to reflux for 30 min, until the color of the solution
changed from yellow to deep red and then back to yellow. The
reaction mixture was cooled to room temperature, and then dppe
(1.35 g, 3.4 mmol) was added. The reaction mixture was filtered
through a pad of Celite, and the resulting benzene solution (containing
the difluoromethylcarboxylate intermediate 10) was stirred intensively
with an aqueous solution of brine for 3 h. The benzene layer was
separated from the brine, dried over anhydrous Na2SO4, and
concentrated under reduced pressure. The residue was dissolved in
methyl tert-butyl ether (150 mL), from which the product slowly
crystallized. The product was collected, washed with several portions
of MTBE, and dried under vacuum to afford the product as a white
solid (1.19 g, 72% yield). Samples for elemental analysis were
recrystallized several additional times from dichloromethane/MTBE.
1H NMR (CDCl3 at 25 °C): δ 7.90−7.79 (m, 4H), 7.75−7.65 (m,
4H), 7.55−7.35 (m, 12H), 6.85 (tdd, 2J(H−F) = 49.3 Hz, 3J(H−P) = 20.7
and 2.9 Hz, 1H), 2.51−2.33 (m, 2H), 2.22−2.06 (m, 2H). 13C{1H}
1
1
(br q, JC−F = 361.7 Hz), 113.88 (q, JC−F = 290.9 Hz). 19F NMR
(CDCl3 at 23 °C): δ −75.5 (s, 3F), −8.8 (br s, 3F). 31P{1H} NMR
(CDCl3 at 23 °C): δ 22.6 (br s). 19F/13C HSQC NMR (CDCl3 at 25
°C): δF/δC −9.0/123.3, −75.7/114.0. IR (ATR, cm−1): 3058 (w),
1675 (s), 1482 (s), 1434 (s), 1415 (s), 1190 (s). Anal. Calcd for
NiC39H30F6O2P2: C, 61.21; H, 3.95; F, 14.90. Found: C, 61.12; H,
3.95; F, 14.81.
Preparation of (dppe)Ni(CF3)(OC(O)CF3) (15). A 20 mL vial was
charged with (PPh3)2Ni(CF3)(OOCCF3) (14; 153 mg, 0.20 mmol),
1,2-bis(diphenylphosphino)ethane (dppe; 105 mg, 0.26 mmol), and
dry dichloromethane (10 mL). The resulting solution was stirred at 25
°C for 5 min, and then the reaction mixture was filtered through a pad
of Celite. The volatiles were removed under reduced pressure, and the
residue was dissolved in diisopropyl ether. The product slowly
separated in the form of yellow crystals. The product was collected,
washed with several portions of diisopropyl ether, and dried under
reduced pressure to afford 15 as a yellow solid (123 mg, 96% yield).
Samples for elemental analysis were recrystallized three additional
1
2
NMR (CDCl3 at 25 °C): δ 133.94 (tdd, JC−F = 304.5, JC−P = 177.1
3
3
and 19.1 Hz), 133.56 (d, JC−P = 12.3 Hz), 133.26 (d, JC−P = 11.6
Hz), 131.74 (d, 4JC−P = 2.1 Hz), 131.06 (d, 4JC−P = 2.1 Hz), 130.28 (d,
1JC−P = 34.1 Hz), 129.07 (d, 2JC−P = 10.2 Hz), 128.98 (d, 2JC−P = 10.9
Hz), 128.46 (d, JC−P = 50.4 Hz), 30.57 (dd, JC−P = 34.1 Hz, 2JC−P
=
1
1
20.4 Hz), 23.65 (dd, JC−P = 26.6 Hz, JC−P = 10.2 Hz). 19F NMR
1
2
2
3
(CDCl3 at 23 °C): δ −89.0 (apparent q, J(F−H) = J(F−P) = 48 Hz).
31P{1H} NMR (CDCl3 at 25 °C): δ 53.7 (td, 3JP−F = 49 Hz, 2JP−P = 35
3
2
Hz), 31.7 (td, JP−F = 53 Hz, JP−P = 35 Hz). 19F/13C HSQC NMR
(CDCl3 at 25 °C): δF/δC −89.1/133.8. IR (ATR, cm−1): 3053 (w),
2898 (w), 1572 (w), 1482 (m), 1434 (s), 1408 (s), 1310 (m), 1277
(m), 1242 (m), 1186 (m), 1102 (s), 1010 (s), 996 (s). HRMS
electrospray (m/z): [M − Cl]+ calcd for C27H25F2P2Pd: 555.0429,
found 555.0436. [M − Cl + CH3CN]+ calcd for C29H28F2NP2Pd
596.0694, found 596.0693; [M − CHF2]+ calcd for C26H24ClP2Pd
539.0071, found 539.0074. Anal. Calcd for PdC27H25ClF2P2: C, 54.84;
H, 4.26; Cl, 6.00; F, 6.43. Found: C, 54.95; H, 4.32; Cl, 5.94; F, 6.28.
Preparation of (dppe)Pd(CF2CF2CF2COO) (13). Complex 13
was obtained via general procedure 1 (white solid, 310 mg, 16% yield).
Methyl tert-butyl ether (MTBE) was used for crystallization instead of
diisopropyl ether. In order to remove cocrystallized solvent, the sample
1
times from dichloromethane/diisopropyl ether. H NMR (CD2Cl2 at
23 °C): δ 8.07−8.00 (m, 4H), 7.82−7.75 (m, 4H), 7.67−7.51 (m,
12H), 2.31−2.19 (m, 4H), 2.12−2.00 (m, 4H). 13C{1H} NMR
3
(CD2Cl2 at 23 °C): δ 160.73 (q, 2JC−F = 36.1 Hz), 133.48 (d, JC−P
=
=
1
2
2
10.9 Hz), 133.42 (qdd, JC−F = 234.3 Hz, JC−P = 137.6 Hz, JC−P
39.5 Hz multiplet partially overlaps with other nearby peaks), 133.07
(d, 3JC−P = 11.6 Hz), 132.05 (d, 4JC−P = 2.7 Hz), 131.82 (d, 4JC−P = 2.0
Hz), 129.24 (d, 2JC−P = 10.2 Hz), 129.14 (d, 2JC−P = 10.9 Hz), 127.84
1
1
1
(d, JC−P = 50.4 Hz), 127.00 (d, JC−P = 40.9 Hz), 114.94 (q, JC−F
=
1
2
290.2 Hz), 29.40 (dd, JC−P = 33.4 Hz, JC−P = 17.0 Hz), 22.28 (dd,
1JC−P = 30.0 Hz, JC−P = 7.9 Hz). 19F NMR (CD2Cl2 at 23 °C): δ
2
−29.0 (dd, JF−P = 43 and 10 Hz, 3F), −75.1 (s, 3F). 31P{1H} NMR
3
(CD2Cl2 at 23 °C): δ 56.5 (dq, 2JP−P = 46 Hz, 3JP−F = 11 Hz, 1P), 45.8
1
for elemental analysis was dried under vacuum at 90 °C for 8 h. H
(apparent quintet, JP−P = JP−F = 45 Hz, 1P). 19F/13C HSQC NMR
(CD2Cl2 at 25 °C): δF/δC −29.2/133.5, −75.2/115.0. 19F/13C HMBC
NMR (CD2Cl2 at 25 °C): δF/δC −75.1/160.7. IR (ATR, cm−1): 3054
(w), 1685 (s), 1573 (w), 1485 (m), 1436 (s), 1421 (s), 1313 (m),
1183 (s). Anal. Calcd for NiC29H24F6O2P2: C, 54.50; H, 3.78; F, 17.84.
Found: C, 54.53; H, 3.69; F, 17.97.
2
3
NMR (CD2Cl2 at 25 °C): δ 7.81−7.73 (m, 8H), 7.65−7.61 (m, 2H),
7.59−7.50 (m, 10H), 2.66−2.56 (m, 2H), 2.26−2.17 (m, 2H).
13C{1H} NMR (CD2Cl2 at 25 °C; resonances of fluoroalkyl partially
assigned from the 19F/13C HSQC spectrum): δ 164.01 (t, 2JC−F = 25.2
Hz), 133.60 (d, 3JC−P = 11.6 Hz), 132.76 (d, 3JC−P = 11.6 Hz), 132.56
(d, 4JC−P = 2.7 Hz), 131.92 (d, 4JC−P = 2.1 Hz), 129.48 (d, 2JC−P = 10.2
Hz), 129.25 (d, 2JC−P = 11.6 Hz), 128.30 (d, 1JC−P = 39.5 Hz), 128.15
General Procedure 2. Synthesis of dppe-Supported Per-
fluoroalkyl Nickel Complexes. In a nitrogen-filled glovebox, a
Schlenk flask was charged with triphenylphosphine (1.00 g, 3.81
mmol) and Ni(COD)2 (500 mg, 1.82 mmol). The flask was sealed
with a septum and then removed from the glovebox. Dry THF (50
mL) was added via cannula, and the resulting dark red mixture was
stirred at 25 °C for 15 min. The solution was then cooled to −78 °C,
and the corresponding carboxylic anhydride or carboxylic chloride (3
mmol) was added dropwise. The solution was slowly warmed to room
temperature over a period of 1 h, and then dppe (876 mg, 2.20 mmol)
was added. The resulting solution was stirred at room temperature for
5 min and then filtered through a pad of Celite. The volatiles were
removed under reduced pressure, and the resulting residue was
(m, −CF2−Pd), 126.39 (d, 1JC−P = 55.9 Hz), 113.08 (broad t, 1JC−F
=
1
2
265.7 Hz), 108.81 (tt, JC−F = 260.9 Hz, JC−F = 30.5 Hz), 31.09 (dd,
1JC−P = 36.8 Hz, 2JC−P = 18.4 Hz), 21.83 (dd, 1JC−P = 30.7 Hz, 2JC−P
=
8.2 Hz). 19F NMR (CD2Cl2 at 25 °C): δ −96.0 (m, 2F), −118.9 (m,
2F), −128.7 (br, 2F). 31P{1H} NMR (CD2Cl2 at 25 °C): δ 57.5 (td,
3JP−F = 41 Hz, 2JP−P = 32 Hz, 1P), 37.3 (m, 1P). 19F/13C HSQC NMR
(CD2Cl2 at 25 °C): δF/δC −96.0/128.2, −118.9/108.8, −128.7/113.1.
19F/13C HMBC NMR (CD2Cl2 at 25 °C): δF/δC −96.0/113.1, −96.0/
128.2 (1J correlation), −118.9/108.8 (1J correlation), −118.9/113.1,
−118.9/164.0, −128.7/108.8, −128.7/113.1 (1J correlation), −128.7/
128.2. IR (ATR, cm−1): 3058 (w), 2919 (w), 1680 (s), 1483 (m),
F
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suspended in diisopropyl ether (50 mL). The product separated in the
form of yellow crystalls. The product was collected, washed with
several portions of diisopropyl ether, and dried under reduced
pressure. Samples for elemental analysis were recrystallized three
additional times from dichloromethane/diisopropyl ether.
2JP−P = 3JP−F = 30 Hz, 1P). 19F/13C HSQC NMR (CD2Cl2 at 25 °C):
δF/δC −110.3/129.6, −120.0/110.8. 19F/13C HMBC NMR (CD2Cl2 at
25 °C): δF/δC −110.3/110.8, −110.3/129.6 (1J correlation), −110.3/
169.0−120.0/110.8 (1J correlation), −120.0/129.6, −120.0/169.0. IR
(ATR, cm−1): 3054 (w), 2956 (w), 1698 (s), 1619 (w), 1587 (w),
1483 (m), 1436 (m), 1351 (m), 1245 (s), 1137 (m), 1098 (s), 1038
(s). Anal. Calcd for NiC29H24F4O2P2: C, 57.94; H, 4.02; F, 12.64.
Found: C, 57.64; H, 4.02; F, 12.66.
Preparation of (dppe)Ni(C2F5)(OC(O)C2F5) (16). Product 16 was
prepared according to general procedure 2 (yellow solid, 640 mg, 48%
yield). 1H NMR (CD2Cl2 at 23 °C): δ 8.06−8.00 (m, 4H), 7.82−7.76
(m, 4H), 7.66−7.59 (m, 4H), 7.59−7.50 (m, 8H), 2.21−2.12 (m, 4H),
2.10−2.00 (m, 4H). 13C{1H} NMR (CD2Cl2 at 25 °C): δ 160.89 (t,
2JC−F = 26.0 Hz), 133.60 (d, 3JC−P = 10.2 Hz), 133.20 (d, 3JC−P = 10.9
Hz), 131.97 (d, 4JC−P = 2.7 Hz), 131.85 (d, 4JC−P = 2.0 Hz), 129.19 (d,
Preparation of (dppe)Ni(CF2CF2CF2COO) (19). Product 19 was
prepared according to general procedure 2 (yellow solid, 422 mg, 36%
yield). 1H NMR (CD2Cl2 at 25 °C): δ 7.96−7.90 (m, 4H), 7.86−7.80
(m, 4H), 7.66−7.61 (m, 2H), 7.61−7.57 (m, 2H), 7.57−7.51 (m, 8H),
2.46−2.36 (m, 2H), 2.06−1.96 (m, 2H). 13C{1H} NMR (CD2Cl2 at
25 °C; resonances of fluoroalkyl partially assigned from the 19F/13C
2
2JC−P = 10.2 Hz), 129.03 (d, JC−P = 10.9 Hz), 128.47 (m, Ni−CF2−
CF3 resonance not observed in 13C spectrum but shift extracted from
2
3
19F/13C HSQC and HMBC experiments), 127.62 (d, 1JC−P = 50.4 Hz),
HSQC spectrum): δ 163.72 (t, JC−F = 22.5 Hz), 133.47 (d, JC−P
=
3
4
1
1
2
10.9 Hz), 132.88 (d, JC−P = 10.2 Hz), 132.21 (d, JC−P = 2.0 Hz),
126.67 (d, JC−P = 40.9 Hz), 120.63 (qtd, JC−F = 285.4 Hz, JC−F
=
4
2
32.0 Hz, 3JC−P = 8.2 Hz, Ni−CF2−CF3), 118.26 (qt, 1JC−F = 286.1 Hz,
131.75 (d, JC−P = 2.7 Hz), 129.35 (d, JC−P = 10.2 Hz), 129.17 (d,
2JC−P = 10.9 Hz), 127.97 (d, 1JC−P = 38.8 Hz), 126.87 (d, 1JC−P = 51.1
2JC−F = 35.4 Hz, CO−CF2−CF3), 105.49 (tq, JC−F = 263.0 Hz, JC−F
1
2
1
1
2
Hz), 126.75 (m, −CF2−Ni), 111.65 (br triplet, JC−F = 261.6 Hz),
= 38.1 Hz, CO−CF2−CF3), 28.98 (dd, JC−P = 35.4 Hz, JC−P = 16.4
107.79 (tt, 1JC−F = 260.2 Hz, 2JC−F = 28.6 Hz), 30.42 (dd, 1JC−P = 36.1
Hz), 22.30 (dd, JC−P = 30.0 Hz, JC−P = 8.9 Hz). 19F NMR (CD2Cl2
1
2
Hz, 2JC−P = 17.7 Hz), 21.23 (dd, 1JC−P = 30.7 Hz, 2JC−P = 8.2 Hz). 19
F
at 23 °C): δ −80.3 (s, 3F, Ni−CF2−CF3), −83.6 (br s, 3F, CO−CF2−
NMR (CD2Cl2 at 25 °C): δ −100.8 (t, 2JF−P = 32 Hz, 2F), −120.4 (m,
2F), −130.0 (br, 2F). 31P{1H} NMR (CD2Cl2 at 25 °C): δ 58.3 (dt,
2JP−P = 44 Hz, 3JP−F = 33 Hz, 1P), 38.2 (m, 1P). 19F/13C HSQC NMR
(CD2Cl2 at 25 °C): δF/δC −100.8/126.8, −120.4/107.8, −130.0/
111.7. 19F/13C HMBC NMR (CD2Cl2 at 25 °C): δF/δC −100.8/111.7,
−120.4/107.8 (1J correlation), −120.4/111.7, −120.4/163.8, −130.0/
111.7 (1J correlation), −130.0/126.8. IR (ATR, cm−1): 3064 (w), 2956
(w), 2918 (w), 1687 (s), 1482 (m), 1434 (m), 1379 (m), 1288 (m),
1221 (m), 1164 (s), 1102 (s), 1052 (s). Anal. Calcd for
NiC30H24F6O2P2: C, 55.34; H, 3.72; F, 17.51. Found: C, 55.19; H,
3.70; F, 17.25.
3
CF3), −102.1 (br t, JF−P = 25 Hz, 2F, Ni−CF2−CF3), −119.8 (br s,
2F, CO−CF2−CF3). 31P{1H} NMR (CD2Cl2 at 23 °C): δ 54.9 (dt,
2JP−P = 49 Hz, 3JP−F = 26 Hz), 45.3 (dt, 2JP−P = 49 Hz, 3JP−F = 28 Hz).
19F/13C HSQC NMR (CD2Cl2 at 25 °C): δF/ δC −80.4/120.7, −83.7/
118.5, −102.3/128.5, −119.9/105.6. 19F/13C HMBC NMR (CD2Cl2
at 25 °C): δF/δC −80.3/128.4, −80.3/120.8 (1J correlation), −83.6/
105.4, −83.6/118.3 (1J correlation), −102.1/120.7, −119.8/105.4 (1J
correlation), −119.8/118.3, −119.8/161.0. IR (ATR, cm−1): 1696 (s),
1485 (w), 1439 (s), 1393 (m), 1319 (s), 1296 (s), 1225 (m), 1154 (s).
Anal. Calcd for NiC31H24F10O2P2: C, 50.37; H, 3.27; F, 25.70. Found:
C, 50.23; H, 3.32; F, 25.76.
Preparation of (dppe)Ni(C3F7)(Cl) (20). Product 20 was
prepared according to general procedure 2 (yellow solid, 570 mg,
47% yield). This compound slowly decomposes in solution. The
analytical sample contained an unidentified decomposition product of
general formula (dppe)NiX2 (∼15% based on 31P NMR spectroscopy
analysis). All attempts to further purify the title complex resulted in
Preparation of (dppe)Ni(C3F7)(OCOC3F7) (17). Product 17 was
prepared according to general procedure 2 (yellow solid, 790 mg, 52%
1
yield). H NMR (CDCl3 at 23 °C): δ 8.06−7.97 (m, 4H), 7.80−7.74
(m, 4H), 7.60−7.43 (m, 12H), 2.17−2.07 (m, 2H), 2.06−1.96 (m,
2H). 13C{1H} NMR (CDCl3 at 23 °C; resonances of fluoroalkyl
groups are assigned from the 19F/13C HSQC spectrum): δ 161.06
(br), 133.65 (d, 3JC−P = 10.9 Hz), 133.18 (d, 3JC−P = 10.9 Hz), 131.87,
131.83, 131.09 (m, Ni-CF2−), 129.25 (d, 2JC−P = 10.2 Hz), 129.05 (d,
2JC−P = 10.9 Hz), 127.73 (d, 1JC−P = 50.4 Hz), 126.56 (d, 1JC−P = 40.2
Hz), 118.17 (m, −CF3), 117.81 (m, −CF3), 110.98 (m, −CF2−),
108.21 (m, −CF2−), 107.38 (m, −CF2−), 28.95 (dd, 1JC−P = 34.1 Hz,
1
extensive decomposition. H NMR (CDCl3 at 23 °C): δ 7.91−7.80
(m, 8H), 7.28−7.40 (m, 12H), 2.20−2.08 (m, 2H), 1.99−1.88 (m,
2H). 13C{H} NMR (CDCl3 at 23 °C): δ 133.72 (d, 3JC−P = 10.2 Hz),
133.81 (low intensity m that overlaps with nearby peaks; resonance
3
observed in 19F/13C HSQC spectrum), 133.51 (d, JC−P = 10.9 Hz),
131.71, 131.29, 128.92−128.61 (four overlapping d), 118.42 (qt, 1JC−F
1
2
2JC−P = 16.4 Hz), 22.32 (dd, JC−P = 29.3 Hz, JC−P = 8.9 Hz). 19F
NMR (CDCl3 at 23 °C): δ −80.5 (s, 3F), −80.8 (s, 3F), −98.4 (br,
2F), −116.9 (br, 2F), −118.3 (s, 2F), −127.1 (s, 2F). 31P{1H} NMR
(CDCl3 at 25 °C): δ 54.2 (dt, 2JP−P = 44 Hz, 3JP−F = 25 Hz, 1P), 44.3
(dt, 2JP−P = 44 Hz, 3JP−F = 29 Hz, 1P). 19F/13C HSQC NMR (CDCl3
at 25 °C): δF/δC −80.6/118.2, −80.9/117.8, −98.5/131.1, −117.0/
107.4, −118.4/111.0, −127.2/108.2. 19F/13C HMBC NMR (CDCl3 at
25 °C): δF/δC −80.5/111.0, −80.8/108.2, −118.3/111.2 (1J
correlation), −118.3/118.1, −127.1/107.6, −127.1/118.0. IR (ATR,
cm−1): 1698 (s), 1486 (w), 1437 (m), 1385 (w), 1330 (s), 1210 (s),
1174 (s), 1119 (s), 1078 (s). Anal. Calcd for NiC33H24F14O2P2: C,
47.23; H, 2.88; F, 31.70. Found: C, 47.37; H, 2.92; F, 31.70.
2
1
2
= 286.8 Hz, JC−F = 40.87 Hz), 111.62 (tq, JC−F = 256.8 Hz, JC−F
=
1
2
32.8 Hz), 29.66 (dd, JC−P = 34.7 Hz, JC−P = 18.4 Hz), 24.63 (dd,
1JC−P = 27.2 Hz, 2JC−P = 9.9 Hz). 19F NMR (CDCl3 at 23 °C): δ −80.4
(t, JF−F = 10 Hz, 3F), −89.9 (m, 2F), −115.3 (br s, 2F). 31P{1H}
3
NMR (CDCl3 at 25 °C): δ 60.4 (dt, 2JP−P = 49 Hz, 3JP−F = 35 Hz, 1P),
44.4 (dt, JP−P = 49 Hz, JP−F = 28 Hz, 1P). 19F/13C HSQC NMR
(CDCl3 at 25 °C): δF/δC −80.5/118.4, −90.0/133.8, −115.4/111.6.
19F/13C HMBC NMR (CDCl3 at 25 °C): δF/δC −80.4/111.7, −80.4/
118.6 (1J correlation). IR (ATR, cm−1): 3055 (w), 1485 (m), 1438 (s),
1326 (s), 1211 (s), 1188 (s). Anal. Calcd for NiC29H24ClF7P2: C,
52.65; H, 3.66; Cl, 5.36; F, 20.10. Found: C, 53.02; H, 3.81; Cl, 5.46;
F, 18.16.
2
3
Preparation of (dppe)Ni(CF2CF2CO2) (18). Product 18 was
prepared according to general procedure 2 (yellow solid, 572 mg, 52%
yield). 1H NMR (CD2Cl2 at 25 °C): δ 8.87−7.78 (m, 8H), 7.63−7.48
(m, 12H), 2.44−2.34 (m, 2H), 2.21−2.10 (m, 2H). 13C{1H} NMR
(CD2Cl2 at 25 °C; resonances of fluoroalkyl group partially assigned
Preparation of (dppe)Ni(C6F5)(Cl) (21). Product 21 was
prepared according to general procedure 2 (yellow solid, 775 mg,
1
65% yield). H NMR (CD2Cl2 at 23 °C): δ 7.97 (m, 4H), 7.68 (m,
4H), 7.60 (m, 2H), 7.57−7.52 (m, 6H), 7.41 (m, 4H), 2.44−2.32 (m,
2
from the 19F/13C HSQC spectrum): δ 168.98 (t, JC−F = 25.9 Hz),
2H), 2.11−1.98 (m, 2H). 13C{1H} NMR (CD2Cl2 at 23 °C): δ 145.89
3
3
1
3
1
133.24 (d, JC−P = 10.9 Hz), 132.73 (d, JC−P = 11.6 Hz), 132.03 (d,
(app dd, JC−F = 226.8 Hz, JC−P = 27.3 Hz), 138.19 (app d, JC−F
=
4JC−P = 2.7 Hz), 131.66 (d, JC−P = 2.1 Hz), 129.59 (m, Ni−CF2−),
4
240 Hz), 137.16 (app d, 1JC−F = 252 Hz), 133.62 (d, 3JC−P = 10.2 Hz),
3
4
2
2
132.95 (d, JC−P = 10.2 Hz), 131.81 (d, JC−P = 2.7 Hz), 131.81 (d,
129.41 (d, JC−P = 10.2 Hz), 129.16 (d, JC−P = 10.9 Hz), 128.46 (d,
4JC−P = 2.0 Hz), 129.15 (d, JC−P = 43.6 Hz), 128.90 (d, JC−P = 10.2
1
2
1JC−P = 38.2 Hz), 126.97 (d, 1JC−P = 41.8 Hz), 110.83 (tt, 1JC−F = 267.0
Hz) 128.67 (d, 2JC−P = 10.9 Hz), 128.63 (d, JC−P = 41.8 Hz), 123.37
1
2
1
2
Hz, JC−F = 21.8 Hz), 29.91 (dd, JC−P = 34.8 Hz, JC−P = 17.7 Hz),
21.93 (dd, 1JC−P = 30.7 Hz, 2JC−P = 8.9 Hz). 19F NMR (CD2Cl2 at 25
°C): δ −110.3 (m, 2F), −120.0 (br, 2F). 31P{1H} NMR (CD2Cl2 at 25
(m), 27.80 (dd, JC−P = 31.3 Hz, 2JC−P = 18.4 Hz), 22.94 (dd, JC−P
=
1
1
28.6 Hz, 2JC−P = 12.3 Hz). 19F NMR (CD2Cl2 at 23 °C): δ −118.6 (m,
°C): δ 59.1 (dt, JP−P = 29 Hz, 3JP−F = 20 Hz, 1P), 38.5 (app quartet,
2F), −161.7 (app t, JF−F = 20 Hz, 1F), −163.6 (m, 2F). 31P{1H}
2
3
G
dx.doi.org/10.1021/om500535x | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
NMR (CD2Cl2 at 23 °C): δ 61.6 (d, 2JP−P = 60 Hz), 48.0 (br d, 2JP−P
=
Calcd for PdC34H29F5P2: C, 58.26; H, 4.17; F, 13.55. Found: C, 58.22;
H, 4.15; F, 13.46.
52 Hz). 19F/13C HSQC NMR (CD2Cl2 at 25 °C): δF/ δC −118.6/
145.9, −162.7/137.0, −164.4/135.8. 19F/13C HMBC NMR (CD2Cl2
at 25 °C): δF/δC −118.6/123.4, −118.6/135.8, −118.6/137.0,
−162.6/135.8, −162.6/137.0 (1J correlation), −162.6/145.9,
−164.4/123.4, −164.4/135.8 (1J correlation), −164.4/137.0,
−164.4/145.9. IR (ATR): cm−1 3076 (w), 1495 (s), 1448 (s), 1435
(s), 1343 (m), 1102 (s).
Preparation of (dppe)Pd(C3F7)(Ph) (24). Product 24 was
prepared according to general procedure 3 (white solid, 485 mg,
92% yield). 1H NMR (CDCl3 at 25 °C): δ 7.77−7.72 (m, 4H), 7.52−
7.45 (m, 4H), 7.42 (t, J = 7.5 Hz, 2H), 7.33−7.25 (m, 10H), 7.17 (t, J
= 7.0 Hz, 2H), 6.75 (app t, J = 7.3 Hz, 2H), 6.72 (t, J = 6.9 Hz, 1H),
2.24−2.14 (m, 4H). 13C{1H} NMR (CDCl3 at 25 °C): δ 157.87 (app
dd, 2JC−P = 117.1 and 12.3 Hz), 139.31 (m, Pd-CF2−), 136.98, 133.38
General Procedure 3. Preparation of Complexes with
General Structure (dppe)Pd(RF)(Ph). In a glovebox, a Schlenk
flask was charged with a stirbar, diphenylzinc (120 mg, 0.55 mmol),
and the corresponding (dppe)Pd(RF)(OOCRF) complex (0.36
mmol). The flask was sealed and removed from the glovebox. Dry
THF (20 mL) was added via cannula. The resulting solution was
stirred at room temperature for 20 min, and then water (0.2 mL) was
introduced via the septum. The reaction mixture was stirred at room
temperature for an additional 20 min until Zn(OH)2 had completely
precipitated. The THF solution was dried over anhydrous Na2SO4,
and the volatiles were removed under reduced pressure. The residue
was crystallized from diethyl ether. The product was collected, washed
with several portions of diethyl ether, and dried under vacuum.
Samples for elemental analysis were recrystallized three additional
times from mixture of dichloromethane and diisopropyl ether.
Preparation of (dppe)Pd(CF3)(Ph) (22). Product 22 was
prepared according to general procedure 3 (white solid, 188 mg,
3
3
1
(d, JC−P = 12.3 Hz), 133.17 (d, JC−P = 10.9 Hz), 131.57 (d, JC−P
=
32.7 Hz), 130.74 (two overlapping signals), 130.3 (d, 1JC−P = 42.9 Hz),
2
2
128.81 (d, JC−P = 9.5 Hz), 128.67 (d, JC−P = 7.5 Hz), 126.50 (d,
3JC−P = 7.5 Hz, Pd−C−CH), 121.99, 119.21 (qt, JC−F = 289.5 Hz,
1
2JC−F = 34.7 Hz, −CF3), 112.04 (tq, 1JC−F = 252.0 Hz, 2JC−F = 30.7 Hz,
1
2
−CF2CF3), 26.97 (dd, JC−P = 24.5 Hz, JC−P = 18.4 Hz), 26.42 (dd,
1JC−P = 25.2 Hz, JC−P = 15.7 Hz). 19F NMR (CDCl3 at 23 °C): δ
2
−79.7 (t, 3JF−F = 13 Hz, 3F), −87.6 (m, 2F), −118.3 (s, 2F). 31P{1H}
NMR (CDCl3 at 25 °C): δ 39.5−38.9 (two overlapping m). 19F/13C
HSQC NMR (CDCl3 at 25 °C): δF/δC −79.7/119.2, −87.6/139.3,
−118.3/112.0. 19F/13C HMBC NMR (CDCl3 at 25 °C): δF/δC
−79.7/112.0, −79.7/119.2 (1J correlation), −87.6/112.0, −118.3/
112.0 (1J correlation), −118.3/119.2. IR (ATR, cm−1): 3061 (w), 1566
(m), 1473 (m), 1436 (s), 1325 (s), 1213 (s), 1180 (s), 1142 (s), 1099
(m). HRMS electrospray (m/z): [M − Ph]+ calcd for C29H24F7P2Pd
673.0271, found 673.0283; [M − Ph + CH3CN]+ calcd for
C31H27F7NP2Pd 714.0536, found 714.0542. Anal. Calcd for
PdC35H29F7P2: C, 55.98; H, 3.89; F, 17.71. Found: C, 55.86; H,
3.89; F, 17.90.
Preparation of (dppe)Pd(CF3)(CH3) (26). A Schlenk flask was
charged with a stirbar and (dppe)Pd(CF3)(OOCCF3) (300 mg, 0.44
mmol). The flask was sealed, placed under vacuum, and then refilled
with nitrogen. The flask was evacuated and refilled with nitrogen three
more times. Dry THF (15 mL) was added via cannula followed by
dimethylzinc (1 mL of 1.2 M solution in THF). The resulting solution
was stirred at room temperature for 20 min, and then water (0.2 mL)
was introduced via the septum. The reaction mixture was stirred at
room temperature for an additional 20 min until Zn(OH)2 had
completely precipitated. The THF solution was dried over anhydrous
Na2SO4, and the volatiles were removed under reduced pressure. The
residue was recrystallized from diethyl ether. The product was
collected, washed with several portions of diethyl ether, and dried
under vacuum. The product was obtained as a white crystalline solid
(207 mg, 80% yield). Samples for elemental analysis were recrystal-
lized several additional times from dichloromethane/diisopropyl ether.
1H NMR (CDCl3 at 25 °C): δ 7.71−7.65 (m, 4H), 7.62−7.57 (m,
4H), 7.49−7.38 (m, 12H), 2.34−2.24 (m, 2H), 2.21−2.12 (m, 2H),
0.59 (app t, 3JH−P = 6.6 Hz, 3H). 13C{1H} NMR (CDCl3 at 25 °C): δ
146.60 (qdd, 1JC−F = 374.7 Hz, 2JC−P = 201.0 and 15.6 Hz), 133.35 (d,
3JC−P = 11.6 Hz), 133.18 (d, 3JC−P = 12.9 Hz), 132.03 (d, 1JC−P = 31.3
Hz), 130.95 (d, 4JC−P = 2.1 Hz), 130.56 (d, 4JC−P = 1.4 Hz), 130.29 (d,
1
79% yield. H NMR (CDCl3 at 25 °C): δ 7.80−7.74 (m, 4H), 7.52−
7.44 (m, 4H), 7.43−7.38 (m, 2H), 7.33−7.26 (m, 10H), 7.20 (t, J =
6.9 Hz, 2H), 6.81 (app t, J = 6.9 Hz, 2H), 6.77 (t, J = 6.9 Hz, 1H),
2.34−2.16 (m, 4H). 13C{1H} NMR (CDCl3 at 25 °C): δ 158.85 (app
d of quintets, 2JC−P = 112.4 Hz, 3JC−F = 2JC−P = 8.9 Hz), 143.63 (qdd,
1JC−F = 373.3 Hz, 2JC−P = 195.5 and 13.6 Hz), 136.70, 133.35−133.19
1
4
(two overlapping d), 131.43 (d, JC−P = 34.1 Hz), 130.83 (d, JC−P
=
4
1
2.1 Hz), 130.76 (d, JC−P = 2.1 Hz), 130.19 (d, JC−P = 41.5 Hz),
2
2
128.95 (d, JC−P = 9.5 Hz), 128.66 (d, JC−P = 10.2 Hz), 126.64 (d,
3JC−P = 7.5 Hz, Pd−C−CH), 122.34, 27.48 (dd, 1JC−P = 25.9 Hz, 2JC−P
= 18.4 Hz), 26.40 (dd, JC−P = 25.2 Hz, JC−P = 15.0 Hz). 19F NMR
1
2
3
(CDCl3 at 25 °C): δ −17.5 (dd, JF−P = 51 and 12 Hz, 3F). 31P{1H}
3
2
NMR (CDCl3 at 25 °C): δ 40.1 (qd, JP−F = 50 Hz, JP−P = 17 Hz),
3
38.3 (app quintet, JP−F
=
2JP−P = 18 Hz). 19F/13C HSQC NMR
(CDCl3 at 25 °C): δF/δC −17.6/143.7. 19F/13C HMBC NMR (CDCl3
at 25 °C): δF/δC −17.5/143.7 (1J correlation), −17.5/158.8. IR (ATR,
cm−1): 3052 (w), 1565 (m), 1470 (m), 1434 (s), 1308 (w), 1239 (m),
1103 (m), 1080 (s), 950 (s). HRMS electrospray (m/z): [M − Ph]+
calcd for C27H24F3P2Pd 573.0335, found 573.0343; [M − F]+ calcd for
C33H29F2P2Pd 631.0742, found 631.0747.
Preparation of (dppe)Pd(C2F5)(Ph) (23). Product 23 was
obtained according to general procedure 3 (white solid, 725 mg,
90% yield). 1H NMR (CDCl3 at 25 °C): δ 7.77−7.72 (m, 4H), 7.52−
7.45 (m, 4H), 7.41 (t, J = 7.2 Hz, 2H), 7.33−7.24 (m, 10H), 7.15 (t, J
= 7.0 Hz, 2H), 6.75 (app t, J = 7.3 Hz, 2H), 6.72 (t, J = 6.8 Hz, 1H),
2.24−2.14 (m, 4H). 13C{1H} NMR (CDCl3 at 25 °C): δ 158.22 (app
d, 2JC−P = 107.7 Hz), 136.93, 136.11 (m, Pd-CF2−), 133.35 (d, 3JC−P
=
3
1
12.3 Hz), 133.21 (d, JC−P = 11.6 Hz), 131.55 (d, JC−P = 33.4 Hz),
2
2
1JC−P = 40.2 Hz), 128.95 (d, JC−P = 9.5 Hz), 128.79 (d, JC−P = 9.5
4
4
130.77 (d, JC−P = 2.0 Hz), 130.73 (d, JC−P = 2.1 Hz), 130.24 (d,
Hz), 28.44 (dd, JC−P = 27.2 Hz, 2JC−P = 19.8 Hz), 27.38 (dd, 1JC−P
=
=
1
1JC−P = 42.2 Hz), 128.85 (d, 2JC−P = 10.2 Hz), 128.66 (d, 2JC−P = 10.2
25.2 Hz, 2JC−P = 15.7 Hz), 0.25 (ddq, 2JC−P = 89.2 and 8.9 Hz, 3JC−F
3
1
Hz), 126.50 (d, JC−P = 7.5 Hz, Pd−C−CH), 122.72 (qtd, JC−F
=
6.8 Hz). 19F NMR (CDCl3 at 25 °C): δ −19.3 (dd, 3JF−P = 53 and 18
Hz, 3F). 31P{1H} NMR (CDCl3 at 25 °C): δ 47.4 (qd, 3JP−F = 52 Hz,
2
3
284.8 Hz, JC−F = 30.0 Hz, JC−P = 9.5 Hz, -CF3), 122.02, 27.01 (dd,
1JC−P = 25.9 Hz, 2JC−P = 18.4 Hz), 26.60 (dd, 1JC−P = 25.9 Hz, 2JC−P
=
2JP−P = 16 Hz), 47.4 (app quintet, JP−F = JP−P = 17 Hz). 19F/13C
HSQC NMR (CDCl3 at 25 °C): δF/δC −19.4/146.8. 19F/13C HMBC
NMR (CDCl3 at 25 °C): δF/δC −19.3/0.3, −19.3/146.6 (1J
correlation). IR (ATR, cm−1): 3053 (w), 2955 (w), 2888(w), 1587
(w), 1573 (w), 1483 (m), 1435 (s), 1411 (m), 1309 (m), 1186 (m),
1158 (m), 1102 (m), 1074 (s). HRMS electrospray (m/z): [M −
CH3]+ calcd for C27H24F3P2Pd 573.0335, found 573.0342; [M − CH3
+ CH3CN]+ calcd for C29H27F3NP2Pd 614.0600, found 614.0603.
Anal. Calcd for PdC28H27F3P2: C, 57.11; H, 4.62; F, 9.68. Found: C,
56.04; H, 4.57; F, 9.81
3
2
15.0 Hz). 19F NMR (CDCl3 at 25 °C): δ −80.1 (s, 3F), −89.6 (dd,
3JF−P = 42 and 32 Hz, 2F). 31P{1H} NMR (CDCl3 at 25 °C): δ 39.6
(tdq, 3JP−F = 32 Hz, 2JP−P = 17 Hz, 4JP−F = 3 Hz, 1P), 38.9 (td, 3JP−F
=
41 Hz, JP−P = 17 Hz, 1P). 19F/13C HSQC NMR (CDCl3 at 25 °C):
δF/δC −80.1/122.7, −89.6/136.1. 19F/13C HMBC NMR (CDCl3 at 25
°C): δF/δC −80.1/122.7 (1J correlation), −80.1/136.1, −89.6/122.7.
IR (ATR, cm−1): 3055 (w), 1564 (m), 1472 (m), 1434 (s), 1292 (s),
1191 (s), 1145 (s), 1099 (m). HRMS electrospray (m/z): [M − Ph]+
calcd for C28H24F5P2Pd 623.0303, found 623.0314; [M − Ph +
CH3CN]+ calcd for C30H27F5NP2Pd 664.0568, found 664.0577. Anal.
2
H
dx.doi.org/10.1021/om500535x | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
Kurahashi, T.; Matsubara, S. J. Am. Chem. Soc. 2008, 130, 17226−
17227.
ASSOCIATED CONTENT
* Supporting Information
Figures giving spectroscopic data for all new compounds. This
material is available free of charge via the Internet at http://
pubs.acs.org.
■
S
(12) For reviews, see: (a) Brothers, P. J.; Roper, W. R. Chem. Rev.
1988, 88, 1293−1326. (b) Morrison, J. A. Adv. Inorg. Chem.
Radiochem. 1983, 27, 293−316.
(13) For the synthesis of first-row-metal trifluoromethyl complexes,
see: King, R. B. Acc. Chem. Res. 1970, 3, 417−427.
(14) For the synthesis of second-row-metal trifluoromethyl
complexes, see: Panthi, B. D.; Gipson, S. L.; Franken, A. Organo-
metallics 2010, 29, 5890−5896.
AUTHOR INFORMATION
Corresponding Author
*E-mail for M.S.S.: mssanfor@umich.edu.
Notes
■
(15) For the synthesis of iridium trifluoromethyl complexes, see:
(a) Brothers, P. J.; Burrell, A. K.; Clark, G. R.; Rickard, C. E. F.; Roper,
W. R. J. Organomet. Chem. 1990, 394, 615−642. (b) Blake, D. M.;
Shields, S.; Wyman, L. Inorg. Chem. 1974, 13, 1595−1600.
(16) For the synthesis of platinum trifluoromethyl complexes, see:
Bennett, M. A.; Chee, H.-K.; Robertson, G. B. Inorg. Chem. 1979, 18,
1061−1070.
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We thank the NSF (CHE-1111563) for support of this
research. AM is a Howard Hughes Medical Institute Interna-
tional Student Research Fellow.
(17) Cavell, K. J. Coord. Chem. Rev. 1996, 155, 209−243.
(18) (a) Shultz, C. S.; Ledford, J.; DeSimone, J. M.; Brookhart, M. J.
Am. Chem. Soc. 2000, 122, 6351−6356. (b) Rix, F. C.; Brookhart, M.;
White, P. S. J. Am. Chem. Soc. 1996, 118, 4746−4764.
(19) For a VT-NMR investigation of conformational dynamics in
fluoroalkyl palladium complexes, see: Hughes, R. P.; Overby, J. S.;
Williamson, A.; Lam, K.-C.; Concolino, T. E.; Rheingold, A. L.
Organometallics 2000, 19, 5190−5201.
(20) (a) Takemoto, S.; Grushin, V. V. J. Am. Chem. Soc. 2013, 135,
16837−16840. (b) Culkin, D. A.; Hartwig, J. F. Organometallics 2004,
23, 3398−3416.
(21) When heating was continued for 8 h total, both 6 and 7
underwent competing decomposition to a variety of side products.
This competing decomposition precluded the isolation of 7 in a pure
form.
(22) The volatiles were evaporated after the formation of the acyl
complex in order to remove excess anhydride and/or free acid that
could be generated in situ via hydrolysis of the anhydride. We found
that evaporation of volatiles after the first step increases the overall
yield. We also found that benzene is a better solvent for the
decarbonylation step. In THF, a significant amount of black precipitate
of elemental palladium formed during the reaction.
(23) (a) Macgregor, S. A.; Neave, G. W. Organometallics 2003, 22,
4547−4556. (b) De Angelis, F.; Sgamellotti, A. Organometallics 2002,
21, 2036−2040. (c) Shultz, C. S.; DeSimone, J. M.; Brookhart, M. J.
Am. Chem. Soc. 2001, 123, 9172−9173. (d) Dartiguenave, M.;
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Merbach, A. E. Inorg. Chem. 1978, 17, 3503−3512.
(24) Treatment of Ni(COD)2 with 1 equiv of dppe followed by
TFAA did not afford 15 but instead formed (dppe)Ni(OCOCF3)2.
(25) Acyl chlorides have been demonstrated to undergo oxidative
addition to Pt0 complexes. For example, see: Wicht, D. K.; Glueck, D.
S.; Liable-Sands, L. M.; Rheingold, A. L. Organometallics 1999, 18,
5130−5140.
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dx.doi.org/10.1021/om500535x | Organometallics XXXX, XXX, XXX−XXX