Stoichiometric and catalytic C-F bond activation by the trans-dihydride NHC complex [Ru(IEt2Me2)2-(PPh3)2H2] (IEt2Me2 = 1,3-diethyl-4,5-dimethylimidazol-2-ylidene)

Article abstract of DOI:10.1039/c5dt01996f

The room temperature reaction of C₆F₆ or C₆F₅H with [Ru(IEt₂Me₂)₂(PPh₃)₂H₂] (1; IEt₂Me₂ = 1,3-diethyl-4,5-dimethylimidazol-2-ylidene) generated a mixture of the trans-hydride fluoride complex [Ru(IEt₂Me₂)₂(PPh₃)₂HF] (2) and the bis-carbene pentafluorophenyl species [Ru(IEt₂Me₂)₂(PPh₃)(C₆F₅)H] (3). The formation of 3 resulted from C-H activation of C₆F₅H (formed from C₆F₆via stoichiometric hydrodefluorination), a process which could be reversed by working under 4 atm H₂. Upon heating 1 with C₆F₅H, the bis-phosphine derivative [Ru(IEt₂Me₂)(PPh₃)₂(C₆F₅)H] (4) was isolated. A more efficient route to 2 involved treatment of 1 with 0.33 eq. of TREAT-HF (Et₃N·3HF); excess reagent gave instead the [H₂F₃]^- salt (5) of the known cation [Ru(IEt₂Me₂)₂(PPh₃)₂H]⁺. Under catalytic conditions, 1 proved to be an active precursor for hydrodefluorination, converting C₆F₆ to a mixture of tri, di and monofluorobenzenes (TON = 37) at 363 K with 10 mol% 1 and Et₃SiH as the reductant.

Full text of DOI:10.1039/c5dt01996f

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Stoichiometric and catalytic C–F bond activation
by the trans-dihydride NHC complex [Ru(IEt Me ) -
2
2 2
Cite this: DOI: 10.1039/c5dt01996f
(
PPh ) H ] (IEt Me = 1,3-diethyl-4,5-dimethyl-
3
2 2
2
2
imidazol-2-ylidene)†
a
a
a
b
Mateusz K. Cybulski, Ian M. Riddlestone, Mary F. Mahon, Timothy J. Woodman
a
and Michael K. Whittlesey*
The room temperature reaction of C
,5-dimethylimidazol-2-ylidene) generated a mixture of the trans-hydride fluoride complex [Ru(IEt
Me (PPh HF] (2) and the bis-carbene pentafluorophenyl species [Ru(IEt Me (PPh )(C )H] (3). The
formation of 3 resulted from C–H activation of C H (formed from C via stoichiometric hydro-
defluorination), a process which could be reversed by working under 4 atm H . Upon heating 1 with
6 6 6 5 2 2 2 3 2 2 2 2
F or C F H with [Ru(IEt Me ) (PPh ) H ] (1; IEt Me = 1,3-diethyl-
4
2
-
2
)
2
)
3 2
2
2
)
2
3
6 5
F
6
F
5
6 6
F
2
C
6
F
5
H, the bis-phosphine derivative [Ru(IEt
2
Me
2
)(PPh
3
)
2
(C
6
F
5
)H] (4) was isolated. A more efficient route to
−
Received 27th May 2015,
Accepted 8th July 2015
3 2 3
2 involved treatment of 1 with 0.33 eq. of TREAT-HF (Et N·3HF); excess reagent gave instead the [H F ]
+
salt (5) of the known cation [Ru(IEt
precursor for hydrodefluorination, converting C
= 37) at 363 K with 10 mol% 1 and Et SiH as the reductant.
2
2
Me )
2
(PPh
3
)
2
H] . Under catalytic conditions, 1 proved to be an active
DOI: 10.1039/c5dt01996f
6 6
F
to a mixture of tri, di and monofluorobenzenes (TON
www.rsc.org/dalton
3
NHC species containing increasingly more nucleophilic Ru–H
ligands. Very recently, we reported an example of such a
Introduction
Recent years have witnessed increasing evidence for the valu- species in the form of the mixed carbene-phosphine complex
able role of N-heterocyclic carbenes (NHCs) and their deriva- [Ru(IEt Me (PPh ] (1; IEt Me = 1,3-diethyl-4,5-dimethyl-
tives in catalytic transformations involving organofluorine imidazol-2-ylidene). The unusual trans-arrangement of the
2
2
)
2
3
)
2
H
2
2
2
1
4
1
substrates.
Thus, organocarbene catalysts have been two hydride ligands imparts highly nucleophilic character to
2
,3
employed for the formation of both C–F and C–CF
3
bonds,
2
Ru–H, as evidenced by the formation of methane and [Ru(IEt -
as well as enantioselective transformations of fluorine contain- Me ) (PPh ) HI] upon addition of the electrophile MeI. We
2
2
3 2
4
ing substrates. Transition metal NHC complexes have also now report our initial findings on both the stoichiometric and
been employed for C–F bond formation through catalytic reactivity of 1 towards aromatic fluorocarbons. As
5
–7
hydrofluorination, but have perhaps received more attention hoped for, the complex displays high activity for the catalytic
in processes in which C–F bonds are broken (Scheme 1), either HDF of C F , undergoing up to five HDF steps in generating
6
6
8
through cross-coupling or, of particular relevance to the work fluorobenzene.
9
–11
reported in this manuscript, hydrodefluorination (HDF).
Prompted by our studies over a number of years on catalytic
HDF of fluoroaromatic substrates using ruthenium NHC
hydride precursors and the elucidation by DFT calculations of
Results and discussion
Stoichiometric C–F and C–H activation of C F and C F H by 1
1
0–13
6
6
6 5
a mechanism involving nucleophilic hydride attack,
we
3
1
1
have set out to investigate the catalytic effectiveness of Ru Monitoring by P{ H} NMR spectroscopy the room tempera-
ture reaction of [Ru(IEt Me (PPh ] (1) with 10 eq. of
either C6F6 or C F H in C H solution showed, over the
2
2
)
2
3 2 2
) H
1
5
6
5
6
6
a
Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.
course of ca. 5 h, complete loss of starting material and the
appearance of two new product peaks at δ 45 and 59. These
were assigned to the hydride fluoride complex [Ru(IEt2-
E-mail: m.k.whittlesey@bath.ac.uk
b
Department of Pharmacy and Pharmacology, University of Bath, Claverton Down,
Bath BA2 7AY, UK
Me
IEt
2
)
2
(PPh
3
)
2
HF] (2) and the pentafluorophenyl complex [Ru
)(C )H] (3) respectively (Scheme 2). The for-
†
Electronic supplementary information (ESI) available. CCDC 1400863–1400866.
For ESI and crystallographic data in CIF or other electronic format see DOI:
0.1039/c5dt01996f
(
2
Me (PPh
2
)
2
3
6 5
F
1
mation of the two products, which were present after 5 h in an
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Scheme 1
Scheme 2
3
1
1
approximate ratio (by P{ H} NMR spectroscopy) of 1 : 0.2
from C and 1 : 0.5 from C H, arise from competing C–F
6
F
6
6 5
F
and C–H activation respectively. C–H activation proved to be
reversible. Thus, addition of H (4 atm) to an in situ generated
2
mixture of 2, 3 and PPh
3
led to the complete disappearance of
3
over 4 h at room temperature. In a more controlled experi-
ment, addition of 4 atm H to a solution containing an iso-
2
lated, crystalline sample of 3 (vide infra) and an equivalent of
PPh led to the complete conversion of the former to a mixture
3
of 1 and 2 within 4 h at 298 K. Generation of the latter could
1
19
be rationalised following analysis of the H and F NMR
spectra of the volatile materials from the C F reaction. This
6
6
revealed the presence of the hydrodefluorination products
H (major species) and both 1,2,3,4- and 1,2,4,5-C
C
6
F
5
6 4 2
F H ,
indicating that 1 must initially activate the C–F bond in C6F6
to give 2 and C F H, which then proved to be at least as reac-
6
5
6 6
tive a substrate as C F , undergoing C–F activation to give the
tetrafluorobenzene isomers (and additional 2), as well as C–H
activation to produce 3. The competitive nature of C–H acti-
vation is clearly shown by the higher ratio of 3 : 2 formed in
Fig. 1 Molecular structure of 2. Solvent, minor disordered component
and hydrogen atoms (with the exception of the hydride ligand) have
been omitted for clarity. Ellipsoids are shown at the 30% probability
level. Selected bond lengths (Å) and angles (°): Ru(1)–C(1) 2.115(2), Ru
1
6
the reaction of 1 with C F H.
6
5
Both 2 and 3 could be isolated from the reaction mixture
following removal of the volatile components and recrystalliza-
tion of the residue. The X-ray structure of 2 (Fig. 1) revealed
retention of the cis arrangement of the two NHC ligands and
(
1)–C(10) 2.109(2), Ru(1)–P(1) 2.3343(6), Ru(1)–P(2) 2.3493(6), Ru(1)–F(1)
.264(2), P(1)–Ru(1)–P(2) 98.66(2), C(1)–Ru(1)–P(1) 170.54(6), C(10)–Ru
1)–F(1) 91.64(8).
2
(
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3
two PPh groups from 1 and, as a result, very little change in
either Ru–C/Ru–P distances and angles. Of particular interest
was the long Ru–F distance of 2.264(2) Å. This is comparable
2
to the value (2.284(5) Å) in [Ru(dmpe) H(FHF)] (dmpe = 1,2-
bis(dimethylphosphino)ethane), which is the only other trans
H–Ru–F complex we could find that has been structurally veri-
1
7
fied. Surprisingly, crystallographically characterised examples
of Ru(L) H(halide) (L = PR or NHC) species with trans H–Ru–
4
3
1
8
halide geometries in general are not that common, despite
complexes of this type being known for over 50 years. Elonga-
1
9
tion in the Ru-F distance in both 2 and [Ru(dmpe) H(FHF)]
2
compared to those in cis-[Ru(dppp)
(
2
F
2
] (dppp = 1,4-bis-
diphenylphosphino)ethane) and trans-[Ru(dppe) ] (dppe =
,2-bis(diphenylphosphino)ethane) (2.056(3)/2.069(3) and
2 2
F
1
2
2
0
.1729(18) Å respectively) presumably results from the pres-
ence of a trans-labilising hydride ligand.
A very clear low frequency doublet of triplets Ru–H signal
1
was apparent for 2 in the room temperature H NMR spectrum
Fig. 2 Molecular structure of 3. All hydrogen atoms, except for Ru–H,
are omitted for clarity. Ellipsoids are shown at the 30% probability level.
Selected bond lengths (Å) and angles (°): Ru(1)–C(1) 2.090(3), Ru(1)–C
in toluene-d
8
at δ −21.7 (with diagnostic JHF and JHP values of
5
2.0 and 19.7 Hz respectively). The IEt Me signals were broad
2
2
and overlapping, but resolved upon cooling to 228 K into eight
sets of N–CH and four sets N–CH CH signals respectively.
The hydride signal at 228 K now appeared as a doublet
of doublet of doublets (JHF = 51.6 Hz, JHP = 25.6 Hz, JHP
4.1 Hz), indicating that the two PPh ligands became in-
equivalent at low temperature. In line with this, the P{ H} (PPh
(
(
10) 2.088(3), Ru(1)–C(19) 2.136(4), Ru(1)–P(1) 2.2783(11), C(1)–Ru(1)–C
10) 173.39(15), C(1)–Ru(1)–C(19) 88.43(14).
2
2
3
=
1
3
3
1
1
)
(C
F
5
)H] (4, Scheme 2) as the major ruthenium contain-
3
2
6
spectrum changed from a broad singlet at room temperature ing product of the reaction following overnight heating at
to what is best described as two very broad, overlapping multi- 343 K. It was found that 4 could also be formed at room temp-
plets spread over ca. 1 ppm at 228 K. We were unable to resolve erature, although very much as the minor partner alongside
1
9
J
PP or JPF splittings even at this low temperature. The F NMR 2 and 3 if a sample of 1 and C
spectrum showed a broad fluoride resonance at δ −354 in both temperature for ca. 100 h (ratio 2 : 3 : 4 = 1 : 0.4 : 0.1). Heating
THF-d8 and toluene-d8 at room temperature, although the an isolated sample of 3 with PPh (2 eq.) at 343–363 K in C H
6 6
6 6
F (10 eq.) was left at room
3
2
2
doublet hydride splitting of ca. 52 Hz was partially resolved in for 5 h failed to give 4, implying (unsurprisingly) that simple
the THF case. Altering the temperature over the range substitution of NHC by phosphine does not account for the
2
48–318 K failed to resolve any further couplings, while the formation of 4.
2
1
addition of CsF also made no effect.
Crystals of the red compound 4 suitable for X-ray crystallo-
The X-ray structure of the second product, the bis-IEt
2
Me
2
graphy were isolated from benzene/hexane and displayed the
pentafluorophenyl complex [Ru(IEt Me ) (PPh )(C F )H] (3), structure shown in Fig. 3. Most noticeable was the distorted
2
2 2
3
6 5
revealed the anticipated square based pyramidal geometry, octahedral geometry now present that resulted from an agostic
with the hydride trans to the vacant site (Fig. 2). The two car- interaction involving one of the NHC-Et groups occupying the
benes were now oriented trans to one another, forcing the site opposite the Ru–H. The need for the agostic stabilisation
PPh
i) the nature of the trans ligand and (ii) the coordinative un- species upon replacing the strongly donating IEt
saturation of the metal centre impacted upon the Ru-Cfluoroaryl in 3 for PPh in forming 4. The agostic distances (Ru⋯C(5),
bond length, which was shorter (2.136(4) Å) than that found in 2.752 Å; Ru⋯H(5A), 2.052 Å) lie in between those in the related
3
and fluoroaryl ring also to be trans. The combination of must reflect the instability of the five-coordinate 16e Ru(II)
Me ligand
(
2
2
3
1
1,12
i
i
related systems.
The positioning of the hydride opposite a vacant site (PPh )
3 2
NHC complexes [Ru(I Pr
2 2 2 2 2 2 2
Me ) (I Pr Me )′Cl] and [Ru(IEt Me )-
2
3
HCl] previously described by our group and are
reflected in the solution spectroscopic properties of the com- within the range considered to be strong interactions. The
2
4
pound, in particular, the very low frequency hydride chemical Ru–C distance to the pentafluorophenyl ligand was 2.160(2) Å.
shift of δ −33.0. This appeared as a doublet of triplets, with
Evidence for the agostic interaction being retained in solu-
a typical cis- P doublet splitting of 30.6 Hz, and a triplet tion was apparent from small, but very clear, doublet F split-
3
1
19
splitting of 7.2 Hz arising from interaction with the two ortho- tings on low frequency resonances for Ru⋯H–C at δ 0.5 and
1
13
1
fluorine atoms of the C F ring.
δ 6.4 in the H and C{ H} NMR spectra respectively. Use of
6
5
1
19
Efforts to accelerate the reaction of 1 with C
6
F
5
H using
H- F HMBC spectroscopy established that the coupling
higher temperatures resulted instead in the isolation of resulted from the ortho-F signal at δ −112 (see ESI†). The
the bis-phosphine pentafluorophenyl complex [Ru(IEt Me )- hydride resonance in 4 (δ −24.7) resonated to higher frequency
2
2
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precise 1 : 1 ratio (i.e. 0.33 eq. TREAT-HF). However, increasing
the stoichiometry to 1 : 3 Ru : HF gave instead the previously
+
14
reported cation [Ru(IEt
2 2 2 3 2
Me ) (PPh ) H] , which was shown
crystallographically to be formed as the relatively unusual
−
27
[
H F ] salt, 5 (see ESI†).
2 3
Catalytic HDF using 1
Initial catalytic studies have shown that 1 is far more active for
HDF than our previously reported [Ru(NHC)(PPh (CO)H
bearing unsaturated or saturated N-aryl substituted
carbenes. As shown in Scheme 4, this reacted via initial phos-
phine loss to give 16-electron [Ru(NHC)(PPh )(CO)H ], which
was converted to the hydride fluoride complex [Ru(NHC)-
PPh )(CO)HF] following hydrodefluorination. Back reaction
3
)
2
2
]
1
0,11
system
3
2
(
3
with the alkysilane reductant regenerated the dihydride
complex, forming a strong Si–F bond in R SiF in the process
which provides the driving force for the reaction.
3
Fig. 3 Molecular structure of 4. All hydrogen atoms, except Ru–H and
those in the agostic methyl group, are omitted. Ellipsoids are shown at
the 30% probability level. Selected bond lengths (Å) and angles (°): Ru
The mixture of C–F and C–H activation products formed in
(
6 6
1)–C(1) 2.060(2), Ru(1)–C(10) 2.160(2), Ru(1)–P(1) 2.3452(6), Ru(1)–P(2) the stoichiometric reaction of 1 and C F suggests that the first
2
.3188(6), P(1)–Ru(1)–P(2) 168.093(19), C(10)–Ru(1)–P(1) 91.56(6), C(1)– step of a comparable catalytic cycle with 1 might be more
Ru(1)–P(2) 89.41(6).
complex, and so the individual stoichiometric reactions of 2, 3
and 4 with Et SiH were investigated to establish the viability of
3
the return reduction steps necessary to complete the catalytic
cycle. It was found that: (i) Treatment of the hydride fluoride
of that in five-coordinate (non-agostic) 3, and appeared as
triplet of doublets, the doublet splitting now arising from
coupling to the other ortho-F signal at δ −106 (see ESI†). These
complex 2 with 1 eq. Et
3
SiH led to the instantaneous reforma-
tion of 1, along with Et SiF; (ii) There was no reaction between
3
couplings help to emphasise the restricted rotation of the C
6 5
F
3
3
and Et SiH (1.5 eq.) at room temperature over 6 h, or even
ring suggested by the steric crowding in the crystal structure
upon heating at 343 K for 4 h; (iii) No reaction occurred
between the bis-phosphine fluoroaryl complex 4 and silane
1
9
and proven by the presence of five different
F NMR
resonances.
(
1.5 eq.) at room temperature overnight, although following
addition of IEt Me (5 eq.), both C and Et SiF appeared
2
2
6
F
4
H
2
3
Formation of 2 via reaction of 1 with ‘HF’
1
9
very quickly in the F NMR spectrum. Over the course of
ca. 2 h, however, the sample began to decompose, shown by
the deposition of black solid material.
In an effort to find a higher yielding route to the hydride fluor-
ide complex 2, the reaction of 1 with Et N·3HF (TREAT-HF)
3
was investigated. This reagent has become quite commonplace
Fig. 4 shows the product distribution from the HDF of C6F6
−
for the formation of transition metal bifluoride ([FHF] ) com-
with 10 mol% 1 carried out with Et
3
SiH as reductant (80 eq.)
2
5
plexes, but has, on occasion, also produced metal fluoride
in C at 363 K. The elevated temperature was adopted in an
6
H
6
2
6
species. As shown in Scheme 3, 2 was formed as the sole
effort to both push catalysis through at a reasonable rate and
Ru containing product upon reaction of 1 with Et N·3HF in a
3
also to try to drive HDF through to lower fluorine containing
products, which are typically more difficult to obtain.
2
8
Remarkably, 1 proved capable of bringing about three and
four HDF steps to a significant extent, affording 96% of the
reaction mixture as isomers of tri- and difluorobenzenes over
2
9
7
2 h. Doubling the reaction time increased the amount of
,2- and 1,4-C and even generated a small amount of
1
6 2 4
F H
fluorobenzene through completion of five HDF steps, giving
an overall turnover number of 37. While an in-depth study of
the regioselectivity of HDF remains to be carried out, the pres-
ence of both 1,2,4,5- and 1,2,3,4-isomers of C
suggests that the very high ortho-regioselectivity found with
Ru(NHC)(PPh (CO)H ] (which converted C H overwhel-
mingly to 1,2,3,4-C ) is less apparent with 1. When HDF
of C F was repeated but now under 4 atm H , the amount of
6 4 2
F H after 72 h
[
3
)
2
2
6 5
F
6 4 2
F H
6
6
2
difluorobenzene products increased (TON = 38), while the rela-
tive ratio of the 1,2 : 1,3 : 1,4 difluorobenzene isomers also
altered. Interestingly, no turnover of the reaction between C6F6
Scheme 3
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Scheme 4
Fig. 4 Product distribution from the catalytic HDF of C
6
F
6
using 10 mol% 1 with 80 eq. Et
3
SiH in C
6
H
6
at 363 K. Reactions run under (top line) Ar (1
2
atm) and (bottom line) H (4 atm) with percentage of products (average of 3 runs) shown after 72 h and (in parentheses) 144 h. HDF products were
1
9
assigned by F NMR spectroscopy.
and 10 mol% 1 took place under 4 atm H /excess NEt
[Ru(IEt Me )(PPh ) (C F )H] (4) are observed, one possibility is
2 2 3 2 6 5
2
3
3
0
(80 equivalents) in the absence of the silane.
that such species are not dead-ends, but can be recycled into
the catalytic cycle, allowing propagation of HDF to continue.
While this may help to explain the bias towards more of the
lower fluorine containing products with a moderate pressure
Conclusions
of H
2
shown in Fig. 4, it fails to explain the change in isomer
In conclusion, we have shown that [Ru(IEt Me ) (PPh ) H
2 2 2 3 2 2
] (1) distribution. We hope to present answers to these questions in
is a far more active catalyst for the hydrodefluorination of C6F6 the near future.
than the previously reported [Ru(NHC)(PPh )(CO)H ] systems,
as reflected in the reduction of C down as far as fluoro-
3
2
6 6
F
benzene. Given the previous mechanistic studies on Ru–H cata-
lysed HDF, this enhanced activity most likely arises from the
greater nucleophilicity of the hydride ligands in 1, arising as a
Experimental
General considerations
result of their trans H–Ru–H geometry. A mechanistic study of All manipulations were carried out using standard Schlenk,
is ongoing to confirm the role of the Ru–H bond, and also high vacuum and glovebox techniques. Solvents were purified
to help rationalise the lower regioselectivity compared to using an MBraun SPS solvent system (hexane, Et O) or under
Ru(NHC)(PPh )(CO)H ]. Moreover, we hope to be able to a nitrogen atmosphere from sodium benzophenone ketyl
1
2
[
3
2
6 6 6 5 3
explain why 1 is so catalytically competent in spite of appear- (benzene). C D and C D CD were vacuum transferred from
ing, at least on the basis of stoichiometric experiments, to be potassium. NMR spectra were recorded on Bruker Avance 400/
far more prone than [Ru(NHC)(PPh )(CO)H ] to unfavourable 500 and Avance III 500 MHz NMR spectrometers and refer-
3
2
1
C–H activation reactions with partially fluorinated substrates enced as follows: H, δ 7.15 (C
H. Given that the catalysis was run under high δ 3.58 (THF-d
temperature conditions where C–H activated products like
6
D
5
H), δ 2.09 (C
); C{ H}, δ 128.0 (C ) and δ 21.3 (C
P{ H}, externally to 85% H PO (δ 0.0); F, externally to
6
D
5
CD
2
H) and
1
3
1
like C
6
F
5
7
6
D
6
6
D
5
CD );
3
3
1
1
19
3
4
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CFCl
3
(δ 0.0). PPh
3
resonances are excluded unless they
[Ru(IEt
2
Me
2
)
2
(PPh
3
)(C
6
F
5
)H] (3). C
6
F
5
H (120 μL, 1.1 mmol)
could be assigned unequivocally. Elemental analyses were per- was syringed into a J. Youngs resealable ampoule containing a
formed by Elemental Microanalysis Ltd, Okehampton, Devon. hexane suspension (5 mL) of 1 (100 mg, 0.11 mmol). The reac-
3
1
32
[
Ru(PPh
literature methods.
Ru(IEt Me (PPh
carried out in benzene rather than as previously described in Yield 53 mg, 58%. H NMR: δ
THF is reported here. This new approach afforded 1 in shorter (dt, 1H, JHP = 30.6 Hz, JHF = 7.2 Hz, Ru–H), 0.98 (t, 6H, JHH
time and in higher yield. [Ru(PPh ] (500 mg, 0.43 mmol) 7.3 Hz, NCH CH ), 1.02 (t, 6H, JHH = 7.3 Hz, NCH CH ), 1.45
and IEt Me (130 mg, 0.86 mmol) were dissolved in benzene (s, 6H, NCCH ), 1.48 (s, 6H, NCCH ), 3.05 (m, 2H, NCH CH ),
5 mL) and stirred in an ampoule sealed with a J. Youngs PTFE 3.60 (m, 4H, NCH CH ), 4.77 (m, 2H, NCH CH ), 6.90–7.05 (br
3
)
4
H
2
]
and IEt
2
Me
2
were prepared according to tion mixture was stirred vigorously at room temperature for
24 h to give a dark orange solid, which was isolated by cannula
[
2
2
)
2
3 2 2
) H ] (1). An alternative synthesis of 1 filtration, washed with hexane (2 × 5 mL) and dried in vacuo.
1
4
1
H
6 6
(C D , 500 MHz, 298 K) −32.95
=
3
)
4
H
2
2
3
2
3
2
2
3
3
2
3
(
2
3
2
3
1
3
1
6 5 6 5 P
tap for 5 min at 298 K. The solution was filtered by cannula m, 9H, PC H ), 7.43–7.49 (m, 6H, PC H ). P{ H} NMR: δ
6 6
into a fresh ampoule and the volatiles were removed in vacuo (C D , 121.5 MHz, 298 K) 59.5 (tt, JPF = 20.7 Hz, JPF = 9.7 Hz).
1
3
1
to leave a sticky orange residue. This was washed with hexane
C{ H} NMR: δ (C D , 126 MHz, 298 K) 9.0 (s, NCH CH ), 9.2
C 6 6 2 3
(
2 × 2 mL) to afford 1 as pale yellow solid. Yield: 279 mg, 70%. (s, NCH
2
CH
3
), 15.3 (s, NCCH ), 42.4 (s,
3
), 15.4 (s, NCCH
3
1
4
Spectroscopic data matched those in the original report.
NCH
2
CH
3
), 43.2 (s, NCH
2
CH ), 123.2 (s, NCCH ), 123.6 (s,
3
3
[
Ru(IEt Me ) (PPh ) HF] (2). C F (50 μL, 0.45 mmol) was NCCH ), 127.1 (d, J = 7.3 Hz, PC H ), 127.4 (s, PC H ), 133.6
2
2 2
3 2
6
6
3
CP
6
5
6
5
added to a benzene (5 mL) solution of 1 (140 mg, 0.15 mmol) (d, JCP = 11.0 Hz, PC
in an ampoule fitted with J. Youngs PTFE tap. The reaction (d, JCP = 12.1 Hz, Ru–CNHC). F NMR: δ
mixture was stirred vigorously for 24 h, filtered by cannula and 298 K) −166.4 (1F, t, JFF = 20.3 Hz, p-C F ), −165.6 (2F, m,
6
H
5
), 142.8 (d, JCP = 26.7 Hz, PC
6
H
5
), 195.9
1
9
F
6 6
(C D , 470 MHz,
6
5
evaporated to dryness to afford an oily red residue. Addition of m-C
6
F
5
), −111.5 (2F, br s, o-C
6
F
5
). Analysis found: C, 60.36;
hexane (1 mL) under the action of vigorous stirring resulted H, 5.74; N, 6.72. C42H N F PRu requires: C, 60.34; H, 5.79;
48 4 5
in a formation of a deep orange suspension (of 3), which was N, 6.70.
filtered by cannula. Leaving the hexane filtrate at room temp-
erature for few days afforded yellow crystals of 2, which taining 1 (45 mg, 48 µmol) and C
were manually separated from red needles of residual 3. Yield heated in C H (0.5 mL) at 343 K overnight to afford a deep
[Ru(IEt
2
Me
2
)(PPh
3
)
2
(C
6
F
5
)H] (4). A J. Young NMR tube con-
6 5
F
H (16 µL, 145 µmol) was
6
6
of 2: 43 mg, 30%. A more efficient route to 2 involved treat- red solution. This was filtered by cannula and the filtrate
ment of 1 with Et N·3HF (TREAT-HF). Thus, TREAT-HF evaporated to dryness. After washing with hexane (3 × 0.5 mL),
6.1 µL, 0.037 mmol) was added by syringe to a benzene solu- the residue was redissolved in a minimal amount of THF and
tion (5 mL) of 1 (100 mg, 0.11 mmol) in an ampoule fitted layered with hexane to afford deep red crystals of 4. Yield:
3
(
1
with a J. Youngs PTFE tap. The reaction mixture was stirred for 13 mg, 28%. H NMR: δ
H
(THF-d
8
, 500 MHz, 298 K) −24.66
3
0 min, the volatiles then removed under vacuum and the (1H, td, JPH = 23.5 Hz, JHF = 6.9 Hz, Ru–H), 0.34 (3H, t, JHH
=
sticky yellow solid washed with hexane (2 mL) to afford 2 as 7.3 Hz, NCH
2
CH
3
), 0.48 (3H, td, JHH = 7.3 Hz, JHF = 1.5 Hz,
1
a pale yellow solid. Yield: 75 mg, 72%. H NMR: δ
H
(C
6
D
5
CD
3
,
NCH
2
CH
3
), 1.92 (s, 3H, NCCH
3
), 1.96 (s, 3H, NCCH
3
), 2.90 (2H,
= 7.3 Hz,
HH
4
00 MHz, 228 K) −21.58 (ddd, 1H, JHF = 51.6 Hz, JHP = 25.0 Hz, q, JHH = 7.3 Hz, NCH CH ), 3.38 (2H, q, J
2
3
3
1
1
JHP = 14.1 Hz, Ru–H), 0.26 (t, 3H, JHH = 6.8 Hz, NCH
2
CH
3
), 0.34 NCH
2
CH
3
), 7.02–7.24 (30H, br m, PC
6
H
5
). P{ H} NMR: δ
P
1
3
1
(
t, 3H, JHH = 6.8 Hz, NCH CH ), 1.10 (t, 3H, JHH = 6.8 Hz, (THF-d
2
3
8
, 202 MHz, 298 K) 52.3 (s). C{ H} NMR: δ
C
(THF-d
8
,
NCH CH ), 1.16 (s, 3H, NCCH ), 1.21 (s, 3H, NCCH ), 1.39 (t, 126 MHz, 298 K) 6.4 (d, JCF = 7.5 Hz, NCH CH ), 9.4 (s,
2
3
3
3
2
3
3
H, JHH = 6.8 Hz, NCH
NCCH
JHH = 6.8 Hz, NCHHCH ), 3.13 (m, 1H, J
2
CH
3
), 1.49 (s, 3H, NCCH
3
), 1.56 (s, 3H, NCCH
3
), 9.8 (s, NCCH
3
), 14.5 (s, NCH
2
CH
3
), 42.5 (s,
3
), 2.32 (m, 1H, JHH = 6.8 Hz, NCHHCH
3
), 2.61 (m, 1H, NCH
2
CH ), 44.0 (s, NCH
3
2
CH ), 124.7 (s, NCCH ), 126.2 (s,
3 3
= 6.8 Hz, NCCH ), 127.9 (virtual triplet (‘vt’), J = 4 Hz, PC H ), 129.0 (s,
3
HH
3
6
5
NCHHCH
3
), 3.36 (m, 1H, JHH = 6.8 Hz, NCHHCH
3
), 5.60 (br m, PC
6
H
H
5
5
), 134.6 (‘vt’, J = 6 Hz, PC
), 194.0 (m, Ru–CNHC). F NMR: δ
6
H
5
), 139.0 (‘vt’, J = 17 Hz,
(THF-d , 470 MHz,
1
9
1
H, JHH = 6.8 Hz, NCHHCH
3
), 5.83 (br m, 1H, JHH = 6.8 Hz, PC
6
F
8
NCHHCH ), 6.45 (br s, 1H, NCHHCH ), 6.80 (br s, 1H, 298 K) −171.5 (1F, t, JFF = 20.2 Hz, p-C F ), −170.1 (1F, m,
3
3
6 5
NCHHCH
3
)*.
p-C
6
F
5
), −168.9 (1F, m, m-C
6
F
5
), −111.8 (1F, m, o-C
6 5
F ), −105.5
1
*
= chemical shift established by H COSY.
P{ H} NMR: δ (C D CD , 121.5 MHz, 298 K): 43.1 (br s). C H N F P Ru requires: C, 64.75; H, 5.01; N, 2.96.
(1F, m, o-C F
6 5
). Analysis found: C, 64.89; H, 4.98; N, 3.01.
31
1
P
6
5
3
51 47 2 5 2
1
3
1
C{ H} NMR: δ
s, NCCH ), 9.1 (s, NCCH
4.2 (s, NCH CH ), 15.0 (s, NCH CH ), 16.2 (s, NCH CH ), 40.5 (100 mg, 0.11 mmol) in a J. Youngs resealable ampoule. The
C
(C
6
D
5
CD
3
, 100 MHz, 228 K) 8.7 (s, NCCH
), 9.4 (s, NCCH
3
), 8.8
[Ru(IEt
2
Me
2
)
2
(PPh
3
)
2
H][H
2
F
3
]
(5). TREAT-HF (17.5 µL,
(
3
3
3
), 13.6 (s, NCH
2
CH ), 0.11 mmol) was added to a benzene (5 mL) solution of 1
3
1
2
3
2
3
2
3
(
d, JCP or JCF = 32.2 Hz, NCH
NCH CH ), 43.2 (s, NCH
s, NCCH ), 123.5 (s, NCCH ), 124.4 (s, NCCH ), 191.4 (m, Ru– orange/red residue was washed with hexane (2 × 2 mL) and
2
CH
3
), 42.0 (d, JCP or JCF = 16.4 Hz, reaction mixture was stirred at room temperature for 30 min at
2
3
2
CH
3
), 122.3 (s, NCCH ), 122.9 298 K, before the sample was reduced to dryness. The sticky
3
(
C
5
3
3
3
1
9
8
NHC). F NMR (THF-d , 470 MHz, 298 K): δ −354.4 (br d, JFH
=
Et
2
O (2 × 2 mL) and then redissolved in THF (5 mL). Addition
O resulted in the precipitation of 5 as an orange solid,
1.6 Hz). Analysis found: C, 68.99; H, 7.15; N, 5.62%. of Et
2
C H N FP Ru·0.5C H requires: C, 68.93; H, 7.10; N, 5.64%.
which was washed further with Et O (2 × 5 mL) and then dried
57
63
4
2
6
14
2
Dalton Trans.
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Paper
Table 1 Crystal data and structure refinement details for compounds 2, 3 and 4
Compound reference
2
3
4
Chemical formula
Formula mass
Crystal system
a/Å
b/Å
c/Å
α/°
β/°
γ/°
C
57
H
70
N
4
FP
2
Ru
C
42
H
48
N
4
F
5
PRu
51 47 2 5 2
C H N F P Ru
945.92
Triclinic
12.6690(2)
13.1530(2)
15.5900(3)
96.300(1)
993.18
835.88
Monoclinic
16.7400(1)
16.5550(1)
19.4760(1)
90.00
109.727(1)
90.00
Orthorhombic
31.0451(7)
8.9768(2)
14.4306(3)
90.0
90.0
90.0
105.626(1)
116.893(1)
2148.63(6)
Pˉ1
3
Unit cell volume/Å
Space group
5080.63(5)
P2
4021.62(17)
Pna2
1
1
/a
No. of formula units per unit cell, Z
No. of reflections measured
No. of independent reflections
4
4
2
94 717
11 623
0.0678
0.0370
0.0767
0.0582
0.0851
22 071
7401
0.0684
0.0402
0.0877
0.0502
0.0942
40 103
9725
0.0478
0.0338
0.0685
0.0516
0.0746
R
int
Final R
Final wR(F ) values (I > 2σ(I))
Final R values (all data)
Final wR(F ) values (all data)
1
values (I > 2σ(I))
2
1
2
in vacuo. Yield: 76 mg, 69%. Crystals suitable for X-ray diffrac- fractometers, respectively. Details of the data collections, solu-
tion were obtained upon layering a concentrated THF-d solu- tions and refinements are given in Table 1. All diffraction
tion with hexane. H NMR: δH (THF-d , 500 MHz, 298 K) measurements were conducted at 150 K using Mo(Kα) radi-
8
1
8
−29.65 (1H, t, JHP = 24.0 Hz, Ru–H), 0.44 (6H, t, JHH = 7.3 Hz, ation and hydride ligands were uniformly refined subject to
NCH
2
CH
3
), 0.88 (6H, t, JHH = 7.3 Hz, NCH
2
CH
3
), 1.81 (6H, s, being a distance of 1.6 Å from the relevant metal centre. Con-
NCCH ), 2.01 (6H, s, NCCH ), 2.75 (4H, q, J
= 7.3 Hz, vergence was straightforward in all cases, and only exceptional
3
3
HH
NCH
2
CH
3
), 3.36 (4H, q, JHH = 7.3 Hz, NCH
2
CH
3
1
), 7.16–7.34 details merit note. In particular, the asymmetric unit in 2 was
seen to comprise one bis-carbene complex and half of a
−
31
(30H, m, P(C
6
H
5
)
3
), 13.68 (2H, br s, [H
2
F
3
] ). P{ H} NMR: δ
P
1
9
(THF-d , 202 MHz, 298 K) 46.1 (s). F NMR: δF (THF-d8, hexane molecule. The latter is proximate to an inversion centre
8
4
70 MHz, 298 K) −115.2 (br s). Analysis found: C, 64.38; which serves to generate the remainder. The fluoride and
H, 5.69; N, 4.84. C54
H, 5.70; N, 4.87.
H
65
N
4
F
3
P
2
Ru·2C
4
D
8
O requires C, 64.73; hydride ligands were modelled subject to being disordered
with each other in a 53 : 47 ratio. Fractional occupancy hydride
atoms were refined with a common isotropic displacement
parameter. In 3, H5A, H5B and H5C were readily located and
Procedures for catalytic HDF
refined with the single restraint of being at a distance of 0.98 Å
A stock solution of 1 was prepared by dissolving 0.0184 g
3
3
from C5. The structures were solved using SHELXS-97 and
(
0.02 mmol) of the complex in 2 mL C H in the glovebox.
6 6
33
refined using full-matrix least squares in SHELXL-97. Crys-
tallographic data for compounds have been deposited with
the Cambridge Crystallographic Data Centre as supplementary
publications CCDC 1400863–1400866.
0
.5 mL aliquots of this solution was syringed into three
J. Young’s resealable NMR tubes, and C F (5.8 μL, 0.05 mmol)
6
6
and Et SiH (63 μL, 0.4 mmol) added to each tube. These were
3
then placed in a pre-heated oil bath at 363 K and monitored by
1
9
F NMR spectroscopy after 72 and 144 h. For reactions per-
formed under H , a C H (0.3 mL) sample of 1 (0.0046 g,
2
6
6
0
.005 mmol) was placed into a medium-walled NMR tube
Acknowledgements
fitted with a resealable valve and freeze–pump–thaw degassed
(
3 cycles). A mixture of C6F6 (5.8 μL, 0.05 mmol), Et SiH We thank the University of Bath and EPSRC for financial
3
6 6
(63 μL, 0.4 mmol) and C H (0.1 mL) was vacuum transferred support.
into the pressure tube, which was then put under 4 atm H2
and placed in a pre-heated oil bath at 363 K. The reaction was
1
9
monitored by F NMR spectroscopy after 72 and 144 h.
References
X-ray crystallography
1
V. P. Reddy, A. Vadapalli, E. Sinn and N. Hosmane, J. Orga-
nomet. Chem., 2013, 747, 43.
Data for 2 and 4 were obtained using a Nonius Kappa
CCD diffractometer, while those for 3 and 5 (see ESI†) were
collected using Agilent SuperNova and Agilent Excaliber dif-
2 Y.-M. Zhao, M. S. Cheung, Z. Lin and J. Sun, Angew. Chem.,
Int. Ed., 2012, 51, 10359; J. Mo, X. Chen and Y. R. Chi,
This journal is © The Royal Society of Chemistry 2015
Dalton Trans.

View Article Online
Paper
Dalton Transactions
J. Am. Chem. Soc., 2012, 134, 8810; X. Dong, Y.-M. Zhao and
J. Sun, Synlett, 2013, 24, 1221; F. Li, Z. Wu and J. Wang,
2011, 696, 780; M. K. Whittlesey and E. Peris, ACS Catal.,
2014, 4, 3152.
Angew. Chem., Int. Ed., 2015, 54, 656; X. Dong, W. Yang, 14 C. J. E. Davies, J. P. Lowe, M. F. Mahon, R. C. Poulten and
W. Hu and J. Sun, Angew. Chem., Int. Ed., 2015, 54, 660. M. K. Whittlesey, Organometallics, 2013, 32, 4927.
J. J. Song, Z. Tan, J. T. Reeves, F. Gallou, N. K. Yee and 15 C D needs to be avoided because of facile H/D exchange
3
6
6
C. H. Senanayake, Org. Lett., 2005, 7, 2193; L.-T. Shen,
P.-L. Shao and S. Ye, Adv. Synth. Catal., 2011, 354, 1943; 16 For a discussion of C–F versus C–H bond activation, see:
with 1. See ref. 14.
X. Dong and J. Sun, Org. Lett., 2014, 16, 2450. See also,
reports on the use of PhenoFluor and PhenFluorMix for
S. A. Johnson, J. A. Hatnean and M. E. Doster, Prog. Inorg.
Chem., 2012, 57, 255.
C–F bond formation. P. Tang, W. Wang and T. Ritter, J. Am. 17 M. K. Whittlesey, R. N. Perutz, B. Greener and
Chem. Soc., 2011, 133, 11482; T. Fujimoto and T. Ritter,
Org. Lett., 2015, 17, 544.
H. U. Vora and T. Rovis, J. Am. Chem. Soc., 2010, 132, 2860;
P. Wheeler, H. U. Vora and T. Rovis, Chem. Sci., 2013, 4,
M. H. Moore, Chem. Commun, 1997, 187.
18 R. G. Ball, B. R. James, J. Trotter, D. K. W. Wang and
K. R. Dixon, J. Chem. Soc., Chem. Commun., 1979, 460;
J. Figueira, M. G. Jardim, J. Rodrigues, A. Valkonen and
K. Rissanen, Inorg. Chem. Commun., 2013, 29, 123;
M. V. Câmpain, R. N. Perutz, B. Procacci, R. J. Thatcher,
O. Torres and A. C. Whitwood, J. Am. Chem. Soc., 2012, 134,
3480.
4
5
1
674; M. Kajjout, M. Smietana, J. Leroy and C. Rolando,
Tetrahedron Lett., 2013, 54, 1658.
J. A. Akana, K. X. Bhattacharyya, P. Müller and J. P. Sadighi,
J. Am. Chem. Soc., 2007, 129, 7736; B. C. Gorske,
C. T. Mbofana and S. J. Miller, Org. Lett., 2009, 11, 4318; 19 J. Chatt and R. G. Hayter, J. Chem. Soc., 1961, 2605.
H. Lv, J.-H. Zhan, Y.-B. Cai, Y. Yu, B. Wang and J.-L. Zhang, 20 D. A. J. Harding, E. G. Hope, G. A. Solan and J. Fawcett,
J. Am. Chem. Soc., 2012, 134, 16216; C. M. Wys, B. K. Tate,
J. Bacsa, M. Wieliczko and J. P. Sadighi, Polyhedron, 2014,
Acta Crystallogr., Sect. C: Cryst. Struct. Commun., 2007, 63,
m383; P. Barthazy, R. M. Stoop, M. Wörle, A. Togni and
A. Mezzetti, Organometallics, 2000, 19, 2844.
8
4, 87.
6
7
F. Nahra, S. R. Patrick, D. Bello, M. Brill, A. Obled, 21 S. A. Macgregor, D. C. Roe, W. J. Marshall, K. M. Bloch,
D. B. Cordes, A. M. Z. Slawin, D. O’Hagan and S. P. Nolan,
ChemCatChem, 2015, 7, 240.
V. I. Bakhmutov and V. V. Grushin, J. Am. Chem. Soc., 2005,
127, 15304; S. P. Reade, D. Nama, M. F. Mahon,
P. S. Pregosin and M. K. Whittlesey, Organometallics, 2007,
26, 3484.
Trifluoromethylation reactions are also possible, but are
stoichiometric: G. G. Dubinina, H. Furutachi and
D. A. Vicic, J. Am. Chem. Soc., 2008, 130, 8600; 22 J. Huang, E. D. Stevens, S. P. Nolan and J. L. Petersen,
G. G. Dubinina, J. Ogikubo and D. A. Vicic, Organometallics,
008, 27, 6233.
T. Schaub, M. Backes and U. Radius, J. Am. Chem. Soc.,
J. Am. Chem. Soc., 1999, 121, 2674.
23 S. Burling, E. Mas-Marzá, J. E. V. Valpuesta, M. F. Mahon
and M. K. Whittlesey, Organometallics, 2009, 28, 6676.
2
8
9
2
006, 128, 15964; Z. Mo, Q. Zhang and L. Deng, Organo- 24 W. Baratta, E. Herdtweck and P. Rigo, Angew. Chem., Int.
metallics, 2012, 31, 6518. For reviews of the field, see:
A. D. Sun and J. A. Love, Dalton Trans., 2010, 39, 10362;
T. Ahrens, J. Kohlmann, M. Ahrens and T. Braun, Chem.
Rev., 2015, 115, 931.
Ed., 1999, 38, 1629; W. Baratta, C. Mealli, E. Herdtweck,
A. Ienco, S. A. Mason and P. Rigo, J. Am. Chem. Soc., 2004,
126, 5549.
25 N. A. Jasim and R. N. Perutz, J. Am. Chem. Soc., 2000, 122,
8685; D. C. Roe, W. J. Marshall, F. Davidson, P. D. Soper
and V. V. Grushin, Organometallics, 2000, 19, 4575;
N. A. Jasim, R. N. Perutz, S. P. Foxon and P. H. Walton,
J. Chem. Soc., Dalton Trans., 2001, 1676; J. Vicente,
J. Gil-Rubio, D. Bautista, A. Sironi and N. Masciocchi,
Inorg. Chem., 2004, 43, 5665; T. Vergote, F. Nahra, A. Welle,
M. Luhmer, J. Wouters, N. Mager, O. Riant and
T. Leyssens, Chem. – Eur. J., 2012, 18, 793; C. Segarra,
E. Mas-Marzá, J. P. Lowe, M. F. Mahon, R. C. Poulten and
M. K. Whittlesey, Organometallics, 2012, 31, 8584;
N. Bramananthan, M. Carmona, J. P. Lowe, M. F. Mahon,
R. C. Poulten and M. K. Whittlesey, Organometallics, 2014,
33, 1986; B. J. Truscott, F. Nahra, A. M. Z. Slawin,
D. B. Cordes and S. P. Nolan, Chem. Commun., 2015, 51, 62.
26 M. C. Pilon and V. V. Grushin, Organometallics, 1998, 17,
1774; D. Noveski, T. Braun and S. Krückemeier, J. Fluorine
Chem., 2004, 125, 959; L. M. Martínez-Prieto, C. Melero,
D. del Río, P. Palma, J. Cámpora and E. Álvarez, Organo-
metallics, 2012, 31, 1425.
S. Kuhl, R. Schneider and Y. Fort, Adv. Synth. Catal., 2003,
3
45, 341; P. Fischer, K. Götz, A. Eichhorn and U. Radius,
Organometallics, 2012, 31, 1374; S. Sabater, J. A. Mata and
E. Peris, Nat. Commun., 2013, 4, 2553; L. Schwartsburd,
M. F. Mahon, R. C. Poulten, M. R. Warren and
M. K. Whittlesey, Organometallics, 2014, 33, 6165;
S. Sabater, J. A. Mata and E. Peris, Organometallics, 2015,
3
4, 1186.
1
0 S. P. Reade, M. F. Mahon and M. K. Whittlesey, J. Am.
Chem. Soc., 2009, 131, 1847; J. A. Panetier, S. A. Macgregor
and M. K. Whittlesey, Angew. Chem., Int. Ed., 2011, 50,
2
783; S. A. Macgregor, D. McKay, J. A. Panetier and
M. K. Whittlesey, Dalton Trans., 2013, 42, 7386.
1 D. McKay, I. M. Riddlestone, S. A. Macgregor, M. F. Mahon
and M. K. Whittlesey, ACS Catal., 2015, 5, 776.
2 S. P. Reade, A. L. Acton, M. F. Mahon, T. A. Martin and
M. K. Whittlesey, Eur. J. Inorg. Chem., 2009, 1774.
3 L. M. Guard, A. E. W. Ledger, S. P. Reade, C. E. Ellul,
M. F. Mahon and M. K. Whittlesey, J. Organomet. Chem.,
1
1
1
Dalton Trans.
This journal is © The Royal Society of Chemistry 2015

View Article Online
Dalton Transactions
Paper
2
7 T. Mathieson, A. Schier and H. Schmidbaur, Z. Naturforsch.,
B: Chem. Sci., 2000, 55b, 1000; F. J. Fernández, M. Alfonso,
H. W. Schmalle and H. Berke, Organometallics, 2001, 20,
Ed., 2013, 52, 9491; L. Zámostná, M. Ahrens and T. Braun,
J. Fluorine Chem., 2013, 155, 132; O. Ekkert,
S. D. A. Strudley, A. Rozenfeld, A. J. P. White and
M. R. Crimmin, Organometallics, 2014, 33, 7027;
S. M. Senaweera, A. Singh and J. D. Weaver, J. Am. Chem.
Soc., 2014, 136, 3002.
3
122; B. G. Harvey, A. M. Arif, A. Glöckner and R. D. Ernst,
Organometallics, 2007, 26, 2872; I. Bernal and S. F. Watkins,
C. R. Chimie, 2014, 17, 586.
2
2
8 For a review of catalytic HDF, see: M. Kuehnel, D. Lentz 30 H. Nakai, K. Jeong, T. Matsumoto and S. Ogo, Organometal-
and T. Braun, Angew. Chem., Int. Ed., 2013, 52, 3328. lics, 2014, 33, 4349.
9 For examples of catalytic HDF in which highly fluorinated 31 R. Young and G. Wilkinson, Inorg. Synth., 1990, 28, 337.
substrates undergo multiple defluorination steps, see: 32 N. Kühn and T. Kratz, Synthesis, 1993, 561.
J. Wu and S. Cao, ChemCatChem, 2011, 3, 1582; W. Zhao, 33 G. M. Sheldrick, Acta Crystallogr., Sect. A: Fundam.
J. Wu and S. Cao, Adv. Synth. Catal., 2012, 354, 574; J. Xiao,
J. Wu, W. Zhao and S. Cao, J. Fluorine Chem., 2013, 146, 76;
G. Podolan, D. Lentz and H.-U. Reissig, Angew. Chem., Int.
Crystallogr., 1990, 46, 467–473; G. M. Sheldrick, SHELXL-97,
a computer program for crystal structure refinement, Univer-
sity of Göttingen, 1997.
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