First Neutral and Cationic Tungsten Imido Alkylidene N-Heterocyclic Carbene Complexes

Article abstract of DOI:10.1002/cctc.201700189

The synthesis of W(NAr′)(NHC)(=CHR)(2,5-Me₂pyr)₂ (1; Ar′: 2,6-iPr₂C₆H₃; NHC: 1,3-diisopropylimidazol-2-ylidene; 2,5-Me₂pyr: 2,5-dimethylpyrrolide; R: CMe₂Ph), W(NAr′)(NHC)(=CHR)(2,5-Me₂pyr)(OC₆F₅) (2), W(NAr′)(NHC)(=CHR)(OSiPh₃)₂ (3), [W(NAr′)(NHC)(=CHR)(OSiPh₃))(MeCN)⁺][B(Ar^F)₄ ^?] (4; B(Ar^F)₄ ^?: B(3,5-(CF₃)₂C₆H₃)₄ ^?), [W(NAr′)(NHC)(=CHR)(2,5-Me₂pyr))⁺][B(Ar^F)₄ ^?] (5), [W(NAr′)(NHC)(=CHR)(OC₆F₅))(tBuCN)⁺][B(Ar^F)₄ ^?] (6), W(NAr′)(NHC)(=CHR)(OtBu)₂ (7), [W(NAr′)(NHC)(=CHR)(OtBu)⁺][B(Ar^F)₄ ^?] (8), and W(NAr′)(NHC)(=CHR)(OCMe(CF₃)₂)₂ (9) is described, and the reactivity of the complexes in olefin metathesis and cyclopolymerization is reported. The cationic complexes 4, 5, and 6 showed high productivity and activity in olefin metathesis reactions, with turnover numbers of up to 40 000 and turnover frequencies (TOF_5min) of up to 31 s^?1, and also substantial functional group tolerance toward esters, nitriles, alcohols, and sulfides, particularly in the cyclopolymerization of α,ω-diynes.

Full text of DOI:10.1002/cctc.201700189

Accepted Article
Title: First Neutral and Cationic Tungsten Imido Alkylidene N
Heterocyclic Carbene Complexes
Authors: Dominik Imbrich, Iris Elser, Wolfgang Frey, and Michael
Rudolf Buchmeiser
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To be cited as: ChemCatChem 10.1002/cctc.201700189
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ChemCatChem
10.1002/cctc.201700189
FULL PAPER
First Neutral and Cationic Tungsten Imido Alkylidene
N-Heterocyclic Carbene Complexes
[
a]
[a]
[b]
*[a]
Dominik A. Imbrich, Iris Elser, Wolfgang Frey, Michael R. Buchmeiser
Abstract: The synthesis of W(NAr’)(NHC)(=CHR)(2,5-Me
Ar’ = 2,6-iPr NHC = 1,3-diisopropylimidazol-2-ylidene, 2,5-
Me Pyr = 2,5-dimethylpyrrolide,
W(NAr’)(NHC)(=CHR)(2,5-Me pyr)(OC
W(NAr’)(NHC)(=CHR)(OSiPh
W(NAr’)(NHC)(=CHR)(OSiPh
2
pyr)
2
(1,
tungsten oxo alkylidene NHC complexes, we were interested in
the question whether tungsten imido alkylidene NHC complexes
could be prepared, too, how these novel compounds would
behave in olefin metathesis reactions and how functional group
tolerant they were.
2
6 3,
C H
2
R = CMe
2
Ph),
(2),
(3),
2
6 5
F )
3 2
)
+
F
-
F
-
[
3
))(MeCN) ][B(Ar )
4
]
(4,
B(Ar )
4
-
=
Me
B(3,5-(CF
3
)
2
-C
6
H
]
3
)
4
),
[W(NAr’)(NHC)(=CHR)(2,5-
+
F
-
2
pyr)) ][B(Ar )
4
(5),
+
F
-
[
W(NAr’)(NHC)(=CHR)(OC
6
F
5
))(tBuCN) ][B(Ar )
4
]
(6),
(7),
(8),
W(NAr’)(NHC)(=CHR)(OtBu)
2
Results and Discussion
+
F
-
[
W(NAr’)(NHC)(=CHR)(OtBu) ][B(Ar )
4
]
W(NAr’)(NHC)(=CHR)(OCMe(CF
3
)
2
)
2
(9), and their reactivity in olefin
In analogy to recently reported molybdenum imido alkylidene
metathesis and cyclopolymerization is reported. The cationic
complexes 4, 5 and 6 showed high productivity and activity in olefin
metathesis reactions with turnover numbers up to 40,000 and
turnover frequencies (TOF5min) up to 31 s and also substantial
functional group tolerance versus esters, nitriles, alcohols and
sulfides particularly in the cyclopolymerization of α,ω-diynes.
.
[7]
2 6 3 2 2
NHC complexes, W(N-2,6-iPr C H )(CHCMe Ph)(OTf) DME
was reacted with a series of free NHCs. Disappointingly, only
decomposition or the formation of obscure side products was
observed. It was therefore necessary to apply an alternative
synthetic approach to tungsten imido alkylidene NHC complexes.
It entailed the reaction of Schrock-type catalysts, i.e. of (W(N-
-
1
[
2l]
2
,6-iPr
2
C
6
H
3
)(CHCMe
2
Ph)(2,5-Me
Ph)(OSiPh ) (pre-3)
Ph)(OtBu)
Ph)(OCMe(CF
2
pyr)
2
(pre-1),
W(N-2,6-
W(N-2,6-
W(N-2,6-
1,3-
[
8]
iPr
iPr
iPr
2
2
2
C
C
C
6
6
6
H
H
H
3
3
3
)(CHCMe
)(CHCMe
)(CHCMe
2
2
2
3 2
)
Introduction
[
9]
2
(pre-7)
and
[
9]
3
)
2
)
2
(pre-9)
with
by
In the last 30 years the field of well-defined, “single-site” olefin
metathesis catalysts was strongly influenced by two major
classes of well-defined olefin metathesis catalysts. Molybdenum-
[
10]
diisopropylimidazol-2-ylidene
followed
further
transformations, and allowed the synthesis of the target
compounds 4, 5, 6 and 8 in high yields (Scheme 1).
[
1]
and tungsten-based Schrock, catalysts
show excellent
Reaction of 1 with one equivalent of pentafluorophenol resulted
in the formation of the monoalkoxide pyrrolide-type (MAP)
properties in terms of activity, enantio-, diastereo- and
regioselectivity, which makes them highly useful in the areas of
[
1b]
[
1c, e, 2]
tungsten NHC complex 2. Complex 1 was converted into 3 via
addition of two equivalents of triphenylsilanol and into 5 by
organic and polymer chemistry.
Equally important,
ruthenium-based Grubbs and Grubbs-Hoveyda type complexes
are characterized by high reactivity, functional group tolerance
and easy handling, which resulted in intense research in this
F
-
addition of one equivalent of N,N-dimethylanilinium B(Ar )
4
F
-
-
(
B(Ar )
4 3 2 6 3 4
= B(3,5-(CF ) -C H ) ). For the synthesis of the cationic
[
3]
versions of 3 and 7, one equivalent of N,N-dimethylanilinium
area.
F
-
B(Ar )
4
was added to 3 and 7, which resulted the cationic
Recently, we reported on the synthesis of cationic tungsten oxo
alkylidene N-heterocyclic carbene (NHC) and molybdenum
imido alkylidene NHC complexes, which in fact represent a new
complexes 4 and 8 in 93 and 73% isolated yield, respectively.
Disappointingly, reactions of 2 or 9 with one equivalent of
F
-
F
-
F
-
[
4]
4 4 4
Na[B(Ar ) ], Ag[B(Ar ) ] or N,N-dimethylanilinium [B(Ar ) ] in
class of well-defined olefin metathesis catalysts. These 16-
electron complexes show very high activity, particularly when
different solvents and at different temperatures did not lead to
the formation of the desired cationic complexes. In these cases,
decomposition of the starting complex or protonation of the NHC
was observed. However, reaction of 5 with one equivalent of
pentafluorophenol in the presence of tBuCN as coordinating
solvent resulted in the formation of the cationic complex 6.
In solution, the alkylidenes in 1, 2, 3, 4, 5 and 6 adopt a syn-
[
5]
supported on silica, and substantial functional group tolerance
in various olefin metathesis reactions including ring-opening
metathesis polymerization (ROMP), the cyclopolymerization of
[
6]
1
,6-hepta- and 1,7-octadiynes, ring-closing metathesis (RCM),
homometathesis (HM) and cross-metathesis (CM). In view of the
most interesting properties of both molybdenum imido and
[
11]
1
configuration
( JC-H = 114.0, 119.2, 114.0, 115.5, 115.5 and
Cl ). However, with 6,
1
16.1 Hz, respectively, all measured in CD
2
2
[
a]
b]
M.Sc. D. A. Imbrich, M.Sc. I. Elser, Prof. M. R. Buchmeiser
Insitute of Polymer Chemistry, University of Stuttgart,
Pfaffenwaldring 55, D-70569 Stuttgart (Germany).
E-mail: michael.buchmeiser@ipoc.uni-stuttgart.de
Dr. W. Frey
7.5% of another isomer (with respect to the syn isomer) were
1
observed at δ = 13.89 ppm in the H NMR. Due to its small
percentage, coupling constants could not be measured and we
therefore only tentatively assign this signal to the anti-isomer.
Complex 6 (Figure 1) crystallizes in the monoclinic space group
[
Institute of Organic Chemistry, University of Stuttgart,
Pfaffenwaldring 55, D- 70569 Stuttgart (Germany).
P2
1
. In the solid state, 6 adopts a distorted square pyramidal
[
12]
configuration (τ
5
= 0.21) with the alkylidene in the apex and
Supporting information for this article is given via a link at the end of
the document.
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ChemCatChem
10.1002/cctc.201700189
FULL PAPER
Scheme 1. Synthetic route to the tungsten imido alkylidene NHC complexes 1 – 9.
the tBuCN trans to the NHC. In the solid state, the tungsten
alkylidene bond is exclusively observed in its syn-configuration.
Complex 7 crystallized out of n-pentane during the reaction. In
neutral 16-electron molybdenum imido alkylidene and tungsten
oxo alkylidene NHC complexes only become active in olefin
metathesis in case they can convert into a cationic 14-electron
complex via dissociation of one anionic ligand, e.g. triflate. Since
pyrrolides, tbutoxides and triphenylsilanolates present in 1, 3
and 7 are all comparably poor leaving groups, these 16-electron
complexes form unreactive 18-electron complexes upon
coordination of an olefin. The 16-electron complex 2 was also
inactive in all tested olefin metathesis reactions (Table 1)
suggesting that the pentafluorophenoxide does not readily
dissociate from the metal, which is in line with findings for
molybdenum imido alkylidene NHC bis(pentaflurophenoxide)
solution,
the
C-H = 120.4 Hz, CD
the monoclinic space group P2
distorted tetrahedral configuration (τ
alkylidene
Cl ). Complex 8 (Figure 2) crystallizes in
. In the solid state, 8 adopts a
adopts
a
syn-configuration
1
(
J
2
2
1
[
13]
4
= 0.86)
with the
alkylidene in the syn-configuration; however, in solution both
1
isomers are observed at δ = 10.57 ( JC-H = 112.3 Hz, syn) and
1
1
2.54 ppm ( JC-H = 140.9 Hz, anti, all CD
2
Cl
2
) in a ratio of 91:9.
The crystal contains only the S-isomer. Similar to 7, compound 9
also crystallized out of n-pentane during the reaction. The
1
[4e]
alkylidene adopts the syn-configuration in solution NMR ( JC-
complexes. In contrast, complex 9 containing two hexafluoro-
H
= 118.8 Hz, CD
2
Cl
2
).
tbutoxide ligands showed moderate productivity, pointing
Next, in order to compare the aforementioned complexes to
existing molybdenum imido and tungsten oxo alkylidene NHC
complexes, the novel catalysts were subjected to simple
benchmark olefin metathesis reactions. Table 1 summarizes the
productivities, i.e. the turnover numbers (TONs) achieved with
complexes 2, 4, 5, 6, 8 and 9 in ring-closing metathesis (RCM),
self-metathesis (SM) and homometathesis (HM) reactions. In
towards some ligand dissociation in the presence of substrate as
1
9
evidenced by
F NMR (Figure 3). Thus, upon addition of
diphenyldiallylsilane to 9, minor amounts of weakly coordinated
hexafluoro-tbutanolate became visible around δ = -78 ppm. The
strong σ-donor propensity of the tbutoxide ligand may be the
reason for the comparably low electrophilicity and productivity of
8 in olefin metathesis reactions. This is supported by the finding
that all cationic olefin metathesis-active molybdenum imido
[
14]
theory,
the metal center, i.e. the cationic complexes 4, 5, 6 and 8 should
those complexes with the lowest electron density at
alkylidene and tungsten oxo alkylidene NHC complexes
[
4a, b, d, e]
[4b, d, e]
be the most active ones. In fact, as outlined earlier,
prepared so far
showed coordination of one solvent
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ChemCatChem
10.1002/cctc.201700189
FULL PAPER
is also reflected by the turnover frequencies (TOFs). For 1,7-
-
1
octadiene,
5
a TOF min, 80 °C of 21 s was determined for
-
1
complex 4 while with 5, a TOF10s, 50 °C of 10 s was reached at
substantially lower temperature. Accordingly, the TOF could not
be determined at 80 °C since the reaction was complete within
seconds using a ratio of 5:1,7-octadiene = 1:1000. Catalyst 6, a
cationic complex, is the most electrophilic one and was thus
expected to be highly reactive. And in fact, using a ratio of 6:
substrate = 1:1000, full conversion was achieved in the reaction
with 1,7-octadiene. The same accounts for the reaction with
ethyl oleate, in which the thermodynamic equilibrium was
reached. In parallel, Z à E isomerization occurred. The high
activity of 6 is also reflected by the high TOF at 5 minutes, TOF
5
-
1
min, in the RCM of 1,7-octadiene, which was 31 s . Notably, 6
must be stabilized by tBuCN; the complex even decomposes in
the presence of an excess of weaker coordinating acetonitrile.
Table 1. Productivities (TONs) of complexes 2, 4, 5, 6, 8 and 9 in selected
olefin metathesis reactions.
Figure 1. Single crystal X-ray structure of 6. Relevant bond lengths (pm)
and angles (°): W(1)-N(4) 174.2(4), W(1)-C(21) 187.6(6), W(1)-O(1)
Substrate/
2
4
5
6
8
9
1
99.7(4), W(1)-N(3) 217.4(5), W(1)-C(1) 218.6(5), N(4)-W(1)-C(21)
02.5(2), N(4)-W(1)-O(1) 146.87(19), C(21)-W(1)-O(1) 110.6(2), N(4)-
reaction type
1
W(1)-N(3) 97.12(19), C(21)-W(1)-N(3) 92.2(2), O(1)-W(1)-N(3) 79.78(18),
N(4)-W(1)-C(1) 92.6(2), C(21)-W(1)-C(1) 103.3(2), O(1)-W(1)-C(1)
RCM
diphenyldiallylsilane
1,7-octadiene
SM
0
0
960
340
870
420
130
430
100
82.18(18) N(3)-W(1)-C(1) 159.45(18). Anion and co-solvent omitted for
[
a]
[a]
[a]
clarity (probability level = 50%).
11000
14700
40000
molecule, which is an indicator for a low electron density at the
metal center. However, this was not observed with 8.
[
b]
[c]
[d]
ethyl oleate
HM
0
-
360
-
260
490
0
-
0
-
Interestingly, compared to those of 4, complex 5 showed higher
productivities in the RCM of 1,7-octadiene. This is attributed to
the stronger σ-donor propensity of the pyrrolide ligand
compared to the triphenylsilyloxy ligand and which obviously
allows for a better stabilization of the cationic intermediate. This
-
860
methyl
undecenoate
(2/8)
670
0
340
600
310
120
1
-octene (Z/E)
(
-
-
3/7)
(2/8)
(2/8)
(2/8)
(3/7)
CM
[
e]
1
1
1
1
-dodecene/
-
-
-
-
480
-
-
-
-
(
17/83)
-decene
[
e]
-dodecene/
-hexene
330
(
16/84)
Reaction conditions unless noted otherwise: 80 °C, catalyst:substrate
=
1
:1000, 3 hours, internal standard: n-dodecane; [a] 80 °C, catalyst : substrate
1:100000, hours, internal standard: n-dodecane. [b] (Z/E ratio: 9-
=
3
octadecene: 11/89; diethyl 9-octadecene-1,18-dioate: 4/96). [c] (Z/E ratio: 9-
octadecene: 20/80; diethyl 9-octadecene-1,18-dioate: 8/92). [d] (Z/E ratio: 9-
octadecene: 19/81; diethyl 9-octadecene-1,18-dioate: 12/88). [e] 80 °C,
catalyst:1-dodecene:substrate 2 = 1:500:500, 3 hours, internal standard: n-
dodecane TON with respect to 1-dodecene.
In the cross metathesis (CM) of 1-dodecene with 1-decene the
corresponding products were obtained in 96% yield with respect
to 1-dodecene (cat:substrate = 1:1000). E/Z ratios were in the
range of 14/86 to 20/80.
Figure 2. Single crystal X-ray structure of 8. Relevant bond lengths (pm) and
angles (°): W(1)-N(3) 172.5(5), W(1)-O(1) 185.1(4), W(1)-C(22) 190.1(6),
W(1)-C(1) 213.5(6), N(3)-W(1)-O(1) 125.0(2), N(3)-W(1)-C(22) 104.3(2),
O(1)-W(1)-C(22) 109.8(2), N(3)-W(1)-C(1) 98.3(2), O(1)-W(1)-C(1) 113.2(2),
C(22)-W(1)-C(1) 103.9(2). Anion and co-solvent omitted for clarity (probability
level = 50%).
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ChemCatChem
10.1002/cctc.201700189
FULL PAPER
N
S
NC CN
HO
OH
M2
M3
M4
O
M1
2
PhMe C
CMe
X
2
Ph
X
α-insertion-derived
β-insertion-derived
OH) , S
X = N(CH OCHMe2, C(CN)2, C(CH
2
)
3
2
2
Figure 4. Monomers M1 – M4 used in Cyclopolymerization and possible
polymer structures.
1
9
had polydispersity indices (D) of 1.6 and 1.5, respectively,
Figure 3. F NMR showing the dissociation of hexafluoro-tbutoxide from
in the presence of diphenyldiallylsilane (CD Cl , r.t.). Bottom: without
9
2
2
indicative for a fairly controlled polymerization. Catalyst 5
substrate; Middle: after one hour in the presence of diphenyldiallylsilane;
Top: after two hours in the presence of diphenyldiallylsilane.
produced only insoluble polymer. The finding that the molecular
weights of poly-M2 prepared by the action of 4 and 8 as
determined by GPC were substantially higher than the
theoretical ones is typical for rigid rod polymers and has been
Molybdenum imido alkylidene NHC complexes have been
shown to possess substantial functional group tolerance in
[
16]
[
4a, d]
observed earlier.
metathesis-based polymerization
as a benchmark for our new complexes. Surprisingly, substantial
functional group tolerance was observed in the
cyclopolymerization of functional diynes (Figure 4, Table 2F),
even with cationic tungsten imido alkylidene NHC complexes 4,
and consequently served
Notably, 6 and 8, both cationic complexes allowed for the
cyclopolymerization of 4,4-dihydroxymethyl-1,6-heptadiyne (M3),
though in moderate yields (25-30%). Such tolerance of protic
groups is remarkable for cationic alkylidenes and has not yet
been observed, neither for cationic molybdenum imido nor for
tungsten oxo alkylidene NHC complexes. The thioether M4 was
successfully cyclopolymerized by catalysts 4, 5, 6, 8 and 9; a
deep purple but insoluble polymer was obtained. Notably, no
free alkyne groups were observed in the resulting polymers,
which points towards cyclopolymerization instead of
intermolecular cross-linking.
[
15]
[
15c]
5
, 6, and 8. Thus, in contrast to Ru-based initiators,
catalysts 4, 6, 8 and 9 allowed for the cyclopolymerization of the
tertiary amine M1; however, only insoluble polymers were
obtained. 4,4-Dicyano-1,6-heptadiyne (M2) was successfully
cyclopolymerized by catalysts 4, 5 and 8; the resulting polymers
Table 2. Cyclopolymerization data for M1 – M4 with catalysts 4, 5, 6, 8 and
9
.
[
b]
[c]
catalyst/ monomer
Yield ,%
M
n
(theo.), g/mol
M
n
, g/mol
PDI
4
4
4
5
5
6
6
6
8
8
8
8
9
9
/ M1
/ M2
/ M4
/ M2
/ M4
/ M1
/ M3
/ M4
/ M1
/ M2
/ M3
/ M4
/ M1
/ M4
85
9700
7100
5500
7100
5500
9700
7600
5500
9700
7100
7600
5500
9700
5500
insoluble
22000
-
Conclusions
>99
>99
>99
28
1.5
insoluble
insoluble
insoluble
insoluble
insoluble
insoluble
insoluble
26000
-
In summary, the first neutral and cationic tungsten imido
alkylidene NHC complexes have been prepared. The cationic
complexes showed moderate to good productivity in various
olefin metathesis reactions. They also show activity in the
cyclopolymerization of functional group containing 1,6-
heptadiynes. Functional group tolerance of the cationic systems
is comparable to the one observed for neutral Mo-imido
alkylidene bistriflates, but significantly exceeds the one of the
analogous cationic molybdenum imido or tungsten oxo
alkylidene NHC complexes. This more pronounced functional
group tolerance is, however, counterbalanced by a reduced
olefin metathesis activity compared to the analogous
molybdenum imido and tungsten oxo alkylidene NHC complexes.
-
-
40
-
25
-
90
-
90
-
>99
30
1.6
insoluble
insoluble
insoluble
insoluble
-
-
-
-
96
[
[
a]
a]
>99
>99
Reaction conditions unless noted otherwise: 80 °C, catalyst:substrate = 1:50.
hours, [a] 80 °C, catalyst : substrate = 1:50, 16 hours; [b] via gravimetric
analysis, [c] via SEC (dimethylacetamide).
Experimental Section
3
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ChemCatChem
10.1002/cctc.201700189
FULL PAPER
General. All manipulations of moisture and air sensitive materials were
(22.5 mg, 0.12 mmol) dissolved in a 1 mL of diethyl ether was added to a
suspension of 1 (100.0 mg, 0.12 mmol) in 5 mL of diethyl ether. The
reaction mixture was stirred for 3 h at room temperature. The reaction
mixture was filtered and all volatiles were removed in vacuo. The yellow
solid was recrystallized from diethyl ether and n-pentane to get
performed under
a
nitrogen atmosphere with standard Schlenk
techniques or in a N
2
-filled glove box (Lab Master 130, MBraun, Garching,
Germany). Methylene chloride, diethyl ether, toluene, n-pentane and
tetrahydrofurane (THF) were dried by a solvent purification system (SPS,
MBraun). 1,2-Dimethoxyethane (DME) and benzene were vacuum
distilled from a dark purple solution of sodium benzophenone ketyl, and
degassed three times by freeze-pump-thaw technique. Starting materials
and all reagents were purchased from Sigma-Aldrich (Munich, Germany),
Alfa Aesar (Karlsruhe, Germany), ABCR (Karlsruhe, Germany) and
Acros Chemicals (Geel, Belgium), dried and, where appropriate, distilled
prior to use. NMR measurements were recorded on a Bruker Avance III
1
analytically pure product; yield 102.3 mg (84%): H NMR (400 MHz,
1
2
CD
2 2 H-
Cl ) δ = 12.13 (s, 1H, W=CH, JC-H = 119.2 Hz), 7.59, (d, 2H, Ar, J
2
2
H
= 7.5 Hz), 7.40 (t, 2H, Ar, JH-H = 7.5 Hz), 7.24 (t, 1H, Ar, JH-H = 6.9 Hz),
7.12 (m, 5H, Ar), 5.56 (s, 1H, pyr), 5.47 (s, 1H, pyr), 5.04 (brs, 1H, iPr),
4.42 (brs, 1H, iPr), 3.52 (brs, 1H, iPr), 2.88 (brs, 1H, iPr), 2.35 (s, 3H,
Me), 2.07 (s, 3H, Me), 1.87 (s, 3H, Me), 1.63 (s, 3H, Me), 1.41 (s, 3H,
2
Me), 1.30 (s, 3H, Me), 1.26 (s, 3H, Me), 1.02 (d, 3H, iPr,
JH-H = 6.7 Hz),
2
4
00. Chemical shifts are reported in ppm relative to the solvent signal.
0.88 (brs, 6H, Me), 0.82 (d, 3H, iPr,
J
H-H = 5.7 Hz), 0.46 (s, 3H,
) δ = -161.42 (m, 2F), -169.49 (m,
2F), 176.86 (m, 1F) ppm; C NMR (101 MHz, CD Cl ) δ = 276.2 (W=C,
C-H = 119.2 Hz), 191.7 (N-C-N), 151.8 (ipso-CMe Ph), 151.0 (ipso-N-
1
9
GC-MS data were recorded on an Agilent Technologies device consisting
of a 7693 auto sampler, a 7890 A GC and a 5975C quadrupole MS. n-
dodecane was used as internal standard. An SPB-5 fused silica column
2 2
Me) ppm; F NMR (376 MHz, CD Cl
1
3
2
2
1
J
2
(
34.13 m x 0.25 mm x 0.25 mm film thickness) was used. The injection
temperature was set to 150 °C. The column temperature ramped from
5 °C to 250 °C within eight minutes and was then held for further five
minutes. The column flow was 1.05 mL per minute. All substrates for HM,
CM, RCM, and SM were either distilled from CaH or recrystallized and
Dipp), 149.6 (CAr), 145.0 (CAr), 142.6 (CArF), 140.2 (CArF), 139.1 (CArF),
136.7 (CArF), 134.7 (CArF), 133.6 (CAr), 132.9 (CAr), 129.1 (CArF), 126.8
(CAr), 126.3 (CAr), 126.1 (CAr), 124.3 (CAr), 122.9 (CAr), 118.9 (C=C),
118.4 (C=C), 108.5 (Cpyr), 106.7 (Cpyr), 66.3, 55.2, 37.1, 30.4, 27.9, 27.3,
26.0, 25.8, 25.0, 24.4, 23.9, 23.5, 21.3, 19.4, 17.3, 15.6 ppm; elemental
4
2
stored under nitrogen. The SEC system consisted of a 1260 Infinity
System (Agilent Technologies Inc.) equipped with a Multi Detector-suite
unit (refractive index detector). For analysis, the Cirrus Multi Detector
Software (Agilent Technologies Inc.) was used. The apparatus was
equipped with a pump, a degasser, and an auto sampler. A pre column
anal. calcd. (%) for C43
53 5 4
H F N OW: C, 56.09; H, 5.80; N, 6.08. Found: C,
56.35; H, 6.08; N, 5.84.
W(N-2,6-iPr
2
C
6
H
3
)(1,3-diisopropylimidazol-2-
Ph)(OSiPh (3). a)
ylidene)(CHCMe
2
3
)
2
A
solution
of
1,3-
(
8 ×50 mm) and one mixed-bed linear S separation column (8 ×300 mm,
diisopropylimidazol-2-ylidene (19.9 mg, 0.13 mmol) in 1 mL diethyl ether
was added dropwise to a stirred solution of pre-3 (136.4 mg, 0.13 mmol),
dissolved in a 6 mL diethyl ether. The reaction mixture was stirred for 3 h
at room temperature. Afterwards it was filtered through a pad of celite. All
volatiles were removed from the yellow solution in vacuo. The yellow
solid was washed with acetonitrile to get analytically pure product; yield
PSS, Mainz, Germany) with a porosity between 100 and 300 Å, particle
−
1
size of 5 µm and a fractionation range of 100 – 300000 g mol were
−
1
used. A flow rate of 0.75 mL min and a column oven temperature of
0 °C were used. The injection volume was set to 100 µL. All detectors
were calibrated at 40 °C. SEC solvents consisted of pure Sample
4
−
1
−1
solutions for SEC had a concentration of 2 g L for samples and 1 g L
for calibration standards. Prior to use, solutions were filtered through
1
17 mg (75%).
0
.2 µm PTFE syringe filters. Evalutation is applying conventional
b) A solution of triphenylsilanol (66.3 mg, 0.24 mmol) in a 1 mL diethyl
ether was added dropwise to stirred suspension of (100 mg,
.12 mmol) in diethyl ether. The reaction mixture was stirred for 3 h at
−
1
calibration against linear PMMA (800 < M
Germany).
n
< 201000 g mol , PSS, Mainz,
a
1
0
room temperature and filtered through a pad of celite. All volatiles were
W(N-2,6-iPr
2
C
6
H
3
)(1,3-diisopropylimidazol-2-
Ph)(2,5-Me pyr) (1). At -30 °C a solution of 1,3-
removed in vacuo. The yellow solid was washed with acetonitrile to get
1
ylidene)(CHCMe
2
2
2
analytically pure product; yield 143.4 mg (86%): H NMR (400 MHz,
1
diisopropylimidazol-2-ylidene (46.6 mg, 0.31 mmol) in 2 mL diethyl ether
was added slowly to a stirred solution of pre-1 (207.7 mg, 0.31 mmol)
dissolved in a 2 mL of diethyl ether. The reaction mixture was stirred for
CD
2
Cl
2
) δ = 9.99 (s, 1H, W=CH,
J
C-H = 114.0 Hz), 7.55 (m, 6H, Ar), 7.26
(
m, 12H, Ar), 7.06 (m, 10 H, Ar), 6.95 (m, 12H, Ar), 4.73 (sept, 1H, iPr,
2
2
J
H-H = 6.6 Hz), 4.32 (brs, 1H, iPr), 4.22 (sept, 1H, iPr, JH-H = 6.6 Hz),
2
3
h at room temperature. The suspension was filtered and the residue
3
.53 (brs, 1H, iPr), 2.06 (s, 3H, Me), 1.07 (d, 3H, iPr, JH-H = 6.7 Hz), 0.97
was washed with diethyl ether. The yellow solid was dried in vacuo to get
2
2
(
d, 3H, iPr,
J
H-H = 5.9 Hz), 0.93 (s, 3H, Me), 0.68 (d, 3H, iPr,
J
J
H-
H-
1
2
2
analytically pure product; yield 214.5 mg (85%): H NMR (400 MHz,
H
= 6.7 Hz), 0.64 (d, 3H, iPr,
JH-H = 6.5 Hz), 0.34 (d, 3H, iPr,
1
2
1
3
2 2 H-
CD Cl ) δ = 10.73 (s, 1H, W=CH, JC-H = 114.0 Hz), 7.47 (d, 2H, J
H
= 6.7 Hz), 0.27 (brs, 6H, iPr) ppm;
2 2
C NMR (101 MHz, CD Cl )
2
= 7.3 Hz), 7.32 (t, 2H, JH-H = 7.3 Hz), 7.13 (m, 6H, Ar), 5.68 (s, 2H, pyr),
1
H
2
δ = 258.6 (W=C, JC-H = 114.0 Hz), 193.8 (N-C-N), 152.2 (ipso-CMe Ph),
2
5
.56 (dd, 2H, pyr, JH-H = 15.1 Hz), 4.72 (brs, 1H, iPr), 4.56 (brs, 1H, iPr),
1
1
1
1
5
2
6
51.1 (ipso-N-Dipp), 148.4 (CAr), 144.3 (CAr), 140.6 (CAr), 139.4 (CAr),
36.9 (CAr), 136.2 (CAr), 135.7 (CAr), 130.4 (CAr), 129.1 (CAr), 128.9 (CAr),
28.6 (CAr), 128.3 (CAr), 127.8 (CAr), 127.5 (CAr), 126.1 (CAr), 125.8 (CAr),
24.9 (CAr), 124.4 (CAr), 123.8 (CAr), 118.2 (C=C), 117.7 (C=C), 54.4,
3.4, 51.7, 36.2, 29.1, 27.5, 27.2, 25.9, 25.5, 24.5, 24.1, 23.7, 23.3,
3
1
1
.31 (brs, 2H, iPr), 2.04 (brs, 6H, iPr), 1.84 (s, 3H, Me), 1.71 (s, 3H, Me),
.52 (s, 3H, Me), 1.44 (brs, 3H, Me), 1.29 (s, 3H, Me), 1.19 (brs, 3H, Me),
2
.11 (brs, 6H, Me), 0.84 (d, 6H, iPr,
J
H-H = 6.6 Hz), 0.79 (brs, 3H, Me),
Cl ) δ = 273.9 (W=C,
C-H = 114.0 Hz), 191.0 (N-C-N), 152.1 (ipso-CMe Ph), 150.6 (ipso-N-
1
3
0
.46 (brs, 3H, Me) ppm; C NMR (101 MHz, CD
2
2
1
J
2
2.3 ppm; elemental anal. calcd. (%) for C67
75 3 2 2
H N O Si W: C, 67.38; H,
Dipp), 141.4 (CAr), 140.8 (CAr), 138.6 (CAr), 138.0 (CAr), 137.5 (CAr), 128.9
.33; N, 3.52. Found: C, 67.30; H, 6.35; N, 3.88.
(
(
C
Ar), 128.6 (CAr), 127.7 (CAr), 127.6 (CAr), 126.8 (CAr), 126.6 (CAr), 126.5
Ar), 124.7 (CAr), 123.7 (CAr), 121.9 (CAr), 119.6 (C=C), 119.2 (C=C),
09.7(Cpyr), 108.3 (Cpyr), 108.0 (Cpyr), 107.4 (Cpyr), 106.6 (Cpyr), 106.2
C
[
W(N-2,6-iPr
ylidene)(CHCMe
of N,N-dimethylanilinium B(Ar )
and a seven drops of MeCN was added slowly to a stirred solution of 3
17.5 mg, 0.015 mmol) dissolved in 2 mL CH Cl . The reaction mixture
2 6 3
C H )(1,3-diisopropylimidazol-2-
1
(
+
F
-
2
Ph)(OSiPh
3
F
)) ][B(Ar )
4
]MeCN (4). At -30 °C a solution
C
pyr), 66.2, 56.5, 35.4, 35.0, 27.9, 27.6, 24.3, 23.6, 22.9, 21.9, 19.8,
-
4
(15.9 mg, 0.015 mmol) in 1 mL CH Cl
2
2
1
8
6.0 ppm; elemental anal. calcd. (%) for C43
.42. Found: C, 61.82; H, 7.32; N, 8.33.
61 5
H N W: C, 62.09; H, 7.39; N,
(
2
2
was stirred for 2 h at room temperature. Then, all volatiles were removed
in vacuo and the product was co-evaporated five times with n-pentane.
The yellow solid was crystallized from diethyl ether and n-pentane to get
W(N-2,6-iPr
2
C
6
H
3
)(1,3-diisopropylimidazol-2-
Ph)(2,5-Me pyr)(OC (2).
ylidene)(CHCMe
2
2
6
F
5
)
Pentafluorophenol
This article is protected by copyright. All rights reserved.

ChemCatChem
10.1002/cctc.201700189
FULL PAPER
1
analytically pure product; yield 31.1 mg (93%): H NMR (400 MHz, C
6
D
6
)
(CAr), 126.2 (CAr), 124.3 (CAr), 123.9 (CAr), 121.2 (CAr), 119.5 (C=C),
1
F
-
δ = 11.55 (s, 1H, W=CH, JC-H = 115.5 Hz), 8.43 (brs, 8H, Ar), 7.69 (s, 4H,
118.1 (m, para-CH (B(Ar )
29.1, 27.6, 24.8, 24.3, 23.9, 23.0, 22.9, 14.4 ppm; elemental anal. calcd.
(%) for C82 W: C 51.26, H 4.51, N 2.92; found: C 51.35, H
4.45, N 3.08.
4
)), 66.3, 55.2 55.0, 34.8, 32.4, 30.7, 30.2,
Ar), 7.21 (m, 10H, Ar), 7.11 (m, 6H, Ar), 7.01 (m, 7H, Ar), 6.26 (s, 2H,
2
2
HC=CH), 4.04 (sept, 2H, iPr,
J
H-H = 6.7 Hz), 3.41 (sept, 2H, iPr,
J
J
H-
H-
4 3
H86BF29N O
2
H
= 7.0 Hz), 1.56 (s, 3H, Me), 1.51 (s, 3H, Me), 1.21(d, 6H, iPr,
2
H
= 6.9 Hz), 0.59 (m, 12H, iPr), 0.49 (d, 6H, iPr, JH-H = 6.4 Hz), 0.40 (s,
1
9
13
3
H, Me) ppm;
F NMR (376 MHz,
C
1
6
D
6
)
δ = -62.08 ppm;
C NMR
W(N-2,6-iPr
2
C
6
H
3
)(1,3-diisopropylimidazol-2-
Ph)(OtBu) (7). A solution of 1,3-diisopropylimidazol-2-
(
101 MHz, CD
2 2
Cl ) δ = 295.7 (W=C, JC-H = 114.0 Hz), 186.7 (N-C-N),
ylidene)(CHCMe
2
2
2
1
62.4 (q, ipso-C,
J
B-C = 49.9 Hz), 150.5 (ipso-CMe
2
Ph), 147.7 (ipso-N-
ylidene (71.5 mg, 0.47 mmol) in 2 mL n-pentane was added dropwise to
a stirred solution of pre-7 (150.0 mg, 0.24 mmol) dissolved 4 mL n-
pentane. The reaction mixture was stored for 3 h at room temperature.
The product crystallized out of the reaction mixture. The yellow solution
was separated from the crystals and the solvent was partially removed in
F
-
Dipp), 144.7 (CAr), 136.4 (CAr), 135.4 (brs, ortho-CH (B(Ar )
4
)), 135.3
F
-
(
CAr), 130.9 (CAr), 130.7 (CAr), 129.4 (m, C-CF (B(Ar ) )), 129.0 (CAr),
3 4
1
1
28.8 (CAr), 128.5 (CAr), 128.0 (CAr), 127.2 (CAr), 126.5 (CAr), 126.4 (CAr),
24.0 (CAr), 123.8 (CAr), 121.1 (CAr), 119.1 (C=C), 118.1 (m, para-CH
F
-
(
B(Ar )
4
)), 66.2, 54.8, 54.1, 31.8, 30.2, 29.1, 25.1, 24.3, 23.7, 22.7,
5.7 ppm; elemental anal. calcd. (%) for C83 OSiW: C, 54.68; H,
.15; N, 3.07. Found: C, 54.59; H, 4.29; N, 3.17.
vacuo and the remaining dissolved product was crystallized at -30 °C;
1
1
4
H75BF24N
4
yield 143.9 mg (65%): H NMR (400 MHz, C
6
D
6
, major isomer syn)
1
2
δ = 10.67 (s, 1H, W=CH,
J
C-H = 120.4 Hz), 7.57 (d, 2H, Ar,
J
H-
2
H
= 8.6 Hz), 7.20 (t, 2H, Ar,
HC=CH), 4.64 (sept, 2H, iPr,
JH-H = 7.4 Hz) 7.5 (m, 4H, Ar), 6.15 (s, 2H,
2
[
W(N-2,6-iPr
ylidene)(CHCMe
.006 mmol) was suspended in 2 mL CH
2
C
6
H
3
)(1,3-diisopropylimidazol-2-
J
H-H = 6.7 Hz), 4.51 (brs, 1H, iPr) 4.40
+
-
2
2
Ph)(2,5-dimepyr) ][B(ArF)
4
]
(5).
and
1
(50 mg,
(sept, 1H, iPr, JH-H = 6.7 Hz), 2.10 (s, 3H, Me), 1.81 (s, 3H, Me), 1.72 (s,
2
0
2
Cl
2
a
solution of
9H, tBu), 1.37 (d, 6H, iPr, JH-H = 6.7 Hz), 1.31 (s, 9H, tBu), 1.29 (d, 3H,
F
-
2
13
dimethylanilinium B(Ar )
4
(62.6 mg, 0.006 mmol) in 2 mL diethyl ether
iPr,
major isomer syn) δ = 254.0 (W=C,
153.7 (ipso-CMe Ph), 152.4 (ipso-N-Dipp), 128.4 (CAr), 126.2 (CAr), 125.4
(CAr), 123.7 (CAr), 123.6 (CAr), 116.1 (C=C), 75.7 (OCMe ), 74.1 (OCMe ),
6 6
JH-H = 6.7 Hz), 0.77 (brs, 15H, iPr) ppm; C NMR (101 MHz, C D ,
1
was added. The suspension immediately turned into a yellow orange
solution. The reaction mixture was stirred for 1 h at room temperature.
Then the solvent was removed and the resulting residue was extracted
twice with n-pentane to remove any dimethylaniline and pyrrole. The
JC-H = 120.4 Hz), 195.8 (N-C-N),
2
3
3
65.9, 53.3, 52.8, 52.2, 50.5, 36.7, 33.6, 33.0, 32.3, 31.2, 27.2, 26.6, 25.3,
24.8, 24.2, 23.2, 23.1, 23.1, 22.6, 15.5 ppm; elemental anal. calcd. (%)
remaining solid was crystallized from a mixture of CH
2 2
Cl , diethyl ether
and n-pentane. 5 was obtained in 92% yield in form of light yellow
for C39
5.57.
63 3 2
H N O W: C, 59.31; H, 8.04; N, 5.32. Found: C, 58.99; H, 8.21; N,
1
1
crystals. H NMR (400 MHz, CD
2
Cl
2
): δ = 12.11 (s, 1H, W=CH,
J
C-
H
= 124.5 Hz), 7.74 (brs, 8H), 7.58 (s, 4H), 7.41 (m, 6H), 7.22 (m, 4H),
2
6
2
,19 (s, 1H), 5,97 (s, 1H), 4.32 (sept, 2H,
J
H-H = 6.6 Hz), 3.29 (sept, 2H,
[
W(N-2,6-iPr
ylidene)(CHCMe
dimethylanilinium B(Ar )
2 6 3
C H )(1,3-diisopropylimidazol-2-
+
F
-
J
H-H = 6.8 Hz), 2.45 (s, 3H), 2.00 (s, 3H), 1.77 (s, 3H), 1.69 (s, 3H), 1,28
2
Ph)(OtBu) ][B(Ar )
4
] (8). At -30 °C a solution of N,N-
1
9
F
-
(
m, 18H), 0.89 (s, 3H), 0.87 (s, 3H) ppm; F NMR (376 MHz, CD
2
Cl
2
):
4
(95.3 mg, 0.09 mmol) in 2 mL diethyl ether was
1
3
1
δ = -62.81 ppm; C NMR (101 MHz, CD
= 124.5 Hz), 172.0 (N-C-N), 162.4 (q, ipso-C
ipso-CMe Ph), 149.4 (ipso-N-Dipp), 144.8 (CAr), 135.4 (brs, ortho-CH
2
Cl
2
): δ = 298.4 (W=C,
J
C-
added to a solution of 3 (71.0 mg, 0.09 mmol) in 2 mL diethyl ether. The
reaction mixture was stirred for 1 h at room temperature. All volatiles
were removed from the yellow solution in vacuo. The yellow oil was co-
evaporated five times with n-pentane. The yellow solid was recrystallized
2
H
JC-B = 50.0 Hz), 150.4
(
(
2
F
-
B(Ar )
4
)), 129.5 (CAr), 129.3 (CAr), 128.8 (CAr), 127.3 (CAr), 126.6 (CAr),
1
24.6 (CAr), 123.9 (CAr), 122.7 (C=C), 121.2 (C=C), 118.1 (m, para-CH
in diethyl ether and n-pentane to get analytically pure product; yield
F
-
1
(
B(Ar )
4
)), 103.5 (Cpyr), 100.3 (Cpyr), 57.7, 56.0, 32.5, 31.1, 29.0, 24.3,
1
21.4 mg (73%): H NMR (400 MHz, CD
2
Cl
2
,
major isomer syn)
2
4.1, 23.6, 23.2, 18.6, 15.8 ppm; elemental anal. calcd. (%) for
W: C 51.77, H 4.09, N 3.50; found: C 51.61, H 4.13, N 3.47.
1
F
-
δ = 10.57 (s, 1H, W=CH, JC-H = 112.3 Hz), 7.74 (s, 8H, B(Ar )
4
), 7.57 (s,
4
), 7.42 (m, 2H, Ar), 7.36 (m, 4H, Ar), 7.22 (m, 4H, Ar),
F
-
69 4
C H65BF24N
4
4
H, B(Ar )
.45(sept, 2H, iPr,
2
2
J
H-H = 6.7 Hz), 3.34 (sept, 2H, iPr, JH-H = 6.9 Hz),
2
[
W(N-2,6-iPr
ylidene)(CHCMe
.036 mmol) was dissolved in 2 mL CH
2
C
6
H
3
)(1,3-diisopropylimidazol-2-
1.80 (s, 3H, Me), 1.65 (s, 3H, Me), 1.53 (s, 9H, tBu), 1.37 (d, 6H, iPr, JH-
+
-
2
2
2
Ph)(OC
6
F
5
)(tBuCN) ][B(ArF)
4
]
(6).
5
(56.8 mg,
H
= 6.7 Hz), 1.25 (d, 6H, iPr,
= 6.8 Hz), 0.96 (d, 6H, iPr,
J
H-H = 6.8 Hz), 1.12 (d, 6H, iPr,
J
H-
2
19
0
2
Cl
2
and
a
solution of
H
J
H-H = 6.9 Hz) ppm; F NMR (376 MHz,
Cl ) δ = 273.9 (W=C,
1
3
pentafluorophenol (6.52 mg, 0.036 mmol) in 1 mL diethyl ether was
added. The reaction mixture was stirred for 10 min at room temperature
followed by the addition of five drops of tbutylnitrile. After another hour of
stirring at room temperature the solvent was removed and the resulting
residue was extracted twice with n-pentane to remove any
dimethylaniline and pyrrole. The remaining solid was crystallized from a
CD
2
Cl
2
) δ = -62.8 ppm; C NMR (101 MHz, CD
2
2
1
2
J
C-H = 112.3 Hz), 178.2 (N-C-N), 162.4 (q, ipso-C JC-B = 49.8 Hz), 151.2
Ph), 148.4 (ipso-N-Dipp), 145.1 (CAr), 144.0 (CAr), 135.2 (brs,
(ipso-CMe
ortho-CH (B(Ar )
(CAr), 127.3 (CAr), 126.3 (CAr), 126.1 (CAr), 125.9 (CAr), 123.6 (CAr), 123.4
2
F
-
F
-
4
4
)), 129.5 (m, ortho-CH (B(Ar ) )), 129.5 (CAr), 128.3
F
-
(CAr), 122.0 (CAr), 121.6 (C=C), 120.9 (C=C), 118.1 (m, para-CH (B(Ar )
)), 88.5 (OCMe ), 66.0, 56.4, 55.5, 54.5, 54.3, 34.5, 34.1, 33.4, 32.8, 32.0,
29.8, 29.0, 23.6, 23.5, 23.3, 23.1, 22.7, 15.4, 14.1 ppm; elemental anal.
calcd. (%) for C67 OW: C, 50.94; H, 4.21; N, 2.66. Found: C,
50.80; H, 4.32; N, 2.82.
4
mixture of diethyl ether and n-pentane. Complex 6 was obtained in 85%
3
1
yield in form of yellow crystals. H NMR (400 MHz, CD
2
Cl
2
, major isomer,
1
syn): δ = 12.39 (s, 1H, W=CH,
J
C-H = 116.1 Hz), 7.73 (brs, 8H, Ar), 7.56
H66BF24N
3
(
s, 4H, Ar), 7.45 (m, 4H, Ar), 7.31 (m, 1H, Ar), 7.23 (s, 3H, Ar), 7.12 (s,
2
2
2
H, HC=CH), 4.26 (sept. 2H, iPr,
J
H-H = 6.7 Hz), 3.50 (sept. 2H, iPr,
J
J
H-
2
H
= 6.9 Hz), 1.93 (s, 3H, Me), 1.73 (s, 3H, Me), 1.35 (d, 6H iPr,
H-
2 6 3
W(N-2,6-iPr C H )(1,3-diisopropylimidazol-2-
2
H
= 6.9 Hz), 1.27 (s, 9H, tBu), 1.19 (d, 6H, iPr, JH-H = 6.7 Hz), 1.01 (d, 6H,
3 2 2
ylidene)(CHCMe Ph)(OCMe(CF ) )
(9).
A
solution
of
1,3-
2
2
2
19
iPr,
J
H-H = 6.7 Hz), 0.84 (d, 6H, iPr,
Cl ): δ = -62.89 (s), -163.10 (m), -164.52 (m), 169.61
s) ppm; C NMR (101 MHz, CD
J
H-H = 6.9 Hz) ppm;
F NMR
diisopropylimidazol-2-ylidene (17.8 mg, 0.12 mmol) in 1 mL diethyl ether
(
(
376 MHz, CD
2
2
was added to a solution of pre-9 (100.0 mg, 0.12 mmol), dissolved in
1
3
1
2
Cl
2
): δ = 298.2 (W=C, JC-H = 116.1 Hz),
C-B = 49.7 Hz), 149.9 (ipso-CMe Ph),
47.8 (ipso-N-Dipp), 145.7 (CAr), 141.3 (CAr), 141.4 (CArF), 140.5 (CArF),
4
mL diethyl ether. The reaction mixture was kept for 3 h at room
2
1
1
1
1
85.7 (N-C-N), 162.4 (q, ipso-C
J
2
temperature. The product crystallized out of the reaction mixture. The
yellow solution was separated from the crystals and the solvent was
F
-
38.9 (CArF), 138.7 (CAr), 137.6 (CArF), 135.4 (brs, ortho-CH (B(Ar )
4
)),
partially removed in vacuo and the remaining dissolved product was
F
-
29.7 (CAr), 129.5 (m, ortho-CH (B(Ar )
4
)), 129.2 (CAr), 127.9 (CAr), 126.6
1
crystallized at -30 °C; yield 80.1 mg (68%): H NMR (400 MHz, CD
2
Cl
2
)
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ChemCatChem
10.1002/cctc.201700189
FULL PAPER
1
δ = 11.25 (s, 1H, W=CH, JC-H = 118.8 Hz), 7.49 (m, 2H, Ar), 7.34 (m, 2H,
Puglisi, R. R. Schrock and A. H. Hoveyda, J. Am. Chem. Soc. 2006, 128,
5153-5157; e) G. A. Cortez, R. R. Schrock and A. H. Hoveyda, Angew.
Chem. Int. Ed. 2007, 46, 4534-4538; f) S. J. Malcolmson, S. J. Meek, E. S.
Sattely, R. R. Schrock and A. H. Hoveyda, Nature 2008, 456, 933-937; g) I.
Ibrahem, M. Yu, R. R. Schrock and A. H. Hoveyda, J. Am. Chem. Soc.
2009, 131, 3844–3845; h) D. R. Cefalo, A. F. Kiely, M. Wuchrer, J. Y.
Jamieson, R. R. Schrock and A. H. Hoveyda, J. Am. Chem. Soc. 2001, 123,
Ar), 7.20 (m, 1H, Ar), 7.09 (m, 2H, Ar), 7.00 (m, 3H, Ar), 4.44 (sept, 2H,
2
iPr, JH-H = 6.5 Hz), 3.82 (brs, iPr, 2H), 1.91 (s, 3H, Me), 1.70 (s, 3H, Me),
2
1
.50 (s, 3H, Me), 1.19 (d, 6H, iPr,
J
H-H = 6.7 Hz), 0.89 (m, 21H) ppm;
1
9
2
F NMR (376 MHz, CD
2
Cl
2
) δ = -75.55 (q, 3F, JF-F = 9.2 Hz) -75.65 (q,
2
2
2
3
H,
= 10.8 Hz) ppm; C NMR (101 MHz, CD
= 118.8 Hz), 190.3 (N-C-N), 151.9 (ipso-CMe
28.9 (CAr), 126.4 (CAr), 126.3 (CAr), 126.0 (CAr), 124.4 (CAr), 118.8 (C=C),
J
F-F = 9.8 Hz), -76.95 (sept, 3F, JF-F = 9.6 Hz),-77.28 (sept, 3F, J
F-
1
3
1
F
2
Cl
2
) δ = 266.3 (W=C,
J
C-
3
139-3140; i) D. S. La, E. S. Sattely, J. G. Ford, R. R. Schrock and A. H.
H
1
2
Ph), 150.7 (ipso-N-Dipp),
Hoveyda, J. Am. Chem. Soc. 2001, 123, 7767-7778; j) S. J. Dolman, E. S.
Sattely, A. H. Hoveyda and R. R. Schrock, J. Am. Chem. Soc. 2002, 124,
6991-6997; k) A. F. Kiely, J. A. Jernelius, R. R. Schrock and A. H.
Hoveyda, J. Am. Chem. Soc. 2002, 124, 2868-2869; l) S. J. Dolman, R. R.
Schrock and A. H. Hoveyda, Org. Lett. 2003, 5, 4899-4902.
2
2
8
2
2.2 (q, CF
9.9, 27.4, 25.0, 24.7, 23.4, 23.2, 18.6, 16.8 ppm; elemental anal. calcd.
W: C, 46.58; H, 5.11; N, 4.18. Found: C, 46.49; H,
3 3
, JC-F = 28.3 Hz), 80.8 (q, CF , JC-F = 27.8 Hz), 52.1, 35.8,
(
%) for C39
H
51
F
12
N
3
O
2
5
.42; N, 4.18.
[3] a) v. M. Marx, A. H. Sullivan, M. Melaimi, S. C. Virgil, B. K. Keitz, D.
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carried out in closed cap vials in 1,2-dichloroethane (2 mL) pasted over
freshly dried neutral alumina oxide using catalysts 2, 4, 5, 6, 8 and 9 and
the corresponding substrates pasted over freshly dried neutral alumina
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General procedure for cyclopolymerization: Reactions were carried
out in 1,2-dichloroethane. 50 mg of the monomer (0.26 – 0.45 mmol)
were dissolved in 0.5 mL solvent. To this solution the corresponding
catalyst dissolved in 0.5 mL solvent was added at once
(
catalyst:monomer = 1:50). Polymerizations with complexes 4, 5, 6 and 8
were run for 3 h at 80 °C. Polymerizations with 9 were run for 16 h at
0 °C. Reaction mixtures were finally cooled to room temperature and
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resulting precipitate was isolated by centrifugation and dried in vacuo.
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1
523595 (6) and 1503538 (8)) can be obtained free of charge from The
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[
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This
work
was
supported
by
the
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Keywords: N-heterocyclic carbene (NHC) • alkylidene •
tungsten • metathesis • cationic
[
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Entry for the Table of Contents
FULL PAPER
D. A. Imbrich, I. Elser, W. Frey, M. R.
Buchmeiser*
Page No. – Page No.
First Neutral and Cationic Tungsten
Imido Alkylidene N-Heterocyclic
Carbene Complexes
Functional group tolerant cationic W-imido alkylidene NHC complexes showed high
productivity and activity in olefin metathesis reactions and also substantial
functional group tolerance.
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