Controlled Oxidation of an NHC-Stabilized Phosphinoaminosilylene with Dioxygen

Article abstract of DOI:10.1021/acs.inorgchem.5b02580

Reaction of the N-heterocyclic carbene-stabilized phosphinoaminosilylene ArN(SiMe₃)Si(IⁱPr)PPh₂ (Ar = 2,6-ⁱPr₂C₆H₃, IⁱPr = 1,3-diisopropyl-4,5-dimethyl-imidazol-2-ylid

Full text of DOI:10.1021/acs.inorgchem.5b02580

Article
pubs.acs.org/IC
Controlled Oxidation of an NHC-Stabilized Phosphinoaminosilylene
with Dioxygen
,
†
‡
§
,‡
Haiyan Cui,* Jianying Zhang, Yunwen Tao, and Chunming Cui*
†Jiangsu Key Laboratory of Pesticide Science, College of Sciences, Nanjing Agricultural University, Nanjing 210095, People’s Republic
of China
‡
State Key Laboratory and Institute of Elemento-organic Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
§Department of Chemistry, Southern Methodist University, 3215 Daniel Avenue, Dallas, Texas 75275-0314, United States
*
S Supporting Information
ABSTRACT: Reaction of the N-heterocyclic carbene-stabilized
i
phosphinoaminosilylene ArN(SiMe )Si(I Pr)PPh (Ar =
3
2
i
i
2
,6- Pr C H , I Pr = 1,3-diisopropyl-4,5-dimethyl-imidazol-2-
2 6 3
ylidene) (2) with dioxygen resulted in the formation of the
i
two products ArN = Si(I Pr)(OSiMe )(OPPh ) (3) and ArN =
3
2
i
Si(I Pr)(OSiMe )PPh (4), and the ratios of the two products
3
2
can be controlled by the reaction temperatures and dioxygen concentrations.
6
INTRODUCTION
oxygen. However, only a few well-characterized products from
■
oxygenation of silylenes with dioxygen have been reported by
several groups (Figure 1). This is probably because the
Controlled oxidation of organic and main group elemental
compounds by dioxygen presents the most environmentally
benign and atom-economic method for the synthesis of desired
oxygen-containing products. Particularly, the oxidation of
reactive intermediates can lead to the discovery of new catalytic
processes for the controlled oxidation of organic and
7
1
,2
1
organometallic substrates. Over the past few decades, extensive
experimental and theoretical studies on the reaction of
dioxygen with carbenes have been conducted. It has been
generally accepted that the reaction may involve the initial
trapping of carbene by O to give highly photolabile carbonyl
2
3
oxides (diradical), which may undergo photolytic decom-
position via two pathways (Scheme 1): (a) loss of single oxygen
atom resulting in the corresponding carbonyl compounds and
(b) rearrangement via dioxiranes to esters.
Figure 1. Known isolated products from reactions of silylenes with
dioxygen.
Scheme 1. Known Mechanisms for the Reactions of
Carbenes and Silylenes with Dioxygen
oxidation by dioxygen cannot be easily controlled. Theoretical
studies on the reaction of silylenes with oxidants have been
8
conducted. Thus, the investigation of the factors that control
the oxidation reactions by dioxygen is of great interest and
crucial to the understanding the reaction mechanism.
RESULTS AND DISCUSSION
Herein, we report on the reaction of the N-heterocyclic carbene
■
i
4
(NHC)-stabilized silylene ArN(SiMe )Si(I Pr)PPh (2, Ar =
3
2
Although the analogous studies on the reactions of silylenes,
i
i
2
,6- Pr C H , I Pr = 1,3-diisopropyl-4,5-dimethylimidazol-2-
2 6 3
the silicon carbene analogues, with dioxygen have received
much less attention, the mechanism has been proposed to be
ylidene) with dioxygen, leading to the formation of the two
i
4
products ArNSi(I Pr)(OSiMe )OPPh (3) and ArNSi-
3
2
very similar to that of carbenes. The great successes on the
5
synthesis of stable silylenes including donor-stabilized silylenes
have stimulated the renewed interest in the reactions of
silylenes with dioxygen and other small molecules containing
Received: July 30, 2015
4
©
XXXX American Chemical Society
A
DOI: 10.1021/acs.inorgchem.5b02580
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
i
(
I Pr)(OSiMe )PPh (4). Interestingly, the product distribu-
Compound 2 exhibits high thermal stability in solutions, but
3
2
tions can be controlled by the reaction temperature and
dioxygen concentration. The phosphinoaminosilylene 2 was
obtained as red crystals in high yield by the reaction of the
it is extremely air and moisture sensitive. Exposure of the red
solution of 2 in tetrahydrofuran (THF) to O at −110 °C
2
resulted in an immediate decoloration. Colorless crystals of 3
were obtained in 64% yield by crystallization from n-hexane at
room temperature (Scheme 2). Compound 3 was fully
characterized by multinuclear NMR, IR spectroscopy, and
i
9
aminochlorosilylene ArN(SiMe )Si(I Pr)Cl (1) with LiPPh
3
2
1
31
13
(
Scheme 2) and has been fully characterized by H, P, C,
29
and Si NMR spectroscopy, elemental analysis, and an X-ray
single-crystal analysis.
31
elemental analysis. The P NMR exhibits at δ 103.8 ppm. The
2
9
Si NMR spectra for the central silicon atom of 3 exhibits a
2
doublet signal at δ −104.00 ppm (SiN, J = 14.51 Hz).
Scheme 2. Reaction of 2 with Dioxygen at Different
Temperatures
SiP
The X-ray crystal-structure analysis confirmed compound 3 to
be an NHC-stabilized 1-siloxy-1-phosphinoxysilaimine, consist-
ing of a four-coordinated silicon atom attached to two oxygen
atoms (Figure 3). The Si1−N1 bond length (1.596(2) Å) is in
The 29Si resonance for the central silicon atom (δ = 4.23
1
ppm, doublet, J = 78.37 Hz) is comparable to most observed
SiP
for the known NHC-supported silylenes (−8.78 to 10.9
1
0
13
Figure 3. Ortep drawing of 3 with ellipsoids given at the 50%
probability level. Hydrogen atoms were omitted for clarity. Selected
bond lengths (Å) and angles (deg): P1−O2 1.619(2), Si1−N1
ppm). The C NMR signal for the NHC central carbon
atom in 2 appears at 166.25 ppm, consistent with those found
10,11
31
in the NHC → Si donor−acceptor complexes.
NMR spectrum of 2 exhibits at δ −33.6 ppm. The structure of
, shown in Figure 2, features a trigonal-pyramidal silicon
The
P
1
.596(2), Si1−O1 1.643(2), Si1−O2 1.661(2), Si1−C13 1.929(3),
Si2−O1 1.646(2), N1−C1 1.369(4), N1−Si1−O1 115.36(12), N1−
Si1−O2 118.61(12), O1−Si1−O2 102.20(11), N1−Si1−C13
2
1
12.00(13), O1−Si1−C13 107.10(12), O2−Si1−C13 99.85(11),
Si1−O1−Si2 133.50(13), P1−O2−Si1 135.49(14).
the range of reported free- and donor-stabilized silaimines
1
3
(
1.568−1.620 Å); Si1−C13 bond length is 1.929(3) Å, which
10,11
is very similar to C−Si coordinate bond length.
represents a rare example of donor-stabilized dioxysilaimine.
Compound
3
Interestingly, the exposure of a solution of 2 in THF to O at
2
room temperature led to the isolation of the new compound 4
as light yellow crystals in 23% yield from n-hexane extract. The
subsequent crystallization also resulted in the isolation of 3 in
ca. 50% yield (Scheme 2). Compound 4 is air and moisture
sensitive and was fully characterized by multinuclear NMR, IR
3
1
spectroscopy, and elemental analysis. The P NMR exhibits at
Figure 2. Ortep drawing of 2 with ellipsoids given at the 50%
probability level. Hydrogen atoms were omitted for clarity. Selected
bond lengths (Å) and angles (deg): P1−Si2 2.3748(7), Si1−N1
29
δ −35.40 ppm. The Si NMR spectra for the central silicon
atom of 4 exhibits a doublet signal at δ −84.94 (Si−P, J
1
=
SiP
1
.7518(15), Si2−N1 1.8132(15), Si2−C16 1.9909(18); N1−Si2−C16
01.58(7), N1−Si2−P1 108.47(5), C16−Si2−P1 99.47(5).
38.26 Hz) ppm. The X-ray crystal-structure analysis confirmed
compound 4 to be an NHC-stabilized 1-siloxysilaimine,
consisting of a four-coordinated silicon atom attached to one
oxygen atom (Figure 4). The Si1−N1 bond length is
1.6021(12) Å, in line with the value found for SiN double
1
center, revealing the presence of a stereochemically active lone
pair of electrons at the Si(II) atom (the sum of angles at the Si2
atom = 309.5°), which is very similar to that of 1. The Si2−C16
bond length (1.9909(18) Å) is in the reported range for NHC-
1
3
bond length (1.568−1.620 Å); Si1−C13 bond length
10,11
(1.9471(16) Å) is a typical coordinate bond length.
The formation of 3 and 4 at room temperature prompted us
to investigate the effects of temperature on the product
distributions. Thus, the reaction of 2 with dioxygen were
conducted from −80 to 40 °C with the fixed concentration and
pressure of dioxygen in 1 min. It was found that the amount of
3 decreased with the elevation of temperatures (Table 1, entries
10
stabilized halosilylenes (1.980(3) and 2.0023(19) Å) but
t
t
longer than those in the NHC → :Si(Si Bu )(R) [R = Bu Si
3
3
11b,c
(
1.933(4) Å), R = H (1.942(3) Å)]
and silacyclopentadie-
The Si2−P1 bond length (2.3748(7) Å) is
comparable to a Si−P single bond (2.27−2.31 Å).
1
1a
nylidenes.
12
B
DOI: 10.1021/acs.inorgchem.5b02580
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
Scheme 3. Proposed Pathways for the Dioxygen Reactions
with 2
Figure 4. Ortep drawing of 4 with ellipsoids given at the 50%
probability level. Hydrogen atoms were omitted for clarity. Selected
bond lengths (Å) and angles (deg): P1−Si1 2.2687(7), O1−Si1
1
1
.6411(10), O1−Si2 1.6482(11), Si1−N1 1.6021(12), Si1−C13
.9471(16), N1−C1 1.3654(18), Si1−O1−Si2 141.03(6), N1−Si1−
−104.617 kcal/mol, while G(3) − G(E) is −12.049 kcal/mol.
From the calculations, we proved that this reaction pathway is
valid in each step. And the calculated free energy data indicated
that the whole pathway could proceed spontaneously.
However, the pathway for the reaction from 2 to 4 is unclear
until now. We assumed the reaction may proceed through the
intermediate silanone D under low concentration of dioxygen,
followed by 1,3-silyl migration to give 4 (Scheme 3, path b).
Since the reactions are rapid even at very low temperature,
attempts to detect the possible intermediates are not possible
under the current conditions.
O1 116.42(6), N1−Si1−C13 113.31(6), O1−Si1−C13 106.33(6),
N1−Si1−P1 110.84(5), O1−Si1−P1 108.22(4), C13−Si1−P1
1
00.42(5), C1−N1−Si1 148.72(11).
a
Table 1. Product Distributions of the Reaction of 2 with
Dioxygen under Different Conditions
c
temperature
O2
pressure
product ratios
actual yield
(%, 3:4)
b
entry
(°C)
(3:4)
1
2
3
4
5
6
7
8
−80
−60
−40
−20
0
1
1:0.05
1:0.08
1:0.14
1:0.21
1:0.29
1:0.71
1:0.38
1:0.74
85.5:4.3
1
79.4:6.3
1
71.4:10.0
63.7:13.4
62.9:18.2
30.4:21.6
57.1:21.7
50.8:37.6
CONCLUSIONS
1
■
1
In summary, we have shown that the reaction of the NHC-
stabilized silylene 2 with dioxygen resulted in the formation of
the two products 3 and 4 with different ratios under different
temperatures and dioxygen concentrations. The results
indicated that 3 and 4 are formed via different reaction
mechanisms. This is the first observation that the reaction
product distributions of a silylene with dioxygen are dependent
on the concentrations of dioxygen and temperatures. Further
studies on the reactions of various silylenes with dioxygen
under controlled manner may lead to the discovery of green
routes for the synthesis of oxygen-containing materials such as
silicones by the oxidation of silylene intermediates with
dioxygen.
40
1
0
0.5
0.1
0
a
b
Conditions: 1 min, 40 mg of 2 in 5 mL of THF. The partial pressure
c
1
relative to that of argon under normal pressure. Determined by H
NMR spectra.
1
−6). However, above 40 °C, a significant amount of impurities
were also formed. Since the temperature is related to the
solubility of dioxygen, the effects of the partial pressure of
dioxygen were also studied by mixing of oxygen with argon at 0
°
C under the normal pressure. It can be seen from Table 1
(entries 5, 7, and 8) that, with the decrease of dioxygen
EXPERIMENTAL SECTION
pressure, the amount of 4 increased substantially. In addition,
the exposure of 4 to dioxygen did not lead to the formation of
■
General Considerations. All operations were performed under an
atmosphere of dry argon or nitrogen by using modified Schlenck line
and glovebox techniques. All solvents were freshly distilled from Na
and degassed immediately prior to use. Elemental analyses were
3
. These experiments indicated that 3 and 4 are formed via
different mechanisms and that dioxygen concentration has
significant effects on the ratios of the two products.
1
13
29
performed on an Elemental Vario EL analyzer. The H, C, and Si
On the basis of these experiments, we proposed the
formation of 3 and 4 are from two pathways. The pathway
for the reaction from 2 to 3 was explored theoretically by
density functional theory (DFT) calculations at the B3LYP/6-
NMR spectroscopic data were recorded on Bruker Mercury Plus 300,
4
00, and 600 MHz NMR spectrometers. Infrared spectra were
recorded on a Bio-Rad FTS 6000 spectrometer. The UV−vis spectra
were recorded on a Shimadzu UV-2450 spectrometer, and emission
spectra were recorded on an Edinburgh Analytical Instruments
3
1G(d,p) level of theory (Scheme 3, path a). The reaction of 2
7c,d
i
9
and O initially gives dioxasilirane C, which underwent first
FL900CD spectrometer. ArN(SiMe )Si(I Pr)Cl (1) (Ar =
2
3
i
i
1
,2-PPh2 migration through transition state TS1 to give
2,6- Pr C H , I Pr = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene)
2 6 3
was synthesized according to published procedure.
silaester E, then 1,3-silyl migration from the nitrogen atom to
the oxygen to afford final product 3 via transition state TS2
Synthesis of Ph PLi·1.5THF. Lithium crumbs (0.35 g, 50 mmol)
2
was added to a stirred solution of Ph PCl (4.41 g, 20 mmol) in THF
2
(
(
Figure 5). And the reaction step from C to E has a barrier
free energy) of 18.56 kcal/mol. And the barrier from E to 3 is
(
50 mL) at −78 °C. The mixture was slowly warmed to room
temperature and stirred overnight, whereupon the solution became
dark red. The volatiles were removed under vacuum. The residue was
extracted with toluene (40 mL). After filtration and removal of
1
4.57 kcal/mol. The energy difference between geometry C
with the total energy of geometry 2 and a triplet oxygen
molecule as G(C) − [G(2) + G( O )], which is −67.141 kcal/
mol. However, the energy difference G(E) − G(C) equals
3
2
solvents, the remaining residue was washed with n-hexane (25 mL ×
1
2) to afford a yellow powder of Ph PLi·1.5THF (5.0 g, 83.3%). H
2
C
DOI: 10.1021/acs.inorgchem.5b02580
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
Figure 5. DFT-calculated free energy profile for synthesis of 3.
NMR (400 MHz, C D ): δ 1.17 (m, 6 H,CH CH O), 3.41 (m, 6H,
145.77, 146.00, 146.22, 149.29 (Ar-C), 153.62 (carbene-C) ppm; 29Si
6
6
2
2
2
CH CH O), 6.95 (m, 2H, Ar-H), 7.17 (m, 4H, Ar-H), 7.89 (m, 4H,
NMR (79.49 MHz, C D ): δ −104.00 (d, SiN, J = 14.51 Hz),
2
2
6
6
SiP
3
1
Ar-H). P NMR (161.97 MHz, C D ): δ −25.03.
8.54 (Si(CH ) ). Anal. Calcd for C H N O PSi : C, 67.71; H, 8.37;
3 3 38 56 3 2 2
6
6
i
Synthesis of ArN(SiMe )Si(I Pr)PPh (2). A solution of Ph PLi·
.5THF (0.30 g, 1 mmol) in THF (5 mL) was added to a stirred
N, 6.23. Found: C, 67.25; H, 8.72; N, 6.44%.
3
2
2
i
1
Synthesis of ArNSi(IPr) (OSiMe )PPh (4). A solution of 2 (0.15
3
2
solution of 1 (0.49 g, 1 mmol) in THF (10 mL) at −78 °C. The
mixture was slowly warmed to room temperature and stirred
overnight. The volatiles were removed under vacuum. The residue
was extracted with toluene (30 mL × 2). After filtration and removal of
g, 0.23 mmol) in THF (5 mL) was placed in a 100 mL Schlenck flask.
The flask was evacuated and placed under an atmosphere of O . The
2
color of the solution soon changed from red to light yellow. Removal
of the solvents afforded light yellow oil. The mixture was extracted
with hexane (30 mL). Concentration to ca. 2 mL and storage at room
temperature overnight afforded light yellow crystals of 4 (0.035 g,
23.1%). Concentration of the filtrates to ca. 1 mL and storage at
ambient temperature overnight afforded colorless crystals of 3 (0.078
solvents, the remaining residue was washed with n-hexane (20 mL ×
1
2
) to afford a red powder of 2 (0.29 g, 45.2%). mp 206−207 °C. H
NMR (400 MHz, C D ): δ 0.15 (s, 9H, Si(CH ) ), 0.24 (d, 3H,
6
6
3 3
CH(CH ) ), 0.33 (d, 3H, CH(CH ) ), 1.17 (d, 3H, CH(CH ) ), 1.24
3
2
3
2
3 2
(
dd, 6H, CH(CH ) ), 1.33 (m, 9H, CH(CH ) , CCH ), 1.53 (s,
1
3
2
3
2
3
g, 50.3%). mp 212−213 °C. H NMR (400 MHz, C D ): δ 0.25 (s,
6
6
3
4
5
2
H, CCH ), 1.82 (d, 3H, CH(CH ) ), 3.27 (m, 1H, CH(CH ) ),
3
3
2
3 2
9
H, Si(CH ) ), 0.69 (d, J = 6.8 Hz, 6H, CH(CH ) ), 1.16 (d, J = 6.7
3
3
3
2
.21 (m, 1H, CH(CH ) ), 5.65 (m, 1H, CH(CH ) ), 6.92−7.04 (m,
3 2 3 2
Hz, 6H, CH(CH ) ), 1.25 (d, J = 6.8 Hz, 6H, CH(CH ) ), 1.34 (s,
3
2
3 2
H, Ar-H), 7.28−7.40 (m, 5H, Ar-H), 7.70 (m, 1H, Ar-H), 8.33 (s,
6
H, CCH ), 1.46 (d, J = 6.8 Hz, 6H, CH(CH ) ), 4.11 (m, 2H, Ar−
H, Ar-H). 3 P NMR (161.97 MHz, C D ): δ −33.66. C NMR
1
13
3
3 2
6
6
CH(CH ) ), 6.13 (m, 2H, carbene−CH(CH ) ), 6.93−7.05 (m, 5H,
3
2
3
2
(
100.61 MHz, d -THF): δ 3.44 (Si(CH ) ), 10.08, 10.45 (CCH3),
8
3 3
Ar-H), 7.18−7.23 (m, 2H, Ar-H), 7.30 (d, J = 7.4 Hz, 2H, Ar-H), 7.72
1
5
1
=
9.61, 20.54, 21.21, 23.01, 24.23, 25.78, 26.10, 27.71, 28.81, 52.43,
31
(s, 2H, Ar-H), 8.09 (s, 2H, Ar-H). P NMR (161.97 MHz, C D ): δ
6 6
5.46 (CH(CH ) ), 123.75, 124.56, 124.73, 125.85, 127.67, 127.77,
3
2
13
2
−35.40. C NMR (100.61 MHz, C
CCH ), 21.18, 22.31, 22.35, 24.48, 25.55 (CH(CH
CH(CH ), 50.87, 50.91 (carbene-CH(CH ), 114.24, 122.78,
26.68, 133.57, 136.49, 139.74, 149.39 (Ar-C), 152.64 (d,, J
6
D
6
): δ 2.55 (Si(CH
3
)
3
), 10.15 (
) ), 28.22 (Ar-
3 2
28.76, 134.60, 138.07, 145.27, 147.54, 149.99 (Ar-C), 166.25 (d, J
14.68 Hz, carbene-C). Si NMR (79.49 MHz, C D ): δ 4.23 (d, Si−
CP
29
3
6
6
1
3
)
2
)
3 2
P, J = 78.37 Hz), 1.45 (Si(CH ) ). Anal. Calcd for C H N PSi :
SiP
3
3
38 56
3
2
2
1
=
CP
C, 71.09; H, 8.79; N, 6.55. Found: C, 71.54; H, 7.88; N, 6.95%. UV−
29
4
−1
−1
44.21 Hz, carbene-C). Si NMR (79.49 MHz, C D ): δ −84.94 (d,
vis (THF): ε = 5.35 × 10 L·mol ·cm .
6
6
1
i
Si−P, JSiP = 38.26 Hz), 8.81 (Si(CH ) ). Anal. Calcd for
Synthesis of ArNSi(IPr)(OSiMe )OPPh (3). A solution of 2 (0.15
3 3
3
2
C H N OPSi : C, 69.36; H, 8.58; N, 6.39. Found: C, 69.35; H,
g, 0.23 mmol) in THF (5 mL) was cooled to 110 °C. The flask was
38 56
3
2
4
−1
−1
8
.95; N, 6.28%. UV−vis (THF): ε226 = 1.0244 × 10 L·mol ·cm .
evacuated and placed under an atmosphere of O . The color of the
2
solution soon changed from red to colorless. Removal of the solvents
afforded light yellow oil. The mixture was extracted with hexane (30
mL). Concentration to ca. 2 mL and storage at room temperature
ASSOCIATED CONTENT
■
* Supporting Information
S
overnight afforded colorless crystals of 3 (0.10 g, 63.5%). mp 108−110
1
°
C. H NMR (400 MHz, C D ): δ 0.25 (s, 9H, Si(CH ) ), 1.02 (dd,
The Supporting Information is available free of charge on the
ACS Publications website at DOI: 10.1021/acs.inorg-
chem.5b02580.
6
6
3 3
1
2H, CH(CH ) ), 1.33 (s, 6H, CCH ), 1.37 (d, J = 6.8 Hz, 6H,
3
2
3
CH(CH ) ), 1.52 (d, J = 7.0 Hz, 6H, CH(CH ) ), 4.16 (m, 2H, Ar−
3
2
3
2
CH(CH ) ), 6.03 (m, 2H, carbene−CH(CH ) ), 6.96−7.20 (m, 7H,
3
2
3 2
Ar-H), 7.36 (d, J = 7.5 Hz, 2H, Ar-H), 7.76 (m, 2H, Ar-H), 7.86 (m,
Text giving NMR spectra, X-ray structural character-
ization data for 2−4, computational details, optimized
geometries, and additional references. (PDF)
Crystallographic data for compounds 2−4 and computa-
tional details. (CIF)
13
2
H, Ar-H). 31P NMR (161.97 MHz, C D ): δ 103.88. C NMR
6 6
(
2
100.61 MHz, C D ): δ 2.17 (Si(CH ) ), 10.02 (CCH ), 21.39,
6
6
3
3
3
1.51, 24.14, 24.43 (CH(CH ) ), 28.52 (Ar-CH(CH ) ), 51.12
3 2 3 2
(
1
carbene-CH(CH ) ), 113.69 (CCH ), 122.35, 126.40, 128.36,
3
2
3
28.43, 128.50, 128.86, 129.08, 130.13, 130.31, 130.35, 130.54, 139.01,
D
DOI: 10.1021/acs.inorgchem.5b02580
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
(
6) (a) Ahmad, S. U.; Szilvas
́
i, T.; Irran, E.; Inoue, S. J. Am. Chem.
AUTHOR INFORMATION
Corresponding Authors
E-mail: haiyancui555@163.com.
E-mail: cmcui@nankai.edu.cn.
Notes
■
Soc. 2015, 137, 5828. (b) Filippou, A. C.; Baars, B.; Chernov, O.;
Lebedev, Y. N.; Schnakenburg, G. Angew. Chem. 2014, 126, 576−581;
Angew. Chem., Int. Ed. 2014, 53, 565. (c) Rodriguez, R.; Troadec, T.;
Gau, D.; Saffon-Merceron, N.; Hashizume, D.; Miqueu, K.;
Sotiropoulos, J.-M.; Baceiredo, A.; Kato, T. Angew. Chem., Int. Ed.
2013, 52, 4426. (d) Ghadwal, R. S.; Azhakar, R.; Propper, K.; Dittrich,
B.; John, M. Chem. Commun. 2013, 49, 5987. (e) Ghadwal, R. S.;
Azhakar, R.; Roesky, H. W.; Propper, K.; Dittrich, B.; Goedecke, C.;
Frenking, G. Chem. Commun. 2012, 48, 8186. (f) Khan, S.; Michel, R.;
Koley, D.; Roesky, H. W.; Stalke, D. Inorg. Chem. 2011, 50, 10878.
*
*
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We are grateful to the National Natural Science Foundation of
China and the 973 Program (Grant No. 2012CB821600), the
Fundamental Research Funds for the Central Universities
(
7) (a) Li, W.; Hill, N. J.; Tomasik, A. C.; Bikzhanova, G.; West, R.
Organometallics 2006, 25, 3802. (b) Yao, S.; Xiong, Y.; Brym, M.;
Driess, M. J. Am. Chem. Soc. 2007, 129, 7268. (c) Xiong, Y.; Yao, S.;
(
Grant No. KJQN201551), the National Natural Science
Foundation of China (Grant No. 21402094), and the Natural
Science Foundation of Jiangsu Province (Grant No.
BK20140678).
̈
Muller, R.; Kaupp, M.; Driess, M. Nat. Chem. 2010, 2, 577.
(d) Rodriguez, R.; Gau, D.; Troadec, T.; Saffon-Merceron, N.;
Branchadell, V.; Baceiredo, A.; Kato, T. Angew. Chem., Int. Ed. 2013,
5
(
(
2, 8980.
8) (a) Su, M.-D.; Chu, S.-Y. J. Phys. Chem. A 1999, 103, 11011.
b) Su, M.-D. J. Phys. Chem. A 2002, 106, 9563.
REFERENCES
■
(
1) (a) Vedernikov, A. N. Acc. Chem. Res. 2012, 45, 803. (b) Mirica,
L. M.; Ottenwaelder, X.; Stack, T. D. P. Chem. Rev. 2004, 104, 1013.
(9) Cui, H.; Cui, C. Dalton Trans. 2011, 40, 11937.
(10) NHC-stabilized halosilylenes: (a) Agou, T.; Hayakawa, N.;
(
c) Lewis, E. A.; Tolman, W. B. Chem. Rev. 2004, 104, 1047.
Sasamori, T.; Matsuo, T.; Hashizume, D.; Tokitoh, N. Chem. - Eur. J.
014, 20, 9246. (b) Filippou, A. C.; Lebedev, Y. N.; Chernov, O.;
Straßmann, M.; Schnakenburg, G. Angew. Chem., Int. Ed. 2013, 52,
974. (c) Al-Rafia, S. M. I.; McDonald, R.; Ferguson, M. J.; Rivard, E.
(
d) Kitajima, N.; Moro-oka, Y. Chem. Rev. 1994, 94, 737. (e) Stahl, S.
2
S. Science 2005, 309, 1824. (f) Stahl, S. S. Angew. Chem. 2004, 116,
480; Angew. Chem., Int. Ed. 2004, 43, 3400. (g) Sawwan, N.; Greer, A.
Chem. Rev. 2007, 107, 3247.
2) (a) Yuan, F.-Q.; Han, F.-S. Org. Lett. 2012, 14, 1218. (b) Zhang,
P.; Wang, Y.; Li, H.; Antonietti, M. Green Chem. 2012, 14, 1904.
c) Liu, C.; Wang, J.; Meng, L.; Deng, Y.; Li, Y.; Lei, A. Angew. Chem.
011, 123, 5250; Angew. Chem., Int. Ed. 2011, 50, 5144. (d) Dondoni,
A.; Massi, A. Angew. Chem. 2008, 120, 4716; Angew. Chem., Int. Ed.
3
6
Chem. - Eur. J. 2012, 18, 13810. (d) Filippou, A. C.; Chernov, O.;
Blom, B.; Stumpf, K. W.; Schnakenburg, G. Chem. - Eur. J. 2010, 16,
(
2
866. (e) Ghadwal, R. S.; Roesky, H. W.; Merkel, S.; Henn, J.; Stalke,
(
2
D. Angew. Chem., Int. Ed. 2009, 48, 5683. (f) Filippou, A. C.; Chernov,
O.; Schnakenburg, G. Angew. Chem., Int. Ed. 2009, 48, 5687.
(11) (a) Gao, Y.; Zhang, J.; Hu, H.; Cui, C. Organometallics 2010, 29,
2
008, 47, 4638. (e) Nicolaou, K. C.; Chen, J. S. Chem. Soc. Rev. 2009,
3063. (b) Tanaka, H.; Ichinohe, M.; Sekiguchi, A. J. Am. Chem. Soc.
2012, 134, 5540. (c) Inoue, S.; Eisenhut, C. J. Am. Chem. Soc. 2013,
135, 18315. (d) Cui, H.; Zhang, J.; Cui, C. Organometallics 2013, 32, 1.
3
8, 2993. (f) Subramaniam, B. Coord. Chem. Rev. 2010, 254, 1843.
(
(
g) Yao, Z.; Hu, X.; Mao, J.; Li, H. Green Chem. 2009, 11, 2013.
h) Apeloig, Y. Nat. Chem. 2015, 7, 468. (i) Wang, Y.; Chen, M.; Xie,
(
12) (a) Karsch, H. H.; Keller, U.; Gamper, S.; Mu
Chem., Int. Ed. Engl. 1990, 29, 295. (b) Inoue, S.; Wang, W.; Pras
C.; Asay, M.; Irran, E.; Driess, M. J. Am. Chem. Soc. 2011, 133, 2868.
c) So, C.-W.; Roesky, H. W.; Gurubasavaraj, P. M.; Oswald, R. B.;
Gamer, M. T.; Jones, P. G.; Blaurock, S. J. Am. Chem. Soc. 2007, 129,
2049.
13) (a) Denk, M.; Hayashi, R. K.; West, R. J. Am. Chem. Soc. 1994,
16, 10813. (b) Lerner, H. W.; Bolte, M.; Schurz, K.; Wiberg, N.;
Baum, G.; Fenske, D.; Bats, J. W.; Wagner, M. Eur. J. Inorg. Chem.
006, 2006, 4998. (c) Klingebiel, U.; Noltemyer, M.; Schmidt, H. G.;
Schmidt-Base, D. Chem. Ber. 1997, 130, 753. (d) Junge, K.; Popowski,
̈
ller, G. Angew.
Y.; Wei, P.; Schaefer, H. F.; Schleyer, P. V.; Robinson, G. H. Nat.
Chem. 2015, 7, 509.
̈
ang,
(
3) (a) Sander, W.; Bucher, G.; Wierlacher, S. Chem. Rev. 1993, 93,
(
1
583. (b) Sander, W.; Schroeder, K.; Muthusamy, S.; Kirschfeld, A.;
Kappert, W.; Boese, R.; Kraka, E.; Sosa, C.; Cremer, D. J. Am. Chem.
Soc. 1997, 119, 7265. (c) Sander, W.; Kirschfeld, A.; Kappert, W.;
Muthusamy, S.; Kiselewsky, M. J. Am. Chem. Soc. 1996, 118, 6508.
1
(
1
(
d) Enders, D.; Breuer, K.; Raabe, G.; Runsink, J.; Teles, J. H.; Melder,
J.-P.; Ebel, K.; Brode, S. Angew. Chem., Int. Ed. Engl. 1995, 34, 1021.
e) Kirschfeld, A.; Muthusamy, S.; Sander, W. Angew. Chem. 1994,
06, 2261; Angew. Chem., Int. Ed. Engl. 1994, 33, 2212. (f) Sander, W.
Angew. Chem. 1990, 102, 362; Angew. Chem., Int. Ed. Engl. 1990, 29,
2
(
1
̈
E.; Michalik, M. Z. Anorg. Allg. Chem. 1999, 625, 1532. (e) Lerner, H.
W.; Scholz, S.; Bolte, M. Z. Anorg. Allg. Chem. 2001, 627, 1638.
3
44. (g) Ganzer, G. A.; Sheridan, R. S.; Liu, M. T. H. J. Am. Chem. Soc.
(
1
f) Niesmann, J.; Klingebiel, U.; Schaf
998, 17, 947. (g) Wiberg, N.; Schurz, K.; Reber, G.; Mu
̈
er, M.; Boese, R. Organometallics
ller, G. J.
1
986, 108, 1517. (h) Bell, G. A.; Dunkin, I. R. J. Chem. Soc., Chem.
̈
Commun. 1983, 1213. (i) Lorberth, J.; Krapf, H.; Noeth, H. Chem. Ber.
967, 100, 3511.
4) (a) Akasaka, T.; Nagase, S.; Yabe, A.; Ando, W. J. Am. Chem. Soc.
988, 110, 6270. (b) Patyk, A.; Sander, W.; Gauss, J.; Cremer, D.
Angew. Chem. 1989, 101, 920; Angew. Chem., Int. Ed. Engl. 1989, 28,
Chem. Soc., Chem. Commun. 1986, 591. (h) Hesse, M.; Klingebiel, U.
Angew. Chem. 1986, 98, 638; Angew. Chem., Int. Ed. Engl. 1986, 25,
1
(
1
6
49. (i) Cui, H.; Cui, C. Dalton Trans. 2015, 44, 20326.
898. (c) Patyk, A.; Sander, W.; Gauss, J.; Cremer, D. Chem. Ber. 1990,
123, 89. (d) Bornemann, H.; Sander, W. J. Am. Chem. Soc. 2000, 122,
6727. (e) Moiseev, A. G.; Leigh, W. J. Organometallics 2007, 26, 6277.
(
f) Haaf, M.; Schmiedl, A.; Schmedake, T. A.; Powell, D. R.;
Millevolte, A. J.; Denk, M.; West, R. J. Am. Chem. Soc. 1998, 120,
1
5
2714. (g) Xiong, Y.; Yao, S.; Driess, M. Angew. Chem., Int. Ed. 2013,
2, 4302.
(
5) For leading reviews on silylenes and NHC-stabilized silylenes,
see: (a) Ghadwal, R. S.; Azhakar, R.; Roesky, H. W. Acc. Chem. Res.
013, 46, 444. (b) Sen, S. S.; Khan, S.; Samuel, P. P.; Roesky, H. W.
2
Chem. Sci. 2012, 3, 659. (c) Mizuhata, Y.; Sasamori, T.; Tokitoh, N.
Chem. Rev. 2009, 109, 3479. (d) Kira, M. J. Organomet. Chem. 2004,
6
6
89, 4475. (e) Gehrhus, B.; Lappert, M. F. J. Organomet. Chem. 2001,
17−618, 209. (f) Haaf, M.; Schmedake, T. A.; West, R. Acc. Chem.
Res. 2000, 33, 704.
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DOI: 10.1021/acs.inorgchem.5b02580
Inorg. Chem. XXXX, XXX, XXX−XXX