Organometallics
Article
4
−
159.86 (t, J = 22.0, 6F, p-C F ), −162.88 (t, J = 22.0, 12F, m-C F ).
13
μL, 0.054 mmol), a dilute solution of the precatalyst (5.4 × 10−
6
5
6 5
Numerous attempts to obtain the C NMR data for this compound
failed; only signals from the solvent were observed in the
corresponding NMR spectra. Anal. Calcd for C H GaF N : C,
mmol; 1.0 mol % vs hydrosilane), the relevant E(C F ) (1.0 mol % vs
hydrosilane), and dry degassed C D Br or C D (0.1 mL). Then the
NMR tube was sealed. The tube was degassed by two freeze−pump−
thaw cycles and charged with pure CO under 6 bar of pressure (0.32
mmol). Afterward, it was introduced in the NMR spectrometer preset
at the desired temperature. The progress of the reaction was
monitored by NMR spectroscopy.
6
5 3
6
5
6
6
3
9
3
30
6
3
9.19; H, 0.25; N, 7.03. Found: C, 39.22; H, 0.27; N, 7.14.
Synthesis of In(NCN) (1-In). Using a protocol similar to that
2
3
described for 1-B, compound 1-In was obtained from 1-H (3.0 g, 7.8
mmol), KH (0.50 g, 13 mmol) and InBr (0.92 g, 2.6 mmol). 1-In
was isolated as a pink powder (0.36g, 0.29 mmol, 11%). H NMR
3
1
Computational Details. The calculations were performed using
1
9
1
(
3
=
C D , 400 MHz, 25 °C): δ 8.20 (s, 3H, CH). F{ H} NMR (C D ,
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60
6
6
6
6
the Gaussian 09 program employing the B3PW91 functional and
using a standard double-ξ polarized basis set: namely, the 6-31(d,p)
set. The solvent effects, in our case for toluene, were taken into
76.5 MHz, 25 °C): δ −154.23 (d, J = 21.4, 12F, C F ), −160.69 (t, J
6
5
1
3
1
21.4, 6F, C F ), −162.77 (t, J = 21.4, 12F, C F ). C{ H} NMR
6
5
6 5
1
(
CD Cl , 400 MHz, 25 °C): δ 164.6 (s, CH), 142.0 (br d, J = 250, o-
6
61
2
2
account during all of the calculations by means of the SMD model.
1
1
C F ), 140.5 (br d, J = 255, m-C F ), 137.0 (br d, J = 250, p-C F ),
5
6
5
6 5
All stationary points were fully characterized via analytical frequency
calculations as either true minima (all positive eigenvalues) or
transition states (one imaginary eigenvalue). The IRC procedure was
used to confirm the nature of each transition state connecting two
minima. Zero-point vibrational energy corrections (ZPVE) were
estimated by a frequency calculation at the same level of theory, to be
considered for the calculation of the total energy values. The
electronic charges (at the DFT level) were computed using natural
1
0
19.9 (br s, ipso-C F ). Anal. Calcd for C H InF N : C, 37.77; H,
.24; N, 6.78. Found: C, 38.01; H, 0.29; N, 6.98.
Synthesis of Zn(NCN) (1-Zn). Using a protocol similar to that
6 5 39 3 30 6
2
described for 1-Al, compound 1-Zn was obtained from 1-H (3.0 g, 7.8
mmol) and Et Zn (1 M in heptane, 2.67 mL, 2.67 mmol) and isolated
as a transparent crystalline solid (1.8 g, 2.1 mmol, 83%). H NMR
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2
1
1
9
1
(
(
C D , 400 MHz, 25 °C): δ 7.93 (s, 2H, CH) ppm. F{ H} NMR
6 6
C D , 376.5 MHz, 25 °C): δ −152.97 (br m, 8F, C F ), −160.04 (br
6
6
6 5
63
1
3
1
population analysis (NPA).
m, 4F, C F ), −162.41 (t, J = 20.8, 8F, C F ). C{ H} NMR (C D ,
6
5
6
5
6
6
Crystal Structure Determination of 1-H,B,Al,Ga,In,Zn and
{B(C F ) }(1-SiEt ). Diffraction data were collected at 100 K using a
4
00 MHz, 25 °C) (some signals from quaternary carbons were not
1
identified): δ 169.03 (s, CH), 141.8 (br d, J = 246, o-C F ), 137.9 (br
6
5 3
3
6
5
d, 1J = 248, m-C F ), 120.6 (br s, ipso-C F ). Anal. Calcd for
Bruker APEX CCD diffractometer with graphite-monochromated Mo
Kα radiation (λ = 0.71073 Å). A combination of ω and θ scans was
carried out to obtain a unique data set. The crystal structures were
solved by direct methods, and the remaining atoms were located from
difference Fourier synthesis followed by full-matrix least-squares
refinement based on F (programs SIR97 and SHELXL-97). Many
hydrogen atoms could be located from the Fourier difference analysis.
Other hydrogen atoms were placed at calculated positions and forced
to ride on the attached atom. The hydrogen atom positions were
calculated but not refined. All non-hydrogen atoms were refined with
anisotropic displacement parameters. Crystal data and details of data
6
5
6 5
C H F N Zn: C, 38.28; H, 0.25; N, 6.87. Found: C, 38.34; H, 0.30;
2
6
2
20
4
N, 7.01.
Synthesis of Et Si(NCN) (1-SiEt ). In the glovebox, 1-H (0.50 g,
3
3
1
.3 mmol) and KH (0.09 g, 2.0 mmol) were placed into a Schlenk
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64
tube equipped with a magnetic stirrer. Dry THF (15 mL) was added
under argon, and the reaction mixture was stirred at room
temperature. After 12 h, the reaction mixture was filtered and all
the volatiles were removed under vacuum. The crude potassium salt
was dried under vacuum for 4 h, and dry toluene (15 mL) was added
followed by addition of Et SiCl (2.25 mL, 1.3 mmol) at −78 °C. The
mixture was stirred overnight at room temperature and then filtered.
All volatiles were removed, and a brownish oily product was obtained
and then dried under vacuum overnight to give 1-SiEt (0.03 g, 0.55
mmol, 42%). The compound apparently exists as a ca. 1/0.9 mixture
3
3
58
C−N single bond (Figure S19), which slowly interconvert at room
1
temperature. H NMR (C D , 400 MHz, 25 °C): δ 7.66 (br s, 1H,
7
8
1
9
1
CH), 0.86 (br m, 9H, CH CH ), 0.59 (br m, 6H, CH CH ). F{ H}
ASSOCIATED CONTENT
3
2
3
2
■
NMR (C D , 376.5 MHz, 25 °C): δ −145.9 (br m C F ), −155.2 (br
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8
6 5
*
sı Supporting Information
m, C F ), −155.5 (t, J = 18.8, C F ), −162.8 (br m, C F ), −164.6
6
5
6
5
6 5
13
1
(
m, C F ). C{ H} NMR (C D , 400 MHz, 25 °C) (some signals
6 5 7 8
from quaternary carbons were not identified): δ 156.6 (br s, 1C, CH),
1
1
1
44.9 (br d, J = 246, o-C F ), 141.1(br d, J = 251, o-C F ), 140.8 (br
6 5 6 5
1
1
1
Selected catalytic results, NMR data, and kinetic plots
d, J = 251, p-C F ), 138.3 (br d, J = 251, m-C F ), 137.3 (br d, J =
6
5
6 5
2
51, p-C F ), 6.4 (s, CH CH ), 4.0 (s, CH CH ). Despite repeated
6 5 3 2 3 2
attempts, a reproducible and satisfactory elemental analysis for 1-SiEt3
C H F N Si) could not be obtained, apparently due to the
(
1
9
16 10
2
extreme air and moisture sensitivity of the compound and possible
formation during pyrolysis of nonpyrolizable silicon carbide.
General Procedure for CO2 Hydrosilylation: NMR-Scale
Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
Reactions. Reaction at 1 bar of CO Pressure. In the glovebox, a
2
Teflon-valved NMR tube was charged with the internal standard
hexamethylbenzene (5.0 mg, 0.0308 mmol), HSiEt (21 μL, 0.13
3
mmol), precatalyst (6.15 × 10− mmol; 5.0 mol % vs hydrosilane),
3
and, when relevant, a solution of E(C F ) (5.0 mol % vs
6
5 3
hydrosilane). Then, dry degassed C D Br or C D (0.5 mL) was
added, and the NMR tube was sealed. The tube was degassed by two
6
5
6
6
■
freeze−pump−thaw cycles and charged with pure CO under 1 bar of
2
Corresponding Author
pressure (0.13 mmol). Afterward, it was introduced in the NMR
spectrometer preset at the desired temperature. The progress of the
reaction was monitored by NMR spectroscopy.
Evgueni Kirillov − Organometallics: Materials and Catalysis
laboratories, Univ Rennes, CNRS, ISCR (Institut des Sciences
Reaction at 6 bar of CO Pressure. In the glovebox, a Wilmad
2
high-pressure Teflon-valved NMR tube was charged with the internal
standard hexamethylbenzene (1.0 mg, 0.00616 mmol), HSiEt (8.6
3
J
Organometallics XXXX, XXX, XXX−XXX