Y. Xiong et al. · Coordination of N-Heterocyclic Carbene to H2SiX2 (X = Cl, OTf) and H3SiOTf (OTf = OSO2CF3) 451
4 H; CHMe2), 4.77 (s, 2 H; SiH2), 7.42 – 7.68 ppm (m, tion analysis. The collected crystals amounted to 0.70 g
8 H; CH=CH in C3N2 ring, arom. H in 2,6-iPr2C6H3). – (0.73 mmol, 83%); m. p. 245 ◦C (decomp.). – 1H NMR
13C{1H} NMR (100.61 MHz, CD2Cl2, 25 ◦C): δ = 21.4, (200.13 MHz, CD2Cl2, 25 ◦C): δ = 0.86 (d, 3J(H,H) =
26.4, 29.0 (CHMe2, CHMe2), 124.9, 127.3, 127.8, 128.3, 6.7 Hz, 24 H; CHMe2), 1.00 (d, 3J(H,H) = 6.7 Hz, 24
132.2, 145.2 ppm (in C3N2 ring, arom. C in 2,6-iPr2C6H3). H; CHMe2), 2.19 (sept, 3J(H,H) = 6.7 Hz, 8 H; CHMe2),
–
29Si{1H} NMR (79.49 MHz, CD2Cl2, 25 ◦C): δ = 4.19 (s, 3 H; SiH3), 6.88 (s, 4 H; CH=CH in C3N2 ring),
−102.5 ppm. – 19F NMR (200.13 MHz, CD2Cl2, 25 ◦C): 7.12 – 7.49 ppm (m, 12 H; arom. H in 2,6-iPr2C6H3). –
δ = −77.2 ppm. – HR ((+)-ESI): m/z = 389 [NHC+H]+. 13C{1H} NMR (100.61 MHz, CD2Cl2, 25 ◦C): δ = 22.9,
– Elemental analysis (%) for C29H38N2Si2O6F6S2: calcd. C 24.5, 28.6 (CHMe2, CHMe2), 123.5, 123.6, 124.4, 130.8,
48.59, H 5.34, N 3.91; found C 48.56, H 5.20, N 3.94. – IR 132.7, 144.6 ppm (in C3N2 ring, arom. C in 2,6-iPr2C6H3).
(KBr, cm−1): v = 3168 (w), 2969 (vs), 2928 (m), 2873 (w),
2211 (w, ν(Si−H)), 1537 (w), 1466 (m), 1390 (w), 1369 (m),
–
29Si{1H} NMR (79.49 MHz, CD2Cl2, 25 ◦C): δ =
−171.0 ppm. – 19F NMR (200.13 MHz, CD2Cl2, 25 ◦C):
1262 (vs), 1160 (s), 1031 (vs), 957 (w), 867 (w), 807 (w), δ = −78.9 ppm. – HR ((+)-ESI): m/z = 389 [NHC+H]+.
758 (m), 638 (vs), 575 (m), 518 (m).
– Elemental analysis (%) for C55H75N4SiO3F3S: calcd. C
69.00, H 7.90, N 5.85; found C 69.11, H 8.08, N 5.75. – IR
(KBr, cm−1): v = 2966 (vs), 2931 (m), 2871 (m), 2179 (w,
Synthesis of [(NHC)SiH3]+(OTf−) (4)
ν
(Si−H)), 1465 (s), 1406 (m), 1365 (m), 1273 (vs), 1223 (m),
To phenylsilane (0.62 mL, 97%, d = 0.88 g mL−1
,
1150 (vs), 1103 (w), 1061 (w), 1031 (vs), 955 (s), 806 (m),
785 (m), 759 (s), 637 (vs), 575 (m), 571 (w), 517 (w).
4.9 mmol) was added dropwise trifluoromethanesulfonic
acid (0.44 mL, 98%, d = 1.71 g mL−1, 4.9 mmol) at −50 ◦C
under stirring. After 10 min a solution of NHC (1.90 g, Single-crystal X-ray structure determinations
4.9 mmol) in toluene (50 mL) was added in situ into
Crystals were mounted on glass capillaries in perfluori-
the solution of produced H3Si(OTf). A colorless precip-
itate was formed immediately. The solvent toluene was
replaced by dichloromethane, from which compound 4
crystallized as colorless plates with a yield of 2.5 g
(4.4 mmol, 90%); m. p. 238 ◦C (decomp.). – 1H NMR
(200.13 MHz, CD2Cl2, 25 ◦C): δ = 1.24 (d, 3J(H,H) =
6.8 Hz, 24 H; CHMe2), 2.28 (sept, 3J(H,H) = 6.8 Hz,
4 H; CHMe2), 3.69 (s, 3 H; SiH3), 7.41 – 7.95 ppm (m,
8 H; CH=CH in C3N2 ring, arom. H in 2,6-iPr2C6H3).
nated oil and measured in a cold N2 flow. The data of 1, 3,
4, and 5 were collected on an Oxford Diffraction Xcalibur
˚
S Sapphire at 150 K (MoKα radiation, λ = 0.71073 A). The
structures were solved by Direct Methods and refined on F2
with the SHELXS/L-97 [28, 29] software package. The posi-
tions of the H atoms were calculated and considered isotrop-
ically according to a riding model.
CCDC 921558, 921559, 921560, and 921561 contain
the supplementary crystallographic data for this paper.
These data can be obtained free of charge from The Cam-
–
13C{1H} NMR (100.61 MHz, CD2Cl2, 25 ◦C): δ =
22.7, 24.7, 29.1 (CHMe2, CHMe2), 125.1, 128.9, 130.7,
132.0, 144.8, 148.4 ppm (in C3N2 ring, arom. C in 2,6-
iPr2C6H3). – 29Si{1H} NMR (79.49 MHz, CD2Cl2, 25 ◦C):
δ = −80.4 ppm. – 19F NMR (200.13 MHz, CD2Cl2, 25 ◦C):
δ = −78.9 ppm. – HR ((+)-ESI): m/z = 389 [NHC+H]+.
– Elemental analysis (%) for C28H39N2SiO3F3S: calcd. C
59.13, H 6.91, N 4.93; found C 58.97, H 6.88, N 4.83. – IR
(KBr, cm−1): v = 3172 (w), 2970 (vs), 2933 (m), 2874 (w),
2230 (w, ν(Si−H)), 1469 (s), 1370 (s), 1327 (w), 1235 (vs),
1248 (vs), 1223 (s), 1161 (vs), 1139 (s), 957 (w), 1061 (w),
1029 (vs), 885 (vs), 804 (m), 773 (m), 759 (s), 637 (vs), 573
(w), 517 (m).
1: Tetragonal, space group P41212, a = b = 14.2410(6),
3
˚
˚
c = 13.425(2) A, V = 27227(3) A , Z = 4, ρcalcd.
=
1.19 Mg m−3, µ(MoKα ) = 0.3 mm−1, 18278 collected re-
flections, 2384 crystallographically independent reflections
[Rint = 0.1161], 2295 reflections with I > 2 σ(I), θmax
=
25◦, R(Fo) = 0.0401 [I > 2 σ(I)], wR(F2) = 0.0976 (all
data), 154 refined parameters.
3: Monoclinic, space group C2/c, a = 23.332(6),
◦
˚
b = 9.201(2), c = 18.102(5) A, β = 117.99(4) , V =
3431.5(1) A , Z = 4, ρcalcd. = 1.39 Mg m−3, µ(MoKα ) =
3
˚
0.3 mm−1, 7466 collected reflections, 3002 crystallograph-
ically independent reflections [Rint = 0.0478], 1907 reflec-
Synthesis of [(NHC)2SiH3]+(OTf−) (5)
To a solution of 4 (0.50 g, 0.88 mmol) in dichloromethane tions with I > 2 σ(I), θmax = 25◦, R(Fo) = 0.0573 [I > 2
(15 mL) was added a solution of NHC (0.34 g, 0.88 mmol) σ(I)], wR(F2) = 0.1402 (all data), 217 refined parameters.
in toluene (10 mL) at room temperature under stirring. Af-
4: Orthorhombic, space group Pbca, a = 16.258(2), b =
3
˚
˚
ter 16 h the reaction mixture was concentrated to 5 mL 17.545(2), c = 21.418(2) A, V = 6109.4(9) A , Z = 8,
and cooled to −20 ◦C. From dichloromethane compound 5 ρcalcd. = 1.24 Mg m−3, µ(MoKα ) = 0.2 mm−1, 25205 col-
crystallized as colorless plates suitable for X-ray diffrac- lected reflections, 5366 crystallographically independent re-
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