Compound 4
2-(1',3'-Diisopropyl-4',5'-dimethyl-1H-imidazol-3'-ium-2'-yl)-1,2,3,3-tetrakis(2'',4'',6''-triisopropylphenyl)trisiliran-1-ide
From: Equilibrium between a cyclotrisilene and an isolable base adduct of a disilenyl silylene
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InChIKey UAEVEYCLEYUIRE-UHFFFAOYSA-N
Synthetic procedure: See article for the definitive version of this procedure and for full experimental details.
A solution of 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (2) (131.6 mg) in toluene-d8 (0.4 mL) was added slowly to a solution of tetra(2,4,6-triisopropylphenyl)trisilacyclopropene (1) in toluene-d8 (0.3 mL) in an NMR tube at −90 °C. The solution was agitated at −90°C to ensure complete mixing and then allowed to warm to 210 K within the probe of the NMR spectrometer before commencing measurement. 1H NMR (300.13 MHz, 210 K, d8-Toluene): δ = 7.35 (br, 2 H, Tip CH), 7.22 (br, 2 H, Tip CH), 7.22 (br, 2 H, Tip CH), 7.17 (br, 4 H, Tip CH), 6.10 (br, 1 H, NCHMe2), 5.33, 5.19, 4.60, 4.32, 4.17 (br, 5H NCHMe2/Tip-iPr-CH), 4.07, 3.82 (br, each 2H, Tip-iPr-CH), 3.73, 3.64, 2.98, 2.90, (br, 4H NCHMe2/Tip-iPr-CH), 2.83, 2.21 (s, each 3H, CH3(N)C=C(N)CH3), 1.811 - 1.23 (br, overlapping), 1.18, 1.02, 0.88, 0.73, 0.68, 0.60, 0.19, 0.07 (iPr CH3). 29Si{1H} NMR (59.62 MHz, 210 K, d8-Toluene): δ = −45.56 (s, SiTip), −95.26 (s, Si(NHC)Tip), −126.7 (s, SiTip2). 13C{1H} NMR (75.46 MHz, 210 K, d8-Toluene): δ = 162.66 (s, NCN), 157.00 (s, Ar-C), 156.59 (s, Ar-C). 156.17 (s, Ar-C), 154.85 (s, Ar-C), 154.81 (s, Ar-C), 154.33 (s, Ar-C), 152.72 (s, Ar-C), 151.98 (s, Ar-C), 149.06 (s, Ar-C), 147.81 (s, Ar-C), 147.48 (s, Ar-C), 146.44 (s, Ar-C), 143.42 (s, Ar-C), 143.36 (s, Ar-C), 140.95 (s, Ar-C), 140.54 (s, Ar-C), 126.62 (s,- NC(CH3)=C(CH3)N-), 122.95 (s, br, Ar-CH), 122.43 (s, br, Ar-CH), 121.79 (s, br, Ar-CH), 121.31 (s, br, Ar-CH), 120.60 (s, br, Ar-CH), 120.19 (s, br, Ar-CH), 118.36 (s, br, Ar-CH), 52.27 (s, NCHMe2), 37.42, 36.64, 35.20, 34.86, 34.57, 33.60, 30.90, 29.43, 29.09, 28.17, 27.38, 27.03, 26.63, 26.30, 25.67, 25.32, 24.92, 24.54, 23.52, 22.53, 22.16, 17.72 (s, some br, Tip-iPr-CH and Tip-iPr-CH3), 10.29 (s, CH3(N)C=C(N)CH3), 9.98 (s, CH3(N)C=C(N)CH3).
