Compound 3

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InChIKey JPIJBIGOKVMXGN-UHFFFAOYSA-N

Compound data: CIF

Synthetic procedure: See article for the definitive version of this procedure and for full experimental details.

1,3-Diisopropyl-4,5-dimethylimidazol-2-ylidene (2) (220 mg) and 1,1,2,3-tetrakis(2,4,6-triisopropylphenyl)trisilacyclopropene (1) (1 g) were dissolved at 25 °C in cyclohexane (20 mL). The volume of the resulting dark green solution was reduced in vacuo to 10 mL. Storage at room temperature for 3 days gave dark green crystals of 3·C₆H₁₂. Yield 294 mg, 23 %. M.p. 132 °C; ¹H NMR (300.13 MHz, 230 K, d₈-Toluene): δ = 7.22 (d, J_HH = 1.4 Hz, 1 H, Tip CH), 7.19, (d, J_HH = 1.4 Hz, 1 H, Tip CH), 7.07 (d, J_HH = 1.2 Hz, 1 H, Tip CH), 7.05 (presumed 1H, obscured by toluene resonance, Tip CH), 7.00 (d, J_HH = 1.1 Hz, 1 H, Tip CH), 6.93 (m, 2H, Tip CH), 6.89 (d, J_HH = 1.4 Hz, 1 H, Tip CH), 6.46 (sept, ³J_HH = 6.9 Hz, 1 H, NCHMe₂), 5.43 (sept, ³J_HH = 6.5 Hz, 1 H, Tip-iPr-CHMe₂), 5.32 (sept, ³J_HH = 7.0 Hz, 1 H, NCHMe₂), 4.43 (sept, ³J_HH = 6.4 Hz, 1 H, Tip-iPr-CHMe₂), 4.16 (sept, ³J_HH = 6.5 Hz, 1 H, Tip-iPr-CHMe₂), 4.0 - 3.7 (m, 4 H, Tip-iPr-CHMe₂ resonances), 3.51 (sept, ³J_HH = 6.4 Hz, 1 H, Tip-iPr-CHMe₂), 2.87 - 2.56 (m, 4 H, Tip-iPr-CHMe₂ resonances), 1.87 (d ³J_HH = 6.9 Hz, 3 H, NCH(CH₃)₂), 1.83 (s, 3 H, CH₃(N)C=C(N)CH₃), 1.62 - 1.34 (m CH₃), 1.33 - 1.0 (m, CH₃), 0.86 (d, 3 H, ³J_HH = 6.2 Hz, Tip-iPr-CH₃), 0.75 (d, 3 H, ³J_HH = 6.2 Hz, Tip-iPr-CH₃), 0.70 - 0.51 (m, 12 H, CH₃), 0.37 (d ³J_HH = 6.8 Hz, 3 H, NCH(CH₃)₂), 0.30 (d ³J_HH = 6.8 Hz, 3 H, Tip-iPr-CH₃). ²⁹Si{¹H} NMR (59.62 MHz, 230 K, d₈-Toluene): δ = 100.91 (Tip₂Si), 51.53 (Tip₂Si=Si(Tip)Si(Tip), −62.91 (Tip₂Si=Si(Tip)Si(Tip)(NHC)). ¹³C{¹H} NMR (75.46 MHz, 230 K, d₈-Toluene): δ = 172.35 (s, NCN), 156.12 (s, Ar-C), 155.37 (s, Ar-C), 154.40 (s, Ar-C), 154.08 (s, Ar-C), 153.51 (s, Ar-C), 153.35 (s, Ar-C), 152.98 (s, Ar-C), 152.78 (s, Ar-C), 148.83 (s, Ar-C), 148.57 (s, Ar-C), 148.47 (s, Ar-C), 147.53 (s, Ar-C), 142.75 (s, Ar-C), 139.02 (s, Ar-C), 138.67 (s, Ar-C), 125.96 (s,- NC(CH₃)=C(CH₃)N- ), 125.00, (s,- NC(CH₃)=C(CH₃)N- ), 122.47 (s, br, Ar-CH), 122.38 (s, br, Ar-CH), 122.24 (s, br, Ar-CH), 121.93 (s, br, Ar-CH), 121.06 (s, br, Ar-CH), 120.93 (s, br, Ar-CH), 120.88 (s, br, Ar-CH), 120.67 (s, br, Ar-CH), 53.89 (s, NCHMe₂) , 50.74 (s, NCHMe₂), 38.25 (s, br, Tip-iPr-CH), 37.72 (s, br, Tip-iPr-CH), 37.64 (s, br, Tip-iPr-CH), 37.48 (s, br, Tip-iPr-CH), 37.24 (s, br, Tip-iPr-CH), 36.56 (s, br, Tip-iPr-CH), 35.83 (s, br, Tip-iPr-CH), 35.33 (s, br, Tip-iPr-CH), 34.70 (s, Tip-iPr-CH), 34.38 (s, Tip-iPr-CH), 34.26 (s, Tip-iPr-CH), 28.40 (s, Tip-iPr-CH₃), 26.64 (s, Tip-iPr-CH₃), 26.33 (s, Tip-iPr-CH₃), 26.21 (s, Tip-iPr-CH₃), 25.79 (s, Tip-iPr-CH₃), 25.35 (s, Tip-iPr-CH₃), 24.98 (s, NCH(CH3)2), 24.86 (s, Tip-iPr-CH3), 24.52 (s, Tip-iPr-CH3), 24.32 (s, Tip-iPr-CH3), 24.17 (s, Tip-iPr-CH3), 24.06 (s, Tip-iPr-CH3), 24.01 (s, Tip-iPr-CH3), 23.93 (s, Tip-iPr-CH3), 23.87 (s, Tip-iPr-CH3), 23.78 (s, Tip-iPr-CH3), 23.53 (s, Tip-iPr-CH3), 22.96 (s, Tip-iPr-CH3), 22.51 (s, Tip-iPr-CH3), 22.14 (s, Tip-iPr-CH3), 21.10 (s, NCH(CH3)2), 20.51 (s, Tip-iPr-CH3), 19.60 (s, NCH(CH3)2), 10.37 (s, CH3(N)C=C(N)CH3), 10.03 (CH3(N)C=C(N)CH3). UV/Vis (hexane): lmax 568 nm, 412 nm; analysis (%calcd., %found for C77H124N2Si3): C (79.58, 79.71), H (10.76; 10.37), N (2.41 , 3.58). The value for N is significantly higher than expected. Values for %C and %H are also very variable (e.g. three runs %C = 74.35, 73.29, 78.79). Together this information suggests that 3 is not amenable to meaningful microanalysis.