Supporting Information © Wiley-VCH 2008 69451 Weinheim, Germany Supporting Information for The Low Basicity of Phosphabenzenes: First Examples of Protonation, Alkylation and Silylation Reactions by Yun Zhang, Fook S. Tham, John F. Nixon, Charlotte Taylor, Jennifer C. Green, and Christopher A. Reed (9 pages) Synthetic Procedures General. Air sensitive materials were handled in a He atmosphere Vac. Atm. Corp. glove box (O2, H2O < 2 ppm). All reactions outside of the dry box were carried out under dry nitrogen in Schlenk tubes with Teflon stopcocks. High purity dichloromethane (Omisolv), benzene, o-dichlorobenzene, and n-hexane were purchased from EM science. Solvents were dried over Na/K, P2O5, or CaH and distilled prior to use. NMR spectra were record on a Varian Inova 400, 500 or Bruker 300 spectrometers for 1H, 13C, and 31P (referenced externally to 85% H3PO4). All carborane reagents were freshly prepared. Et3Si(CHB11Me5Br6),1 Et3Si(CHB11Me5Cl6),1 arenium ion salts [H(arene)][CHB11Me5Cl5] (arene = mesitylene, o-xylene and toluene),1 and CH3(CHB11Me5Br6)2 were prepared by literature methods. (1) Reed, C. A.; Kim, K-C.; Stoyanov, E. S.; Stasko, D.; Tham, F. S.; Mueller, L. J.; Boyd, P. D. W. J. Am. Chem. Soc. 2003, 125, 1796-1804. (2) Kato, T.; Stoyanov, E.; Geier, J.; Grutzmacher, H.; Reed, C. A. J. Am. Chem. Soc. 2004, 126, 12451. [H(C3P3tBu3)][CHB 11Me5Br6], 6. Freshly prepared Et3Si(CHB11Me5Br6) (148 mg, 0.185 mmol) was combined with (C3P3tBu3), 4 (55.4 mg, 0.185 mmol), in a 5 mL vial with a stir bar. Approximately 1 mL of benzene was added to yield a pale yellow solution. A white powdery precipitate was formed when 3 drops of TfOH (~2 eq) was added to this solution. Dry nhexane (~2 mL) was added to ensure complete precipitation of the product. The resulting white precipitate was filtered off, washed with dry n-hexane (~2 mL) and dried under vacuum (153 mg, 84 %). The final product was re-dissolved in CH2Cl2 and layered with n-hexane to yield X-ray quality crystals. 1H NMR (Figure S1) in (300 MHz, δ, CD2Cl2, 25 ºC): 0.11 (s, 15H, BCH3), 1.54 (bs, 1H, BCH), 1.84 (s, 27H, tBu), 9.46 (d, 1H, 1JH-P = 595 Hz, PH). 31P NMR (Figure S2) (122 MHz, δ, CD2Cl2, 25 ºC): 85.11 (dt, 1P, 2JP-P = 49.0 Hz, 1JP-H = 592 Hz), 304.49 (d, 2P, 2JP-P = 49.2 Hz). ). 31P NMR (1H-Dec, 122 MHz, δ, CD2Cl2, 25 ºC): 85.07 (t, 1P, 2JP-P = 48.7 Hz), 304.47 (d, 2P, 2JP-P = 48.9 Hz). [H(C3P3tBu3)][CHB 11Cl11]. This was prepared in an analogous manner to 6 from 4 and Et3Si(CHB11Me5Cl6). 1H NMR (Figure S3) (300 MHz, δ, d4-o-dichlorobenzene, 25 ºC): 1.54 (s, 18H, tBu), 1.60 (s, 9H, tBu), 2.98 (bs, 1H, BCH), 9.22 (d, 1H, 1 JH-P = 586 Hz, PH). 31P NMR (122 MHz, δ, CD2Cl2, 25 ºC): 81.68 (dt, 1P, 2JP-P = 48.3 Hz, 1JP-H = 590 Hz), 302.69 (d, 2P, 2 JP-P = 48.3 Hz). 31P NMR (1H-Dec, 122 MHz, δ, d4-o-dichlorobenzene, 25 ºC): 81.88 (t, 1P, 2JP-P = 48.8 Hz), 302.91 (d, 2P, 2 JP-P = 48.5 Hz). [H(PC5H2t-Bu3)][CHB 11Me5Cl6], 7. This was prepared in an analogous manner to 6 from 5 and Et3Si(CHB11Me5Cl6). X-ray crystals were grown from CD2Cl2/hexanes. 1H NMR (Figure S5) (300 MHz, δ, CD2Cl2 25 °C): 0.13 (15HMe, s), 1.48 (9HBut, s), 1.61 (18HBut, s), 8.45 (1H, dd, 3JPH = 36, 4JHH = 4.6 Hz), 9.32 (1H, dt, 4JHH = 4.6Hz, 1JPH = 627 Hz) ppm). 31P NMR (Figure S6) (122 MHz, δ, CD2Cl2, 25 ºC) 60.2 (dt, 1JPH = 625 Hz, 3JPH = 36 Hz). 31P NMR (1H-Dec, 122 MHz, δ, CD2Cl2, 25 ºC): 60.2 (s). [Me(C3P3tBu3)][CHB11Me5Br6], 8. Freshly prepared CH3(CHB11Me5Br6) (50.1 mg, 0.073 mmol) was combined with (C3P3tBu3) 5 (19.5 mg, 0.065 mmol) in a 5 mL vial with a stir bar. The reaction vial was cooled down to dry ice temperature before addition of 2 mL cold CH2Cl2 (-90 ºC). The reaction was allowed to warm up to room temperature with stirring before all volatiles were removed by vacuum. The resulting pale yellow solid (59 mg, 83 %) was re-dissolved in CD2Cl2 for NMR spectroscopic analysis. 1H NMR (400 MHz, δ, 25 ºC): 0.11 (s, 15H, BCH3), 1.55 (bs, 1H, CH), 1.82 (s, 27H, tBu), 3.50 (d, 3H, CCH3, 2JH-P = 18.6 Hz). 31P NMR (Figure S7) (122 MHz, δ, 25 ºC): 133.8 (tq, 1P, 2JP-P = 52.0 Hz, 2JP-H = 19.0 Hz), 302.6 (d, 2P, 2JP-P = 52.0 Hz). ). 31P NMR (1H-Dec, 122 MHz, δ, CD2Cl2, 25 ºC): 133.4 (t, 1P, 2JP-P = 52.2 Hz), 302.2 (d, 2P, 2JP-P = 52.0 Hz). Figure S1. 1H NMR spectrum of [H(C3P3tBu3)][CHB11Me5Br6] 6 in CD2Cl2. tBu BCH3 1 JHP = 595 Hz CD2Cl2 CH 31 Figure S2. P and 31P{1H} NMR spectrum of [H(C3P3tBu3)][CHB11Me5Br6] 6 in CD2Cl2. 31 P NMR doublet of triple 85.11 ppm 2 JPP = 49.0 Hz 1 JPH = 592 Hz doublet 304.49 ppm 2 JPP = 49.2 Hz 306.5 306.0 305.5 305.0 304.5 304.0 304.0 303.5 303.0 302.5 302.0 301.5 90 89 88 87 86 85 2P 325 84 83 82 81 1P 300 275 250 225 31 2 P NMR H Dec 200 175 150 125 100 75 50 JPP = 48.9 Hz 1 2 306.5 306.0 305.5 305.0 304.5 304.0 304.0 303.5 303.0 302.5 87.5 325 300 275 250 225 302.0 87.0 JPP = 48.7 Hz 301.5 86.5 200 86.0 85.5 175 85.0 84.5 150 84.0 84.0 83.5 125 83.0 83.0 82.5 82.0 100 75 50 Figure S3. 1H NMR spectrum of [H(C3P3tBu3)][CHB11Cl11] in d4-ODCB. 1H NMR 1.54 ppm 1.60 ppm tBu 9.22 ppm 1JPH = 586.3 Hz 2.98 ppm CH d4-ODCB 10 9 27 H 1H 1H 8 7 6 5 4 3 2 1 0 Figure S4. 31 31 P and 31P{1H} NMR spectrum of [H(C3P3tBu3)][CHB11Cl11] in d4-ODCB. 302.89 ppm 302.49 ppm 2 JPP = 48.3 Hz P 304.2 325 304.0 304.0 303.8 303.8 303.6 300 303.4 303.2 302.8 302.6 302.4 302.2 302.0 302.0 301.8 250 301.6 301.4 301.2 301.0 301.0 87 225 200 86 85 84 175 83 304.2 300 304.0 304.0 303.8 303.8 303.6 303.4 275 303.2 303.0 302.8 302.6 302.4 250 302.2 302.0 302.0 79.67 ppm 79.26 ppm 18.86 ppm 1 JPH = 590.0 Hz 82 81 80 150 79 78 77 125 76 100 75 50 82.28 ppm 81.88 ppm 81.48 ppm 2 JPP = 48.8 Hz 303.10 ppm 302.71 ppm 2 JPP = 48.5 Hz P H-Dec 325 303.0 275 31 1 84.48 ppm 84.09 ppm 83.70 ppm 2 JPP = 48.3 Hz 301.8 301.6 301.4 225 301.2 83.4 301.0 301.0 200 175 83.2 83.0 82.8 150 82.6 82.4 82.2 82.0 81.8 81.6 125 81.4 81.2 81.0 80.8 80.6 100 80.4 80.2 75 50 Figure S5. 1H NMR spectrum of [H(PC5 H2tBu3)][CHB11Me5Cl6], 7, in CD2Cl2. 0.5 10.4 1.9 10.2 10.0 9.8 9.6 9.4 9.2 9.0 8.8 8.6 8.4 0.5 8.2 8.0 2.0 11 10 9 27.4 8 7 6 5 4 3 2 15.0 1 0 -1 Figure S6. 31 P and 31P{1H} NMR spectrum of [H(PC5H2tBu3)][CHB11Me5Cl6], 7, in CD2Cl2. 31P 70 31 68 66 64 62 60 58 56 54 52 50 68 66 64 62 60 58 56 54 52 50 P{1H} 70 Figure S7. 31 31 P and 31P{1H} NMR spectrum of [Me(C3P3tBu3)][CHB11Me5Br6], 8, in CD2Cl2 at room temperature. doublet 302.6 ppm 2 JPP = 52.0 Hz P Triplet of quartet 133.8 ppm 2 JPP = 52.0 Hz 2 JPH = 19.0 Hz 135.4 303.6 303.4 303.2 300 302.8 302.6 302.4 275 302.2 302.0 301.8 250 301.6 135.2 135.0 135.0 P H-Dec 303.6 300 303.4 303.2 303.0 302.8 302.6 302.4 275 302.2 302.0 301.8 301.6 134.8 134.6 134.4 134.2 134.0 133.8 133.6 133.4 133.2 133.0 132.8 132.6 132.4 132.2 132.0 301.4 225 200 doublet 302.2 ppm 2 JPP = 52.0 Hz 31 1 303.0 175 150 125 triplet 133.4 ppm 2 JPP = 52.2 Hz 301.4 301.2 250 301.0 300.8 135.2 135.0 135.0 134.8 134.6 134.4 134.2 134.0 133.8 133.6 133.4 133.2 133.0 132.8 132.6 132.4 132.2 132.0 132.0 131.8 225 200 175 150 125