Compound 5

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Compound data: 1H NMR

Compound data: 13C NMR

Compound data: 19F NMR

Compound data: Crystallographic data

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

To a solution of (3c)Rh(cod)Cl (15.0 mg, 6.7 µmol) in CDCl₃ (1.5 mL) in a 5-mm NMR tube was bubbled carbon monoxide for 5 minutes at room temperature. Immediate colour change from orange to pale yellow was observed, and clean formation of 5 was confirmed by ¹H NMR monitoring. After evaporation, compound 5 was obtained as a yellow powder (12.1 mg, 5.2 µmol, 78% yield, ignoring contamination with hexanes). Recrystallization from chloroform/hexane (vapour diffusion) under CO atmosphere at room temperature afforded single crystals suitable for X-ray crystallographic analysis. NOTE: Compound 5 is mildly sensitive to water, decomposing to formamide. ¹H NMR (300 MHz, CDCl₃) δ 12.33 (d, ²J_Rh-H = 2.5 Hz, 1H), 8.00–7.61 (m, 39H), 7.16 (d, J = 7.5 Hz, 1H); ¹³C NMR (126 MHz, CH₃CN) δ 242.4 (d, ¹J_Rh-Carbene = 38.4 Hz, 3°), 184.7 (d, ¹J_Rh-CO = 53.0 Hz, 4°), 181.5 (d, ¹J_Rh-CO = 77.4 Hz, 4°), 141.8 (4°), 141.6 (4°), 141.1 (4°), 140.8 (4°), 140.5 (4°), 139.8 (4°), 132.7 (q, ²J_C-F = 31.2 Hz, 4°), 132.4 (q, ²J_C-F = 31.2 Hz, 4°), 131.5 (3°), 130.6 (3°), 129.0 (3°), 127.7 (3°), 127.5 (3°), 127.4 (3°), 127.0 (3°), 126.1 (3°), 122.9 (br q, ²J_C-F = 273 Hz, 4°), 122.5 (3°), 122.1 (3°), (Note: The signals in the aromatic region could not be fully counted, due to the broad and complex spectrum) 90.5 (4°), 86.4 (4°); ¹⁹F NMR (282 MHz, CDCl₃) δ −63.2; IR (DCM solution): 2086.4 and 2006.2 cm⁻¹. HRMS (m/z): [M−CO−Cl]⁺ calcd. for C₉₈H₄₁F₄₈NORh, 2262.1471; found, 2262.1535 (Note: Due to the labile nature of CO, only the mono carbonyl complex was detected.).