Fig. 4. Investigation of the scope of the photocatalytic CO₂-to-CO conversion.

Green colored circles and numbers denote the positions of the carbon atoms labeled and the percent incorporation of the carbon isotope. See Supplementary pages 40–45. Conditions in Ch1, for A, B, C, E, F: [¹³C]CO₂ (0.36 mmol), BIH (0.87 mmol, 2.4 equiv.); phenol (2.0 mmol, 5.5 equiv.); Ru PS (0.45 mol%, 1.62 µmol); Re(CO)₃(bpy)Br Re cat (0.45 mol%, 1.62 µmol), phosphine P2 (0.036 mmol, 0.1 equiv.) in ACN. Conditions in Ch1, for D: [¹³C]CO₂ (0.44 mmol), BIH (0.95 mmol, 2.12 equiv.); phenol (2.44 mmol, 5.5 equiv.); Ru PS (0.45 mol%, 1.95 µmol); Re(CO)₃(bpy)Br Re cat (0.45 mol%, 1.95 µmol), phosphine P2 (0.044 mmol, 0.1 equiv.) in ACN. ^aConditions in Ch1: [¹³C]CO₂ (0.60 mmol), BIH (1.56 mmol, 2.60 equiv.); phenol (4.0 mmol, 6.6 equiv.); Ru PS (0.54 mol%, 3.3 µmol); Re(CO)₃(bpy)Br Re cat (0.53 mol%, 3.2 µmol), phosphine P2 (0.072 mmol, 0.12 equiv.) in ACN. ^bSee Supplementary page 94.