Photocatalytic Hydrogenation of Acetophenone

The ruthenium catalyst solution used for the photocatalytic TH was prepared by dissolving the complexes 1, 4–7 (0.02 mmol) in 2-propanol (5 mL). The catalyst solution (250 μL, 1.0 μmol) and a 0.1 M solution of NaOiPr (200 μL, 20 μmol) in 2-propanol were added subsequently to the acetophenone solution (1.0 mmol) in 2-propanol or a 2-propanol/MeOH (1:1 v/v) mixture (final volume 10 mL). The resulting solutions were stirred in a thermostated water bath at 30 °C. Irradiation of the samples was carried out using a 300 W Xenon Arc Lamp (LSB530A, LOT-Oriel, Darmstadt, Germany), emitting in the range 200–2500 nm (solar simulator). Samples were purged with Ar at least 15 min before irradiation. The reaction was sampled by removing an aliquot of the reaction mixture, which was quenched by the addition of diethyl ether (1:1 v/v), filtered over a short silica pad and submitted to GC analysis. The base addition was considered as the start time of the reaction. The S/C molar ratio was 1000/1, whereas the base concentration was 2 mol% with respect to the ketone substrate (0.1 M).