Abstract
The chemoselective hydrogenation of molecules containing multiple reducible groups using H(2) presents inherent challenges. Here we show a homoleptic nanocluster [Au(40)(ArC≡C)(22)](Et(4)N)(2) (Au(40) for short, ArC≡C is 3,5-bis(trifluoromethyl)-phenylacetylide) is synthesized in high yield and its structure is elucidated using single-crystal X-ray diffraction. DFT calculations reveals that Au(40) features a superatomic 20-electron configuration of (1S)(2)(1P)(6)(1D)(10)(1F)(2). Au(40)/TiO(2) exhibits 100% selectivity and activity for the hydrogenation of 4-nitroacetophenone in water, free of base and under mild conditions (80 °C, H(2) 10 bar). The turnover numbers reach a value of 335,569, and the turnover frequencies 5829 h(-)(1) is an order of magnitude higher than those observed in the well-established Au/TiO(2) system. The improved catalytic performance of Au(40) is attributed to the synergy of its enhanced durability, unique molecular structure. This work demonstrates that tailoring the surface coordination structure is an effective way to modulate the catalytic performance of cluster catalysts.