The synergic effects at the molecular level in CoS2 for selective hydrogenation of nitroarenes?

Green Chemistry Pub Date: 2017-12-22 DOI: 10.1039/C7GC03122J

Abstract

Catalytic functionalized aniline formation from nitroarenes is a core technology in the synthesis of pharmaceuticals, agrochemicals, and fine chemicals. However, control of chemoselectivity still poses particular challenges with aromatic nitro substrates bearing one or more reducible groups. Here, we report the low-cost synthesis of a porous carbon supported CoS2 catalyst (CoS2/PC) and successfully apply the catalyst in the chemoselective hydrogenation of nitroarenes. For hydrogenation of 3-nitrostyrene, the catalyst furnishes a superior selectivity of 99% towards 3-aminostyrene at a conversion of >99%. Density functional theory calculations together with X-ray absorption fine structure spectroscopy reveal that terdentate and tetrahedral coordinated Co atoms in CoS2 (labeled as Co3 and Co4) are possible active sites. The face to face located Co3 and Co4 sites make the reaction rather local, and Co3 and Co4 sites are occupied by substrates and H2, respectively, which is beneficial to the superior activity and selectivity. The Co3–Co4 “synergic active site pair” in CoS2 makes the investigation of the synergic effects at the molecular level a reality on heterogeneous catalysts.

Graphical abstract: The synergic effects at the molecular level in CoS2 for selective hydrogenation of nitroarenes
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