Few-layer Black Phosphorous Catalyzes Radical Additions to Alkenes Faster than Low-valence Metals

Abstract

The substitution of catalytic metals by p-block main elements has a tremendous impact not only in the fundamentals but also in the economic and ecological fingerprint of organic reactions. Here we show that few-layer black phosphorous (FL-BP), a recently discovered and now readily available 2D material, catalyzes different radical additions to alkenes with an initial turnover frequency (TOF₀) up to two orders of magnitude higher than representative state-of-the-art metal complex catalysts at room temperature. The corresponding electron-rich BP intercalation compound (BPIC) KP₆ shows a nearly twice TOF₀ increase with respect to FL-BP. This increase in catalytic activity respect to the neutral counterpart also occurs in other 2D materials (graphene vs. KC₈) and metal complex catalysts (Fe⁰ vs. Fe^2- carbon monoxide complexes). This reactive parallelism opens the door for cross-fertilization between 2D materials and metal catalysts in organic synthesis.

Keywords: 2D materials; alkenes; black phosphorus; iron; p-block catalysis; radical addition.