Pt@MIL-101(Fe) for efficient visible light initiated coproduction of benzimidazoles and hydrogen from the reaction between o-Phenylenediamines and alcohols

A Pt@MIL-101(Fe) nanocomposite, with Pt nanoparticles (NPs) fully embedded and well dispersed in the matrix of MIL-101(Fe), was prepared via a microwave-assisted self-assembly of MIL-101(Fe) in the presence of PVP-capped Pt colloids (PVP = polyvinylpyrrolidone). The as-obtained Pt@MIL-101(Fe) nanocomposite shows a superior activity for the one-pot reaction between o-phenylenediamines and alcohols to synthesize benzimidazoles under visible light, with concomitant generation of clean energy hydrogen, ascribed to an efficient mass diffusion and substrate-catalyst interactions imparted by the MOFs. The embedding of the Pt NPs within the MIL-101(Fe) contributes to the relatively high stability of Pt@MIL-101(Fe), since the aggregation of the Pt NPs can be significantly inhibited. This study not only provides a green and atom-efficiency strategy for the synthesis of benzimidazoles with concomitant generation of clean hydrogen, but also demonstrates that a rational fabrication of metal NPs/MOFs nanocomposites is important for them to be used as multifunctional catalysts for light initiated one-pot tandem/cascade reactions.