Palladium Nanoparticles Confined in the Cages of MIL-101: An Efficient Catalyst for the One-Pot Indole Synthesis in Water

A hydrothermally stable metal organic framework, MIL-101, was used as support for a metallic Pd nanoparticle catalyst. With the characterization of X-ray photoelectron spectroscopy, X-ray diffraction, N-2 physisorption, scanning electron microscopy, transmission electron microscopy, and CO chemisorption, the resulting Pd nanoparticles were identified to be confined in the cages of MIL-101. During the one-pot indole synthesis between 2-iodoaniline and phenylacetylene in water, the as-prepared Pd catalyst was more active and stable than the metallic Pd nanoparticles supported on MCM-41. The enhanced catalytic properties were found to depend on both the texture and the surface chemistry of the MIL-101 support.