Palladium-1,10-phenanthroline complex encaged in Y zeolite: An efficient and highly recyclable heterogeneous catalyst for aminocarbonylation

• PdCl2(phen)@Y exhibits high aminocarbonylation activity for synthesis of amides.
• PdCl2(phen)@Y is re-used up to 16 times without any loss of activity in reaction.
• Double protection for the active Pd complex accounts for excellent recyclability.

A promising route for catalytic synthesis of amides by aminocarbonylation of aryl iodides with amines is described using a palladium-1,10-phenanthroline complex encaged in Y zeolite. Complete conversions for aryl iodides and good to excellent yields (71–97%) of various amides were obtained at low Pd loadings of 0.6 mol%. The turnover frequency (TOF) could be up to 139 h−1. A satisfactory yield was obtained even after the catalyst was reused 16 times and the total turnover number (TON) for the 16 cycles was up to 2250. As evidenced by atomic absorption spectrophotometry, UV–vis spectroscopy and X-ray photoelectron spectroscopy, the palladium complex could well nestle down in the supercages of the zeolite without leaching during the recycling process. The significantly enhanced recyclability could be attributed to the double-protection strategy provided by the ligand and the zeolite structure for Pd0 species generated in situ within supercages preventing the migration and leaching of palladium. The supported catalyst has the advantages of easy handing, good to excellent yields, and outstanding recycling capacity for aminocarbonylation reactions of aryl iodides.

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