A porous organic polymer supported Pd/Cu bimetallic catalyst for heterogeneous oxidation of alkynes to 1,2-diketones

Abstract

A porous organic polymer (POP–POPh₃) was readily prepared by oxidation of POP-PPh₃ with H₂O₂. After coordination with PdCl₂ and a co-catalyst of a CuBr₂ precursor, a Pd/Cu bimetal-loaded porous organic polymer (Pd/Cu@POP–POPh₃) was afforded. The NMR and XPS characterizations indicated that both Pd(II) and Cu(II) could coordinate with the PO bonds in the polymer. Furthermore, the catalyst has high surface areas, hierarchical porosity and good thermostability. The Pd/Cu@POP–POPh₃ catalyst was successfully used in heterogeneous oxidation of alkynes with O₂ as the oxidant to afford corresponding 1,2-diketones in high to excellent yields (76–99%). A series of alkynes with various functional groups performed well in the process. Remarkably, the heterogeneous catalyst can be reused for five cycles without significant loss of catalytic activity in oxidation of diphenylacetylene.