Click-based porous organic framework containing chelating terdentate units and its application in hydrogenation of olefins

Abstract

Click reaction of 2,6-diethynylpyridine and tetrakis(4-azidophenyl)methane gave rise to a porous organic framework containing chelating terdentate 2,6-bis(1,2,3-triazol-4-yl)pyridyl units (BTP-POF). BTP can serve as a promising linkage of an organic framework and as an effective stabilizer of palladium nanoparticles (NPs) owing to its structural preference and strong chelating ability with palladium. The well-dispersed palladium NPs in interior pores and external surface of BTP-POF were readily obtained, the NPs in interior pores have a small size and narrow size distribution; they show excellent catalytic activity, high stability and good reusability in palladium-catalyzed hydrogenation of olefins at 25 °C. The mean diameter of palladium NPs was increased from 1.8 to 2.5 nm after recycling for seven runs, but no obvious loss of catalytic activity and agglomeration of palladium NPs was observed. Mercury drop test, filtration experiment and ICP analysis suggest that Pd/BTP-POF is a heterogeneous catalytic system in the hydrogenation of olefins.