Four new triphenylphosphine-derived cage ligands were modularly synthesized dynamic imine chemistry (DIC), and their absolute structures were characterized by single crystal X-ray diffraction (SXRD), nuclear magnetic resonance (NMR) and high resolution mass spectroscopy (HRMS). In contrast to small-molecule analogues, cage ligands demonstrate superior activity and selectivity. The Rh/Cage-L2 catalyst exhibits remarkable performance with an aldehyde selectivity of 89%, accompanied by a TOF value of 2665 h and an / ratio of 2.
View Article and Find Full Text PDFRevealing key factors that modulate the regioselectivity in heterogeneous hydroformylation requires identifying and monitoring the dynamic evolution of the truly active center under real reaction conditions. However, unambiguous in situ characterizations are still lacking. Herein, we elaborately construct a series of Rh-POPs catalysts for propylene hydroformylation which exhibited tunable regioselectivity.
View Article and Find Full Text PDFSulfur poisoning and regeneration are global challenges for metal catalysts even at the ppm level. The sulfur poisoning of single-metal-site catalysts and their regeneration is worthy of further study. Herein, sulfur poisoning and self-recovery are first presented on an industrialized single-Rh-site catalyst (Rh /POPs).
View Article and Find Full Text PDFHeterogeneous, metal, single-site catalysts often exhibit higher catalytic performance than other catalysts because of their maximized atom efficiency of 100 %. Reported herein is a precoordination/solvothermal polymerization strategy to fabricate a stable mononuclear Pd-metalized porous organic polymer catalyst (Pd@POP). Pd@POP was easy to use in regioselective organic reactions because the internal structure of this Pd@POP can be easily modified.
View Article and Find Full Text PDFA series of Mg-porphyrin complex doped divinylbenzene (DVB) based porous organic polymers (POPs) were systematically afforded through the method of free radical polymerization under solvothermal conditions. These POP catalysts have physical advantages of high surface areas, hierarchical pore structures, high thermal stability and spatially separated active Mg-porphyrin sites, which lead to very high efficiency in the conversion of CO to cyclic carbonates with the aid of tetra-n-butyl ammonium bromide (TBAB) as a nucleophile. The effect of the doping ratio (Mg-porphyrin complex to DVB) on catalytic efficiency was studied and discussed, and the detrimental embedding effect was found.
View Article and Find Full Text PDFA novel palladium nanoparticle (NP)-metalated porous organic ligand (Pd NPs/POL-xantphos) has been prepared for the chemoselective decarbonylation of aldehydes. This heterogenous catalyst not only has excellent catalytic activity and chemoselectivity, but also holds high activity after 10 runs of reuse. The effective usage of this method is demonstrated through the synthesis of biofuels such as furfuryl alcohol (FFA) via the highly chemoselective decarbonylation of biomass-derived 5-hydroxy-methylfurfural (HMF) with a TON up to 1540.
View Article and Find Full Text PDFThiophenes containing an adjacent C≡C group as ligands for Pd-promoted organic reactions are reported for the first time. These ligands were utilized as catalytic sites and integrated into the skeleton of conjugated microporous polymers. By employing these CMP materials as selective regulators, oxidative Heck reactions between arylboronic esters and electronically unbiased alkenes provide highly selective linear products.
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