A family of microporous and robust Ln(iii)-based metal-organic frameworks (1-Ln, Ln = Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb) have been obtained using 4,4',4''-nitrilotribenzoic acid (HNTB) in NMP-HCl solvent. Both single-crystal and powder X-ray diffraction analyses demonstrate that 1-Ln are isostructural and possess 3D frameworks with permanent porosity for Ar and CO adsorption. Strikingly, the incorporation of both Lewis acidic lanthanide ions and the basic triphenylamine group into 1-Ln makes them efficient acid-base catalysts for both cycloaddition of epoxides with CO and one-pot cascade deacetalization-Knoevenagel reactions. The systematic catalytic studies show that 1-Tb and 1-Yb possess the best catalytic activities for both reactions, indicating the catalytic activities of these Ln-MOFs are strongly dependent on metal Lewis acid sites embedded in the frameworks.
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http://dx.doi.org/10.1039/d2ra06545b | DOI Listing |
Nat Commun
December 2024
Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, 610064, China.
The activation of C-C bond of benzocyclobutenones under mild reaction conditions remains a challenge. We herein report a photoinduced catalyst-free regio-specific C1-C8 bond cleavage of benzocyclobutenones, enabling the generation of versatile ortho-quinoid ketene methides for aza-[4 + 2]-cycloaddition with imines, which offers a facile route to isoquinolinone derivatives, including seven family members of protoberberine alkaloids, gusanlung A, B, D, 8-oxotetrahydroplamatine, tetrahydrothalifendine, tetrahydropalmatine, and xylopinine. Furthermore, the catalytic enantioselective version of this strategy is also realized by merging synergistic photocatalysis and chiral Lewis acid catalysis.
View Article and Find Full Text PDFNat Commun
December 2024
Center of Artificial Photosynthesis for Solar Fuels and Department of Chemistry, School of Science, Westlake University, Hangzhou, China.
Natural enzymes feature distinctive second spheres near their active sites, leading to exquisite catalytic reactivity. However, incumbent synthetic strategies offer limited versatility in functionalizing the second spheres of heterogeneous catalysts. Here, we prepare an enzyme-mimetic single Co-N atom catalyst with an elaborately configured pendant amine group in the second sphere via 1,3-dipolar cycloaddition, which switches the oxygen reduction reaction selectivity from the 4e to the 2e pathway under acidic conditions.
View Article and Find Full Text PDFMacromol Rapid Commun
December 2024
Hunan Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China.
The CO-epoxide addition to cyclic carbonate is of great significance but usually requires high temperatures and CO pressures. Herein, a spirobifluorene-based porous organic polymer catalyst is designed with a Co-salen complex immobilized on the backbone (ST-CoSalen-POP) to enable CO fixation under mild conditions. ST-CoSalen-POP possesses a high Co-loading content (9.
View Article and Find Full Text PDFOrg Lett
December 2024
School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, Shihezi, Xinjiang 832003, China.
Easily obtainable and efficient chiral -symmetric bipyridine-,'-dioxide ligands with Ni(OTf) were developed for application in catalyzing [3 + 2] cycloaddition reactions to synthesize optically active fused pyrazolidines or pyrazoline derivatives featuring three contiguous stereogenic centers by employing azomethine imines and α,β-unsaturated 2-acyl imidazoles, affording the corresponding adducts with the opposite configuration compared to previous synthetic products in 80-98% yields with 28-99% ee and >20:1 dr. In addition, subsequent amplification experiments and derivative transformations of the product further demonstrated the efficient catalytic performance of the catalyst Ni(II)-bipyridine-,'-dioxide complexes and the practicality of this synthesis methodology.
View Article and Find Full Text PDFChemistry
December 2024
Guangdong Pharmaceutical University, Guangzhou Higher Education Mega Center, 510006, Guangzhou, CHINA.
Among the various studies on CO2 utilization, the sustainable and cost-effective fixation of CO2 into cyclic carbonates remains one of the most intriguing subjects. To this end, a novel type of composite dicationic ionic liquid material, DIL@PDIL, was developed. This composite consists of a dicationic ionic liquid (DIL), DMAP[TMGH]Br, supported on a polymeric dicationic ionic liquid (PDIL), P-DVB/Im[TMGH]Br.
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