Protonated Porphyrins: Bifunctional Catalysts for the Metal-Free Synthesis of N-Alkyl-Oxazolidinones

Perfluoroalkyl-Decorated Noble-Metal-Free MOFs for the Highly Efficient One-Pot Four-Component Coupling between Aldehydes, Amines, Alkynes, and Flue Gas CO2

The non-noble-metal catalysed-multicomponent reactions between flue gas CO2 and cheap industrial raw stocks into high value-added fine chemicals is a promising manner for the ideal CO2 utilization route. To achieve this, the key fundamental challenge is the rational development of highly efficient and facile reaction pathway while establishing compatible catalytic system. Herein, through the stepwise solvent-assisted linker installation, post-synthetic fluorination and metalation, we report the construction of a series of perfluoroalkyl-decorated noble-metal-free metal-organic frameworks (MOFs) PCN-(BPY-CuI)-(TPDC-Fx ) [BPY=2,2'-bipyridine-5,5'-dicarboxylate, TPDC-NH2 =2'-amino-[1,1':4',1''-terphenyl]-4,4''-dicarboxylic acid] that can catalyze the one-pot four-component reaction between alkyne, aldehyde, amine and flue gas CO2 for the preparation of 2-oxazolidinones. Such assembly endows the MOFs with superhydrophobic microenvironment, superior water resistance and highly stable catalytic site, leading to 21 times higher turnover numbers than that of homogeneous counterparts. Mechanism investigation implied that the substrates can be efficiently enriched by the MOF wall and then the adsorbed amine species act as an extrinsic binding site towards dilute CO2 through their strong preferential formation to carbamate acid. Moreover, density functional theory calculations suggest the tetrahedral geometry of Cu in MOF offers special resistance towards amine poisoning, thus maintaining its high efficiency during the catalytic process.