Continuous-Flow Production of Succinic Anhydrides via Catalytic ß-Lactone Carbonylation by Co(CO)4⊂Cr-MIL-101.

Industrial synthesis of succinic acid relies on hydrocarbon oxidation or biomass fermentation routes that suffer from energy-costly separation processes. Here we demonstrate an alternate route to succinic anhydrides via ß-lactone carbonylation by heterogeneous bimetallic ion-pair catalysis in Co(CO)4--incorporated Cr-MIL-101 (Co(CO)4⊂Cr-MIL-101, Cr-MIL-101 = Cr3O(BDC)3F, H2BDC = 1,4-benzenedicarboxylic acid). Postsynthetically introduced Co(CO)4- facilitates CO insertion to ß-lactone substrates activated by the Lewis acidic Cr(III) centers of the metal-organic framework (MOF), leading to catalytic carbonylation with activity and selectivity profiles that compare favorably to those reported for homogeneous ion-pair catalysts. Moreover, the heterogeneous nature of the MOF catalyst enables continuous production of succinic anhydride through a packed bed reactor, with room temperature ß-propiolactone carbonylation activity of 1300 molAnhydride·molCo-1 over 6 h on stream. Simple evaporation of the fully converted product stream yields the desired anhydride as isolated solids, highlighting the unique processing advantages conferred by this first example of heterogeneous ß-lactone carbonylation pathway.

Heterogeneous Epoxide Carbonylation by Cooperative Ion-Pair Catalysis in Co(CO)4--Incorporated Cr-MIL-101.

Despite the commercial desirability of epoxide carbonylation to ß-lactones, the reliance of this process on homogeneous catalysts makes its industrial application challenging. Here we report the preparation and use of a Co(CO)4--incorporated Cr-MIL-101 (Co(CO)4⊂Cr-MIL-101, Cr-MIL-101 = Cr3O(BDC)3F, H2BDC = 1,4-benzenedicarboxylic acid) heterogeneous catalyst for the ring-expansion carbonylation of epoxides, whose activity, selectivity, and substrate scope are on par with those of the reported homogeneous catalysts. We ascribe the observed performance to the unique cooperativity between the postsynthetically introduced Co(CO)4- and the site-isolated Lewis acidic Cr(III) centers in the metal-organic framework (MOF). The heterogeneous nature of Co(CO)4⊂Cr-MIL-101 allows the first demonstration of gas-phase continuous-flow production of ß-lactones from epoxides, attesting to the potential applicability of the heterogeneous epoxide carbonylation strategy.

Protein-targeted corona phase molecular recognition.

Corona phase molecular recognition (CoPhMoRe) uses a heteropolymer adsorbed onto and templated by a nanoparticle surface to recognize a specific target analyte. This method has not yet been extended to macromolecular analytes, including proteins. Herein we develop a variant of a CoPhMoRe screening procedure of single-walled carbon nanotubes (SWCNT) and use it against a panel of human blood proteins, revealing a specific corona phase that recognizes fibrinogen with high selectivity. In response to fibrinogen binding, SWCNT fluorescence decreases by >80% at saturation. Sequential binding of the three fibrinogen nodules is suggested by selective fluorescence quenching by isolated sub-domains and validated by the quenching kinetics. The fibrinogen recognition also occurs in serum environment, at the clinically relevant fibrinogen concentrations in the human blood. These results open new avenues for synthetic, non-biological antibody analogues that recognize biological macromolecules, and hold great promise for medical and clinical applications.