Heterovalent Metal Pair Sites on Metal–Organic Framework Ordered Macropores for Multimolecular Co-Activation

Abstract

The precise design of catalytic metal centers with multiple chemical states to facilitate sophisticated reactions involving multimolecular activation is highly desirable but challenging. Herein, we report an ordered macroporous catalyst with heterovalent metal pair (HMP) sites comprising Cu II −Cu I on the basis of a microporous metal−organic framework (MOF) system. This macroporous HMP catalyst with proximity heterovalent dual copper sites, whose distance is controlled to ∼2.6 Å, on macropore surface exhibits a co-activation behavior of ethanol at Cu II and alkyne at Cu I , and avoids microporous restriction, thereby promoting additive-free alkyne hydroboration reaction. The desired yield enhances dramatically compared with the pristine MOF and ordered macroporous MOF both with solely isovalent Cu II −Cu II sites. Density functional theory calculations reveal that the Cu-HMP sites can stabilize the Bpin-Cu II −Cu I -alkyne intermediate and facilitate C−B bond formation, resulting in a smooth alkyne hydroboration process. This work provides new perspectives to design multimolecular activation catalysts for sophisticated matter transformations.

Single-Crystalline Ordered Nanoporous Metal–Organic Frameworks for Lipase Immobilization and Structured Lipid Production

“…As illustrated in Figure a, the XPS survey spectra of SOM-MIX31 showed an intense peak for N 1s, which was absent from CuBTC reported in the literature, demonstrating the successful incorporation of 1,2,3-benzotriazole. The deconvoluted XPS spectra showed two satellite peaks and one main peak in the Cu 2p 3/2 region (as shown in Figure b), which presented a shift to lower binding energy compared to CuBTC reported in the literature (∼933 eV for MOF-199 vs 934.4 eV for CuBTC) . Cu became more electronegative, suggesting that it reaccepted electrons from the nitrogen atom of the new ligand .…”