Functionalized Metal–Organic Framework as a Biomimetic Heterogeneous Catalyst for Transfer Hydrogenation of Imines

• Published in: ACS applied materials & interfaces Vol. 9; no. 11; pp. 9772 - 9777
• Main Authors: Chen, Jingwen, Zhang, Zhiguo, Bao, Zongbi, Su, Ye, Xing, Huabin, Yang, Qiwei, Ren, Qilong
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 22.03.2017
• Subjects: Brønsted acid; biomimetic catalyst; hydrogenation; metal−organic frameworks; Hantzsch ester; imine
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.7b00562

Mimicking a biocatalytic system has been one of the prevalent strategies for the design of novel and efficient chemical transformations. Among the enzyme-catalyzed reactions, the cooperative interplay of Lewis- and Brønsted-acidic functionalities at active sites represents a common feature in activating reactants. Employing MIL-101­(Cr) as a biomimetic platform, we customize a sulfonic group (SO3H) into its hierarchical pores to generate a heterogeneous catalyst for transfer hydrogenation of imines by using Hantzsch ester as the reductant. Both aldimines and ketimines were efficiently converted to their hydrogenated counterparts in a manner similar to metal enzymes. The Cr3+ node and sulfonic acid functionality encapsulated in MOF cages worked cooperatively in promoting this transformation, resulting in an enhanced reactivity as compared to its homogeneous analogue. Furthermore, MIL-101­(Cr)-SO3H could be recycled for many times without considerable loss in reactivity.