A functionalized Hf(iv)–organic framework introducing an efficient, recyclable, and size-selective heterogeneous catalyst for MPV reduction. (27th February 2023)

• Record Type: Journal Article
• Authors: Das, Aniruddha; Das, Asit Kumar
• Is Part Of: New journal of chemistry. Volume 47:Number 11(2023)
• Page Start: 5347
• Page End: 5355
• Publication Date: 2023-02-27
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/d2nj06066c
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : A newly functionalized Hf(iv )-based UiO-66 MOF (CSMCRI-KNC′ ) was synthesized followed by successful characterization and employed as a solid heterogeneous catalyst on MPV reduction. Abstract : UiO-66 (UiO = University of Oslo) metal–organic frameworks (MOFs) exhibit high thermal and chemical stability, large surface area, and defined pore shape and size. On the other hand, Meerwein–Ponndorf–Verley (MPV) reduction is a selective hydrogenation reaction of carbonyl group through hydrogen transfer between ketones (aldehydes) and alcohols. Herein, in this work, a Hf(iv )-based UiO-66 MOF called CSMCRI-KNC (CSMCRI-KNC = Central Salt and Marine Chemicals Research Institute-Krishnath College) was synthesized using a 2-((2-hydroxy-4-methoxy-benzyl)amino) terephthalic acid linker via the solvothermal procedure. The guest-free form of CSMCRI-KNC (called CSMCRI-KNC′ ) was successfully employed as a reusable heterogeneous catalyst for the hydrogen-transfer reaction between carbonyl compounds and alcohol (isopropanol). The catalyst showed a high yield, high conversion, broad substrate scope, and high stability on the MPV reduction reaction. Interestingly, the catalyst was size-selective too. The catalytic performance of CSMCRI-KNC′ was compared with its Zr analog, UiO-66-NH2 (Hf), UiO-66-NH2 (Zr), UiO-66(Hf), and UiO-66(Zr). Interestingly, our developed catalyst showed much better activity compared to the others. The systematized research discovered that the excellent performance of CSMCRI-KNC′ predominantly originated from the more positively charged Hf(iv ) species of [Hf6 (OH)4 (O)4 ] 12+, which could boost the activation of the carbonyl group and instantaneously endorse the hydrogen-transfer process assisted by the available basic sites on CSMCRI-KNC′ . The incorporation of the functional group also contributed to the excellent catalytic performance of CSMCRI-KNC′ . Notably, the preparation of CSMCRI-KNC′ avoided the utilization of an expensive organic linker, and the prepared CSMCRI-KNC′ showed superior or similar catalytic activity than most reported Zr/Hf-containing catalysts, meaningfully empowering it to be a more practical option in the field of catalysis, and hydrogen transfer reactions.