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.

A dual-active MOF (CSMCRI-KNC′) was successfully employed for the detection of the explosive FOX-7 and as a heterogeneous catalyst for the synthesis of barbituric acid and its derivatives under mild conditions.

A novel and transition-metal-free strategy has been developed for the synthesis of aryl esters starting from corresponding benzylic primary alcohols as the exclusive substrates using tert-butyl hydroperoxide (TBHP) as a terminal oxidant in the presence of catalytic amount of tetrabutylammonium iodide (TBAI) and imidazole, where the aliphatic alcohols remained unaffected. These reactions are highly chemoselective and associated with high yield and wide applicability accommodating a wide range of substituents. Excellent chemoselectivity has also been demonstrated through intramolecular competition experiments. This protocol can be considered as an important analogue of Tishchenko reaction using benzylic alcohols as the substrates instead of benzaldehydes.

This study reports the green synthesis of Fe₃O₄@PPE nanoparticles using agricultural waste, showcasing their wide-ranging biological activities and catalytic efficiency in the synthesis of nitriles.