Carboxylate‐Functionalized Zeolitic Imidazolate Framework Enables Catalytic N‐Formylation Using Ambient CO₂

Abstract

From the perspective of sustainable and green chemistry, capturing and converting CO 2 into valueadded chemicals to create a surplus carbon cycle is beyond CCS technologies. As a key bioactive fragment, the CN bond widely existed in medicine and pesticide. [3] Catalytic N-formylation using CO 2 as a C1 building block can not only realize the upgrading of CO 2 but also relieve the environmental pressure.Hitherto, significant progress has been achieved in the catalytic upgrading of CO 2 into N-formyl compounds using hydroborane, dihydrogen, or hydrosilane as a reductant. The application of hydroborane is restricted by its sensitivity to air and moisture. [4] Commonly, dihydrogen is regarded as an ideal H-donor owing to its high reducibility and atom economy. However, precious metallic catalysts [5] or harsh experimental conditions [6] are required for releasing its protons to participate in the reaction. Meanwhile, the aromatic amines show low activity in the catalytic system, with dihydrogen as a reducing agent. [7] Alternatively, hydrosilanes, the by-products of the silicone industry, have the appropriate reducing ability, ease to handle, and high selectivity. [8,9] Various catalytic systems of high efficiency (e.g., N-heterocyclic carbenes, [10] N,N,N′,N′-tetr amethylguanidine, [11] 1-butyl-3-methylimidazolium chloride, [12] betaine, [13] and Cs 2 CO 3 [14] ) have been developed for reductive upgrading of CO 2 into N-formylated compounds. Also, some drawbacks are often encountered, such as the strong causticity of superbases, [15] complicated preparation process for ionic liquids, [16] or lack of catalyst stability and reusability. [17] As porous crystalline materials, metal−organic frameworks (MOFs) are widely applied in gas adsorption and separation, [18,19] drug delivery, [20] and heterogeneous catalysis [21] due to their adjusTable structure and rich reticular chemistry of structures. Therefore, it would be an interesting strategy to use MOFs as a catalytic platform for upgrading CO 2 . More importantly, the high affinity of MOFs to CO 2 will increase local CO 2 concentration around the catalytic sites. [22] This provides an opportunity to design catalytic materials that integrate CO 2 adsorption and activation. Up to now, the CO 2 catalytic conversion systems on the basis of MOF-based catalytic systems are mainly divided into two categories: i) directly catalytic reduction of CO 2 to platform molecules such as methanol, [23] and ii) catalytic cycloaddition reaction using CO 2 and energy-rich Catalytic upgrading of CO 2 into value-added chemicals to build the excess carbon cycle is of great significance. In this work, carboxylate-functionalized zeolitic imidazolate framework (F-ZIF-90) with good crystallinity and porosity is constructed from ZIF-90 and employed as a robust heterogeneous catalyst to boost the reductive N-functionalization of various amines with CO 2 to furnish N-formyl compounds (up to 99% yield) in the presence of PhSiH 3 under an ambient environment. The imidazole carboxylate species (COO...

In situ activation of COOH-functionalized ZIF-90-enabled reductive CO2N-formylation

“…S5c, ESI†). 12 Compared with ZIF-90, the peak at 531.58 eV in the O 1S spectrum corresponded to the CO bond in ZIF-90-C, while the band at 532.82 eV was attributed to the C–O bond in ZIF-90-C (Fig. S5d, ESI†), which further proved the construction of active sites (–COOH) in ZIF-90-C.…”

“…As a class of metal–organic frameworks (MOFs), zeolitic imidazolate frameworks (ZIFs) not only possess a high specific surface area, high porosity, and structural diversity, 10 but also show an excellent performance in CO 2 capture and multiphase catalysis. 11,12 In particular, the existence of organic ligands ( e.g. , –CHO) in ZIF-90 facilitates the introduction of functional groups via post-synthesis modification.…”

“…As a class of metal-organic frameworks (MOFs), zeolitic imidazolate frameworks (ZIFs) not only possess a high specific surface area, high porosity, and structural diversity, 10 but also show an excellent performance in CO 2 capture and multiphase catalysis. 11,12 In particular, the existence of organic ligands (e.g., -CHO) in ZIF-90 facilitates the introduction of functional groups via post-synthesis modification. 13 However, the structures of ZIFs are easily destroyed in a strong acid or base environment, which forms the basis for the functionalization process of the catalysts 14 and substrates for N-formylation.…”

Removal of carbon dioxide using zeolitic imidazolate frameworks: Adsorption and conversion via catalysis

“…[228,229] It can be converted via chemical reaction (Figure 12), photocatalysis, and electrochemical methods (Figure 1). The chemical transformation of CO 2 can be achieved via cycloaddition with epoxides to produce cyclic carbonates, hydrogenation, N-formaylation, [230] and synthesis of dimethyl carbonate (DMC) from CO 2 and methanol (Figure 12). The following sections summarize most of the findings for these topics.…”

A Review on Removal of Carbon Dioxide (CO2) using Zeolitic Imidazolate Frameworks: Adsorption and Conversion via Catalysis

“…It can be converted via chemical reaction (Figure 12), photocatalysis, and electrochemical methods (Figure 1). The chemical transformation of CO2 can be achieved via cycloaddition with epoxides to produce cyclic carbonates, hydrogenation, N-formaylation [230] , and synthesis of dimethyl carbonate (DMC) from CO2 and methanol (Figure 12). The following sections summarize most of the findings for these topics.…”