Ethylene diamine post‐synthesis modification on open metal site Cr‐MOF to access efficient bifunctional catalyst for the Hantzsch condensation reaction

Abstract

Ethylene diamine functionalized MIL‐101(Cr) was established to be an efficient organocatalyst for single‐pot synthesis of polyhydroquinolines via four‐component condensation reaction between aldehydes, dimedone, β‐ketoecters and ammonium acetate in aqueous medium. Ethylene diamine of the parent open metal site MIL‐101(Cr) has been carried out through a post‐synthetic modification (PSM) technique. Efficient transformation, mild condition, easy product isolation and the potential high recycbility of the organocatalyst are the key feature of this protocol.

Engineering Metal–Organic Framework Catalysts for C−C and C−X Coupling Reactions: Advances in Reticular Approaches from 2014–2018

“…The poor stabilityo fM OFs makes them unsuitable for catalytic reruns.H owever, with advancements in post-synthesis modification techniques, it is possible for MOFs to be stabilized. Notably,K noevenagel condensation, [28] aldol condensation, [29] Suzuki-Miyaura coupling, [30] Ullmann coupling, [31] Sonogashira coupling, [32] Chan-Lam coupling, [33a] Mizoroki-Heck coupling, [34] Hantzchc oupling, [35] Glaser coupling, [36] Fischere sterification, [37] Friedel-Crafts' aroylation, [38] and aerobic oxidation [39] have all been demonstrated. Furthermore, the large open structures of MOFs ( Figure 2) enables smaller active metal nanoparticles (Table 1) and homogeneous catalysts to be incorporated into the framework, thereby making them useful for catalytic applications.…”

“…Several organic transformations have been catalyzed by using metal–organic frameworks. Notably, Knoevenagel condensation, aldol condensation, Suzuki–Miyaura coupling, Ullmann coupling, Sonogashira coupling, Chan–Lam coupling, Mizoroki–Heck coupling, Hantzch coupling, Glaser coupling, Fischer esterification, Friedel–Crafts’ aroylation, and aerobic oxidation have all been demonstrated.…”

Porous triazine polymer: A novel catalyst for the three‐component reaction

“…Covalent organic polymers (COPs) are a class of porous frameworks with light elements (e.g., C, H, N, B, O) as the organic building blocks are linked by covalent bonds. Besides the similar properties as those of metal-organic frameworks, [1][2][3][4][5][6][7] such as high crystalline properties, large surface area, and open-pore structures, [8][9][10] the open porous structures and outstanding stability of COPs under acidic and basic conditions due to the strong covalent bonding between organic groups [11][12][13] turn them into excellent host frameworks for many FGs (functional groups), such as proton carriers [14] electron acceptors, [15] and enzymes. [16] The COPs cavities have also been investigated as nano-reactors for organic reactions.…”

A new Brønsted acid MIL‐101(Cr) catalyst by tandem post‐functionalization; synthesis and its catalytic application

“…[17] Post-functionalization of MOFs has opened a new window to design a broad range of modified MOFs and different functional groups have been immobilized into their frameworks to produce heterogeneous catalysts for many chemical reactions. [18][19][20][21][22][23][24][25][26] Among different known MOFs, MIL-101(Cr)is a suitable candidate for postfunctionalization because of its high surface area, attainable cages, high thermal and chemical stabilities, and lots of coordinatively unsaturated metal sites (CUSs) upon dehydration process. [27,28] It is a chromium (III) terephthalate MOF with three-dimensional porous structure which presents two types of mesoporous cages with diameters of 2.9 and 3.4Å accessible through microporous windows of 1.2 and 1.6Å, respectively.…”