Design and synthesis of squaramide-based MOFs as efficient MOF-supported hydrogen-bonding organocatalysts

Abstract

Herein, we utilize a new, squaramide-based ligand, combined with a postsynthetic exchange (PSE) synthetic approach to prepare a series of Cu(ii)-squaramide MOFs that are active catalysts for the Friedel-Crafts reaction.

Potential Utilization of Metal–Organic Frameworks in Heterogeneous Catalysis: A Case Study of Hydrogen‐Bond Donating and Single‐Site Catalysis

“…In 2016, Cohen and co-workersr eported an alternative approach for the synthesis of stable squaramide MOF catalysts using post-synthetic exchange (PSE) technique. [40] They synthesized as table Cu- (Figure 10 d). Moreover,a uthors have prepared as eries of isostructural MOF catalysts (denoted as Cu(dbda) x (tptc) 1À Àx , x = 0.75, 0.49, 0.18, 0; H 4 tptc = p-terphenyl- 3,5,3'',5''-tetracarboxylic acid) (Figure 10 b) through PSE approach from Zn(dbda) x (tptc) 1À Àx MOF precursor andc ompared their catalytic activity with previous reported HBD MOF catalysts under optimum conditions.…”

“…In 2016, Cohen and co‐workers reported an alternative approach for the synthesis of stable squaramide MOF catalysts using post‐synthetic exchange (PSE) technique . They synthesized a stable Cu‐based squaramide MOF [ Cu(dbda) ] from the Zn II analog [ Zn(dbda) ] by adopting the PSE process (Figures 10 a and c).…”

“…(a) H 4 dbda ligands tructure, (b) H 4 tptc ligand structure, (c) the squaramideligand connectivity in Zn(dbda)(left), crystal packing modelo f Zn(dbda) along c-axis (right), (d) reaction conditionso fF-C alkylation using MOF catalysts.Figure ci sa dapted with permission from ref [40]…”

CoFe2O4/TMU‐17‐NH2 as a hybrid magnetic nanocomposite catalyst for multicomponent synthesis of dihydropyrimidines

“…Over the past three decades, the synthesis of metal–organic frameworks (MOFs) as porous crystalline hybrid materials by assembling metal nodes and organic ligands has attracted considerable attention with the aim of finding meaningful applications in various fields such as gas storage and separation, drug delivery, optics, sensing and biomedical imaging . Due to the diversity in metal centres and functional groups, high surface area and tunable porosity, MOFs can be valid as versatile heterogeneous catalysts . Among various catalyst separation techniques in organic synthesis, a simple magnetic isolation process eliminates the requirement of catalyst filtration and centrifugation; so, MOFs based on a magnetic support provide easy manipulation.…”

Crystallographic investigation into the self-assembly, guest binding, and flexibility of urea functionalised metal-organic frameworks

“…For example, grafting hydrogen bond donor functionality, such as amides (11)(12)(13)(14)(15)(16)(17)(18)(19)(20), ureas (21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32), thioureas (33), and squaramides (34)(35)(36), (Figure 1(a)) onto the organic scaffold of the MOF can enhance properties including carbon dioxide capture (13,15,17,18), anion binding (20,21), sensing (28), and organocatalytic activity (6). Urea-functionalised MOFs in particular have been found to catalyse FriedelCrafts reactions between pyrroles and nitroalkenes (22,24,27,29,31), Henry reactions between aldehydes and nitromethane (23), and the methanolysis of epoxides (25).…”