Metallosalen‐Based Ionic Porous Polymers as Bifunctional Catalysts for the Conversion of CO₂ into Valuable Chemicals

Abstract

A series of new metallosalen-based ionic porous organic polymers (POPs) were synthesized for the first time using a simple unique strategy based on the free-radical copolymerization reaction. Various techniques were used to characterize the physicochemical properties of these catalysts. These well-designed materials endowed high surface area, hierarchical porous structures, and enhanced CO /N adsorptive selectivity. Moreover, these POPs having both metal centers (Lewis acid) and ionic units (nucleophile) could serve as bifunctional catalysts in the catalytic conversion of CO into high value-added chemicals without any additional co-catalyst under mild and solvent-free conditions, for example, CO /epoxides cycloaddition and Nformylation of amines from CO and hydrosilanes. The results demonstrated that the irregular porous structure was very favorable for the diffusion of substrates and products, and the microporous structural property resulted in the enrichment of CO near the catalytic centers in the CO -involved transformations. Additionally, the superhydrophobic property could not only enhance the chemoselectivity of products but also promote the stability and recyclability of catalysts.

Porous Organic Polymers for CO2 Storage and Conversion Reactions

“…Recently, Ji et al. have shown that DVB@ISZ POP network bearing the ionic liquid and Zn(salen) moieties can activate the Si−H bond of hydrosilane and N−H bond of the reactant amine so that N‐formylation can proceed smoothly in for a wide range of amines with CO 2 and PhSiH 3 …”

Charged Metalloporphyrin Polymers for Cooperative Synthesis of Cyclic Carbonates from CO2 under Ambient Conditions

“…[12] Nevertheless, this binary catalytic system still required an additional cocatalyst as an ucleophile (e.g.,t etrabutylammoniumb romide;T BAB), which implemented the catalytic cyclea nd increased the overall efficiency.M oreover,i nspired by the design of bifunctional catalysts, as eries of hierarchical POPs with multiple active sites, which included metallosalenc omplexes and ionic liquid (IL) units, were also synthesized and employed as efficient catalysts in the chemicalc onversion of CO 2 into valuable chemicals withoutt he use of cocatalysts. [13] Regrettably,ahigher reaction temperature (> 100 8C) was often required to obtain the excellent catalytic properties, which was undesirablei ns ome applications.…”

“…Herein,b ased on our previous studies [13,15] and the rational construction strategy of bifunctionalc atalysts, [7d, 16] aluminum porphyrin-based ionic porous organic polymers (Al-iPOPs) were synthesized successfully by af acile one-pot method.T his promising presynthetic technique was based on the typical Yamamoto-Ullmann coupling reactionb etween 5,10,15,20-tetrakis(4-bromophenyl)porphyrin-aluminum(III) chloride (Al-TBPP) and brominated ILs, which include 1,3-bis(4-bromobenzyl)imidazolium bromide (IL-1) and 1,3-bis(4-bromophenyl)imidazolium bromide (IL-2;S cheme 2). To the best of our knowledge, this is the first example of POPs that have both IL moieties and metalloporphyrin skeletons in one 3D porous material prepared by aw ell-designed strategy.M oreover,w eu sed various characterization techniques,w hich included solid-state 13 CNMR spectroscopy,F TIR spectroscopy,e lementala nalysis, inductively coupled plasma optical emission spectroscopy (ICP-OES), thermogravimetric analysis (TGA),S EM, Cryo-SEM, TEM, X-ray photoelectron spectroscopy (XPS), and CO 2 /N 2 adsorption-desorption measurements, to understand the special physicochemical properties of these catalysts. These polymers were endowed with outstanding swelling features, good CO 2philic properties, and excellent CO 2 /N 2 selectivity.T hus, these heterogeneous POP-based materials were efficient bifunctional catalysts to catalyzet he cycloaddition of CO 2 with epoxides withoutany additives under mild conditions.…”

Hybrid Catalysts for CO2 Conversion into Cyclic Carbonates

“…Several catalysts, working under both homogeneous and heterogeneous conditions, were developed for the conversion of CO 2 into cyclic carbonates via reaction with epoxides. In particular, metal oxides [21], metal-organic frameworks (MOFs) [22][23][24], metal salts [25], metal complexes [12,[26][27][28], Lewis base systems [29], ionic liquids (ILs) [30][31][32][33][34][35], and organic polymers [32,36,37] were proposed as catalysts for this reaction. Based on the environmental impact and the cost efficiency, the overall sustainability of this process has to be evaluated and improved according to some key criteria such as (i) the presence of solvents, (ii) the use of metal species, (iii) the achieved yields and selectivity, and (iv) the required reaction conditions (temperature, pressure, reaction time).…”