Cationic Zn-Porphyrin Immobilized in Mesoporous Silicas as Bifunctional Catalyst for CO₂ Cycloaddition Reaction under Cocatalyst Free Conditions

Abstract

Immobilization of metalloporphyrin onto a solid support is highly desirable in the chemical industry. Herein, we reported for the first time the efficient immobilization of cationic zincporphyrin complexes on mesoporous SBA-15 by a simple one-pot method by refluxing 5,10,15,20-tetrakis­(4-pyridyl)­porphyrin zinc­(II) (Zn-TPy), SBA-15, and 3-(trimethoxysilyl)­propyl bromide in toluene, DMF, NMP, or THF. Studies suggest that solid catalyst with high Zn content, stiochiometric Br–/Zn ratio, and uniform distribution of active sites could be obtained using DMF as the solvent, possibly related to its suitable polarity. The bifunctional solid material with both Lewis acid site and nucleophile acts as an efficient catalyst for catalyzing cycloaddition of CO2 and epoxides under cocatalyst free conditions. Compared with the homogeneous counterpart, the solid catalyst is more active (TOF = 1686 h–1 versus 370 h–1). This suggests that the closely connected Lewis acid and Br– in the solid material could enhance their cooperation during the catalytic process. This work provides an efficient method for the synthesis of bifunctional solid catalyst exhibiting enhanced cooperation activation effect for the CO2 cycloaddition reaction.

Hierarchical Porous and Zinc‐Ion‐Crosslinked PIM‐1 Nanocomposite as a CO2 Cycloaddition Catalyst with High Efficiency

“…[37] These results demonstrate the excellent universality of PIM-COONa-Zn as ah eterogeneouscatalyst. PIM-COONa-Zn, owing to the auxiliary nucleophilic effect of Cl À and the electron-donatingn ature of the benzene ring, affords higher efficiency towards EPC and styrene oxide.…”

“…However,f or allyl glycidyl ether,t he efficiency is relatively lower,b ecause the bulky alkyl chain may bring abouts teric hindrance and lead to limited approachability of the substrate. [37] These results demonstrate the excellent universality of PIM-COONa-Zn as ah eterogeneouscatalyst.…”

Highly Porous Metalloporphyrin Covalent Ionic Frameworks with Well‐Defined Cooperative Functional Groups as Excellent Catalysts for CO2 Cycloaddition

“…Yang et al. have previously discussed the importance of the Br:metal ratio for the ability of a catalyst to catalyze reactions . Their findings would also explain the high catalytic activity of Zn‐CIF2‐C 2 H 5 and Zn‐CIF2‐C 2 H 4 .…”

“…Cyclic carbonates produced from CO 2 cycloaddition can be used in various applications, including aprotic polar solvents, electrolytes in batteries, and raw materials for the production of polycarbonates, polyurethanes, and some pharmaceuticals . To achieve a high reaction rate, it is essential that the nucleophilic halide anions and the Lewis acidic sites are in close proximity to function cooperatively . Various catalysts have been developed for CO 2 cycloaddition, including organic catalysts ( N ‐heterocyclic carbenes, ionic liquids, polyionic liquids), metal complexes (e.g.…”

Hybrid Catalysts for CO2 Conversion into Cyclic Carbonates

“…In a more recent study, Yang and co-workers proposed for the first time the efficient immobilization of cationic zinc porphyrin complexes on mesoporous SBA-15 via a simple one-pot route by refluxing 5,10,15,20-tetrakis(4-pyridyl)porphyrin zinc(II) (Zn-TPy), SBA-15, and 3-(trimethoxysilyl)propyl bromide in toluene, dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), or tetrahydrofuran (THF) [62]. The bifunctional solid material with both a Lewis acid site and nucleophile (bromide or iodide) catalyzed the CO 2 conversion into cyclic carbonates under solvent-free conditions at 120 • C and 1.5 MPa.…”