Novel iron(iii) catalyst for the efficient and selective coupling of carbon dioxide and epoxides to form cyclic carbonates

Abstract

Re-cycling carbon dioxide with iron". The synthesis of cyclic organic carbonates in high yield, stereo- and chemo-selectivity was accomplished through the coupling of carbon dioxide and epoxides, catalysed by a novel air-stable and easy-to-handle thioether-triphenolate iron(iii) complex

Synthesis of cyclic carbonate via the coupling reaction of carbon dioxide with epoxide at ambient pressure

“…The observed behavior was ascribed to poorer electrophilicity of Cu 2+ and higher steric hindrance of acac − compared to zinc halides, resulting in more challenging coordination of SO on the metal center. Both of poorer electrophilicity and higher steric hindrance give negative effects on the attack of metallic active site to the oxygen atom contained in SO and the coordination of SO with metal center to form a transition state, which is believed to be the rate‐determining step for the formation of SC from SO and CO 2 . In view of the influence of Lewis acidity strength on the reaction, the activity of several other commonly available Lewis acids was also tested (Table , entries 5−7).…”

Thioether-triphenolate bimetallic iron(iii) complexes as robust and highly efficient catalysts for cycloaddition of carbon dioxide to epoxides

“…9 The new ligands were purified by recrystallization or by column chromatography and fully characterized by NMR experiments, elemental analysis, MS, and FT-IR (see ESI †). These ligands were chosen in order to study the influence of the substituents on the aromatic rings on the catalytic activity resulting by diminishing (L H ) and increasing (L Cum ) the steric bulk.…”

“…The complexes C H and C Cum were obtained by reaction of the corresponding sodium salt obtained by reaction with 3 equivalents of NaH in THF with an equimolar amount of anhydrous FeCl 3 in analogy to the procedure used for the synthesis complex C t-Bu . 9 Scheme 2. Synthetic strategy for the production of the pro-ligands and of the iron(III) complexes.…”

“…The ligand precursor 6,6'-(((5-(tert-butyl)-2-hydroxy-1,3phenylene)bis(methylene))bis(sulfanediyl))-bis(2,4-di-tert-butylphenol) (L t-Bu , Scheme 2) and the corresponding iron(III) complex (C t-Bu , Scheme 2) were synthesized according to the reported procedure. 9 Deuterated solvents were purchased from Euriso-Top or Sigma-Aldrich and used as received.…”

Carbon Dioxide Oversolubility in Nanoconfined Liquids for the Synthesis of Cyclic Carbonates

“…[9] The importance of this catalytic transformation has been highlighted recently by Kleij, [10] North, [11] and Kerton. [12] Among the most widely employed catalysts [13] are binary systems that combine a suitable nucleophile (most often a halide) and a Lewis acid, such as porphyrine, salen and salphen-based derivatives of Al [14] , Mg [15] , Co [16] , Fe [17] , Nb [18] , Zn [19] , alkali metal halides [20] , imidazolium [21] , phosphonium [22] , and ammonium salts. [23] In recent years, organocatalysts have also shown promise as an important alternative in the field of CO2 functionalization.…”