Recyclable bifunctional aluminum salen catalyst for CO2 fixation: the efficient formation of five-membered heterocyclic compounds was written by Luo, Rongchang;Yang, Zhi;Zhang, Wuying;Zhou, Xiantai;Ji, Hongbing. And the article was included in Science China: Chemistry in 2017.Reference of 21252-69-7 This article mentions the following:
A variety of unique Al(salen) complexes functionalized by imidazolium-based ionic liquid (IL) moieties with the salen ligand at the two sides of 3,3′-position have been successfully prepared, rather than familiar 5,5′-position reported previously. The catalytic activity obtained by these bifunctional catalysts could be superior to those of the binary type catalysts in the formation of five-membered heterocyclic compounds from the cycloaddition reaction of CO2 and three-membered heterocyclic compounds (including terminal epoxides and N-substituted aziridines), presumably due to the distinguished intramolecularly synergistic catalysis, which might lead to perform the cycloaddition reaction at ambient conditions and retain excellent yield and unprecedented chemo- or regioselectivity. Moreover, the polyether-based trifunctional Al(salen) catalysts with the best catalytic performance could be regenerated and reused at least eight times without any obvious decreases in catalytic activity. Finally, the kinetic investigation suggested the structure of catalysts had important influences on the catalytic activity, thereby proposing the possible reaction mechanism. In the experiment, the researchers used many compounds, for example, 1-Octyl-1H-imidazole (cas: 21252-69-7Reference of 21252-69-7).
1-Octyl-1H-imidazole (cas: 21252-69-7) belongs to imidazole derivatives. Many natural products, especially alkaloids, contain the imidazole ring. These imidazoles share the 1,3-C3N2 ring but feature varied substituents. Imidazole is incorporated into many important biological compounds. The most pervasive is the amino acid histidine, which has an imidazole side-chain. Histidine is present in many proteins and enzymes, e.g. by binding metal cofactors, as seen in hemoglobin.Reference of 21252-69-7
Referemce:
Imidazole – Wikipedia,
Imidazole | C3H4N2 – PubChem