Unexpected intramolecular N-arylcyano-β-diketiminate cyclization in new aminoquinoline derivative complexes of aluminium for CO2 fixation into cyclic carbonates
| Autor: | Alan R. Cabrera, Javier Martínez, David Moreno da Costa, Rene S. Rojas, Constantin G. Daniliuc, Luis Borja, Celso Quintero, Pablo Jaque, Oleksandra S. Trofymchuk, Camilo Verdugo |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Reaction mechanism
chemistry.chemical_element 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Medicinal chemistry Catalysis 0104 chemical sciences Aminoquinoline Reaction rate chemistry.chemical_compound chemistry Aluminium Intramolecular force Materials Chemistry medicine Moiety 0210 nano-technology Derivative (chemistry) medicine.drug |
| Zdroj: | New Journal of Chemistry. 43:12059-12068 |
| ISSN: | 1369-9261 1144-0546 |
| Popis: | New 4-amino-3-iminoquinoline derivative ligands (L1–4) were synthesized through an intramolecular exo-dig cyclization of anionic β-diketiminates, containing an N-benzonitrile moiety. The effect of the alkali-metal in this reaction was investigated and an inverse effect between the size of the cation and the cyclization rate was revealed. The effect of the reaction temperature was also studied, in which a direct dependence was observed. Kinetic and theoretical studies were performed in an attempt to clarify the reaction mechanism, obtaining a first-order reaction rate dependence with an activation energy of 20.6 kcal mol−1, with DFT-based calculations supporting the proposed mechanism. In addition, four new aluminium complexes were isolated in high yields (C1–4), which were evaluated as catalysts for the preparation of cyclic carbonates from epoxides and CO2, thus becoming the first examples of the use of β-diketiminate ligands in this catalytic process. The reactions were performed at 80 °C and 1 bar CO2 pressure under solvent-free conditions. We were able to prepare a large variety of cyclic carbonates in excellent selectivities and yields, employing the aluminium complex C3. The L1–4 ligands and C1–4 complexes were characterized using NMR, FT-IR, HRMS, and X-ray diffraction methods. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|