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http://hdl.handle.net/1843/59439| Tipo: | Artigo de Periódico |
| Título: | Metal-cocatalyst interaction governs the catalytic activity of M II-porphyrazines for chemical fixation of CO2 |
| Autor(es): | Julia Poliana da Silva Caldas Leal Werberson de Almeida Bezerra Rafael Pavão das Chagas Chris Hebert de Jesus Franco Felipe Terra Martins Alexandre Moreira Meireles Felipe Cesar Torres Antonio Paula Homem-de-Mello Thiago Teixeira Tasso Jorge Luiz Sônego Milani |
| Resumo: | Chemical fixation of CO2 to produce cyclic carbonates can be a green and atomic efficient process. In this work, a series of porphyrazines (Pzs) containing electron-withdrawing groups and central MII ions (where M = Mg, Zn, Cu, and Co) were synthesized and investigated as catalysts for the cycloaddition of CO2 to epoxides. Then, the efficiency of the Pzs was tested by varying cocatalyst type and concentration, epoxide, temperature, and pressure. MgIIPz bearing trifluoromethyl groups (1) showed the best conversion, producing, selectively, 78% of propylene cyclic carbonate (PCC), indicating that a harder and stronger Lewis acid is more effective for epoxide activation. Moreover, cocatalyst variation showed a notable effect on the reaction yields. Spectrophotometric titrations, MALDI-TOF mass spectra, and theoretical calculations suggest poisoning of the catalyst when tetrabutylammonium chloride (TBAC) and large amounts of tetrabutylammonium bromide (TBAB) were used in the system. The same was not observed for tetrabutylammonium iodide (TBAI), indicating that the metal–cocatalyst interaction may govern the reaction rate. In addition, two rare examples of crystalline structures were obtained, proving the distorted square pyramidal geometry with water molecule as axial ligand. This is one of the first studies reporting Pzs as catalysts for the chemical fixation of CO2, and we believe that the intricate balance between cocatalyst concentration and conversion efficiency shown here may aid future studies in the area. |
| Assunto: | Anions Catalisadores de metal Eteres Compostos metálicos Química inorgânica |
| Idioma: | eng |
| País: | Brasil |
| Editor: | Universidade Federal de Minas Gerais |
| Sigla da Instituição: | UFMG |
| Departamento: | ICX - DEPARTAMENTO DE QUÍMICA |
| Tipo de Acesso: | Acesso Restrito |
| Identificador DOI: | https://doi.org/10.1021/acs.inorgchem.1c01462 |
| URI: | http://hdl.handle.net/1843/59439 |
| Data do documento: | 2021 |
| metadata.dc.url.externa: | https://pubs.acs.org/doi/10.1021/acs.inorgchem.1c01462 |
| metadata.dc.relation.ispartof: | Inorganic Chemistry |
| Aparece nas coleções: | Artigo de Periódico |
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