Heteroleptic Copper(I) Complexes Based on NHC Carbenes as Catalysts for the Synthesis of Imines and Propargylamine Derivatives

• Autor(a) principal: Costa, Diogo Manuel da Conceição
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/163571
• topic: Copper(I); BIAN; NHC; Heteroleptic complexes; Imines; Propargylamines; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

Throughout the last decades, researchers have been working on new methodologies to develop more sustainable processes to produce relevant chemical compounds. One of the main focuses of these research were on catalytic systems, that can be improved by: reducing the amount of catalyst used, a lesser quantity of solvent, decreasing the reaction's tempera-ture, and avoiding harsh conditions or toxic reagents. Therefore, in this work several copper(I) complexes were synthesized, and their cata-lytic activity was tested on two main reactions: (1) imine formation via direct aerobic oxidation of an alcohol and an amine and (2) coupling of an aldehyde, an amine and an alkyne for the synthesis of propargylamines, that are precursors for a wide variety of biologically active compounds, highly relevant in pharmaceutic and medicinal chemistry. Since the product of the first reaction, an imine, is the intermediate of the second one, a parallel between both re-actions can be established, allowing to compare a complex's catalytic activity in both reactions. Among the complexes synthesized, the highlight goes to heteroleptic copper(I) com-plexes, where the copper centre is coordinated by a bis(imino)acenaphthene (BIAN) ligand and a N-heterocyclic carbene, with or without the acenaphthene backbone. The NHCs have been employed as ligands with great success over the last years, due to their unique behaviour when bonding with transition metals, as well as BIANs, thanks to the properties that their structure grants them. The choice on copper relies on its low toxicity and cost, in addition to its chemical properties. All the compounds, complexes and their precursors synthesized in this work were char-acterized by 1H NMR. The ones that were not reported in literature were additionally charac-terized by 13C NMR, IR, EA and X-ray diffraction crystallography, when suitable single crys-tals were obtained.