| Texto completo | |
| Autor(es): |
Marcon, Rodrigo Oliveira
;
Bonvent, Jean-Jacques
;
Brochsztain, Sergio
Número total de Autores: 3
|
| Tipo de documento: | Artigo Científico |
| Fonte: | Langmuir; v. 38, n. 6, p. 9-pg., 2022-02-15. |
| Resumo | |
Chemical reduction of N,N'-bis(2-phosphonoethyl)-1,4,5,8-naphthalenediimide (PNDI) with the reducing agent sodium dithionite gave stable colored reduced species, both in homogeneous solutions and in self-assembled thin films. When colorless PNDI aqueous solutions were titrated with the reducing agent, stepwise reduction was observed, giving first the radical anion (PNDI-center dot) and then the dianion (PNDI2-) species, which were detected by UV-visible-NIR spectroscopy, allowing the unambiguous determination of absorption maxima and molar absorptivities for each species. The radical anion PNDI-center dot was found to form pi-dimers in water, but monomeric PNDI-center dot was formed in the presence of the cationic surfactant cetyltrimethylammonium bromide, indicating association with the micelles. Thin films of PNDI with 25 layers were grown by the zirconium phosphonate method on quartz substrates. Reduction of the films with sodium dithionite also produced radical anions and dianions of PNDI. However, reduction in the films was much slower than in solution, evidencing the compactness of the films. Moreover, reduction in the films did not proceed to completion, even with excess of the reducing agent, which can be attributed to the repulsion of negative charges within the film. (AU) | |
| Processo FAPESP: | 16/05496-2 - Síntese e caracterização de organosílicas mesoporosas contendo imidas aromáticas e suas aplicações na área de energia |
| Beneficiário: | Sergio Brochsztain |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |
| Processo FAPESP: | 20/15230-5 - Centro de Pesquisa e Inovação de Gases de Efeito Estufa - RCG2I |
| Beneficiário: | Julio Romano Meneghini |
| Modalidade de apoio: | Auxílio à Pesquisa - Programa Centros de Pesquisa em Engenharia |