Two different pathways for assembling bis-urea in benzene and toluene

Autor(es)

Alvarenga, Bruno Giordano ^[1] ; Bernardino, Kalil ^[2] ; de Moura, Andre Farias ^[2] ; Sabadini, Edvaldo ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Inst Chem, Dept Phys Chem, CP 6154, BR-13083970 Campinas, SP - Brazil

^[2] Univ Fed Sao Carlos, Dept Chem, Rodovia Washington Luis Km 235, CP 676, BR-13565905 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Molecular Modeling; v. 24, n. 7 JUL 2018.
• Citações Web of Science: 0

Resumo

The thermodynamic stability of assemblies formed by a bis-urea-based supramolecular polymer, 2,4-bis(2-ethylhexylureido)toluene (EHUT), was investigated in solutions using either benzene or toluene as the solvent. Starting from a higher temperature in which EHUT was soluble in both solvents, molecules spontaneously self-organized into tubular assemblies upon cooling and these assemblies were stable in a wide range of temperatures. However, the systems followed different paths below a specific temperature: while the supramolecular polymer remained stable in toluene, EHUT molecules underwent precipitation in benzene. The causes for these different behaviors were explored by molecular dynamics simulations, which provided support for stronger enthalpic stabilization of the tubular assemblies in toluene as compared to benzene. This stabilization was due mainly to the better interaction energy of trapped toluene molecules instead of benzene ones. For both cases, lowering the temperature makes the solvent penetration inside the tubes less favorable, which reduces the stability of supramolecular structures upon cooling. (AU)

• Processo FAPESP: 14/04515-8 - Polímeros supramoleculares de bis-ureias em solução: o balanço das interações soluto-solvente
• Beneficiário: Bruno Giordano Alvarenga
• Linha de fomento: Bolsas no Brasil - Doutorado
• Processo FAPESP: 13/07296-2 - CDMF - Centro de Desenvolvimento de Materiais Funcionais
• Beneficiário: Elson Longo da Silva
• Linha de fomento: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 12/15147-4 - Estudo computacional da termodinâmica de associação de sistemas auto-organizados
• Beneficiário: André Farias de Moura
• Linha de fomento: Auxílio à Pesquisa - Regular