Aminas cíclicas como ligantes ancilares em complexos [RuCl2(p-cimeno)(amina)]: catalisadores duais promissores para ROMP de norborneno e ATRP de metacrilato de metila
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Data
2020-02-17
Autores
Cruz, Thaís Regina
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Universidade Estadual Paulista (Unesp)
Resumo
Novos complexos de rutênio(II) contendo aminas cíclicas pirrolidina = pop, piperidina = pip e peridroazepina = pep; RuCl2(η6-p-cimeno)(pirrolidina)] (1), [RuCl2(η6-p-cimeno)(piperidina)] (2) e [RuCl2(η6-p-cimeno)(peridroazepina)] (3) foram sintetizados com sucesso. Os complexos 1, 2 e 3 foram caracterizados por meio de espectroscopia de FTIR e UV-Vis, análise elementar, RMN, voltametria cíclica e métodos computacionais. O complexo 3 também foi estudado por cristalografia de raio-X de um monocristal. Estes compostos foram avaliados como precursores catalíticos para ROMP de norborneno (NBE) e para ATRP de metil metacrilato (MMA). A síntese do polinorborneno (poliNBE) via ROMP usando os complexos 1, 2 e 3 como pré-catalisadores na presença de etil diazoacetato (EDA) foi avaliada sob diferentes razões de [EDA]/[Ru] e [NBE]/[Ru], temperatura (25 e 50 °C) e tempo de reação (5-60 min). Os maiores rendimentos de poliNBE foram obtidos com [NBE]/[EDA]/[Ru] = 5000/28/1 para 60 minutos em 50 ºC. A massa molecular apresentou uma ordem de magnitude de 105 g mol-1 com valores de IPD variando de 1,3. a 3,6. A atividade catalítica dos complexos em ROMP de NBE demonstrou a seguinte ordem de reatividade: 3 > 2 > 1, a qual é relatado pelo melhor efeito -doador da amina. A polimerização de MMA via ATRP foi conduzida usando 1, 2 e 3 como como catalisadores na presença de etil-α-bromoisobutirato (EBiB) como iniciador. Os testes catalíticos foram avaliados em função do tempo de reação usando a razão molar inicial de [MMA]/[EBiB]/[Ru] = 1000/2/1 em 95 ºC. Para o complexo 3, a massa molecular aumentou linearmente com a conversão, entretanto, as massas moleculares experimentais foram maiores do que as teóricas.
Novel arene ruthenium(II) complexes bearing cyclic amines pirrolidine = pop, piperidine = pip e peridroazepine = pep; RuCl2(η6-p-cymene)(pyrrolidine)] (1), [RuCl2(η6-p-cymene)(piperidine)] (2) and [RuCl2(η6-p-cymene)(peridroazepine)] (3) were successfully synthesized. The complexes 1-3 were have been fully characterized by means of FTIR and UV-Vis spectroscopy, elemental analysis, NMR, cyclic voltammetry and computational methods. The complex 3 has been also studied by single crystal X-ray crystallography. These compounds were evaluated as catalytic precursors for ROMP of norbornene (NBE) and for ATRP of methyl methacrylate (MMA). The polynorbornene (polyNBE) syntheses via ROMP using the complexes 1, 2 e 3 as pre-catalysts in the presence of ethyl diazoacetate (EDA) were evaluated under different [EDA]/[Ru] and [NBE]/[Ru] ratios, temperature (25 and 50 °C) and reaction time (5-60 min). The highest yields of polyNBE were obtained with [NBE]/[EDA]/[Ru] = 5000/28/1 for 60 minutes at 50 ºC. The molecular weight showed an order of magnitude of 105 g mol−1 with PDI values ranging from 1.3 to 3.6. The catalytic activity of the complexes for ROMP of NBE showed the following order of reactivity: 3 > 2 > 1, which is related to the greater -donation from the amine. MMA polymerization via ATRP was conducted using the 1, 2 and 3 as catalysts in the presence of ethyl-αbromoisobutyrate (EBiB) as initiator. The catalytic tests were evaluated as a function of the reaction time using the initial molar ratio of [MMA]/[EBiB]/[Ru] = 1000/2/1 at 95 °C. For complex 3, molecular weights increased linearly with conversion, however, the experimental molecular weights were higher than the theoretical ones.
Novel arene ruthenium(II) complexes bearing cyclic amines pirrolidine = pop, piperidine = pip e peridroazepine = pep; RuCl2(η6-p-cymene)(pyrrolidine)] (1), [RuCl2(η6-p-cymene)(piperidine)] (2) and [RuCl2(η6-p-cymene)(peridroazepine)] (3) were successfully synthesized. The complexes 1-3 were have been fully characterized by means of FTIR and UV-Vis spectroscopy, elemental analysis, NMR, cyclic voltammetry and computational methods. The complex 3 has been also studied by single crystal X-ray crystallography. These compounds were evaluated as catalytic precursors for ROMP of norbornene (NBE) and for ATRP of methyl methacrylate (MMA). The polynorbornene (polyNBE) syntheses via ROMP using the complexes 1, 2 e 3 as pre-catalysts in the presence of ethyl diazoacetate (EDA) were evaluated under different [EDA]/[Ru] and [NBE]/[Ru] ratios, temperature (25 and 50 °C) and reaction time (5-60 min). The highest yields of polyNBE were obtained with [NBE]/[EDA]/[Ru] = 5000/28/1 for 60 minutes at 50 ºC. The molecular weight showed an order of magnitude of 105 g mol−1 with PDI values ranging from 1.3 to 3.6. The catalytic activity of the complexes for ROMP of NBE showed the following order of reactivity: 3 > 2 > 1, which is related to the greater -donation from the amine. MMA polymerization via ATRP was conducted using the 1, 2 and 3 as catalysts in the presence of ethyl-αbromoisobutyrate (EBiB) as initiator. The catalytic tests were evaluated as a function of the reaction time using the initial molar ratio of [MMA]/[EBiB]/[Ru] = 1000/2/1 at 95 °C. For complex 3, molecular weights increased linearly with conversion, however, the experimental molecular weights were higher than the theoretical ones.
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Palavras-chave
Rutênio, Areno, ATRP, ROMP, Norborneno, Metacrilato de metila, Ruthenium, Arene, Norbornene, Methyl metacrylate