Complexos heterobimetálicos de RuII/PdII como catalisadores bifuncionais para a obtenção de copolímeros via acoplamento da ROMP e polimerização de etileno.
Data
2023-01-23
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Universidade Estadual Paulista (Unesp)
Resumo
O monômero funcionalizado NBE-Aril-Br foi sintetizado através de uma adaptação dos parâmetros da esterificação de Steglich, utilizando o 5-norborneno-2-ácido carboxílico e o 4-Bromofenol, sendo caracterizado por FTIR e RMN de 1H. O complexo [RuCl2(p-cimeno)(pipNH2)] (complexo 1) foi obtido a partir da reação entre o ligante 4-(aminometil)piperidina (pipNH2) e o dímero precursor [Ru(p-cimeno)Cl2]2, enquanto o complexo [(NBE-Aril)Pd(PPh3)2Br] (complexo 2) foi sintetizado pela reação de adição oxidativa entre o complexo precursor [Pd(PPh3)4] e NBE-Aril-Br. Para se obter o complexo heterobimetálico [RuCl2(p-cimeno)(-Schiff-pip)Pd(NBE-Aril)PPh3] (complexo 3), o complexo 1 foi reagido com o complexo 2 na presença de salicilaldeído, enquanto o complexo heterobimetálico [RuCl2(p-cimeno)(-pipNH2)Pd(Ph)(PPh3)Br)] (complexo 4) foi sintetizado a partir da síntese direta entre o complexo 1 e o precursor [PhPd(PPh3)2Br]. Os complexos foram analisados por espectroscopia de FTIR, UV-Vis e RMN de 1H e/ou 31P{1H}. O comportamento eletroquímico dos complexos foi investigado por voltametria cíclica. A atividade catalítica do complexo 4 foi avaliada em reações de ROMP de norborneno, no qual variou-se a temperatura (25 e 50 °C) e o tempo de reação (10-60 min). A melhor condição de polimerização com complexo 4 foi quando se utilizou VEDA = 5 L, [NBE]/[Ru] = 5000, 25 °C e 60 minutos. Estudos cinéticos acompanhados por UV-Vis simulando as condições de ROMP de NBE com o complexo 4 foram conduzidos, onde foi possível obter as constantes de velocidade e estimar os parâmetros termodinâmicos de ativação (Ea, H‡, S‡, G‡) utilizando a equação de Eyring.
The functionalized monomer NBE-Aryl-Br was synthesized through an adaptation of the Steglich esterification parameters, using 5-norbornene-2-carboxylic acid and 4- Bromophenol, it was characterized by FTIR and 1H NMR. The complex [RuCl2(pcymene)(pipNH2)] (complex 1) was obtained from the reaction between the ligand 4- (aminomethyl)piperidine (pipNH2) and the precursor dimer [Ru(p-cymene)Cl2]2, while the complex [(NBE-Aryl)Pd(PPh3)2Br] (complex 2) was synthesized by the oxidative addition reaction between the precursor complex [Pd(PPh3)4] and NBE-Aryl-Br. To obtain the heterobimetallic complex [RuCl2(p-cymene)(-Schiff-pip)Pd(NBEAryl)PPh3] (complex 3), complex 1 was reacted with complex 2 in the presence of salicylaldehyde, and the complex [RuCl2(p-cymene)(-pipNH2)Pd(Ph)(PPh3)Br)] (complex 4) was synthesized from the direct synthesis between complex 1 and the precursor [PhPd(PPh3)2Br]. The complexes were analyzed by FTIR, UV-Vis and 1H and/or 31P NMR spectroscopy. The electrochemical behavior of the complexes was investigated by cyclic voltammetry. The catalytic activity of complex 4 was evaluated in norbornene ROMP reactions, in which the temperature (25 and 50 °C) and the reaction time (10-60 min) were varied. The best polymerization condition with complex 4 was found when using VEDA = 5 L, [NBE]/[Ru] = 5000, 25 °C and 60 minutes. Kinetic studies in the UV-Vis simulating the ROMP conditions of NBE with complex 4 were conducted, where it was possible to obtain the rate constants and estimate the thermodynamic parameters of activation (Ea, H ‡ , S ‡ , G ‡ ) using the Eyring equation.
The functionalized monomer NBE-Aryl-Br was synthesized through an adaptation of the Steglich esterification parameters, using 5-norbornene-2-carboxylic acid and 4- Bromophenol, it was characterized by FTIR and 1H NMR. The complex [RuCl2(pcymene)(pipNH2)] (complex 1) was obtained from the reaction between the ligand 4- (aminomethyl)piperidine (pipNH2) and the precursor dimer [Ru(p-cymene)Cl2]2, while the complex [(NBE-Aryl)Pd(PPh3)2Br] (complex 2) was synthesized by the oxidative addition reaction between the precursor complex [Pd(PPh3)4] and NBE-Aryl-Br. To obtain the heterobimetallic complex [RuCl2(p-cymene)(-Schiff-pip)Pd(NBEAryl)PPh3] (complex 3), complex 1 was reacted with complex 2 in the presence of salicylaldehyde, and the complex [RuCl2(p-cymene)(-pipNH2)Pd(Ph)(PPh3)Br)] (complex 4) was synthesized from the direct synthesis between complex 1 and the precursor [PhPd(PPh3)2Br]. The complexes were analyzed by FTIR, UV-Vis and 1H and/or 31P NMR spectroscopy. The electrochemical behavior of the complexes was investigated by cyclic voltammetry. The catalytic activity of complex 4 was evaluated in norbornene ROMP reactions, in which the temperature (25 and 50 °C) and the reaction time (10-60 min) were varied. The best polymerization condition with complex 4 was found when using VEDA = 5 L, [NBE]/[Ru] = 5000, 25 °C and 60 minutes. Kinetic studies in the UV-Vis simulating the ROMP conditions of NBE with complex 4 were conducted, where it was possible to obtain the rate constants and estimate the thermodynamic parameters of activation (Ea, H ‡ , S ‡ , G ‡ ) using the Eyring equation.
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Catalisador multifuncional, Areno, Heterobimetálico, ROMP, Polinorborneno, Cinética, Multifunctional catalyst, Arene, Heterobimetallic, Polynorbornene, Kinetics