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Doctoral Thesis
DOI
https://doi.org/10.11606/T.75.2012.tde-16012012-162606
Document
Author
Full name
José Luiz Silva Sá
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 2011
Supervisor
Committee
Lima Neto, Benedito dos Santos (President)
Deflon, Victor Marcelo
Batista, Nouga Cardoso
Giovani, Wagner Ferraresi de
Silva, Caio Marcio Paranhos da
Title in Portuguese
Efeitos eletrônicos e estéricos de ligantes ancilares: relação estrutura-reatividade em complexos do tipo [RuCl2(PPh3)x(amina)y] para polimerização de olefinas via metátese
Keywords in Portuguese
Catálise homogênea
Ligantes ancilares
Metátese de olefinas
Abstract in Portuguese
Os complexos do tipo [RuCl2(PPh3)2amina], amina = pip (1) ou pep (2), foram estudados como iniciadores catalíticos para reações de ROMP de NBE, NBD e oxaNBE-OMe e na ROMCP de NBE com NBD e oxaNBE-OMe com NBE. O complexo [RuCl2(PPh3)(pep)(isn)] (3) foi estudado na ROMP de NBE e NBD. Os complexos 2 e 3 são inéditos e suas caracterizações são discutidas e correlacionadas com o complexo com 1. As reações de catálises foram realizadas com variações de tempo, volume de solvente e temperatura, em atmosfera de Ar ou ar e na presença de EDA.
O rendimento foi quantitativo na ROMP de NBE com o complexo 1 em 2 mL de CHCl3, por 5 min a 25 °C em Ar, com IPD de 1,9 e Mw na ordem de 106 g mol-1. Com o complexo 2, os rendimentos foram quantitativos (IPD ~ 3 e Mw na ordem de 104 g mol-1) e independentes do tempo (5 -120 min) e volume de solvente (2 - 8 mL). Com 3, os rendimentos diminuíram com o aumento do volume de solvente, mas com IPD ~ 2 e Mw na ordem de 104 g mol-1. Em todos os casos os rendimentos diminuíram em atmosfera de ar e com polímeros polimodais.
Rendimentos quantitativos de poliNBD foram obtidos com 1 a 40 °C e com 2 a 25 °C na faixa de volume de solvente estudada, por 60 e 120 min, em Ar. Os rendimentos com 3 foram inferiores a 35%. Foram também obtidos rendimentos quantitativos em atmosfera de ar em certas combinações de tempo e volume de solvente, indicando que os complexos são robustos para atividades em soluções contendo O2. Todos os polímeros de NBD foram insolúveis.
Obteve-se até 70% de poli(NBE-co-NBD) isolado a partir de reações com 1 e reações quantitativas com 2, dependendo da fração molar NBE:NBD usada, indicando as razões de reatividades do complexos.
A ROMP de oxaNBE-OMe com 1 ou com 2 formou 15 a 30% de rendimento, a 40 °C por 24 h em Ar. Na ROMCP desse monômero com NBE obteve-se de 5 a 30% de rendimento, dependendo da fração molar. Os rendimentos são maiores nas frações molares com maior quantidade de NBE. Poli(oxaNBE-OMe) foi solúvel, enquanto que seus copolímeros foram pouco solúveis.
São realizadas discussões quantos às características eletrônicas e de impedimentos estéricos nos complexos estudados nas polimerizações via metátese, selecionando-se os ligantes ancilares frente às condições de reações para obtenções de bons rendimentos e características dos polímeros isolados.
Title in English
Electronic and steric effects of ancillary ligands: structure-reactivity relationship in [RuCl2(PPh3)x(amine)y] complex types for ring opening metathesis polymerization of olefins
Keywords in English
Ancillary ligand
Homogeneous catalysis
Olefin metathesis
Abstract in English
The complexes of type [RuCl2(PPh3)2amina], amine = pip (1) or pep (2), were studied as catalytic initiators for ROMP of NBE, NBD and oxaNBE-OMe and for ROMCP of NBE with NBD and oxaNBE-OMe with NBE. The complex [RuCl2(PPh3)(pep)(isn)] (3) was studied for ROMP of NBE and NBD. The complexes 2 and 3 are novels and their characterizations are discussed and correlated with the complex 1. The catalysis reactions were performed with variations of time, volume of solvent and temperature, either in Ar or air atmosphere, in the presence of EDA.
The yield was quantitative for ROMP of NBE with complex 1 in 2 mL of CHCl3 for 5 min at 25 °C in Ar, with PDI of 1.9 and Mw in the order of 106 g mol-1. With the complex 2, the yields were quantitatives (PDI ~ 3 and Mw in the order of 104 g mol-1) and independent of time (5 - 120 min) and volume of solvent (2 - 8 mL). With 3, the yields decreased when increasing the volume of solvent, but with PDI ~ 2 and Mw in the order of 104 g mol-1. In all the cases, the yields decreased in air atmosphere with polymodal polymers.
Quantitative yields of poliNBD were obtained with 1 at 40 °C and with 2 at 25 °C in the range of the studied volume of solvent, for 60 and 120 min, in Ar. The yields with 3 were less than 35%. Quantitative yields were also obtained in air atmosphere in some combinations of time and volume of solvent, indicating that the complexes are robust for activities in solutions containing O2. All polyNBD were insoluble.
It was obtained up to 70% of poly(NBE-co-NBD) isolated from reactions with 1 and quantitative reactions were obtained with 2, depending on the NBE:NBD molar fraction used, indicating the reactivity ratios for the complexes.
The ROMP of oxaNBE-OMe with 1 or with 2 yielded 15 to 30% at 40 °C for 24h in Ar. In the ROMCP of this monomer with NBE, it was obtained from 5 to 30% yield, depending on the molar fraction. Yields are higher in molar fractions with higher amount of NBE. Poly(oxaNBE-OMe) was soluble, while its copolymers were poorly soluble.
Discussions are held on the electronic characteristics and steric hindrances in the studied complexes for the metathesis polymerization, selecting the ancillary ligands as a function of the reaction conditions to obtain good yields and to improve the characteristics of the isolated polymers.
 
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JoseLuizSilvaSa.pdf (2.41 Mbytes)
Publishing Date
2012-04-27
 
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