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Copolímeros estatísticos biodegradáveis de epsilon-caprolactona e L,L-dilactídeo - síntese, caracterização e propriedades. / Biodegradable statistical copolimers of epsilon-caprolactone e L,L-lactide - synthesis, caracterization and properties.Castro, Maria Leonora de 07 April 2006 (has links)
Copolímeros de e-caprolactona e l,l-dilactídeo têm sido investigados com a finalidade de desenvolver materiais biodegradáveis para aplicações médicas. As sínteses dos homopolímeros e copolímeros de epsilon-caprolactona e l,l-dilactídeo por abertura de anel e polimerização em massa transcorreram a 120oC sob atmosfera de nitrogênio, usando o octanoato de estanho como iniciador. A composição dos copolímeros variou de 5,90% a 97,30% em massa de l,l-dilactídeo. As massas molares dos polímeros sintetizados foram determinadas por viscosimetria capilar e cromatografia de permeação em gel (GPC). A composição dos copolímeros foi determinada por RMN de 13C. As propriedades térmicas e mecânicas foram avaliadas por DSC e DMTA. O grau de cristalinidade e as fases cristalinas dos copolímeros foram determinados por difração de raios X (WAXS). Foram observadas altas taxas de conversão de monômeros para os homopolímeros e para os copolímeros Co60 ao Co90 (taxas de 70-80%). Os homopolímeros e copolímeros sintetizados apresentaram altas massas molares (M w até 106.500 g/mol para os copolímeros) e moderada polidispersidade (1,50). As análises de RMN de 13C demonstraram a predominância da formação de copolímeros estatísticos e a ausência da transesterificação durante a polimerização em massa. As propriedades dinâmico-mecânicas foram fortemente dependentes da estrutura cristalina e do grau de cristalinidade dos copolímeros. Os copolímeros sintetizados apresentaram propriedades mecânicas variando do flexível ao rígido termoplástico. Os copolímeros com composição próxima a equimolar (Co30 ao Co40) apresentaram os mais baixos graus de cristalinidade (13 a 15%) e, por conseqüência, apresentaram maior taxa de degradação (20% em 408 horas para o Co40), em comparação com os demais copolímeros. / Copolymers of epsilon-caprolactone with l,l-lactide have been investigated in order to develop biodegradable materials for medical applications. The synthesis of homopolymers and copolymers of e-caprolactone with l,l-lactide by ring-opening bulk polymerization was performed using stannous octoate as initiator at 120 ºC under nitrogen atmosphere. The copolymers composition was varied from 5.90 to 97.30 % in mass of l,l-lactide. The molecular weight of synthesized polymers were determined by viscometry and GPC. The copolymers composition was determined by 13C NMR. Thermal and mechanical properties have been evaluated by DSC and DMTA. The degree of crystallinity and the crystalline phase of copolymers were determined by WAXS. High conversion was observed for homopolymers and copolymers Co60 to Co90 of l,l-lactide (70-80%). The homopolymers and copolymers presented hight molecular weight (M w up to 106,500 g/mol for copolymers) and low polydispersivity (1,50). The analyses by 13C- NMR spectroscopy have shown the predominance of statistical copolymers formation and the transesterification reaction did not occur during the bulk polymerization. Thermal and mechanical properties were dependent on the crystalline phase and of the degree of crystallinity. The synthesized copolymers presented mechanical properties from rubbery to stiff thermoplastics. The copolymers with equimolar composition presented low degree of crystallinity (13 ? 15%) and higher degradation (20% during 408 hours for Co40).
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Copolímeros estatísticos biodegradáveis de epsilon-caprolactona e L,L-dilactídeo - síntese, caracterização e propriedades. / Biodegradable statistical copolimers of epsilon-caprolactone e L,L-lactide - synthesis, caracterization and properties.Maria Leonora de Castro 07 April 2006 (has links)
Copolímeros de e-caprolactona e l,l-dilactídeo têm sido investigados com a finalidade de desenvolver materiais biodegradáveis para aplicações médicas. As sínteses dos homopolímeros e copolímeros de epsilon-caprolactona e l,l-dilactídeo por abertura de anel e polimerização em massa transcorreram a 120oC sob atmosfera de nitrogênio, usando o octanoato de estanho como iniciador. A composição dos copolímeros variou de 5,90% a 97,30% em massa de l,l-dilactídeo. As massas molares dos polímeros sintetizados foram determinadas por viscosimetria capilar e cromatografia de permeação em gel (GPC). A composição dos copolímeros foi determinada por RMN de 13C. As propriedades térmicas e mecânicas foram avaliadas por DSC e DMTA. O grau de cristalinidade e as fases cristalinas dos copolímeros foram determinados por difração de raios X (WAXS). Foram observadas altas taxas de conversão de monômeros para os homopolímeros e para os copolímeros Co60 ao Co90 (taxas de 70-80%). Os homopolímeros e copolímeros sintetizados apresentaram altas massas molares (M w até 106.500 g/mol para os copolímeros) e moderada polidispersidade (1,50). As análises de RMN de 13C demonstraram a predominância da formação de copolímeros estatísticos e a ausência da transesterificação durante a polimerização em massa. As propriedades dinâmico-mecânicas foram fortemente dependentes da estrutura cristalina e do grau de cristalinidade dos copolímeros. Os copolímeros sintetizados apresentaram propriedades mecânicas variando do flexível ao rígido termoplástico. Os copolímeros com composição próxima a equimolar (Co30 ao Co40) apresentaram os mais baixos graus de cristalinidade (13 a 15%) e, por conseqüência, apresentaram maior taxa de degradação (20% em 408 horas para o Co40), em comparação com os demais copolímeros. / Copolymers of epsilon-caprolactone with l,l-lactide have been investigated in order to develop biodegradable materials for medical applications. The synthesis of homopolymers and copolymers of e-caprolactone with l,l-lactide by ring-opening bulk polymerization was performed using stannous octoate as initiator at 120 ºC under nitrogen atmosphere. The copolymers composition was varied from 5.90 to 97.30 % in mass of l,l-lactide. The molecular weight of synthesized polymers were determined by viscometry and GPC. The copolymers composition was determined by 13C NMR. Thermal and mechanical properties have been evaluated by DSC and DMTA. The degree of crystallinity and the crystalline phase of copolymers were determined by WAXS. High conversion was observed for homopolymers and copolymers Co60 to Co90 of l,l-lactide (70-80%). The homopolymers and copolymers presented hight molecular weight (M w up to 106,500 g/mol for copolymers) and low polydispersivity (1,50). The analyses by 13C- NMR spectroscopy have shown the predominance of statistical copolymers formation and the transesterification reaction did not occur during the bulk polymerization. Thermal and mechanical properties were dependent on the crystalline phase and of the degree of crystallinity. The synthesized copolymers presented mechanical properties from rubbery to stiff thermoplastics. The copolymers with equimolar composition presented low degree of crystallinity (13 ? 15%) and higher degradation (20% during 408 hours for Co40).
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Novel M(II) beta-diketiminate complexes for the polymerization of lactideWhitehorne, Todd 08 1900 (has links)
Des ligands diketimines porteurs de substituants N-benzyl, N-9-anthrylmethyl et N-mesitylmethyl (nacnacBnH, nacnacAnH, and nacnacMesH) ont été synthétisés par condensation d’une amine et d’acétyl acétone ou son monoacétal d’éthylène glycol. La chlorination de la position 3 a été effectuée à l’aide de N-chlorosuccinimide conduisant à la formation des ligands ClnacnacBnH et ClnacnacAnH. Cette même position 3 a également été substituée par un groupement succinimide par lithiation du nacnacBnH, suivi de la réaction avec le N-chlorosuccinimide (3-succinimido-nacnacBnH). Les ligands N-aryl nacnacippH et nacnacNaphH (ipp = 2-isopropylphenyl, Naph = 1-naphthyl) ont été préparés selon les procédures reportées dans la littérature.
La réaction de ces ligands avec Zn(TMSA)2 (TMSA = N(SiMe3)2) conduit à la formation des complexes nacnacAnZn(TMSA) et ClnacnacBnZn(TMSA). La protonation avec l’isopropanol permet l’obtention des complexes nacnacAnZnOiPr et ClnacnacBnZnOiPr.
La réaction avec Mg(TMSA)2 permet quant à elle la formation des complexes nacnacAnMg(TMSA), nacnacMesMg(TMSA), ClnacnacBnMg(TMSA) et ClnacnacAnMg(TMSA). La protonation subséquente à l’aide du tert-butanol permet l’obtention du nacnacMesMgOtBu et du ClnacnacBnMgOtBu, alors que l’on observe uniquement une décomposition avec les ligands possédant des substituants N-anthrylmethyl.
La réaction de ces diketimines avec Cu(OiPr)2 conduit aux dimères hétéroleptiques [nacnacBnCu(μ-OiPr)]2 et [3-Cl-nacnacBnCu(μ-OiPr)]2 lors de l’usage des ligands stériquement peu encombrés. Lors de l’utilisation de ligands plus encombrés, la stabilisation du complexe hétéroleptique par dimérisation n’est plus possible, conduisant, par un échange de ligand, à la formation des complexes homoleptiques Cu(nacnacipp)2 et Cu(nacnacNaph)2. Les complexes homoleptiques Cu(nacnacBn)2 et Cu(3-succinimido-nacnacBn)2 ont été obtenus à partir des ligands N-benzyl. Les ligands encore plus encombrés tels que nacnacAnH, nacnacMesH ou ceux comportant des substituants N-methylbenzyl ne présentent alors plus de réactivité avec le Cu(OiPr)2.
La plupart des complexes ont été caractérisés par Diffraction des Rayons X. Les complexes homoleptiques ainsi que ceux de TMSA sont monomériques, alors que ceux formés à partir d’alkoxides se présentent sous forme de dimères à l’état solide. Tous les complexes d’alkoxides ainsi que les nacnacAnMg(TMSA)/BnOH et ClnacnacAnMg(TMSA)/BnOH présentent une réactivité modérée à haute en matière de polymérisation du rac-lactide (90% de conversion en 30 secondes à 3 heures). Le nacnacAnZnOiPr permet la synthèse d’un polymère hautement hétérotactique (Pr = 0.90) quand le ClnacnacBnMgOtBu/BnOH génère un polymère isotactique à -30°C (Pr = 0.43). Tous les autres catalyseurs produisent des polymères atactiques avec une légère tendance hétérotactique (Pr = 0.48 – 0.55). Les complexes hétéroleptiques [nacnacBnCu(μ-OiPr)]2 et [3-Cl-nacnacBnCu(μ-OiPr)]2 se révèlent être de très bons catalyseurs pour la polymérisation du rac-lactide présentant une conversion complète du monomère à température ambiante, en solution, en 0,5 à 5 minutes. Le [nacnacBnCu(μ-OiPr)]2 est actif en présence ou absence d’isopropanol, agissant comme agent de transfert de chaine à haute activité (k2 = 32 M–1•s–1) dans le dichlorométhane. Dans l’acétonitrile, le THF, le dichloromethane et le toluène, [nacnacBnCu(μ-OiPr)]2 conduit à une étroite polydispersité, possédant respectivement des kobs = 2.4(1), 5.3(5), 3.6-4.4 and 10(1) min–1. Aucune réaction parasite, telle qu’une trans-esterification, une épimerisation ou une décomposition du catalyseur, n’a été observée. Les complexes homoleptiques en présence d’alcool libre semblent présenter un équilibre avec une petite quantité de leurs équivalents hétéroleptiques, permettant une polymérisation complète, en moins de 60 min, à température ambiante. Tous les catalyseurs de cuivre présentent un haut contrôle de la polymérisation avec une polydispersité égale ou inférieure à 1.1. Les polymères obtenus sont essentiellement atactiques, avec une légère tendance à l’hétérotacticité à température ambiante et -17°C. Le [nacnacBnCu(μ-OiPr)]2 polymérise également la -butyrolactone (BL), l’-caprolactone (CL) et la -valerolactone (VL) avec des constantes respectivement égales à kobs = 3.0(1)•10–2, 1.2–2.7•10–2, et 0.11(1) min–1. Les homopolymères présentent une étroite polydispersité d’approximativement 1.1. Les polymérisations par addition séquentielle ont mis en évidence une trans-estérification (non observée dans les homopolymérisations) si BL ou CL sont introduits après un bloc lactide. / Diketimine ligands bearing N-benzyl, N-9-anthrylmethyl and N-mesitylmethyl substituents (nacnacBnH, nacnacAnH, and nacnacMesH) were prepared from condensation of amine with either acetyl acetone or its ethylene glycol monoketal. Chlorination of the 3-position was achieved using N-chlorosuccinimide, yielding ClnacnacBnH and ClnacnacAnH. The 3-position was also substituted by succinimido by lithiation of nacnacBnH followed by reaction with N-chlorosuccinimide (3-succinimido-nacnacBnH). N-aryl ligands nacnacippH and nacnacNaphH (ipp = 2-isopropylphenyl, Naph = 1-naphthyl) were prepared from literature. The ligands were reacted with Zn(TMSA)2 (TMSA = N(SiMe3)2) to yield nacnacAnZn(TMSA) and ClnacnacBnZn(TMSA). Protonation with isopropanol gave nacnacAnZnOiPr and ClnacnacBnZnOiPr. Reaction of the diketimines with Mg(TMSA)2 afforded nacnacAnMg(TMSA), nacnacMesMg(TMSA), ClnacnacBnMg(TMSA) and ClnacnacAnMg(TMSA). Subsequent protonation with tert-butanol produced nacnacMesMgOtBu and ClnacnacBnMgOtBu, but only decomposition was observed with N-anthrylmethyl substituents. Reaction of the diketimines with Cu(OiPr)2 yielded the heteroleptic [nacnacBnCu(μ-OiPr)]2 and [3-Cl-nacnacBnCu(μ-OiPr)]2 when using sterically undemanding ligands. When sterically more demanding diketimines were used, stabilization of the heteroleptic complex by dimerization was not possible, resulting in the formation of the homoleptic complexes Cu(nacnacipp)2 and Cu(nacnacNaph)2 by ligand exchange. Homoleptic complexes were also prepared with N-benzyl ligands, i. e. Cu(nacnacBn)2 and Cu(3-succinimido-nacnacBn)2. Even bulkier ligands such as nacnacAnH, nacnacMesH or N-methylbenzyl substituents failed to react with Cu(OiPr)2. Most complexes were characterized by single crystal X-ray diffraction. TMSA complexes and homoleptic complexes were monomeric, alkoxide complexes were dimeric in the solid state. All alkoxide complexes, as well as nacnacAnMg(TMSA)/BnOH and ClnacnacAnMg(TMSA)/BnOH were moderately to highly active in rac-lactide polymerization (90% conversion in 30 sec to 3 h). nacnacAnZnOiPr produced highly heterotactic polymer (Pr = 0.90), ClnacnacBnMgOtBu/BnOH produced slightly isotactic polymer at –30 °C (Pr = 0.43), all other catalysts produced atactic polymers with a slight heterotactic bias (Pr = 0.48 – 0.55). Heteroleptic complexes [nacnacBnCu(μ-OiPr)]2 and [3-Cl-nacnacBnCu(μ-OiPr)]2 are very highly active rac-lactide polymerization catalysts, with complete monomer conversion at ambient temperature in solution in 0.5 – 5 min. [nacnacBnCu(μ-OiPr)]2 specifically polymerized in the presence or absence of isopropanol as a chain-transfer reagent with very high activity (k2 = 32 M–1•s–1), in methylene chloride. While in acetonitrile, THF, dichloromethane and toluene has a kobs = 2.4(1), 5.3(5), 3.6-4.4 and 10(1) min–1, respectively. [nacnacBnCu(μ-OiPr)]2 yields narrow polydispersities and no evidence of side reactions such as transesterification, epimerization or catalyst decomposition. The homoleptic complexes in the presence of free alcohol, seem to be in equilibrium with small amounts of the respective heteroleptic complex, which are sufficient to complete polymerization in less than 60 min at room temperature. All Cu catalysts show high control of polymerization with polydispersities of 1.1 and below. The obtained polymers were essentially atactic, with a slight heterotactic bias at ambient temperature and at –17 °C. [nacnacBnCu(μ-OiPr)]2 polymerizes -butyrolactone (BL), -caprolactone (CL) and -valerolactone (VL) with rate constants of kobs = 3.0(1)•10–2, 1.2–2.7•10–2, and 0.11(1) min–1, respectively. Homopolymers showed narrow polydispersities of appr. 1.1. Sequential addition polymerizations showed evidence for transesterification (not seen in homopolymerizations) if BL or CL are introduced after a lactide block.
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Síntese de amino-complexos de rutênio e suas aplicações como catalisadores em reações de metátese: polimerização via metátese por abertura de anel, metátese cruzada e autometátese / Syntheses of ruthenium-amine-based complexes and its applications in metathesis reactions: ring opening metathesis polymerization, cross metatathesis and selfmetathesisFonseca, Larissa Ribeiro da 12 September 2016 (has links)
Os não-carbeno complexos pentacoordenados do tipo [RuCl2(PPh3)2(amina)], sendo as aminas pirrolidina, azocano e dietilamina, foram sintetizados e caracterizados por análise elementar, espectroscopia de absorção na região do infravermelho, espectroscopia de absorção na região do ultravioleta e visível, espectroscopia de ressonância magnética nuclear de fósforo-31 e espectroscopia de ressonância paramagnética eletrônica. Estudos da teoria do funcional da densidade dos complexos foram realizados para buscar melhor interpretação dos resultados experimentais obtidos. O complexo [RuCl2(PPh3)2(pirrolidina)] exibiu uma geometria do tipo pirâmide de base quadrada em solução, com a amina na posição apical e as trifenilfosfinasestão trans-posicionada. Os complexos [RuCl2(PPh3)2(azocano)] e [RuCl2(PPh3)2(dietilamina)] exibiram geometria do tipo bipirâmide trigonal na qual as duas trifenilfosfinas estão trans-posicionadas no eixo axial. O complexo [RuCl2(PPh3)2(pirrolidina)] exibiu boa atividade catalítica nas polimerizações de norborneno e norbornadieno, tanto em atmosfera de argônio quanto em ar a 25 °C, como observado com os complexos similares [RuCl2(PPh3)2(peridroazepina)] e [RuCl2(PPh3)2(piperidina)]. Os complexos [RuCl2(PPh3)2(azocano)] e [RuCl2(PPh3)2(dietilamina)] obtiveram baixo rendimento de polimerização mesmo a 40 °C. Acredita-se que a geometria do tipo pirâmide de base quadrada seja a ativa para formação da espécie metal-carbeno com o etil diazoacetato no período de indução e favorável para iniciar a reação de polimerização via metátese por abertura de anel. A geometria do tipo bipirâmide trigonal pode dificultar o período de indução. Os estudos teóricos corroboraram com essa discussão. Os polinorbornenos, polinorbornadienos e seus copolímeros obtidos com os três complexos ativos foram caracterizados por espectroscopia de ressonância magnética nuclear de carbono-13, calorimetria exploratória diferencial, análise dinâmico-mecânica, termogravimetria e microscopia eletrônica de varredura. O complexo [RuCl2(PPh3)2(peridroazepina)] foi eficiente na metátese cruzada entre lignina metacrilada e o 10-undecen-1-ol para modificar a lignina Protobind 2400, e a lignina modificada foi solúvel em diversos solventes. O complexo [RuCl2(PPh3)2(peridroazepina)] também foi utilizado na autometátese da olefina terminal do 10-undecen-1-ol para obtenção de um diol que foi usado como segmento flexível e extensor de cadeia em reações de poliuretanas com óleo de mamona ou poli(ε-caprolactona) diol. Esse diol, quando utilizado em pequenas quantidades (10% em massa) nas poliuretanas derivadas do óleo de mamona, foi capaz de prover características adesivas a um material inicialmente rígido. Os resultados das reações de poliuretanas derivadas da poli(ε-caprolactona) diol não apresentaram resultados satisfatórios. / Non-carbene five-coordinate [RuCl2(PPh3)2(amina)] complexes, with pyrrolidine, azocane and diethylamine, were synthesized and characterized by elemental analysis, infrared absorption spectroscopy, ultraviolet-visible absorption spectroscopy, phosphorus-31 nuclear magnetic resonance and electron paramagnetic resonance. Density functional theory studies of the complexes were performed to complete and improve the experimental studies. [RuCl2(PPh3)2(pyrrolidine)] presented a square pyramidal geometry in solution, with the amine in the apical position and trans-positioned phosphines. [RuCl2(PPh3)2(azocane)] and [RuCl2(PPh3)2(diethyl amine)] exhibited a trigonal bipyramidal geometry in solution, with two phosphine molecules trans-positioned in the axial axis. [RuCl2(PPh3)2(pyrrolidine)] presented activity for ring opening metathesis polymerization of norbornene and norbornadiene under either air or inert atmosphere of argon at 25 °C, as observed with the parent complexes with perhydroazepine and piperidine. The latter three complexes presented square pyramidal geometries and high yields of polynorbornene and polynorbornadiene, different from the trigonal bipyramidal geometry of the complexes with azocane and diethylamine, which showed lower yields for polymerization even at 40 °C. This suggests that the cyclic amines in the apical position of the square pyramidal geometry provoke less steric hindrance, which provides prompt reactivity for ring opening metathesis polymerization. The bipyramidal geometry can hinder the induction period. Theoretical studies corroborate this discussion. The polynorbornenes, polynorbornadienes, and their copolymers obtained with the three active complexes were characterized by carbon-13 nuclear magnetic resonance, differential scanning calorimetry, dynamic mechanical analysis, thermogravimetry analysis, and scanning electron microscopy. [RuCl2(PPh3)2(perhydroazepine)] was efficient to perform cross metathesis between the methacrylate lignin and 10-undecen-1-ol to modify the Protobind 2400 lignin, and the modified lignin was soluble in several solvents. Self-metathesis of the terminal olefin in 10-undecen-1-ol was conducted in the presence of [RuCl2(PPh3)2(perhydroazepine)] and ethyl diazoacetate to form a bioderived diol. The diol was utilized as soft segment and chain extender in polyurethane reactions with castor oil or poly(ε-caprolactone) diol. At only 10 wt% of the diol, an adhesive characteristic was observed in the castor oil-based polyurethane. The results from poly(ε-caprolactone) diol-based polyurethane were not satisfactory.
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Síntese de amino-complexos de rutênio e suas aplicações como catalisadores em reações de metátese: polimerização via metátese por abertura de anel, metátese cruzada e autometátese / Syntheses of ruthenium-amine-based complexes and its applications in metathesis reactions: ring opening metathesis polymerization, cross metatathesis and selfmetathesisLarissa Ribeiro da Fonseca 12 September 2016 (has links)
Os não-carbeno complexos pentacoordenados do tipo [RuCl2(PPh3)2(amina)], sendo as aminas pirrolidina, azocano e dietilamina, foram sintetizados e caracterizados por análise elementar, espectroscopia de absorção na região do infravermelho, espectroscopia de absorção na região do ultravioleta e visível, espectroscopia de ressonância magnética nuclear de fósforo-31 e espectroscopia de ressonância paramagnética eletrônica. Estudos da teoria do funcional da densidade dos complexos foram realizados para buscar melhor interpretação dos resultados experimentais obtidos. O complexo [RuCl2(PPh3)2(pirrolidina)] exibiu uma geometria do tipo pirâmide de base quadrada em solução, com a amina na posição apical e as trifenilfosfinasestão trans-posicionada. Os complexos [RuCl2(PPh3)2(azocano)] e [RuCl2(PPh3)2(dietilamina)] exibiram geometria do tipo bipirâmide trigonal na qual as duas trifenilfosfinas estão trans-posicionadas no eixo axial. O complexo [RuCl2(PPh3)2(pirrolidina)] exibiu boa atividade catalítica nas polimerizações de norborneno e norbornadieno, tanto em atmosfera de argônio quanto em ar a 25 °C, como observado com os complexos similares [RuCl2(PPh3)2(peridroazepina)] e [RuCl2(PPh3)2(piperidina)]. Os complexos [RuCl2(PPh3)2(azocano)] e [RuCl2(PPh3)2(dietilamina)] obtiveram baixo rendimento de polimerização mesmo a 40 °C. Acredita-se que a geometria do tipo pirâmide de base quadrada seja a ativa para formação da espécie metal-carbeno com o etil diazoacetato no período de indução e favorável para iniciar a reação de polimerização via metátese por abertura de anel. A geometria do tipo bipirâmide trigonal pode dificultar o período de indução. Os estudos teóricos corroboraram com essa discussão. Os polinorbornenos, polinorbornadienos e seus copolímeros obtidos com os três complexos ativos foram caracterizados por espectroscopia de ressonância magnética nuclear de carbono-13, calorimetria exploratória diferencial, análise dinâmico-mecânica, termogravimetria e microscopia eletrônica de varredura. O complexo [RuCl2(PPh3)2(peridroazepina)] foi eficiente na metátese cruzada entre lignina metacrilada e o 10-undecen-1-ol para modificar a lignina Protobind 2400, e a lignina modificada foi solúvel em diversos solventes. O complexo [RuCl2(PPh3)2(peridroazepina)] também foi utilizado na autometátese da olefina terminal do 10-undecen-1-ol para obtenção de um diol que foi usado como segmento flexível e extensor de cadeia em reações de poliuretanas com óleo de mamona ou poli(ε-caprolactona) diol. Esse diol, quando utilizado em pequenas quantidades (10% em massa) nas poliuretanas derivadas do óleo de mamona, foi capaz de prover características adesivas a um material inicialmente rígido. Os resultados das reações de poliuretanas derivadas da poli(ε-caprolactona) diol não apresentaram resultados satisfatórios. / Non-carbene five-coordinate [RuCl2(PPh3)2(amina)] complexes, with pyrrolidine, azocane and diethylamine, were synthesized and characterized by elemental analysis, infrared absorption spectroscopy, ultraviolet-visible absorption spectroscopy, phosphorus-31 nuclear magnetic resonance and electron paramagnetic resonance. Density functional theory studies of the complexes were performed to complete and improve the experimental studies. [RuCl2(PPh3)2(pyrrolidine)] presented a square pyramidal geometry in solution, with the amine in the apical position and trans-positioned phosphines. [RuCl2(PPh3)2(azocane)] and [RuCl2(PPh3)2(diethyl amine)] exhibited a trigonal bipyramidal geometry in solution, with two phosphine molecules trans-positioned in the axial axis. [RuCl2(PPh3)2(pyrrolidine)] presented activity for ring opening metathesis polymerization of norbornene and norbornadiene under either air or inert atmosphere of argon at 25 °C, as observed with the parent complexes with perhydroazepine and piperidine. The latter three complexes presented square pyramidal geometries and high yields of polynorbornene and polynorbornadiene, different from the trigonal bipyramidal geometry of the complexes with azocane and diethylamine, which showed lower yields for polymerization even at 40 °C. This suggests that the cyclic amines in the apical position of the square pyramidal geometry provoke less steric hindrance, which provides prompt reactivity for ring opening metathesis polymerization. The bipyramidal geometry can hinder the induction period. Theoretical studies corroborate this discussion. The polynorbornenes, polynorbornadienes, and their copolymers obtained with the three active complexes were characterized by carbon-13 nuclear magnetic resonance, differential scanning calorimetry, dynamic mechanical analysis, thermogravimetry analysis, and scanning electron microscopy. [RuCl2(PPh3)2(perhydroazepine)] was efficient to perform cross metathesis between the methacrylate lignin and 10-undecen-1-ol to modify the Protobind 2400 lignin, and the modified lignin was soluble in several solvents. Self-metathesis of the terminal olefin in 10-undecen-1-ol was conducted in the presence of [RuCl2(PPh3)2(perhydroazepine)] and ethyl diazoacetate to form a bioderived diol. The diol was utilized as soft segment and chain extender in polyurethane reactions with castor oil or poly(ε-caprolactone) diol. At only 10 wt% of the diol, an adhesive characteristic was observed in the castor oil-based polyurethane. The results from poly(ε-caprolactone) diol-based polyurethane were not satisfactory.
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Novel M(II) beta-diketiminate complexes for the polymerization of lactideWhitehorne, Todd 08 1900 (has links)
Des ligands diketimines porteurs de substituants N-benzyl, N-9-anthrylmethyl et N-mesitylmethyl (nacnacBnH, nacnacAnH, and nacnacMesH) ont été synthétisés par condensation d’une amine et d’acétyl acétone ou son monoacétal d’éthylène glycol. La chlorination de la position 3 a été effectuée à l’aide de N-chlorosuccinimide conduisant à la formation des ligands ClnacnacBnH et ClnacnacAnH. Cette même position 3 a également été substituée par un groupement succinimide par lithiation du nacnacBnH, suivi de la réaction avec le N-chlorosuccinimide (3-succinimido-nacnacBnH). Les ligands N-aryl nacnacippH et nacnacNaphH (ipp = 2-isopropylphenyl, Naph = 1-naphthyl) ont été préparés selon les procédures reportées dans la littérature.
La réaction de ces ligands avec Zn(TMSA)2 (TMSA = N(SiMe3)2) conduit à la formation des complexes nacnacAnZn(TMSA) et ClnacnacBnZn(TMSA). La protonation avec l’isopropanol permet l’obtention des complexes nacnacAnZnOiPr et ClnacnacBnZnOiPr.
La réaction avec Mg(TMSA)2 permet quant à elle la formation des complexes nacnacAnMg(TMSA), nacnacMesMg(TMSA), ClnacnacBnMg(TMSA) et ClnacnacAnMg(TMSA). La protonation subséquente à l’aide du tert-butanol permet l’obtention du nacnacMesMgOtBu et du ClnacnacBnMgOtBu, alors que l’on observe uniquement une décomposition avec les ligands possédant des substituants N-anthrylmethyl.
La réaction de ces diketimines avec Cu(OiPr)2 conduit aux dimères hétéroleptiques [nacnacBnCu(μ-OiPr)]2 et [3-Cl-nacnacBnCu(μ-OiPr)]2 lors de l’usage des ligands stériquement peu encombrés. Lors de l’utilisation de ligands plus encombrés, la stabilisation du complexe hétéroleptique par dimérisation n’est plus possible, conduisant, par un échange de ligand, à la formation des complexes homoleptiques Cu(nacnacipp)2 et Cu(nacnacNaph)2. Les complexes homoleptiques Cu(nacnacBn)2 et Cu(3-succinimido-nacnacBn)2 ont été obtenus à partir des ligands N-benzyl. Les ligands encore plus encombrés tels que nacnacAnH, nacnacMesH ou ceux comportant des substituants N-methylbenzyl ne présentent alors plus de réactivité avec le Cu(OiPr)2.
La plupart des complexes ont été caractérisés par Diffraction des Rayons X. Les complexes homoleptiques ainsi que ceux de TMSA sont monomériques, alors que ceux formés à partir d’alkoxides se présentent sous forme de dimères à l’état solide. Tous les complexes d’alkoxides ainsi que les nacnacAnMg(TMSA)/BnOH et ClnacnacAnMg(TMSA)/BnOH présentent une réactivité modérée à haute en matière de polymérisation du rac-lactide (90% de conversion en 30 secondes à 3 heures). Le nacnacAnZnOiPr permet la synthèse d’un polymère hautement hétérotactique (Pr = 0.90) quand le ClnacnacBnMgOtBu/BnOH génère un polymère isotactique à -30°C (Pr = 0.43). Tous les autres catalyseurs produisent des polymères atactiques avec une légère tendance hétérotactique (Pr = 0.48 – 0.55). Les complexes hétéroleptiques [nacnacBnCu(μ-OiPr)]2 et [3-Cl-nacnacBnCu(μ-OiPr)]2 se révèlent être de très bons catalyseurs pour la polymérisation du rac-lactide présentant une conversion complète du monomère à température ambiante, en solution, en 0,5 à 5 minutes. Le [nacnacBnCu(μ-OiPr)]2 est actif en présence ou absence d’isopropanol, agissant comme agent de transfert de chaine à haute activité (k2 = 32 M–1•s–1) dans le dichlorométhane. Dans l’acétonitrile, le THF, le dichloromethane et le toluène, [nacnacBnCu(μ-OiPr)]2 conduit à une étroite polydispersité, possédant respectivement des kobs = 2.4(1), 5.3(5), 3.6-4.4 and 10(1) min–1. Aucune réaction parasite, telle qu’une trans-esterification, une épimerisation ou une décomposition du catalyseur, n’a été observée. Les complexes homoleptiques en présence d’alcool libre semblent présenter un équilibre avec une petite quantité de leurs équivalents hétéroleptiques, permettant une polymérisation complète, en moins de 60 min, à température ambiante. Tous les catalyseurs de cuivre présentent un haut contrôle de la polymérisation avec une polydispersité égale ou inférieure à 1.1. Les polymères obtenus sont essentiellement atactiques, avec une légère tendance à l’hétérotacticité à température ambiante et -17°C. Le [nacnacBnCu(μ-OiPr)]2 polymérise également la -butyrolactone (BL), l’-caprolactone (CL) et la -valerolactone (VL) avec des constantes respectivement égales à kobs = 3.0(1)•10–2, 1.2–2.7•10–2, et 0.11(1) min–1. Les homopolymères présentent une étroite polydispersité d’approximativement 1.1. Les polymérisations par addition séquentielle ont mis en évidence une trans-estérification (non observée dans les homopolymérisations) si BL ou CL sont introduits après un bloc lactide. / Diketimine ligands bearing N-benzyl, N-9-anthrylmethyl and N-mesitylmethyl substituents (nacnacBnH, nacnacAnH, and nacnacMesH) were prepared from condensation of amine with either acetyl acetone or its ethylene glycol monoketal. Chlorination of the 3-position was achieved using N-chlorosuccinimide, yielding ClnacnacBnH and ClnacnacAnH. The 3-position was also substituted by succinimido by lithiation of nacnacBnH followed by reaction with N-chlorosuccinimide (3-succinimido-nacnacBnH). N-aryl ligands nacnacippH and nacnacNaphH (ipp = 2-isopropylphenyl, Naph = 1-naphthyl) were prepared from literature. The ligands were reacted with Zn(TMSA)2 (TMSA = N(SiMe3)2) to yield nacnacAnZn(TMSA) and ClnacnacBnZn(TMSA). Protonation with isopropanol gave nacnacAnZnOiPr and ClnacnacBnZnOiPr. Reaction of the diketimines with Mg(TMSA)2 afforded nacnacAnMg(TMSA), nacnacMesMg(TMSA), ClnacnacBnMg(TMSA) and ClnacnacAnMg(TMSA). Subsequent protonation with tert-butanol produced nacnacMesMgOtBu and ClnacnacBnMgOtBu, but only decomposition was observed with N-anthrylmethyl substituents. Reaction of the diketimines with Cu(OiPr)2 yielded the heteroleptic [nacnacBnCu(μ-OiPr)]2 and [3-Cl-nacnacBnCu(μ-OiPr)]2 when using sterically undemanding ligands. When sterically more demanding diketimines were used, stabilization of the heteroleptic complex by dimerization was not possible, resulting in the formation of the homoleptic complexes Cu(nacnacipp)2 and Cu(nacnacNaph)2 by ligand exchange. Homoleptic complexes were also prepared with N-benzyl ligands, i. e. Cu(nacnacBn)2 and Cu(3-succinimido-nacnacBn)2. Even bulkier ligands such as nacnacAnH, nacnacMesH or N-methylbenzyl substituents failed to react with Cu(OiPr)2. Most complexes were characterized by single crystal X-ray diffraction. TMSA complexes and homoleptic complexes were monomeric, alkoxide complexes were dimeric in the solid state. All alkoxide complexes, as well as nacnacAnMg(TMSA)/BnOH and ClnacnacAnMg(TMSA)/BnOH were moderately to highly active in rac-lactide polymerization (90% conversion in 30 sec to 3 h). nacnacAnZnOiPr produced highly heterotactic polymer (Pr = 0.90), ClnacnacBnMgOtBu/BnOH produced slightly isotactic polymer at –30 °C (Pr = 0.43), all other catalysts produced atactic polymers with a slight heterotactic bias (Pr = 0.48 – 0.55). Heteroleptic complexes [nacnacBnCu(μ-OiPr)]2 and [3-Cl-nacnacBnCu(μ-OiPr)]2 are very highly active rac-lactide polymerization catalysts, with complete monomer conversion at ambient temperature in solution in 0.5 – 5 min. [nacnacBnCu(μ-OiPr)]2 specifically polymerized in the presence or absence of isopropanol as a chain-transfer reagent with very high activity (k2 = 32 M–1•s–1), in methylene chloride. While in acetonitrile, THF, dichloromethane and toluene has a kobs = 2.4(1), 5.3(5), 3.6-4.4 and 10(1) min–1, respectively. [nacnacBnCu(μ-OiPr)]2 yields narrow polydispersities and no evidence of side reactions such as transesterification, epimerization or catalyst decomposition. The homoleptic complexes in the presence of free alcohol, seem to be in equilibrium with small amounts of the respective heteroleptic complex, which are sufficient to complete polymerization in less than 60 min at room temperature. All Cu catalysts show high control of polymerization with polydispersities of 1.1 and below. The obtained polymers were essentially atactic, with a slight heterotactic bias at ambient temperature and at –17 °C. [nacnacBnCu(μ-OiPr)]2 polymerizes -butyrolactone (BL), -caprolactone (CL) and -valerolactone (VL) with rate constants of kobs = 3.0(1)•10–2, 1.2–2.7•10–2, and 0.11(1) min–1, respectively. Homopolymers showed narrow polydispersities of appr. 1.1. Sequential addition polymerizations showed evidence for transesterification (not seen in homopolymerizations) if BL or CL are introduced after a lactide block.
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