Tripodal borate ligands, including Tp and Tm, are some of the most widely used in organometallic chemistry and were originally prepared, as anions, from the reaction of the relevant heterocycle with an alkali metal borohydride. However, an alternate route, allowing access to zwitterionic, charge-neutral, scorpionates was recently developed within the Bailey group using tris(dimethylamino)borane as the boron source. This thesis describes the expansion of the borane synthetic route to create new, charge-neutral, zwitterionic, tris(methimazolyl)borate (ZTm) ligands containing B-N, B-O and B-C coordinate bonds. Unusual reactivity with isonitrile donors is also presented which has allowed access to boron substituted anionic Tm ligands from the charge-neutral starting material, (HNMe2)ZTm. Attempts to control the helical chirality of ZTm complexes, by using chiral imidazoline donors on the central boron are also described. The borane synthetic route has allowed access to the novel ligand ZThp, the first example of a tripod based on 2-hydroxypyridine ligand arms. As with Tm, this ligand exhibits helical chirality upon complexation and demonstrates how individual atom hybridisation within the ligand arms affects the helicity and thus the chirality of flexible scorpionate ligands. Coordination studies of both zwitterionic and boron-substituted anionic Tm ligands have shown a tendency for the formation of ‘sandwich’ complexes of the form L2M with some metal precursors, whilst the formation of the corresponding ‘half-sandwich’ complexes of these ligands with ruthenium and rhodium was found to be disfavoured.

Previous work in the Rosenberg group showed that the half-sandwich complexes Ru(η5-indenyl)Cl(PR2H)(PPh3) (2i), where R = cyclohexyl (Cy), isopropyl (Pri), phenyl (Ph), para-tolyl (Tolp), react with the strong, bulky base KOBut to give highly reactive complexes Ru(η5-indenyl)(PR2)(PPh3) (6i) containing a ruthenium-phosphorus double bond, Ru=PR2. The reactions of these phosphido complexes 6i with some reagents, such as alkenes, carbon monoxide and dihydrogen, illustrate their rich and varied reactivity. To better understand the mechanisms of these reactions (whether the indenyl effect is necessary), synthesis of analogous secondary phosphine complexes containing the pentamethylcyclopentadienyl (Cp*) ligand, Ru(η5-Cp*)Cl(PPh3)(PR2H) (2) were prepared via ligand substitution at Ru(η5-Cp*)Cl(PPh3)2 (1). Cp* phosphido complexes Ru(η5-Cp*)(PR2)(PPh3) (6) were generated in situ and their reactivity was investigated to see if they behaved similarly to the indenyl complexes. Experimental evidence in this thesis suggests that variable hapticity is not necessary in our indenyl system. In addition, these experimental evidence highlights enhanced lability of ligand at the bulky Cp*Ru fragment and higher Bronsted basicity of the phosphido ligand (PR2-) in Cp* phosphido 6 relative to the indenyl analogues 6i. / Graduate / 2017-12-11 / 0488 / yangjin@uvic.ca

Wolfram-Ruthenium-Zweikernkomplexe mit verbrückenden Bis(thioaldehyd)-Liganden: Synthese und Reaktivität in elektrophilen und nucleophilen Additionen. / Tungsten-ruthenium binuclear complexes with bridging bis-thioaldehyde ligands: Synthesis and reactivity in electrophilic und nucleophilic additions.

Neue Indenyl-Ruthenium-Thioaldehyd-Komplexe wurden in einer fünfstufigen Synthese ausgehend von Ruthenium-(III)-chlorid erhalten. Die Thioaldehyd-Komplexe und alle Zwischenprodukte wurden NMR-spektroskopisch sowie kristallographisch untersucht und charakterisiert. Die neuartigen Verbindungen wurden auf ihre Reaktivität in Hetero-Diels-Alder-Reaktionen und nucleophilen Additionen hin untersucht. / Novel indenyl ruthenium thioaldehyde complexes were obtained in a five-step synthesis starting from ruthenium (III) chloride. The thioaldehyde complexes and all intermediates were characterized by NMR spectroscopy as well as X-Ray diffraction. The reactivity of the new compounds in hetero Diels-Alder reactions and nucleophilic additions was studied.

ABSTRACT Solventless reactions of substituted cyclopentadienyl metal carbonyls of iron and ruthenium with electron donor ligands have been carried out. The reactions between CpFe(CO)2I and a range of phosphine ligands occurred in melt phase and yielded two typical compounds : salt product, [CpFe(CO)2PR3]I, and non-salt product, CpFe(CO)PR3I with the salt product being predominant. The complex [CpFe(CO)2]2 was used to catalyze these reactions. The progress of the reactions was followed by 1H NMR spectroscopy. The characterization of products correlates well with the products obtained when working in solution medium. The presence of a Me substituent on the Cp ring was found to favour the salt product formation but generally led to lower rates of reaction. Solventless reactions between RCpRu(CO)2I (R = H, Me) and solid phosphine ligands were also carried out. It has been observed that the ruthenium complexes were less reactive compared with their iron analogues but led to the same types of products namely salt and non-salt. The phosphite ligands were found to be less reactive than their phosphine analogues. In fact, the solventless reactions between RCpM(CO)2I (R = H, Me; M = Fe, Ru) were very slow even in the presence of [CpFe(CO)2]2 as a catalyst. However, when Me3NO.2H2O was added to the reaction mixture in solventless conditions, the non-salt product was obtained in a short period of time at 80oC. A range of cyclopentadienyl based metal complexes e.g [CpMo(CO)3]2, [MeCpRu(CO)2]2 etc. and palladium based compounds such as PdO, Pd/CaCO3 5% etc. were found to be good catalysts for the solventless reactions between CpFe(CO)2I and PPh3. Solventless migratory-insertion reactions have been successfully conducted between CpFe(CO)2CH3 and a range of solid phosphine ligands. Only the acetyl products, CpFe(CO)[PR3]COCH3 were obtained. SO2 insertion into RCpFe(CO)2R’ (R = H, CH3; R’ = CH3, CH2Ph) occurred quite easily at room temperature. However, when R was a carboxylic acid group, CO2H, no reaction took place. CO insertion into the same systems did not happen in solventless conditions.

Thesis advisor: Amir H. Hoveyda / We have synthesized Ru-carbene isocyanide complexes that promote both ring-opening metathesis polymerization of norbornene as well as cycloisomerization of diethyl diallylmalonate. We have also synthesized a N-heterocyclic carbene complex bearing a biphenylthiol moiety, and we installed this ligand on a Ru-carbene to produce a racemic chiral bidentate Ru-thiolate complex. Although the Ru-thiolate was found to initiate more slowly than the corresponding biphenoxide catalyst, both perform ring-opening/cross-metathesis (ROCM) with similar efficiency. Several other bidentate Ru-complexes were synthesized where the anionic ligand was varied (tosylate, pivalate, and phenylthiolate), as well as a new Re-alkylidene bis-pyrrolide. We have expanded the scope of Ru-catalyzed enantioselective ROCM of cyclopropenes utilizing a variety of ester, ketone, ether, and aliphatic olefin cross-partners. The utility of this method was demonstrated in the enantioselective total synthesis of the marine natural product (+)-sporochnol, which was synthesized in 8% overall yield across eleven linear steps. Additionally, we have developed an enantio- and Z-selective ROCM of enol ethers and oxabicycles; we propose the origin of Z-selectivity to arise from a lower barrier to ruthancyclobutane cleavage/formation for the cis-substituted ruthenacyclobutane vs the trans-substituted ruthenacyclobutane (which is favored for ROCM of oxabicycles and styrene). We also have found that stereogenic-at-Ru complexes are capable of undergoing non-metathesis isomerization through polytopal rearrangements. This observation may explain why cyclopropene ROCM suffers from low enantioselectivity for many substrates. We have developed a diasteroselective ROCM reaction, which utilizes commercially available ruthenium dichloride catalysts in the presence of chiral allylic alcohols and cyclopropenes. Our investigation revealed that the presence of a hydroxyl group dramatically accelerates the rate of ROCM vs the corresponding methyl ether and delivered products in high yield and diastereoselectivity. Furthermore, we found that the methyl ether delivered the opposite diastereomer vs the allylic alcohol; this led us to propose that intramolecular H-bonding between the hydroxyl proton and a chloride ligand controls the diastereoselectivity and enhances the rate of the ROCM. Protic additives have also been found to promote polytopal rearrangements in stereogenic-at-Ru complexes; H-bonding may facilitate olefin metathesis in a similar fashion to polytopal rearrangement by reducing the trans effect during the transition state to ruthenacyclobutane formation. A number of synthetically useful allylic alcohols and strained olefin substrates efficiently provide products in high diastereoselectivity and with good E:Z selectivity (89:11-97:3 dr, 4:1-11:1 E:Z). We have developed a Mo-catalyzed Z-selective cross-metathesis (CM) reaction. A wide range of olefin cross partners were found to be effective for both enol ether and allylic amide substrates (51-97% yield, 81 to 98% Z). We applied our Z-selective CM method to the synthesis of KRN7000, a potent immunostimulant (the Z-allylic amide was obtained in 85% yield and 96% Z). We also utilized Z-selective CM in the formal synthesis of an enol ether plasmalogen C18 (plasm)-16:0 (PC), a lipid membrane component found in mammalian brain tissue (the enol ether was obtained in >98:2 Z selectivity). Z-selective cross-metathesis is therefore a new tool for synthetic chemists to access important building blocks for the synthesis of biologically active molecules. We have developed a Z-selective cross-metathesis of vinyl and allyl boronates. Reactions of both substrate classes proceed to between 50-95% conv and deliver Z-vinylboronate and Z-crotylboronate products in 85-93% Z selectivity. Allylboronate CM provides Z-crotylboronates which can be used for diastereoselective crotylation. The utility of Z-selective vinylboronate CM was demonstrated in the synthesis of a dienyl boronate (obtained in 83% yield and >98% Z) that will be utilized in the total synthesis of the potent anti-cancer agent disorazole C1. / Thesis (PhD) — Boston College, 2012. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand) in partial fulfilment of the requirements for the degree of Master of Science in Engjneering Johannesburg, 1994 / Recent international investigations into new advanced materials have shown that the intennetallic compound, RuA1, possesses prormising characteristics for high-temperature use in corrosive environments. In order to optimise production of this alloy, an understanding of the Ru-A1 system is necessary. [Abbreviated Abstract. Open document to view full version]

A reatividade dos complexos do tipo [RuCl2(PPh3)2(amina)], onde a amina = 3,5-dimetilpiperidina (complexo 1) ou piperidina (complexo 2), foi investigada na polimerização via metátese por abertura de anel (ROMP) de norborneno (NBE) e norbornadieno (NBD), na presença de etildiazoacetato (EDA), como fonte de carbeno, em CHCl3. O objetivo foi observar a combinação dos efeitos eletrônicos e estéricos da PPh3 com uma amina como ligantes ancilares na reatividade em ROMP. Os resultados com o complexo 1 foram comparados aos resultados obtidos com o complexo 2. Na ROMP de NBE, o complexo 1 proporcionou um rendimento de 70% de poliNBE (Mn = 8,3 &times; 104 g/mol; IPD = 2,03), enquanto o complexo 2 promoveu reação quantitativa (Mn = 1,2 x 105 g/mol; IPD = 1,90) com razões molares [NBE]/[Ru] = 5000 e [EDA]/[Ru] = 48 e 1,1 &micro;mol de Ru por 5 min a 25 &deg;C. Os poliNBEs apresentaram um &sigma;c = 0,38, determinado por RMN de 13C{1H} e uma Tg = 37 &deg;C, determinada através das análises de DSC e DMTA. Na ROMP de NBD com o complexo 1 obteve-se rendimento quantitativo, com IPD = 2,62 com razão molar [NBD]/[Ru] = 5000 por 20 min a 25 &deg;C, enquanto que a reação com o complexo 2 resultou em um rendimento de 55%, com IPD = 2,16 nas mesmas condições. Concluiu-se que a presença dos dois grupos metila no anel piperidina no complexo 1 proporcionou um aumento no período de indução para produzir a espécie metal carbeno, o que justifica os menores rendimentos na ROMP de NBE quando comparado com o complexo 2. No entanto, o maior sinergismo eletrônico amina&rarr;Ru&rarr;monômero contribuiu para uma melhor ativação de olefinas mais difíceis de serem polimerizadas como o NBD, como ocorre no caso com o complexo 1.<br />Poli[NBE]-co-[NBD] foram obtidos via ROMP com os complexos 1 e 2 como iniciadores. As reações de copolimerização foram realizadas utilizando uma quantidade fixa de NBE ([NBE]/[Ru] = 5000) com diferentes concentrações de NBD ([NBD]/[Ru] = 500, 1000, 1500 e 2000) em CHCl3, iniciadas com EDA à temperatura ambiente. A presença de NBD nas cadeias de poliNBE foi caracterizada por RMN de 1H e de 13C{1H} para todos os casos onde a quantidade de NBD foi variada, suportando a formação de poli[NBD]-co-[NBD]. Considerando que a microestrutura do poli[NBD]-co-[NBD] não foi influenciada pela quantidade de NBD nem pelo tipo de iniciador, os valores de Mn e de IPD foram otimizados quando se aumentou a concentração de NBD no meio reacional. O aumento da quantidade de NBD propiciou um aumento na densidade de entrecruzamento resultando em um aumento na Tg e no módulo de armazenamento (E\'). A análise morfológica da superfície dos polímeros por MEV mostrou uma estrutura altamente porosa para os poliNBEs sintetizados e indicou uma diminuição no tamanho desses poros para os poli[NBD]-co-[NBD] isolados, alcançando uma superfície totalmente lisa com a composição [NBE]5000[NBD]2000, para ambos os catalisadores. / The reactivity of the new complex [RuCl2(PPh3)2(3,5-Me2piperidine)], complex 1, was investigated for ring opening metathesis polymerization (ROMP) of norbornene (NBE) and norbornadiene (NBD) in the presence of ethyl diazoacetate (EDA) in CHCl3. The aim is to observe the combination of PPh3 and an amine as ancillary ligands in the reactivity for ROMP. Thus, the results with the complex 1 were compared to the results obtained when the amine is piperidine (complex 2). Reaction with the complex 1 provides 70% yield of isolated polyNBE (Mn = 8.3 &times; 104 g/mol; PDI = 2.03), whereas the complex 2 provides quantitative reaction (Mn = 1.2 &times; 105 g/mol; PDI = 1.90) with [NBE]/[Ru] = 5000, [EDA]/[Ru] = 48 and 1.1 &micro;mol of Ru for 5 min at 25 &deg;C. The resulting polymers showed a &sigma;c = 0,38, determined by 13C NMR, and Tg =37 &deg;C, determined by DSC and DMTA. For ROMP of NBD, the complex 1 showed quantitative yield with PDI = 2.62 when [NBD]/[Ru] = 5000 for 20 min at 25 &deg;C, whereas the reaction with the complex 2 reached 55% with PDI = 2.16 in the same conditions. It is concluded that the presence of the two methyl groups in the piperidine ring provides an increase in the induction period to produce the Ru-carbene species justifying better polyNBE results with the complex 2, and a greater amine&rarr;Ru&rarr;monomer synergism which contributed to the best activation of olefin with greater difficulty of being polymerized as NBD, as in the case with the complex 1.<br />Copolymers of NBE with NBD were obtained via ROMP with the complexes 1 and 2 as initiators. The copolymerizations reactions were performed using a fixed quantity of NBE ([NBE]/[Ru] = 5000) with different concentrations of NBD ([NBD]/[Ru] = 500, 1000, 1500 and 2000) in CHCl3, initiated with EDA at room temperature. The presence of NBD in the polyNBE chains was characterized by 1H and 13C NMR. Whereas the copolymer microstructure was influenced neither by the NBD quantity nor by the initiator type, the Mn and PDI values were improved when increasing the NBD quantity in the medium. When raising the NBD amount, DMA results indicated increased cross-linking with increasing Tg and E\' storage modulus, as well as the fact that SEM micrographs indicated decreased pore sizes in the porous isolated copolymers.

O novo monômero-ligante 3-imidapiridina-exo-7-oxabiciclo[2.2.1]-hept-5-eno-2,3-dicarboxilato (oxaNBE(3imdpy)) foi sintetizado e caracterizado por análise elementar (CHN), FTIR, difração de Raios-X e RMN (1H e 13C). Trata-se de um ligante monodentado com uma unidade de piridina apta a se coordenar a um centro metálico por uma extremidade da molécula, enquanto que a outra extremidade possui uma olefina cíclica que pode ser polimerizada via metátese por abertura do anel. Foram realizados estudos adicionais com monômeros-ligantes similares apresentando duas unidades de piridina por composto (oxaNBE(3amdpy)2 e NBE(3amdpy)2). Foi também sintetizado o monômero oxaNBE(imdPh). O composto oxaNBE(3imdpy) reagiu com o complexo cis-[Ru(H2O)2(phen)2], obtido in situ a partir do cis-[RuCl2(phen)2] em uma mistura 1:1 EtOH/H2O, onde phen é 1,10-fenantrolina, formando o novo complexo cis-[Ru(phen)2(oxaNBE(3imdpy)2](PF6)2. Esse complexo foi caracterizado por análise elementar (CHN), FTIR, RMN (1H; 13C; COSY; NOE), voltametria cíclica, espectrofotometria UV-vis, cálculos computacionais ab initio e investigou-se fotólise contínua e luminescência. Observou-se um único par redox por voltametria cíclica nos solventes MeOH (E1/2 = 0,63 V vs Ag/AgCl) e DMF (E1/2 = 0,72 V vs Ag/AgCl). Os espectros eletrônicos em MeOH, DMF, CH3CN, CH2Cl2 e CHCl3 apresentaram absorções típicas de complexos polipiridínicos de rutênio na regiâo de 440-500 nm que foram atribuídas a transferências de carga do metal para o ligante (MLCT) do Ru(4d) para a phen. A influência do meio sobre o comportamento em solução mediante fotólise foram avaliadas. Os espectros de absorção na região do UV-vis exibem perfis espectrais semelhantes em MeOH, CH2Cl2, CHCl3 e CH3CN, não obtendo-se correlações lineares com os parâmetros característicos dos solventes. Observou-se que os espectros eletrônicos na ausência ou presença de luz ambiente em MeOH, CH2Cl2 e CH3CN não apresentaram mudanças significativas, exceto para CHCl3. Fotólises a 450 nm indicaram mudanças espectrais nos solventes CHCl3 e CH2Cl2. Os espectros de emissão (excitação em 450 nm) do complexo não mostraram diferenças nos diferentes meios. O monômero-ligante oxaNBE(3imdpy) e o similar monômero oxaNBE(imdPh) formaram polímeros em presença de catalisadores de rutênio por 16 horas à temperatura ambiente, não ocorrendo o mesmo com o metalo-monômero cis-[Ru(phen)2(oxaNBE(3imdpy)2](PF6)2. Os monômeros-ligantes oxaNBE(3amdpy)2 e NBE(3amdpy)2oxaNBE(3amdpy)2 não formaram polímeros, bem como seus respectivos complexos. / The novel monomer-ligand 3-imidepyridine-exo-7-oxabicycle[2.2.1]-hept-5-ene-2,3-dicarboxylate (oxaNBE(3imdpy)) was synthesized and characterized by elemental analysis (CHN), FTIR, X-ray diffraction and NMR (1H e 13C). It is a monodentate compound with a pyridine ligand able to be coordinated to a metal center via one side of the molecule, while the other side has a cyclic olefin that can undergo ring-opening metathesis polymerization. Additional studies were carried out using similar monomers featuring two pyridine units per molecule (oxaNBE(3amdpy)2 and NBE(3amdpy)2). It was also synthesized the monomer oxaNBE(imdPh). The compound oxaNBE(3imdpy) reacted with cis-[Ru(H2O)2(phen)2], obtained in situ from cis-[RuCl2(phen)2] in 1:1 EtOH/H2O mixture, where phen is 1,10-phenanthroline, given cis-[Ru(phen)2(oxaNBE(3imdpy)2](PF6)2. This novel complex was characterized by elemental analysis (CHN), FTIR, NMR (1H; 13C; COSY; NOE), cyclic voltammetry, UV-vis spectrophotometry, quantum mechanical calculations, continuous photolysis and luminescence. The complex showed a single redox process in the cyclic voltammogram either in MeOH (E1/2 = 0.63 V) or DMF (E1/2 = 0.72 V vs Ag/AgCl) as solvent. The electronic spectra in MeOH, DMF, CH3CN, CH2Cl2 and CHCl3 showed typical absorptions of polypyridinic-ruthenium complexes in 440-500 nm range that were attributed to metal to ligand charge transfers (MLCT) from Ru(4d) to phen. The influence of the solvent on the complex behavior at room temperature as a function of time and under photolysis was studied. The UV-vis spectra showed similar spectral profiles in MeOH, CH2Cl2, CHCl3 and CH3CN, without linear clear correlations with characteristic parameters from the solvents. It was observed that the electronic spectra either in absence or presence of ambient light in MeOH, CH2Cl2 and CH3CN did not show significant spectral changes, except for CHCl3. The photolysis at 450 nm indicated changes in CHCl3 and CH2Cl2. The emission spectrum (excitation at 450 nm) of the complex did not show differences in different solvents. The monomer-ligand oxaNBE(3imdpy) and the similar monomer oxaNBE(imdPh) were polymerized in presence of ruthenium-based catalysts for 16 h at room temperature, contrary to the metal-monomer cis-[Ru(phen)2(oxaNBE(3imdpy)2](PF6)2. The monomer-ligands oxaNBE(3amdpy)2 and NBE(3amdpy)2 did not form polymers, as well as the related complex, under similar conditions.

Um novo iniciador para metátese do tipo GH nitro-substituído [Ru(1-CH3-4-CO2-Py+)2(IMesH2)(=CH-2-(2-PrO)-5-NO2-C6H3)][OTf-]2 (3b) foi preparado. Os comprimentos de ligação e deslocamentos químicos foram comparáveis aos do iniciador 3a ([Ru(1-CH3-4-CO2-Py+)2(IMesH2)(=CH-2-(2-PrO)-C6H3)][OTf-]2), embora o substituinte NO2 na porção benzilideno resulte numa ligação Ru-O mais curta. A comparação entre os iniciadores do tipo GH e 5-NO2-GH indica que a substituição dos cloretos por pseudo-haletos resulta em maior polarização da ligação Ru=C e uma ligação Ru-O mais forte. O iniciador 3b e os iniciadores análogos do tipo GH [Ru(1-CH3-4-CO2-Py+)2(IMesH2)(=CH-2-(2-PrO)-C6H4)][OTf-]2 (3a) e [RuCl(1-CH3-4-CO2-Py+)(IMesH2)(=CH-2-(2-PrO)-C6H4)][OTf-] (5a) foram usados para reações de ROMP em meio homogêneo e em meio bifásico líquido/líquido usando o líquido iônico [BDMIM+][BF4-] e tolueno. Os catalisadores foram ativos para a ROMP de monômeros a base de norborneno (NBE), cis-cicloocteno (COE) e diciclopentadieno (DCPD) em meio homogêneo com bons rendimentos. O catalisador mono-iônico 5a foi mais ativo que os catalisadores 3a e 3b. As reações de ROMP em meio bifásico permitiram a síntese de polímeros com baixos valores de IPD (1,2-2,4) e altos rendimentos. O uso de um agente de transferência de cadeia (ATC) gerou polímeros com baixo teor de metal (entre 10 e 80 ppm), o que corresponde a uma remoção de 98-99,4% do Ru inicial. Em adição, o uso do ATC permitiu a realização de experimentos de reciclagem em meio bifásico para a ROMP de NBE, onde 3a e 5a foram ativos por vários ciclos. Apesar de menos ativo, 3a foi mais estável, por manter a atividade por maior número de ciclos. Foi observada baixa contaminação de Ru nos polímeros após cada ciclo (8-75 ppm), o que representa uma remoção de 98-99,9%. <br /> Como uma segunda parte do trabalho, os novos complexos [RuCl2(PPh3)2(4-CH2R-pip)], com R = H (1), Ph (2) e OH (3), foram sintetizados e aplicados como iniciadores para a ROMP de norborneno (NBE) e norbornadieno (NBD) sob diferentes tempos de reação, temperaturas e concentrações de monômero. Houve uma clara diferença nos rendimentos de homopolímero na ordem 1 > 2 > 3 na razão molar [monômero]/[Ru] = 5000 a 25 &deg;C de 5-60 min. A diferença nos rendimentos tende a desaparecer a 50 &deg;C, com rendimentos quantitativos para 15-30 min usando qualquer iniciador. Os resultados dos copolímeros obtidos a TA por 60 min a partir de soluções contendo quantidades fixas de NBE e quatro quantidades diferentes de NBD sugerem que o tipo de iniciador também afeta as reações, com maior inserção de NBD com 1. A ocorrência de ligações cruzadas aumentou com o aumento da carga de NBD, evidenciado pelo decréscimo nos valores de Mc e aumento valores de Tg. <br /> Em outra parte do doutorado, o novo complexo de RuIII [RuCl3(PCy3)2] foi sintetizado e caracterizado, se mostrando estável ao ar. O complexo foi aplicado como iniciador para ROMP em ar e apresentou significante diferença na reatividade para norborneno (NBE) e norbornadieno (NBD). Rendimentos quantitativos de poliNBD foram obtidos instantaneamente a 25 &deg;C, enquanto 40 % de poliNBE foi produzido em 5 min a 25 &deg;C e 95% em 60 min a 50 &deg;C. A copolimerização de NBE e NBD com diferentes razões molares iniciais [NBD]/[Ru] a 25 &deg;C resultaram em materiais com uma grande quantidade de NBD. Os valores de Tg mudaram de 37 (poliNBE) para 90 &deg;C (poli[NBE-co-NBD]) com o aumento da carga de NBD. A caracterização morfológica mostrou que os copolímeros apresentam uma tendência a serem mais organizados com a diminuição da carga de NBD, com um padrão bem definido do tipo favo de mel para a amostra contendo a menor quantidade de NBD. / A novel Grubbs-Hoveyda (GH) nitro-substituted ionic metathesis initiator [Ru(1-CH3-4-CO2-Py+)2(IMesH2)(=CH-2-(2-PrO)-5-NO2-C6H3)][OTf-]2 (3b) has been prepared. Bond lengths and chemical shifts were comparable to 3a ([Ru(1-CH3-4-CO2-Py+)2(IMesH2)(=CH-2-(2-PrO)-C6H3)][OTf-]2), although the NO2 substituent in the benzilidene moiety affords shorter Ru-O bond. Comparison between GH and 5-NO2-GH initiators indicates that the replacement of chlorides by pseudo-halides result in higher polarization of Ru=C bond and stronger Ru-O bond. 3b and the parent GH initiators [Ru(1-CH3-4-CO2-Py+)2(IMesH2)(=CH-2-(2-PrO)-C6H4)][OTf-]2 (3a) and [RuCl(1-CH3-4-CO2-Py+)(IMesH2)(=CH-2-(2-PrO)-C6H4)][OTf-] (5a) were used for ROMP reactions under homogeneous and biphasic liquid/liquid conditions using the ionic liquid [BDMIM+][BF4-] and toluene. The catalysts were active for ROMP of norbornene(NBE)-based monomers, cis-cicloocteno (COE) and dicyclopentadiene (DCPD) under homogeneous conditions providing good yields. The monoionic catalyst 5a was more active than the dicationic 3a and 3b. ROMP under biphasic conditions allowed for preparing polymers with lower PDIs (1.2-2.4) and higher yields. The use of a chain transfer agent (CTA) allowed for polymers with low metal content (range between 10 and 80 ppm), which corresponds to a Ru-removal of 98-99.4%. In addition, the use of a CTA allowed for recycling experiments under biphasic conditions for ROMP of NBE, were 3a and 5a were active for several cycles. Besides less active, 3a was more stable, once it was active for more cycles. Low Ru contamination was observed for the polymers after each cycle (8-75 ppm), a Ru-removal of 98-99.8%. <br /> As a second part of the work, the novel [RuCl2(PPh3)2(4-CH2R-pip)] complexes, with R = H (1), Ph (2) or OH (3), were synthesized and applied as initiators for ROMP of norbornene (NBE) and norbornadiene (NBD) under different reaction times, temperatures and monomer concentrations. There was clear difference in the homopolymer yields in the order 1 > 2 > 3 at [monomer]/[Ru] molar ratio of 5000, at 25 &deg;C for 5-60 min. Difference in the yields tend to disappear at 50 &deg;C, with quantitative yields for 15-30 min with any type of initiator. Results from copolymers obtained at RT for 60 min from fixed amounts of NBE with four different amounts of NBD suggest that the type of initiator also affects the reactions, with more insertion of NBD with 1. The occurrence of cross-linking enhanced as the NBD loading increased, evidenced by decrease in the Mc and increase in the Tg values. <br /> In other part of PhD, the novel RuIII complex [RuCl3(PCy3)2] was synthesized and characterized, being stable in air. The complex was applied as initiator for ROMP in air and presented significant difference in reactivity for ROMP of norbornene (NBE) and norbornadiene (NBD). Quantitative yields of polyNBD were obtained instantaneously at 25 &deg;C, whereas 40 % of polyNBE resulted for 5 min at 25 &deg;C or 95% for 60 min at 50 &deg;C. Copolymerization of NBE and NBD with different starting [NBD]/[Ru] molar rations at 25 &deg;C resulted in materials with large amount of NBD. Tg values changed from 37 (polyNBE) to 90 &deg;C (poly[NBE-co-NBD]) as the NBD loading increased. Morphological characterization showed that the copolymers present a tendency to be more organized as the NBD loading decreases, with a well-defined honeycomb-like pattern for the copolymer isolated from the run with the lowest NBD load.