Cinnamyl alcohol (AC) and cinnamyl acetate (ACM) were used as substrates in olefin metathesis reactions catalyzed by RuCl2(PCy3)2(=CHPh), first-generation Grubbs catalyst-G1, and RuCl2(PCy3)(H2IMes)(= CHPh), second-generation Grubbs catalyst-G2. The reactions occurred in the same reaction conditions for both substrates, 50 °C, for 24 h, in the proportions Ru:substrate of 1:1 and 1:10 mol. At the end of each experiment, the reaction mixture was evaluated by GC-MS and NMR of 13C{1H}. The results revealed different products when G1 and G2 are applied in the metathesis of AC, 1,5-diphenyl-2-pentene and stilbene, respectively. When ACM is the substrate, no product is noted with G1 and stilbene was the compound obtained with G2 as catalyst. In this study, we have presented a discussion about the electronic and steric influence of the ancillary ligands in the yield and type of product formed in the catalytic process.

Diesters of norbornene 2,3-dicarboxylic acid (NBE-(COOR)2), in which R is an alkyl group, were synthesized from one-pot synthesis method with 5-norbornene-2,3-dicarboxylic acid and methanol and ethanol. The new monomers were, respectively, the dimethyl ester NBE-(COOCH3)2 and diethyl ester NBE-(COOCH2CH3)2. Norbornene was mixed with these monomers at different proportions and copolymerized via ring-opening metathesis polymerization (ROMP) with 1st generation Grubbs' catalyst. All experiments were conducted under air atmosphere to obtain the isolated polymer. Yield results show that elongation of the R group influenced the copolymerization process. At the same co-monomer proportion, the yield decreases as a function of the R group elongation. Thermogravimetric analysis (TGA) was performed and, in all cases, more than one thermal degradation process was observed. The first process was assigned to pendent group degradation, whereas the second process was assigned to main chain degradation. These thermal processes were also influenced by different elongation of the aliphatic group of the pendent chain.

Complexos do tipo [RuCl2(PPh3)2(amina)x], com NH2Ph (1; x = 2), NH2Bz (2; x = 2) and NHBuPh (3; x = 1) na presença de etildiazoacetato (EDA), foram aplicados em reações de polimerização via metátese por abertura de anel (ROMP) de norborneno (NBE), norbornadieno (NBD) e diciclopentadieno (DCPD). Rendimentos quantitativos de poliNBE foram obtidos a 50 °C por 30 min usando 1 e por 5 min usando 2. Isso ocorreu a 25 °C por 5 min quando foi usado 3. Os valores do índice de polidispersidade (PDI) variaram de 3,5 a 1,6 (Mw = 104-105 g mol-1). O complexo 3 foi ativo para ROMP de NBD e DCPD, bem como para copolimerização de NBE com NBD ou com DCPD. O maior caráter σ-doador de NH2Bz em 2, em relação a NH2Ph em 1, favoreceu a reatividade do complexo 2 que é hexacoordenado como 1. O ângulo de cone de NHBuPh definiu a pentacoordenação em 3 e a sua melhor reatividade para ROMP, apesar do baixo caráter σ-doador como o de NH2Ph.

[RuCl2(PPh3)2(amine)x]-type complexes, with NH2Ph (1; x = 2), NH2Bz (2; x = 2) and NHBuPh (3; x = 1) in the presence of ethyldiazoacetate (EDA), were investigated for ring opening metathesis polymerization (ROMP) of norbornene (NBE), norbornadiene (NBD) and dicyclopentadiene (DCPD). Quantitative yields of polyNBE were obtained at 50 °C for 30 min with 1 and for 5 min with 2, whereas this occurred at 25 °C for 5 min with 3. Polydispersity index (PDI) values ranged from 3.5 to 1.6 (Mw = 104-105 g mol-1). Complex 3 was active for ROMP of NBD and DCPD, as well as for copolymerizations of NBE with either NBD or DCPD. The high σ-donor character of NH2Bz favored the reactivity of the six-coordinated complex 2, contrary to complex 1. The large cone angle of NHBuPh defined the fivecoordination in 3 and the best reactivity for ROMP, in spite of the low σ-donor character as in NH2Ph.

Ring Opening Metathesis Polymerization (ROMP) of cyclic olefins is a powerful transition metal-catalyzed reaction for syntheses of polymers and copolymers. The key feature of this reaction is the [2+2]-cycloaddition mechanism, with retention of the olefinic unsaturation in the polymer chain and occurrence of living polymerization. With the development of metal-carbene type catalysts for this process, many addressed polymeric materials have been successfully prepared to be employed in several fields of the science and technology. This review summarizes recent examples of syntheses of polymers with amphiphilic features such as block, graft, brush or star copolymers; as well syntheses of biomaterials, dendronized architectures, photoactive polymers, cross-linked or self-healing materials, and polymers from renewed supplies.

Cálculos de orbitais moleculares para o complexo cis-[Ru(bpy)2Lx](PF6) 2, onde bpy é 2,2'-bipiridina e L é 3-aminopiridina (complexo 1 com x = 2), foram realizados com o programa Gaussian 03 usando o método DFT. A estrutura eletrônica e as propriedades moleculares de 1 foram caracterizadas no vácuo e em solução com acetonitrila e comparadas com os resultados obtidos para o complexo com L = 5,6-bis(3-amidopiridina)-7-oxanorborneno (complexo 2 com x = 1). Os espectros eletrônicos dos complexos 1 e 2 foram investigados por TD-DFT. Os dados experimentais de voltametria cíclica, UV-vis, fotoquímica e fotofísica foram comparados com dados teóricos de maneira a estabelecer a influência de L nas transições eletrônicas e interpretar as diferenças entre os comportamentos fotoquímicos desses complexos.

MO calculations were carried out on a cis-[Ru(bpy)2Lx](PF6) 2 complex, where bpy is 2,2'-bipyridine and L is 3-aminopyridine (complex 1 with x = 2), with the Gaussian 03 package using the DFT method. The electronic structure and molecular properties of 1 were characterized in vacuum and in acetonitrile solution, and the results were compared to those obtained from the complex with L = 5,6-bis(3-amidopyridine)-7-oxanorbornene (complex 2 with x = 1). The electronic spectra of 1 and 2 were investigated by TD-DFT. Experimental data from cyclic voltammetry, UV-visible spectroscopy, photochemical and photophysical experiments were compared to the theoretical data to discover the influence of L on the electronic transitions and to interpret the differences between the photochemical behaviors of these complexes.

A polimerização via metátese por abertura de anel (ROMP) de norborneno (NBE) ocorre em presença do complexo fac-[RuCl2(S-DMSO)3(O-DMSO)] e etildiazoacetato (5 μL), onde DMSO é dimetilsulfóxido coordenado pelo átomo de enxofre ou de oxigênio. O rendimento é 62% (PDI = 1,64) à temperatura ambiente por 5 min e 88% (PDI = 1,93) a 50 ºC por 30 min, com [NBE]/[Ru] = 516 em CHCl3. Na presença de NBu4ClO4 o rendimento é 90% (PDI = 1,64) à temperatura ambiente por 5 min. O complexo é praticamente inativo quando uma ou duas moléculas de DMSO são substituídas por piridina, imidazol, 2-metil-imidazol ou benzoimidazol. A formação in situ da espécie catalítica e os comportamentos das moléculas de DMSO como ligantes ancilares nas reatividades dos complexos de RuII são discutidas nesse trabalho.

The ring-opening metathesis polymerization (ROMP) of norbornene (NBE) occurs in the presence of the fac-[RuCl2(S-DMSO)3(O-DMSO)] complex and ethyldiazoacetate (5 μL), where DMSO is S- or O-bonded dimethylsulfoxide. The yield is 62% (PDI = 1.64) at room temperature for 5 min and 88% (PDI = 1.93) at 50 ºC for 30 min, with [NBE]/[Ru] = 516 in CHCl3. The yield is 90% (PDI = 1.64) in the presence of NBu4ClO4 at room temperature for 5 min. The complex is practically inactive when one or two molecules of DMSO are replaced by pyridine, imidazole, 2-methyl-imidazole or benzimidazole. The in situ formation of the catalytic species and the behavior of the DMSO molecules as ancillary ligands in the reactivity of the RuII complexes are discussed.

Some aspects of the olefin metathesis reactions are summarized here (types of reactions, mechanism and catalysts). In particular, the research groups that have been working on this chemistry in Brazil are presented. The main goal of this paper is to make this type of reaction more widely known in the Brazilian chemical community.

O acoplamento do extrator por "purge and trap" com a cromatografia gasosa foi utilizado para quantificar o dimetilssulfeto em bebidas alcoólicas. Muito boa performance foi obtida usando-se uma coluna HP-FFAP e um detector seletivo de massas operando em modo SIM (m/z 62): limite de detecção de 8 x 10-9 mol L-1; boa repetibilidade e tempo total de análise de 25 minutos. O método foi aplicado em 60 amostras de bebidas alcoólicas (cachaça, tiquira, grapa, uísque, brandy, vodca, rum e uma tequila). As amostras de cachaças exibiram a maior concentração de dimetilssulfeto (mediana de 3.16 x 10-4 mol L-1) seguidas pelas amostras de grapa (mediana de 1.45 x 10-4 mol L-1). Não foi observada a presença de dimetilssulfeto nas amostras de rum analisadas.

A purge and trap concentrator coupled to gas chromatography was used to quantify dimethylsulphide in distilled beverages. A very good performance was obtained using a HP-FFAP column and a mass selective detector operating in SIM mode (m/z 62): detection limit 8 x 10-9 mol L-1; good repeatability and total time of analysis 25 minutes. The method has been applied for sixty samples of alcoholic beverages (cachaças, tiquiras, grappas, whiskies, brandies, vodkas, rum and a tequila). The cachaças exhibit the highest content of dimethylsulphide (median 3.16 x 10-4 mol L-1), followed by grappa (median 1.45 x 10-4 mol L-1). The presence of dimethylsulphide was not observed in the samples of rum.

The quantitative chemical analysis of the Brazilian sugar cane spirit distilled from glass column packaged with copper, stainless steel, aluminum sponge, or porcelain balls is described. The main chemical compounds determined by gas chromatography coupled with flame ionization (FID) and flame photometric (FPD) detectors and liquid chromatography coupled with diode array detector are aldehydes, ketones, carboxylic acids, alcohols, esters and dimethylsulfite (DMS). The spirits produced either in columns filled with copper or aluminum pot still exhibits the lowest DMS contents but the higher sulfate and methanol contents, whereas spirits produced in stainless steel or porcelain showed higher DMS concentration and lower teors of sulfate ion and methanol. These observations are coherent with DMS oxidation to sulfate, with methanol as by product, in the presence of either copper or aluminum.

Utilizando métodos colorimétricos foram investigadas as presenças de íon amônio, uréia e aminoácidos em 51 amostras de aguardente de cana-de-açúcar (cachaça) e em 9 amostras de aguardente de mandioca (tiquira). Foram semelhantes os teores médios de íon amônio determinados para as aguardentes-de-cana (0,013mmoles/L) e de mandioca (0,010mmoles/L). As tiquiras apresentaram teores médios de aminoácidos (0,290mmoles/L) e uréia (1,45mmoles/L) superiores aos da aguardente-de-cana: 0,093mmoles/L e 0,316mmoles/L, respectivamente.

Ammonium ion, urea and amino acids were quantified by using colorimetric methods in 51 samples of sugar cane spirit (cachaça) and 9 samples of cassava spirit (tiquira). The average contents of ammonium ion for sugar cane (0.013mmoles/L) and cassava (0.010mmoles/L) spirits are similar. Tiquiras present average contents of amino acids (0.290mmoles/L) and urea (1.45mmoles/L) higher than in sugar cane, which are 0.093mmoles/L and 0.316mmoles/L, respectively.

A presença de 51 compostos voláteis, entre álcoois e ésteres, em aguardentes de cana (cachaça) foi investigada por cromatografia gasosa de alta resolução. Os seguintes compostos foram identificados e quantificados: metanol, 1,4-butanodiol, álcool 2-feniletílico, álcool amílico, álcool cetílico, álcool cinâmico, n-decanol, geraniol, álcool isoamílico, isobutanol, mentol, n-butanol, n-dodecanol, n-propanol, n-tetradecanol, propionato de amila, acetato de etila, benzoato de etila, heptanoato de etila, valerato de isoamila, propionato de metila, butirato de propila. O teor médio de álcoois superiores (262 mg/ 100 mL de álcool anidro a.a.) e o teor médio de ésteres (24 mg/100 mL a.a.) em cachaças são menores que os encontrados em outros destilados. O teor médio de metanol em cachaças, (6 mg/100 mL a.a.) é o mesmo que o encontrado em rum e menor em relação ao encontrado em destilados de uva. Com relação aos compostos analisados, não foram observadas diferenças significativas no perfil químico qualitativo das cachaças analisadas.

The presence of 51 volatile compounds, among alcohols and esters in Brazilian sugar-cane spirit (cachaça), were investigated by high-resolution gas chromatography (HRGC). The following alcohols and esters were identified and quantified: methanol, 1,4-butanodiol, 2-phenylethyl alcohol, amyl alcohol, cetyl alcohol, cynamic alcohol, n-decanol, geraniol, isoamyl alcohol, isobutanol, menthol, n-butanol, n-dodecanol, n-propanol, n-tetradecanol, amyl propionate, ethyl acetate, ethyl benzoate, ethyl heptanoate, isoamyl valerate, methyl propionate, propyl butyrate. The average higher alcohols content (262 mg/100 mL in anhydrous alcohol a.a.) and total esters content (24 mg/100 mL a.a.) in cachaças, are smaller than in other spirits. The average methanol content in cachaças (6 mg/100 mL a.a.) is the same as in rum, but smaller than in wine spirit. No qualitative differences of chemical profile among cachaças have been observed.