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New monomeric ligands inserted in ruthenium polypyridine complexes generated metallomonomers that were copolymerized with NBE by ROMP resulting in metallopolymers.

Made available in DSpace on 2019-10-04T12:16:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-09-09 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Nickel(II) complexes of Schiff base derived from cycloalkylamines (cycloalkyl = cyclopentyl (cpen), cyclohexyl (chex), and cycloheptyl (chep)) were synthesized: [Ni-II(L-cpen)(2)] (1), [Ni-II(L-chex)(2)] (2), and [Ni-II(L-chep)(2)] (3). The Schiff base-Ni-II complexes 1-3 were characterized by FTIR, UV-Vis, elemental analysis, and computational methods. Electrodeposited films of complexes 1-3 were obtained by potential cycling CH2Cl2 on platinum electrode, and their electrochemical behavior were characterized by cyclic voltammetry. The polymerization of vinyl acetate (VAc) initiated by azobisisobutyronitrile (AIBN) at 55 degrees C were conducted according to an organometallic-mediated radical polymerization (OMRP) mechanism. The best conversions were obtained using a ratio of [VAc]/[AIBN]/[Ni] = 542/3.25/1, reaching 50, 69 and 85% in 12 h for 1, 2 and 3, respectively. The kinetic of polymerization mediated by complex 1 exhibited a linear dependence of ln([VAc](0)/[VAc]) versus time, supporting a constant radical concentration; while for the complexes 2 and 3, the radical concentration was constant for a short period of time. The increase of molecular weights with the conversion coupled with low polydispersities indicate a certain level of control of the polymerization when using the complexes [Ni-II(L (R))(2)] as controlling agents. Univ Estadual Piaui, Ctr Ciencias Nat, BR-64002150 Teresina, PI, Brazil Univ Estadual Paulista, UNESP, Fac Ciencias & Tecnol, BR-19060900 Presidente Prudente, SP, Brazil Univ Fed Uberlandia, Inst Quim, Uberlandia, MG, Brazil Univ Fed Triangulo Mineiro, Dept Quim, Uberaba, Brazil Univ Sao Paulo, Inst Quim Sao Carlos, Sao Carlos, SP, Brazil Univ Estadual Paulista, UNESP, Fac Ciencias & Tecnol, BR-19060900 Presidente Prudente, SP, Brazil FAPESP: 2013/11883-0 FAPESP: 2013/10002-0

Novel dimethyl sulfoxide ruthenium(II) complexes of N-heterocyclic carbenes [RuCl2(S-dmso)2(SIMes)] (1), [RuCl2(S-dmso)2(IMes)], (2) [RuCl2(S-dmso)2(SIDip)] (3), and [RuCl2(S-dmso)2(IDip)] (4) were successfully synthesized. The complexes 1–4 were characterized by elemental analysis, FTIR, UV-Vis, 1H and 13C NMR, and computational studies. The polynorbornene (polyNBE) syntheses via ROMP using the complexes 1–4 as pre-catalysts in the presence of ethyl diazoacetate (EDA) were evaluated under different [EDA]/[Ru] and [NBE]/[Ru] ratios, temperatures (25 and 50 °C) and times (5–60 min). Quantitative yields of polyNBEs using [NBE]/[EDA]/[Ru] = 5000/28/1 for 10 min at 25 °C were obtained. The order of magnitude of 105 g mol−1 for Mn and PDI values ranging from 1.2 to 3.5 were measured by SEC. An investigation combining experimental data and computational calculations was performed to elucidate the mechanism of ROMP of NBE mediated by the complexes 1–4 as pre-catalysts. The proposed mechanism suggests the occurrence of a dissociative reaction of the complexes 1–4, losing a dmso ligand as the first step, resulting in a 14-electron species, which reacts with EDA to form the metal-carbene, followed by discoordination of the second dmso molecule for coordination of NBE.

Made available in DSpace on 2020-12-12T01:16:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-05-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Arene ruthenium(II) complexes bearing the cyclic amines RuCl2(η6-p-cymene)(pyrrolidine)] (1), [RuCl2(η6-p-cymene)(piperidine)] (2), and [RuCl2(η6-p-cymene)(peridroazepine)] (3) were successfully synthesized. Complexes 1–3 were fully characterized by means of Fourier transform infrared, UV–visible, and NMR spectroscopy, elemental analysis, cyclic voltammetry, computational methods, and one of the complexes was further studied by single crystal X-ray crystallography. These compounds were evaluated as catalytic precursors for ring-opening metathesis polymerization (ROMP) of norbornene (NBE) and atom-transfer radical polymerization (ATRP) of methyl methacrylate (MMA). NBE polymerization via ROMP was evaluated using complexes 1–3 as precatalysts in the presence of ethyl diazoacetate (EDA) under different [NBE]/[EDA]/[Ru] ratios, temperatures (25 and 50°C), and reaction times (5–60 min). The highest yields of polyNBE were obtained with [NBE]/[EDA]/[Ru] = 5000/28/1 for 60 min at 50°C. MMA polymerization via ATRP was conducted using 1–3 as catalysts in the presence of ethyl-α-bromoisobutyrate (EBiB) as initiator. The catalytic tests were evaluated as a function of the reaction time using the initial molar ratio of [MMA]/[EBiB]/[Ru] = 1000/2/1 at 95°C. The increase in molecular weight as function of time indicates that complexes 1–3 were able to mediate the MMA polymerization with an acceptable rate and some level of control. Differences in the rate of polymerization were observed in the order 3 > 2 > 1 for the ROMP and ATRP. Faculdade de Ciências e Tecnologia UNESP – Univ. Estadual Paulista Instituto de Química de São Carlos Universidade de São Paulo Instituto de Química Universidade Federal de Uberlândia, P.O. Box 593 Departamento de Química Universidade Federal do Triangulo Mineiro Programa de Pós‐Graduação em Ciências Exatas e Tecnológicas at Universidade Federal de Goiás Faculdade de Ciências e Tecnologia UNESP – Univ. Estadual Paulista FAPESP: 2017/06329-5 FAPESP: 2018/06340-1

Made available in DSpace on 2020-12-12T01:09:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-02-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The synthesis, spectroscopic properties and crystal structure of the novel complex fac-[RuCl2(DMSO-S)3(n-butylamine)] (DMSO-S = sulfur-bonded dimethylsulfoxide) have been reported. The coordination environment of the ruthenium atom is best described as a distorted octahedral, where three DMSO ligands occupy one face of the octahedron, while the two chlorido and the amine ligand occupy the other one. The catalytic activity of fac-[RuCl2(DMSO-S)3(n-butylamine)] was probed in two processes, ring-opening metathesis polymerization (ROMP) and atom-transfer radical polymerization (ATRP). The ROMP of norbornene (NBE) was carried out in the presence of ethyl diazoacetate (EDA) for 5 min at 50 °C which afforded yields around 80%. Poly(norbornadiene) was only produced by photoinduced ROMP leading to 27% yield. The catalytic activity for ATRP of methyl methacrylate (MMA) and styrene (St) for 8 h resulted in 88 and 33%, respectively. Instituto de Química de São Carlos Universidade de São Paulo, 13560-970 Faculdade de Ciências e Tecnologia UNESP – Univ. Estadual Paulista, 19060-900 Departamento de Química Universidade Federal do Triângulo Mineiro, 38025-440 Faculdade de Ciências e Tecnologia UNESP – Univ. Estadual Paulista, 19060-900 FAPESP: 2017/06329-5 FAPESP: 2018/06340-1

Changes in molecular mobility throughout the metathesis copolymerization of a norbornene functionalized with a palm olein monomer and a pure norbornene were monitored in situ by time-domain 1H NMR, using a ruthenium catalyst. Reaction progress to produce branched palm oil-based copolymers was studied as a function of the amounts of monomers and catalyst. Transverse relaxation rates were determined from CPMG experiments and the results were in accordance with the reactivity ratios, which indicated production of gradient copolymers. Properties of the resulting material observed through TD-NMR measurements of the isolated copolymers corroborated the type of the used monomers. TD-NMR demonstrated to be a useful tool for learning copolymerization reactions, particularly in ROMP, for the first time.

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.

Made available in DSpace on 2018-12-11T16:50:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-08-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Ring-opening metathesis polymerization (ROMP) of norbornadiene (NBD) with [RuCl2(PPh3)2(pyrrolidine)] as the starting complex was evaluated as a function of reaction time, solvent volume, and atmosphere type at 25 °C. Quantitative yields of polyNBD were obtained either under inert argon atmosphere or in air, with 2 mL of CHCl3, for 30 min. Copolymerization of NBD with norbornene (NBE) resulted in 100–70% yield under argon, depending on the NBE/NBD molar ratio, and in 70% yield in air, with 2 mL, for 120 min. TGA, DSC, and DMA measurements and swelling tests supported the occurrence of cross-linking in homopolyNBD and in the copolymers isolated from polymers. SEM micrographs showed porous polymeric NBD materials with pores that decreased in size when increasing the amount of NBD in the starting reaction composition. Results from amine parent complexes when the amine was piperidine or perhydroazepine are also discussed, with high cross-linking degree from reaction with the pyrrolidine complex. Instituto de Química de São Carlos Universidade de São Paulo, CP 780 Centro de Ciências da Natureza Universidade Estadual do Piauí Faculdade de Ciências e Tecnologia UNESP Univ Estadual Paulista Faculdade de Ciências e Tecnologia UNESP Univ Estadual Paulista FAPESP: 2011/12571-7 FAPESP: 2012/23948-7

Made available in DSpace on 2018-12-11T16:49:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-11-15 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Ruthenium(II) complexes of Schiff base derived from cycloalkylamines (cycloalkyl = cyclopentyl (1a), cyclohexyl (1b), cycloheptyl (1c), and cyclooctyl) (1d) were synthesized: [RuCl(CyPen-Salen)(PPh3)2] (2a), [RuCl(CyHex-Salen)(PPh3)2] (2b), [RuCl(CyHep-Salen)(PPh3)2] (2c), and [RuCl(CyOct-Salen)(PPh3)2] (2d). The Schiff base-RuII complexes 2a-d were characterized by elemental analysis, FTIR, UV-Vis, 1H-, 13C and 31P NMR, and cyclic voltammetry. The complexes 2a-d were evaluated as catalytic precursors for ROMP of norbornene (NBE) and for ATRP of methyl methacrylate (MMA). The syntheses of polynorbornene (polyNBE) via ROMP with complexes 2a-d as pre-catalysts were evaluated under different reaction conditions ([HCl]/[Ru], [EDA]/[Ru], [NBE]/[Ru], and temperature). The highest yields of polyNBE were obtained with [NBE]/[HCl]/[Ru] = 5000/25/1 M ratio in the presence of 5 μL of EDA for 60 min at 50 °C. MMA polymerization via ATRP was conducted using the complexes 2a-d in the presence of ethyl-α-bromoisobutyrate (EBiB) as initiator. The catalytic tests were evaluated as a function of the reaction time using the initial molar ratio of [MMA]/[EBiB]/[Ru] = 1000/2/1 at 85 °C. The linear correlation of ln([MMA]0/[MMA]) and time indicates that the concentration of radicals remains constant during the polymerization and that the ATRP of MMA mediated by 2a-d proceeds in a controlled manner. Molecular weights increased linearly with conversion, however, the experimental molecular weights were higher than the theoretical ones. Faculdade de Ciências e Tecnologia UNESP Univ Estadual Paulista Instituto de Química de São Carlos Universidade de São Paulo Instituto de Química UFU Universidade Federal de Uberlândia Faculdade de Ciências e Tecnologia UNESP Univ Estadual Paulista FAPESP: 2013/10002-0

Made available in DSpace on 2018-11-26T15:44:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-05-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The novel, non-carbene complex -[RuCl2(PPh3) (2)(azocane)] (1) of trigonal bipyramid geometry was synthesized, characterized (CHN elementary analysis, FTIR, EPR, and 31P NMR), and applied as catalyst precursor for ring opening metathesis polymerization (ROMP) and atom transfer radical polymerization (ATRP). ROMP of norbornene (NBE) resulted in 70% yield at 50 degrees C in 60 min, with [NBE]/[1] = 5000, and 15% yield from ROMP of norbornadiene was obtained under the same conditions. ATRP of methyl methacrylate (MMA) resulted in ca. 20% conversion at 85 degrees C in 9 h, with [MMA]/[1] = 1000, and increased to ca. 50% in the presence of Al(OiPr) (3), with narrower PDI values. With [MMA]/[1] = 200, ca. 50% yield was obtained at 85 degrees C in 6 h either in the absence or presence of Al(OiPr) (3). ATRP of styrene resulted in 9 and 16% conversion at 110 degrees C in 7 h in the absence or presence of Al(OiPr) (3), respectively, with [St]/[1] = 1000. Results are discussed considering the five-coordinated molecular geometry of the starting complex and the arrangements required in ROMP and ATRP to initiate the reactions. Univ Estadual Paulista, Fac Ciencias & Tecnol, BR-19060900 Presidente Prudente, SP, Brazil Univ Sao Paulo, Inst Quim Sao Carlos, BR-13560970 Sao Carlos, SP, Brazil Univ Estadual Piaui, Ctr Ciencias Nat, BR-64002150 Teresina, PI, Brazil Univ Estadual Paulista, Fac Ciencias & Tecnol, BR-19060900 Presidente Prudente, SP, Brazil FAPESP: 2013/10002-0 FAPESP: 2011/12571-7 FAPESP: 06/57577-4

Made available in DSpace on 2018-11-26T15:37:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-02-24 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Prope The catalytic activity of the five-coordinated [RuCl2(PPh3)(S-dmso)(2)] complex was investigated for ring opening metathesis polymerization (ROMP) of norbornene (NBE) and for atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA). Syntheses via ROMP of polyNBE were dependent on the ethyl diazoacetate (EDA) amount, used as starting carbene source, monomer concentration, temperature, and reaction time. The best polyNBE yields were obtained at 50 degrees C for 120 min with [NBE]/[Ru] = 5000 in presence of 5 mu L of EDA. MMA polymerization via ATRP was conducted as a function of time with different ethyl 2-bromoisobutyrate initiator and monomer concentrations. The kinetic data for ATRP show linear increase between MMA conversion and molecular weight. Kinetic studies with the six-coordinated [RuCl2(S-dmso)(3)(O-dmso)] complex also showed an increase in the molecular weight with conversion, but with a marked deviation from theoretical molecular weights. This is consistent with the better control in the polymerization supported by electronic and steric properties of the PPh3 ligand in the title complex (C) 2016 Elsevier B.V. All rights reserved. Univ Estadual Paulista, Fac Ciencias & Tecnol, BR-19060900 Presidente Prudente, SP, Brazil Univ Sao Paulo, Inst Quim Sao Carlos, BR-13560970 Sao Carlos, SP, Brazil Univ Estadual Paulista, Fac Ciencias & Tecnol, BR-19060900 Presidente Prudente, SP, Brazil FAPESP: 2013/10002-0 Prope: 2180/002/14-PROPe/CDC

Made available in DSpace on 2020-12-12T00:58:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-11-10 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The complex cis,fac-[RuCl2(DMSO–O)(DMSO–S)3] [1] reacted with aniline (NH2Ph) under reflux to produce the complex trans,cis,cis-[RuCl2(DMSO–S)2(NH2Ph)2] [2], whereas at room temperature the resulting complex was cis,fac-[RuCl2(DMSO–S)3(NH2Ph)] [3]. The complexes were characterized by FTIR, EPR, 1H and 13C NMR, electronic spectra, and the crystal structure of 2 was determined by single X-ray crystallography. The influence of NH2Ph and DMSO as ancillary ligands in the new complexes was then evaluated for ring-opening metathesis polymerization (ROMP) of norbornene (NBE), norbornadiene (NBD), and dicyclopentadiene (DCPD) in presence of ethyl diazoacetate (EDA) with different [monomer]/[Ru] molar ratios. Homopolymers of NBE with molecular weights in the order of magnitude of 105 g.mol–1 and insoluble polymers in CHCl3 from NBD and DCPD were obtained in different yields depending of the starting complex, reaction time (5 and 30 min), and temperature (25 and 50 °C). Valorous results were obtained for polyNBD, polyDCPD, and copolymerizations from NBE with NBD or DCPD using the new complexes, affording higher yields than with 1. In conclusion, beneficial effects are observed when DMSO and the weak σ-donor NH2Ph ligands are arranged in the same coordination sphere of Ru(II) pre-catalysts for ROMP. Instituto de Química de São Carlos Universidade de São Paulo Departamento de Química Universidade Federal do Triângulo Mineiro Faculdade de Ciências e Tecnologia UNESP Univ. Estadual Paulista Faculdade de Ciências e Tecnologia UNESP Univ. Estadual Paulista FAPESP: 2017/06329-5 FAPESP: 2018/06340-1

Made available in DSpace on 2019-10-04T12:15:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-10-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Two novel monomers, norbornenyl buriti olein (NBO) and norbornenyl buriti ester (NB-FAME), were synthesized by reactions of 5-norbornene-2-carboxylic acid with triglycerides and with methyl esters from buriti oil, respectively. No polymers were produced via ROMP of NBO or NB-FAME using Grubbs second-generation catalyst at 30 degrees C for 1 h. However, copolymers of NBO or NB-FAME in the presence of norbornene (NBE) were obtained raising the initial compositions of the buriti oil-derived monomers from 20 to 80%, under the same conditions. The polymers were insoluble in water and typical organic solvents. In chloroform at 30 degrees C for 48 h, the polymers from synthesis with 80 wt% of buriti oil-derived monomers resulted in a mass gain of 1709% for polymer from NBO and 929 wt% for polymer from NB-FAME. SEM micrographs showed smooth morphologies and non-porous surfaces, which differ from the porous polyNBE. TGA analyses indicated thermal stability up to 200 degrees C. The poly(NBO-co-NBE) and poly(NB-FAME-co-NBE) have been proved to be the final products. Univ Sao Paulo, Inst Quim Sao Carlos, CP 780, BR-13560970 Sao Carlos, SP, Brazil Univ Estadual Piaui, Ctr Ciencias Nat, BR-64002150 Teresina, PI, Brazil Univ Estadual Paulista, Fac Ciencias & Tecnol, BR-19060900 Presidente Prudente, SP, Brazil Univ Estadual Paulista, Fac Ciencias & Tecnol, BR-19060900 Presidente Prudente, SP, Brazil FAPESP: 2017/06329-5

Made available in DSpace on 2018-12-11T16:52:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-04-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Dimethyl sulfoxide ruthenium(II) complexes of N-heterocyclic carbenes derived from cycloalkylamines (cycloalkyl = cyclopentyl (1a), cyclohexyl (1b), cycloheptyl (1c), and cyclooctyl (1d)) were synthesized: [RuCl2(S-dmso)2(IPent)] (2a), [RuCl2(S-dmso)2(IHex)] (2b), [RuCl2(S-dmso)2(IHept)] (2c), and [RuCl2(S-dmso)2(IOct)] (2d). The imidazolium salts 1a-1d were characterized by FTIR, UV–vis, and 1H and 13C NMR spectroscopy, while their respective dimethyl sulfoxide ruthenium(II) complexes (2a-2d) were characterized by elemental analysis, FTIR, UV–vis, 1H and 13C NMR, and cyclic voltammetry. The complexes 2a-2d were evaluated as catalytic precursors for ROMP of norbornene (NBE) and for ATRP of methyl methacrylate (MMA). The polynorbornene (polyNBE) syntheses via ROMP using the complexes 2a-2d as pre-catalysts were evaluated under reaction conditions of [EDA]/[Ru] = 28 (5 μL), [NBE]/[Ru] = 5000 at 50 °C as a function of time. The polymerization of MMA via ATRP was conducted using the complexes 2a-2d in the presence of ethyl 2-bromoisobutyrate (EBiB) as the initiator. All tests were using the molar ratio [MMA]/[EBiB]/[Ru] = 1000/2/1 and conducted at 85 °C. The linear correlation of ln([MMA]0/[MMA]) and time clearly indicates that the concentration of radicals remains constant during the polymerization and that the ATRP of MMA mediated by 2a-2d proceeds in a controlled manner. Faculdade de Ciências e Tecnologia UNESP Univ Estadual Paulista, CEP 19060-900 Instituto de Química de São Carlos Universidade de São Paulo, CEP 13560-970 Instituto de Química UFU Universidade Federal de Uberlândia, CEP 38400-902 Faculdade de Ciências e Tecnologia UNESP Univ Estadual Paulista, CEP 19060-900

This investigation combines theoretical results and experimental data to elucidate the main kinetic and mechanism for the ring opening metathesis polymerization of norbornene by means of the [RuCl2(PPh3)2(piperidine)] complex as catalyst initiator. Structural species were defined and a kinetic profile of the entire reaction is depicted. The determined mechanism showed an associative reaction between the [RuCl2(PPh3)2(piperidine)] complex initiator and ethyl diazoacetate as the first step, resulting in a metal-carbene species. This species loses one triphenylphosphine molecule (PPh3) and the global rate-determining step is associated with a removal of the second PPh3 molecule due to an electronic trans-synergism between piperidine and this PPh3 molecule. Entropic factors are crucial to the spontaneity observed for the dissociation of both PPh3 ligands. The step following the rate-determining one is associated with the binding of a norbornene molecule and a similar trans-synergism between this monomer and piperidine activates the catalysis. This electronic effect maintains the system in a very important conformation along the catalytic chain.

Olefin metathesis of ethyl linoleate (EL) was investigated under different conditions of substrate amount, temperature, and catalyst. Second-generation Grubbs catalyst (G2) was used in experiments at 20 and 50 ºC for 24 and 48h, whereas first-generation Grubbs catalyst (G1) and [RuCl2(PPh3)2perhydroazepine] (LN) were used in experiments at 50 ºC for 24h, with the latter also being investigated in the presence or absence of SnCl2 as co-catalyst. Catalytic products were analyzed for GC-MS and discussed in terms of relative percent of the metathesis products. With G2 as catalyst, GC-MS chromatograms were similar in all the amounts of EL investigated at 50 ºC for 24h, except for ethyl hexadec-9-enoate (compound K), which was obtained with different percentage as a function of EL amount (55% for 2 and 5 mL and 65% for 8 mL). An α,ω-dicarboxylic acid with m/z = 444.00 (compound L) was produced from the experiments at 50 ºC for 24h with similar percentage as a function of EL amount. However, the relative percentage of L changed with the increase of EL volume in the experiments at 20 ºC (ca. 18, 27, and 28%, with 2, 5, and 8 mL of EL, respectively). The olefin metathesis of EL conducted by G1 reached lower selectivity than that conducted by G2 for 24h at 50 ºC. Several intense peaks reached with G1 were similar to those obtained with G2, in addition to new peaks of medium intensity. Compound L showed higher m/z, similar to that presented with G2, but with lower relative proportion in the mixture. LN was inert for olefin metathesis of EL; however, it was activated in the presence of SnCl2 at 50 ºC for 24h. Different compounds and selectivity as a function of the catalyst type and reaction conditions were obtained.

This work describes the use of the ATR-FTIR technique to investigate the ring-opening metathesis polymerization (ROMP) of norbornene with amine-based Ru complexes of type [RuCl2(PPh3)2(amine)]. Polymerization rates (RP) were determined by monitoring the appearance of the polymer absorption band at 970 cm−1 (trans-CH=CH) or the disappearance of the monomer absorption band at 1336 cm−1 (cis-CH=CH). The results revealed that the amines, as ancillary ligands (pyrrolidine, piperidine, and peridroazepine), present an effective contribution to the polymerization rate (Rp).

Made available in DSpace on 2018-12-11T16:50:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-10-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Atom transfer radical polymerizations (ATRP) of styrene (St) and methyl methacrylate (MMA) mediated by [RuCl2(PPh3)2(amine)] complexes, with amine = pyrrolidine (1), piperidine (2), or perhydroazepine (3), were investigated as a function of time, temperature, and concentrations of monomers and 2-bromoisobutyrate as initiator. The plots of ln([M]0/[M]) vs. time and molecular weights vs. monomer conversion were linear and the dispersity indexes decreased with increasing monomer conversions. The complexes 1, 2, and 3 were able to mediate the polymerizations with acceptable rate and level of control. Differences in the rate and control of polymerization were observed in the order 3 > 2 > 1 for both monomers. The activities were discussed considering the steric hindrance and electronic characteristics of the amines as ancillary ligands in the metal centres, considering studies by cyclic voltammetry and NMR. Faculdade de Ciências e Tecnologia UNESP Univ Estadual Paulista Instituto de Química de São Carlos Universidade de São Paulo Centro de Ciências da Natureza Universidade Estadual do Piauí Faculdade de Ciências e Tecnologia UNESP Univ Estadual Paulista FAPESP: 2013/10002-0

Made available in DSpace on 2022-04-28T18:59:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-07-01 [RuCl2(S-DMSO)2(X-py)2] type complexes, with X = H (1), 4-CONH2 (2), or 3-CONH2 (3), exhibited trans,cis,cis conformational isomer (species A), with additional cis,cis,cis isomer type (species B) for 1. Electronic spectra with bands in the wavelength range of 270-450 nm were unchanged for 120 min at 25 °C in CH3CN. Irradiation at 350 nm provided replacement of DMSO ligands by CH3CN solvent molecules. Cyclic voltammetry studies in CH3CN revealed an electrochemical-chemical process with a Ru-(S-DMSO) to Ru-(O-DMSO) linkage isomerization for species B from 1. The complexes were inactive for the ring-opening metathesis polymerization (ROMP) of norbornene (NBE) for 60 min at 25°C. However, polyNBE was produced by aging the complex solutions for 90-200 min at 25°C, raising the temperature to 50°C, irradiating the solutions at 350 nm for 5-10 min or when the complexes were in the presence of NBu4ClO4. © 2014 Elsevier B.V. All rights reserved. Instituto de Química de São Carlos Universidade de São Paulo, P.O. Box 780, 13560-970 São Carlos, SP Faculdade de Ciencias e Tecnologia Universidade Estadual Paulista, 19060-900 Presidente Prudente, SP Faculdade de Ciencias e Tecnologia Universidade Estadual Paulista, 19060-900 Presidente Prudente, SP

Made available in DSpace on 2019-10-06T15:52:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-12-15 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) A series of [RuCl(dppb)(μ-Cl)3Ru(dppb)(amine)] complexes, where amine is pyrrolidine (1), piperidine (2) or perhydroazepine (3), were synthesized and characterized by elemental analysis, FTIR, UV–Vis, and 1H, 13C{1H} and 31P{1H} NMR spectroscopy. The electrochemistry properties of the complexes 1–3 were investigated by cyclic voltammetry and exhibited two successive single-electron oxidation processes. The presence of two redox pairs suggests the formation of a dimeric species in which two different fragments, {Ru(amine)(dppb)} and {RuCl(dppb)}, were connected via three μ-chloro bridges. The complexes 1–3 were evaluated as catalytic precursors for ROMP of norbornene (NBE) and norbornadiene (NBD), as well as for ATRP of methyl methacrylate (MMA). The polynorbornene (polyNBE) syntheses via ROMP using the complexes 1–3 as pre-catalysts were assessed under reaction conditions of [EDA]/[Ru] = 28 (5 μL) and [NBE]/[Ru] = 5000 as a function of time at 25 or 50 °C. Polymerization of MMA via ATRP was conducted using the complexes 1–3 in the presence of ethyl 2-bromoisobutyrate (EBiB) as initiator. Differences in the catalytic activities and polymerization controls were observed in the order 3 > 2 > 1 for both reactions. The activities were discussed considering the steric hindrance and electronic characteristics of the amines as ancillary ligands in the metal center using cyclic voltammetry and NMR studies. Faculdade de Ciências e Tecnologia UNESP Univ Estadual Paulista Instituto de Química de São Carlos Universidade de São Paulo Instituto de Química Universidade Federal de Uberlândia, P.O. Box 593 Instituto de Ciências Exatas e Naturais Do Pontal Universidade Federal de Uberlândia, Rua Vinte, 1600 Faculdade de Ciências e Tecnologia UNESP Univ Estadual Paulista CAPES: 001 FAPESP: 2017/06329-5 FAPESP: 2018/06340-1

This chapter provides an overview on new polyester materials from plant oil. In recent years, industrial and academic research teams have been strongly involved in replacing conventional polyesters from petroleum-based material with biodegradable ones. The goal is to design good performance materials that, after use, could be susceptible to microbial and environmental degradation, using adequate solid waste management disposal practices without any adverse environmental impact. It is necessary to develop new routes to enhance the properties of biodegradable polymers. In fact, polyesters are considered the most competitive biodegradable polymers commercialized so far. Unsaturated polyester resins (UPRs) incorporated with plant oil are interesting materials because of their high modulus, strength, durability, and thermal and chemical resistance, which are provided by high cross-linking density.

A novel monomer norbornene palm olein (NPO) was isolated from reaction of 5-norbornene-2-carboxylic acid with triglycerides from red palm olein, with one norbornene (NBE) unit per NPO. No polymer from ROMP of NPO with a 2nd generation Grubbs catalyst was produced. ROMP of NPO in the presence of free NBE at 30 °C with different amounts of each monomer resulted in products with different physical states. Viscous liquids, soft solids, and cracked solids resulted from reactions with 90%, 80–40%, and 20% NPO, respectively. The soft solids were insoluble in water, acetic acid, and typical organic solvents. Swelling experiments in slightly polar organic solvents resulted in a mass gain of up to 800%, as in chloroform at 30 °C for 48 h. SEM micrographic images showed non-porous materials, and TGA analyses indicated thermal stability up to 300 °C. A poly(NPO-co-NBE) type has been suggested as the resulting product.

The [RuCl3(PCy3)2] complex presented high reactivity toward ring opening metathesis polymerization (ROMP) of norbornadiene (NBD) in a non-degassed solution upon addition of ethyl diazoacetate (EDA). Quantitative yields of polyNBD were obtained instantaneously at 25 °C. ROMP of norbornene (NBE) occurred better at 50 °C for 60 min, with 95% of isolated polyNBE. Copolymers with different porous structures were obtained from ROMP of NBE in the presence of NBD with different starting [NBE]/[NBD] molar ratios at 25 °C. SEM micrographs showed a more organized porous structure as the NBD loading decreased. A well-defined honeycomb-like pattern was recorded for the copolymer from the run with an NBE : NBD molar ratio load of 5000 : 500. The Tg values varied from 37 °C in polyNBE to 90 °C in poly[NBE-co-NBD] as the NBD loading increased.

Copolymers from norbornene (NBE) with norbornadiene (NBD) were synthesized via ring opening metathesis copolymerization varying the mole fractions of the comonomers (0.8 : 0.2; 0.6 : 0.4; 0.4 : 0.6; 0.2 : 0.8) for a total monomer quantity of 5000 equivalents/[Ru]. The batch reactions were performed with [RuCl2(PPh3)2(amine)] complex types as precatalysts, where amine is perhydroazepine (1) or piperidine (2), in CHCl3 (2 mL) in the presence of ethyl diazoacetate (5 μL) for different intervals of times (5, 30, 60, and 120 min) at 40°C. The copolymers were characterized by 13C NMR. Quantitative yields of isolated materials were obtained from solutions with NBD : NBE 0.8 : 0.2 mole fraction in the presence of 1, decreasing to 70% for NBD : NBE 0.2 : 0.8 solutions. Concerning 2, the yields were 70% at most. Polymeric materials obtained with 1 were less soluble in CHCl3 than those synthesized with 2. The dependence of the reaction yields and occurrence of crosslinking on the starting NBE : NBD proportion related to reactivity of the complexes 1 and 2 were discussed. A few differences in the amines such as ancillary ligands were sufficient to change the reactivity of the {RuCl2(PPh3)} moiety complex to provide copolymers with different compositions. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

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.

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 concerning the steric hindrance and the electronic perturbation in the properties of the N-bound site when replacing the amines. Thus, the results with 1 were compared to the results obtained when the amine is piperidine (complex 2). Reaction with 1 provides 70% yield of isolated polyNBE (Mn = 8.3 × 104 g/mol; PDI = 2.03), whereas 2 provides quantitative reaction (Mn = 1.2 × 105 g/mol; PDI = 1.90) with [NBE]/[Ru] = 5000, [EDA]/[Ru] = 48 and 1.1 μmol of Ru for 5 min at 25 °C. The resulting polymers showed c.a. 62% of trans-polyNBE, determined by 1H NMR, and Tg = 32 °C, determined by DSC and DMTA. For ROMP of NBD, 1 showed quantitative yield with PDI = 2.62 when [NBD]/[Ru] = 5000 for 20 min at 25 °C, whereas the reaction with 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 2, and a greater amine ⟶ σ Ru ⟶ π monomer synergism which contributed to the best activation of less tensioned olefin as NBD.

The presence of paramagnetic species in the aqueous ring opening metathesis polymerizations of the exo,exo-7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid monomer with RuCl3 and K2[RuCl5H2O] compounds was studied using ESR techniques. It was observed that the intensities of the RuIII signals in the ESR spectra decrease on the time scale of the induction period so that the ROMP can take place. The intensity of the RuIII signal almost disappeared 50 min after reacting with K2[RuCl5H2O] and after 100 min in the case of RuCl3. Reactions of the cis-[Ru(NH3)4(H2O)2](tfms)3 and [Ru(NH3)5H2O](tfms)3 complexes with the monomer and different organic compounds representing the organic functions in the monomer (furan, norbornene, but-2-ene-1,4-diol and formic, acetic, oxalic and maleic acids) were also monitored by ESR and UV/vis spectra. It was deduced that the organic acids provide the disappearance of the RuIII signal. The proton NMR relaxation times of the residual water in D2O for reactions with oxalic acid suggested that the presence of paramagnetic ions in the solution decreases along with the disappearance of the ESR signal for RuIII. It was suggested that diamagnetic Ru species were indeed produced in the medium.

Polynorbornadiene and polynorbornene were synthesized via ring opening metathesis polymerization (ROMP) with [RuCl 2 (PPh 3 ) 2 (amine)] as catalyst precursors, amine = piperidine ( 1 ) or perhydroazepine ( 2 ) in the presence of 5 μL of ethyl diazoacetate (EDA) ([monomer]/[Ru] = 5000; 40 °C with 1 ; 25 °C with 2 ). The effects of the solvent volume (2–8 mL of CHCl 3 ), reaction time (5–120 min) and atmosphere type (argon and air) on the yields were investigated to observe the behavior of the two different precursors. Quantitative yields were obtained for 60 or 120 min regardless of the starting volumes, either in argon or air, with both Ru species. However, low yields were obtained for short times (5–30 min) when the reactions are performed with large volumes (6–8 mL). In argon, the yields were larger with 2 , associated to a faster propagation reaction controlled by the Ru active species. In air, the yields were larger with 1 , associated to a higher resistance to O 2 of the starting and propagating Ru species. The different activities between 1 and 2 are discussed considering the steric hindrance and electronic characteristics of the amines such as ancillary ligands and their arrangements with PPh 3 and Cl − ions in the metal centers.

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. 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.

Cu(II) ions previously coordinated with typical electroplating organic additives were investigated as an alternative source of metal for plating bath. The coordination complexes were isolated from reaction between CuSO 4 and organic additives as ligands (oxalate ion, ethylenediamine or imidazole). Deposits over 1010 steel were successfully obtained from electroplated baths using the complexes without any addition of free additives, at pH = 4.5 (H 2 SO 4 /Na 2 SO 4 ). These deposits showed better morphologies than deposits obtained from CuSO 4 solution either in the absence or presence of oxalate ion as additive (40 mmol L − 1 ), at pH = 4.5 (H 2 SO 4 /Na 2 SO 4 ). It is suggestive that the starting metal plating coordinated with additives influences the electrodeposition processes, providing deposits with corrosion potentials shifted over + 200 mV in 0.5 mol L − 1 NaCl (1 mV s − 1 ). The resistance against corrosion is sensitive to the type of additive-complex used as precursor. The complex with ethylenediamine presented the best deposit results with the lowest pitting potential (− 0.27 V vs 3.0 mol L − 1 CE). It was concluded that the addition of free additives to the electrodeposition baths is not necessary when working with previously coordinated additives. Thus, the complexes generated in ex-situ are good alternatives as plating precursors for electrodeposition bath.

Polynorbonerne with high molecular weight was obtained via ring opening metathesis polymerization using catalysts derived from [RuCl2(PPh2Bz)2L] (1 for L = PPh2Bz; 2 for L = piperidine) type of complexes when in the presence of ethyl diazoacetate in CHCl3. The polymer precipitated within a few minutes at 50 °C when using 1 with ca. 50% yield ([NBE]/[Ru] = 5000). Regarding 2, for either 30 min at 25 °C or 5 min at 50 °C, more than 90% of yields are obtained; and at 50 °C for 30 min a quantitative yield is obtained. The yield and PDI values are sensitive to the [NBE]/[Ru] ratio. The reaction of 1 with either isonicotinamide or nicotinamide produces six-coordinated complexes of [RuCl2(PPh2Bz)2(L)2] type, which are almost inactive and produce only small amounts of polymers at 50 °C for 30 min. Thus, we concluded that the novel complexes show very distinct reactivities for ROMP of NBE. This has been rationalized on account of a combination of synergistic effects of the phosphine–amine ancillary ligands.

This paper presents the synthesis, MO calculations, and photochemical and photophysical properties of cis-[Ru(bpy)2(3Amdpy2oxaNBE)](PF6)2 (2), where bpy is 2,2'-bipyridine and 3Amdpy2oxaNBE is the novel 5,6-bis(3-amidopyridine)-7-oxanorbornene chelate-ligand (1). Complex 2 is considered in relation to the cis-[Ru(bpy)2(3Amnpy)2](PF6)2 (3) analogous complex, where 3Amnpy is 3-aminopyridine. Complexes 2 and 3 exhibit absorptions near 350 nm and in the 420-500 nm region attributable to a contribution from MLCT transitions (dpi-->bpy and dpi-->L; L=3Amdpy2oxaNBE or 3Amnpy). Whereas complex 3 is photochemically reactive, complex 2 shows luminescence either at 77 K or at room temperature in fluid solution. The emission of 2 assignable as an MLCT (Ru-->bpy) emission is characterized by a long lifetime at room temperature (650 ns in CH3CN and 509 ns in H2O). It is independent of lambdairr, but it is temperature dependent; i.e., it increases as the temperature is lowered. Considering the chelate ring of 1 contributes to the stability of the complex 2 under continuous light irradiation, the difference in the primary photoprocesses of 3 (loss of 3Amnpy) and 2 (luminescence) may be caused by a lowering of the lowest excited state from 3 to 2. The surface crossing to the lowest MC state value of 987 cm-1 (similar to that of [Ru(bpy)3]2+) will be prevented in the case of complex 2, and as a result, efficient 3Amdpy moiety loss cannot occur. The electronic depopulation of the {Ru(bpy)2} unit and population of a bpy* orbital upon excitation are evident by comparing the photophysical properties with those of a [Ru(bpy)3]2+ related complex. Moreover, a reduction of a bpy ligand in the MLCT excited state is indicated by time-resolved spectra that show features typical of bpy*-. The photocatalytic property of 2 is spectroscopically demonstrated by oxidative quenching using either methylviologen2+ or [RuCl(NH3)5]+2 electron-acceptor ions.

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.

The novel complex [RuCl2(PPh3)2(pyrrolidine)] exhibited a square pyramidal (SQP) type geometry, with the amine in the apical position and trans-positioned phosphines. There was activity observed for ROMP of norbornene (NBE) either under air or an inert atmosphere of argon at 25 °C. Saturation profile-fitting describes the curves of yields as a function of time (5–120 min) under either atmosphere. The results were sensitive to the solution volume in the range of 2–8 mL of CHCl3, mainly under air. Quantitative yields under argon for 120 min at any solution volume were obtained. The order of magnitude of 103–105 g mol−1 for Mw and PDI values ranging from 1.6 to 3.5 was measured by SEC. In most of the cases, the ratios of yields from the runs under argon and air were close to the unit, indicating an insignificant loss of reactivity of the active species in the presence of molecular oxygen from air. A parent complex with diethylamine, but with trigonal bipyramidal (TBP) type geometry, was inactive for ROMP. The activity in these types of complexes was compared with that of already reported Ru-amine-based complexes in terms of electronic effects, with an additional discussion involving the synergism in the novel ttt-[RuCl2(PPh3)2(perhydroazepine)(isonicotinamide)] complex.

Complexes of the type [RuCl 2 (PPh3)2(N III ) 2 ], where N III = 4-X-pyridines [X = C(O)NH2(isonicotinamide), H (pyridine), CH 3 (4-picoline) or NH 2 (4-amino-pyridine)] were investigated for catalysis of norbomene via ring-opening metathesis polymerization (ROMP). The results show that the yields are greater than 70% in CHCl 3 when [NBE]/[Ru] = 3000 (M n ∼ 10 4 to 10 5 and M w /M n ∼ 1.2-2.0) at 50 ± 1 °C for 5 min. Considering the complex with isonicotinamide under similar conditions but for [NBE]/[Ru] = 5000, the yield reaches 94% of isolated polymer with M w /M n = 1.2. The behavior of the amine complexes were observed by 31 P{ 1 H} and 1 H NMR analyses leading to the conclusion that a five-coordinated diamine-monophosphine complex is the active initiator. This 16-electron complex becomes inert when N III is a good σ-donor ligand, such as pyridine, 4-picoline or 4-amino-pyridine. Consequently, there is a decrease in catalytic activity since the subsequent step represents the exit of an amine ligand in order that the ROMP reaction can occur successfully.

Spectroscopic (IR, 31P NMR and UV–Vis) and electrochemical studies on fac-[Mn(CO)3(L′–L′)(L)]0/+,where L′–L′ = 1,2-bis(diphenylphosphino)ethane (dppe) or 1,10-phenanthroline (phen) and L = bromide, triflate, imidazole (im), isonicotinamide (isn) or N-(2-hydroxyethyl)isonicotinamide (heisn), were undertaken to understand the effect of various ligands on the CO–Mn–L and CO–Mn–(L′–L′) bonding characteristics of these complexes. Crystal structures for L = triflate/L′–L′ = dppe, L = triflate/L′–L′ = phen and L = isn/L′–L′ = phen are reported and they show that the two Mn–O(OSO2CF3) and Mn–N(isn) distances are similar. The tricarbonyl complexes exhibit two major bands in the 250–300 and 350–450 nm region of the UV–Vis spectrum. The lowest energy bands have been assigned as a contribution from both the metal-centered (MC) and metal to ligand (dπ → L′–L′) charge transfer (MLCT) transitions. The energy of this maximum absorption decreases in the order Br− ∼ triflate > im > isn ∼ heisn. The cyclic four-component mechanism fac - Mn ( I ) → - e fac - Mn ( II ) → mer - Mn ( II ) → + e mer - Mn ( I ) → fac - Mn ( I ) was observed at room temperature by voltammetric techniques for all the cases. On the basis of d metal orbital splitting, an electronic molecular orbital diagram is proposed. In this model, the ligands along the z-axis play a relevant role in the reverse of the HOMO energies of the fac/mer isomers by stabilizing the metal d z 2 orbital relative to dxy in mer-Mn(II).

Reaction between [RuCl 2 (PPh 3 ) 3 ] and piperidine (pip) gives the novel [RuCl 2 (PPh 3 ) 2 (pip)] complex, which quantitatively polymerizes norbornene (NBE) via ring opening metathesis polymerization for less than 1 min at RT, in the presence of 5 μL of ethydiazoacetate. An M w / M n value of 1.05 is obtained if amounts of norbornene are added in several batches up to the [NBE]/[Ru] = 5.000. Norbornadiene is polymerized with 48% yield for 5 min at RT. The precursor complex gives only 63% of polynorbornene and 6% of polynorbornadiene for 5 min at 50 °C. 31 P{ 1 H} NMR analyses indicate that the new complex does not undergo dimerization in solution as it occurs in the case of the precursor complex. It is proposed that the presence of the piperidine is appropriated in enhancing the rate of reaction and controlling the ruthenium metathesis catalysis via a highly active five-coordinated mononuclear Ru(II) complex.

The differentiation between cachaca and rum using analytical data referred to alcohols (methanol, propanol, isobutanol, and isopentanol), acetaldehyde, ethyl acetate, organic acids (octanoic acid, decanoic acid, and dodecanoic acid), metals (Al, Ca, Co, Cu, Cr, Fe, Mg, Mn, Ni, Na, and Zn), and polyphenols (protocatechuic acid, sinapaldehyde, syringaldehyde, ellagic acid, syringic acid, gallic acid, (-)-epicatechin, vanillic acid, vanillin, p-coumaric acid, coniferaldehyde, coniferyl alcohol, kaempferol, and quercetin) is described. The organic and metal analyte contents were determined in 18 cachaca and 21 rum samples using chromatographic methods (GC-MS, GC-FID, and HPLC-UV-vis) and inductively coupled plasma atomic emission spectrometry, respectively. The analytical data of the above compounds, when treated by principal component analysis, hierarchical cluster analysis, discriminant analysis, and K-nearest neighbor analysis, provide a very good discrimination between the two classes of beverages.

The catalyst precursor trans-[RuCl2(dppe)2] has been synthesized by solid state reaction of RuCl3 · 3H2O with tetrabutylammonium chloride (TBAC) and subsequent coordination with 1,2-bis-(diphenylphosphine)ethane (dppe) in dichlromethane solution. Reaction time, yield, work up and cleanness were improved by this method when compared with classical procedures. Use of tetrabutylammonium bromide (TBAB) as catalyst has afforded a novel trans-[RuBrCl(dppe)2] whose crystal structure was analyzed.

Using high-performance liquid chromatography (HPLC) and 2,4-dinitrophenylhydrazine as a derivatizing reagent, an analytical method has been developed for the analysis of ketones in hydro-alcoholic matrices, colored or not. The determination is carried out at 365 nm using a UV–Vis diode-array detector (DAD). For the ketones as their 2,4-dinitrophenylhydrazones, a good separation was achieved with a Supelco C18 column (25 cm×4.6 mm×5 μm) using a (methanol/acetonitrile)-water elution gradient. The methodology is simple, rapid, exhibits good reproducibility, and allows the analysis of both ketones and aldehydes in the same run. The application of this method to 34 sugar-cane spirits and 13 rums allowed the identification and quantification of acetone, acetophenone, cyclopentanone and 2,3-butanedione, at detection limits of 10 μg/l (2,3-butanedione) to 20 μg/l (cyclopentanone).

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.

The presence of ethyl carbamate in cachacas, tiquiras, whiskies and grapes was investigated by GC-MS, monitoring the m/z 62 ion. The external standard method was used for quantitation in 188 samples (126 cachacas, 37 tiquiras, 6 grappas and 19 whiskies). The results of the study for cachaca were analysed considering the geographic origin, distillation type (still or column), bottle coloration (amber or transparent) and ageing. The average contents of ethyl carbamate in cachacas and tiquiras were 0.77 and 2.4 mg L-1, respectively. These values were higher than the mean concentration found in grapes (0.045 mg L-1) and whiskies (0.14 mg L-1). On average the cachacas distilled in column tend to present higher values of ethyl carbamate than those from still. In the sampling studied it was not possible to define a correlation between content of ethyl carbamate, bottle coloration and ageing time.

The electrodeposition of copper onto AISI 1010 steel using an alkaline electrolyte based on glycerol has been studied. The influence of NaOH concentration and the addition of sulfate as supporting electrolyte were investigated by voltammetric techniques. For a NaOH concentration ≥ 0.6 M the plating bath was stable and immersion deposition onto steel was avoided. Voltammetric studies and SEM analysis indicated that the reduction process occurs through two different copper(II) species. The copper films were golden in colour, even in the high hydrogen evolution region, indicating that glycerinate anions prevent the copper deposits becoming darker. The presence of the sulfate anions affected the morphology of the copper films, acting as brighteners.

The novel [RuCl 2 (PPh 3 ) 2 (4-CH 2 R-pip)] complexes, with R = H (complex 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 is a clear difference in the homopolymer yields in the order 1 > 2 > 3 at [monomer]/[Ru] molar ratio of 5000, at 25 °C for 5–60 min. Difference in the yields tends to disappear at 50 °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 M c and increase in the T g values, besides the influence of the type of initiator.