Atom Transfer Radical Polymerization of Methyl Methacrylate Mediated by Grubbs 1st and 2nd Generation Catalysts: Insight into the Active Species

Afonso, Maria Beatriz Alves; Gonçalves, Lucas Gomes; Borim, Patrícia Aparecida; Sá, José Luiz Silva; Goi, Beatriz E.; Carvalho, Valdemiro P.

doi:10.21577/0103-5053.20160314

Cited by 4 publications

(5 citation statements)

References 23 publications

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“…Despite the enormous amount of research available on the catalytic behavior of Grubbs’ first- and second-generation catalysts, few in-depth and comparative characterization studies on the catalysts itself are available. ,, The stability of the pre-catalyst as determined by UV–visible light spectroscopy in CH 2 Cl 2 , a solvent widely used in olefin metathesis reactions, ,, will thus be discussed. In addition, an electrochemical study employing cyclic voltammetry (CV), linear sweep voltammetry (LSV), and square wave voltammetry (SW), which gives insight into the valence electron properties under varied potentials, will be presented.…”

Section: Results and Discussionmentioning

confidence: 99%

Comparison of the Spectroscopically Measured Catalyst Transformation and Electrochemical Properties of Grubbs’ First- and Second-Generation Catalysts

2021

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According to UV−vis spectroscopy (0.10 mM, CH 2 Cl 2 at 25 °C), the catalyst transformation (which could possibly include ligand dissociation with active catalyst formation, dimer formation, and decomposition) rate constants (k obs ) of Grubbs' first (1) and second (2) generation catalysts are 7.48 × 10 −5 and 1.52 × 10 −4 s −1 , respectively. From 31 P NMR (0.1 M, CD 2 Cl 2 , at 25 °C), the catalyst transformation was 5.1% for 1 and 16.5% for 2 after 72 h. However, due to the larger concentrations of the NMR samples compared to the UV−vis samples, the extent of transformation did not correspond. The oxidation potential of the Ru II /Ru III couple of 2 (E°' = 27.5 mV at v = 200 mV s −1 ) was considerably lower than that of 1 (E°' = 167 mV at v = 200 mV s −1 ). In the case of 1, a second reduction peak appeared at slow scan rates. This may probably be ascribed to an electrochemically active compound that was formed from the intermediate cation 1 •+ and the subsequent reduction of the latter. The oxidation/ reduction of 1 proceeds according to an E r C i electrochemical mechanism (E r = electrochemically reversible step, C i = chemically irreversible step), whereas 2 proceeds according to an E r C r electrochemical mechanism (E r = electrochemically reversible step, C i = chemically reversible step).

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Section: Results and Discussionmentioning

confidence: 99%

Comparison of the Spectroscopically Measured Catalyst Transformation and Electrochemical Properties of Grubbs’ First- and Second-Generation Catalysts

2021

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“…In our research group, noncarbene ruthenium-based complexes have been studied for ROMP and ATRP. [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] Many of these compounds have exhibited good activity, forming polymers and copolymers in high yields, with different thermal and morphological characteristics. Among these precatalysts, ruthenium amine compounds have produced polymers from norbornene (NBE) and norbornadiene (NBD) by ROMP and controlled methyl methacrylate (MMA) and styrene (St) polymerization via ATRP.…”

Section: Introductionmentioning

confidence: 99%

“…Ruthenium complexes bearing p ‐cymene with different types of ligands such as phosphines, Schiff bases, and N ‐heterocyclic carbenes with a general formula of [RuCl 2 ( p ‐cymene)(L)] have been investigated as ROMP or ATRP catalysts. In our research group, noncarbene ruthenium‐based complexes have been studied for ROMP and ATRP . Many of these compounds have exhibited good activity, forming polymers and copolymers in high yields, with different thermal and morphological characteristics.…”

Section: Introductionmentioning

confidence: 99%

Dual catalytic performance of arene‐ruthenium amine complexes for norbornene ring‐opening metathesis and methyl methacrylate atom‐transfer radical polymerizations

Cruz

Silva

Oliveira

et al. 2020

Applied Organom Chemis

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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.

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“…During the past 15 years, easy and efficient synthesis of rutheniumbased ROMP catalysts has been developed by our group [18][19][20][21][22][23][24]. Recently, some of the complexes have been successfully applied to controlled/living radical polymerizations of vinyl monomers [25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Accessible ring opening metathesis and atom transfer radical polymerization catalysts based on dimethyl sulfoxide ruthenium(II) complexes bearing N-heterocyclic carbene ligands

Idehara

Gois

Fernandez

et al. 2018

Molecular Catalysis

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Dimethyl sulfoxide ruthenium(II) complexes of N-heterocyclic carbenes derived from cycloalkylamines (cycloalkyl = cyclopentyl (1a), cyclohexyl (1b), cycloheptyl (1c), and cyclooctyl (1d)) were synthesized: [RuCl 2 (Sdmso) 2 (IPent)] (2a), [RuCl 2 (S-dmso) 2 (IHex)] (2b), [RuCl 2 (S-dmso) 2 (IHept)] (2c), and [RuCl 2 (S-dmso) 2 (IOct)] (2d). The imidazolium salts 1a-1d were characterized by FTIR, UV-vis, and 1 H and 13 C NMR spectroscopy, while their respective dimethyl sulfoxide ruthenium(II) complexes (2a-2d) were characterized by elemental analysis, FTIR, UV-vis, 1 H and 13 C 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.

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Atom Transfer Radical Polymerization of Methyl Methacrylate Mediated by Grubbs 1st and 2nd Generation Catalysts: Insight into the Active Species

Cited by 4 publications

References 23 publications

Comparison of the Spectroscopically Measured Catalyst Transformation and Electrochemical Properties of Grubbs’ First- and Second-Generation Catalysts

Comparison of the Spectroscopically Measured Catalyst Transformation and Electrochemical Properties of Grubbs’ First- and Second-Generation Catalysts

Dual catalytic performance of arene‐ruthenium amine complexes for norbornene ring‐opening metathesis and methyl methacrylate atom‐transfer radical polymerizations

Accessible ring opening metathesis and atom transfer radical polymerization catalysts based on dimethyl sulfoxide ruthenium(II) complexes bearing N-heterocyclic carbene ligands

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