ChemInform Abstract: Latent Olefin Metathesis Catalysts

Monsaert, Stijn; Vila, Ana Lozano; Drozdzak, Renata; Voort, Pascal Van Der; Verpoort, Francis

doi:10.1002/chin.201014213

Cited by 3 publications

(4 citation statements)

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“…10 Unfortunately, we found previously that purification of a catalyst bearing a quaternary ammonium chloride fragment could be very difficult, probably due to interactions with a CuClÂPCy 3 complex formed during the reaction. Other attempts, such as use of alternative ligand exchange protocols, 11 were also ineffective in this case. It seems even more problematic to place a quaternary ammonium cation on the NHC ligand, due to strongly basic conditions required to generate the free NHC from the corresponding imidazolinium salt (Scheme 1).…”

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confidence: 97%

“…12 This strategy should allow us to work (till the final step) with uncharged non-polar compounds, which can be conveniently purified by standard techniques (distillation, column chromatography etc.). The synthesized Ru complexes (6, 8, 10), bearing trialkylamino groups after treatment with methyl chloride, shall yield ammonium tagged complexes (7,9,11,Scheme 2).…”

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confidence: 99%

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Highly active catalysts for olefin metathesis in water

Skowerski¹,

Szczepaniak

Wierzbicka³

et al. 2012

Catal. Sci. Technol.

110

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confidence: 97%

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confidence: 99%

Highly active catalysts for olefin metathesis in water

Skowerski¹,

Szczepaniak

Wierzbicka³

et al. 2012

Catal. Sci. Technol.

110

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“…As a novel feature of olefin metathesis, latent catalytic systems were developed for controlled ring‐opening metathesis polymerization (ROMP) applications . Bidentate Schiff bases (N, O) were used as promising ligand candidates in the design and development of latent ruthenium alkylidene and indenylidene catalysts . Schiff bases can be synthesized easily through one‐pot procedures.…”

Section: Introductionmentioning

confidence: 99%

Nonaqueous and Aqueous Emulsion ROMP Reactions Induced by Environment-Friendly Latent Ruthenium Indenylidene Catalyst Bearing Morpholine Substituted Bidentate (N, O) Schiff Bases

Öztürk

Kolberg

Şehitoğlu

2017

Macromol. Chem. Phys.

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In this study, a novel latent ruthenium indenylidene catalyst, bearing morpholine substituted bidentate (N, O) Schiff base is used in nonaqueous emulsion ring‐opening metathesis polymerization (ROMP) reactions for the first time. This novel catalyst has unique features such as latency and high silica gel affinity. The performance of the catalyst is tested on ring‐closing metathesis (RCM), ROMP reactions, and aqueous emulsion ROMP reactions. In addition, nonaqueous (using immiscible binary organic solvents: n‐hexane and dimethylformamide) emulsion ROMP reactions are carried out for the first time using latent ruthenium catalysts. The latency of the catalyst allows us to control the molecular weight of emulsion ROMP polymers by varying HCl/Ru ratio, keeping the nanoparticle sizes stable between 26 and 75 nm in aqueous emulsion and 51 and 208 nm in nonaqueous emulsion ROMP reactions. In addition, high silica gel affinity of the catalyst allows us to synthesize pure RCM products with ruthenium contamination less than 1 ppm.

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“…Control of this process is crucial for many olefin metathesis applications, and the ability to slow or speed up the rate of initiation has important consequences for applications in materials synthesis and the range of reaction conditions available. For example, slow initiating catalysts or latent catalysts wherein initiation can be triggered by some external stimulus are important in ROMP applications where physical manipulation of the catalyst within the monomer prior to polymerization is advantageous. − On the other hand, fast initiating catalysts are advantageous for ROMP applications where more monodisperse polymers are desired. Furthermore, rapidly initiating catalysts allow for other metathesis reactions (such as cross metathesis or asymmetric ring closing metathesis) to be run at much lower temperatures, leading to increased selectivity.…”

Section: Introductionmentioning

confidence: 99%

Kinetic and Thermodynamic Analysis of Processes Relevant to Initiation of Olefin Metathesis by Ruthenium Phosphonium Alkylidene Catalysts

et al. 2010

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Initiation processes in a family of ruthenium phosphonium alkylidene catalysts, some of which are commercially available, are presented. Seven 16-electron zwitterionic catalyst precursors of general formula (H(2)IMes)(Cl)(3)Ru=C(H)P(R(1))(2)R(2) (R(1) = R(2) = C(6)H(11), C(5)H(9), i-C(3)H(7), 1-Cy(3)-Cl, 1-Cyp(3)-Cl, 1-(i)Pr(3)-Cl; R(1) = C(6)H(11), R(2) = CH(2)CH(3), 1-EtCy(2)-Cl; R(1) = C(6)H(11), R(2) = CH(3), 1-MeCy(2)-Cl; R(1) = i-C(3)H(7), R(2) = CH(2)CH(3), 1-Et(i)Pr(2)-Cl; R(1) = i-C(3)H(7), R(2) = CH(3), 1-Me(i)Pr(2)-Cl) were prepared. These compounds can be converted to the metathesis active 14-electron phosphonium alkylidenes by chloride abstraction with B(C(6)F(5))(3). The examples with symmetrically substituted phosphonium groups exist as monomers in solution and are rapid initiators of olefin metathesis reactions. The unsymmetrically substituted phosphonium alkylidenes are observed to undergo reversible dimerization, the extent of which is dependent on the steric bulk of the phosphonium group. Kinetic and thermodynamic parameters of these equilibria are presented, as well as experiments that show that metathesis is only initiated through the monomers; thus dedimerization is required for initiation. In another detailed study, the series of catalysts 1-R(3) were reacted with o-isopropoxystyrene under pseudo-first-order conditions to quantify second-order olefin binding rates. A more complex initiation process was observed in that the rates were accelerated by catalytic amounts of ethylene produced in the reaction with o-isopropoxystyrene. The ability of the catalyst to generate ethylene is related to the nature of the phosphonium group, and initiation rates can be dramatically increased by the intentional addition of a catalytic amount of ethylene.

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ChemInform Abstract: Latent Olefin Metathesis Catalysts

Cited by 3 publications

References 1 publication

Highly active catalysts for olefin metathesis in water

Highly active catalysts for olefin metathesis in water

Nonaqueous and Aqueous Emulsion ROMP Reactions Induced by Environment-Friendly Latent Ruthenium Indenylidene Catalyst Bearing Morpholine Substituted Bidentate (N, O) Schiff Bases

Kinetic and Thermodynamic Analysis of Processes Relevant to Initiation of Olefin Metathesis by Ruthenium Phosphonium Alkylidene Catalysts

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