Ionic Liquids as Solvents for Rhodium and Platinum Catalysts Used in Hydrosilylation Reaction

Zieliński, W.; Kukawka, Rafał; Maciejewski, Hieronim; Śmiglak, Marcin

doi:10.3390/molecules21091115

Cited by 29 publications

(11 citation statements)

References 31 publications

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“…To reduce the F-content of compounds and fluorous solvent, an alternative way is to use the different solubility of “light fluorous compounds” (less than 60% of F-content) [ 5 , 11 ] between high and low temperature in a common organic solvent. In this method, a fluorous chain-containing metal catalyst could be soluble at high temperature during the catalytic reactions, but insoluble at room temperature (or lower temperature) for the recovery of catalysts via a simple liquid-solid separation [ 12 , 13 , 14 , 15 , 16 , 17 ]. This is a typical application of “light fluorous” metal catalysts in the so-called “thermomorphic condition”.…”

Section: Introductionmentioning

confidence: 99%

Short-Chained Platinum Complex Catalyzed Hydrosilylation under Thermomorphic Conditions: Heterogeneous Phase Separation at Ice Temperature

Chiu

Tessema

et al. 2021

Molecules

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Homogeneous catalysts PtCl2[5,5′-bis-(n-ClCF2(CF2)3CH2OCH2)-2,2′-bpy] (2A) and PtCl2[5,5′-bis-(n-HCF2(CF2)3CH2OCH2)-2,2′-bpy] (2B), which contained short fluorous chains, were synthesized and used in catalysis of hydrosilylation of alkynes. In these reactions the thermomorphic mode was effectively used to recover these catalysts from the reaction mixture up to eight cycles by taking advantage of heterogeneous phase separation at ice temperature. This kind of catalysis had previously been observed in fluorous catalysts of platinum containing about 50% F-content, but in this work the percentage of F-content is decreased to only about 30%, by which we termed them as “very light fluorous”. Our new type of catalyst with limited number of F-content is considered as the important discovery in the fluorous technology field as the reduced number of fluorine atoms will help to be able to comply the EPA 8-carbon rule. The metal leaching after the reaction has been examined by ICP-MS, and the testing results show the leaching of residual metal to be minimal. Additionally, comparing these results to our previous work, fluorous chain assisted selectivity has been observed when different fluorous chain lengths of the catalysts are used. It has been found that there exists fluorous chain assisted better selectivity towards β-(E) form in the Pt-catalyzed hydrosilylation of non-symmetric terminal alkyne when the Pt catalyst contains short fluorous chain (i.e., 4 Cs). Phenyl acetylenes showed the opposite regioselectivity due to pi-pi interaction while using the same catalyst via Markovnikov’s addition to form terminal vinyl silane, which is then a major product for Pt-catalyzed hydrosilylation of terminal aryl acetylene with triethylsilane. Finally, the kinetic studies indicate that the insertion of alkyne into the Pt-H bond is the rate-determining step.

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Section: Introductionmentioning

confidence: 99%

Short-Chained Platinum Complex Catalyzed Hydrosilylation under Thermomorphic Conditions: Heterogeneous Phase Separation at Ice Temperature

Chiu

Tessema

et al. 2021

Molecules

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“…Likewise, in the 2nd part of this research, the fluorous long-chained pyridine (4- R f -CH 2 OCH 2 -py where R f = C 11 F 23 ), as a base catalyst, works under thermomorphic conditions with a feature of homogeneously catalyzing phospha-Michael addition at a high temperature in a neat reaction where the reactants serve as the solvent, forming heterogeneous precipitation at a lower temperature. The thermomorphic method is an alternative way to use the different solubility of fluorous long-chained compounds between high and low temperature in the common organic compounds [ 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. In this method, a fluorous chain-containing pyridine-based catalyst could be soluble at high temperatures during the catalytic reactions, but insoluble at room temperature for the recovery of catalysts via a simple liquid–solid separation [ 36 , 37 , 38 ].…”

Section: Introductionmentioning

confidence: 99%

Recoverable Phospha-Michael Additions Catalyzed by a 4-N,N-Dimethylaminopyridinium Saccharinate Salt or a Fluorous Long-Chained Pyridine: Two Types of Reusable Base Catalysts

et al. 2021

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Phospha-Michael addition, which is the addition reaction of a phosphorus-based nucleophile to an acceptor-substituted unsaturated bond, certainly represents one of the most versatile and powerful tools for the formation of P-C bonds, since many different electrophiles and P nucleophiles can be combined with each other. This offers the possibility to access many diversely functionalized products. In this work, two kinds of basic pyridine-based organo-catalysts were used to efficiently catalyze phospha-Michael addition reactions, the 4-N,N-dimethylaminopyridinium saccharinate (DMAP·Hsac) salt and a fluorous long-chained pyridine (4-Rf-CH2OCH2-py, where Rf = C11F23). These catalysts have been synthesized and characterized by Lu’s group. The phospha-Michael addition of diisopropyl, dimethyl or triethyl phosphites to α, β-unsaturated malonates in the presence of those catalysts showed very good reactivity with high yield at 80–100 °C in 1–4.5 h with high catalytic recovery and reusability. With regard to significant catalytic recovery, sometimes more than eight cycles were observed for DMAP·Hsac adduct by using non-polar solvents (e.g., ether) to precipitate out the catalyst. In the case of the fluorous long-chained pyridine, the thermomorphic method was used to efficiently recover the catalyst for eight cycles in all the reactions. Thus, the easy separation of the catalysts from the products revealed the outstanding efficacy of our systems. To our knowledge, these are good examples of the application of recoverable organo-catalysts to the DMAP·Hsac adduct by using non-polar solvent and a fluorous long-chained pyridine under the thermomorphic mode in phospha-Michael addition reactions.

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“…41,42 We have also developed a number of effective catalytic systems based on diverse platinum and rhodium complexes immobilized in the most important kinds of ionic liquids. [43][44][45][46] However, in addition to the application of ionic liquids as immobilizing agents, more and more frequently attempts are made at obtaining metal ioncontaining ionic liquids with catalytic properties. One of examples are halometallate ionic liquids which can be dened as ionic liquids formed by the reaction of metal halide with an organic halide salt.…”

Section: Introductionmentioning

confidence: 99%

New anionic rhodium complexes as catalysts for the reduction of acetophenone and its derivatives

2019

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Ionic Liquids as Solvents for Rhodium and Platinum Catalysts Used in Hydrosilylation Reaction

Cited by 29 publications

References 31 publications

Short-Chained Platinum Complex Catalyzed Hydrosilylation under Thermomorphic Conditions: Heterogeneous Phase Separation at Ice Temperature

Short-Chained Platinum Complex Catalyzed Hydrosilylation under Thermomorphic Conditions: Heterogeneous Phase Separation at Ice Temperature

Recoverable Phospha-Michael Additions Catalyzed by a 4-N,N-Dimethylaminopyridinium Saccharinate Salt or a Fluorous Long-Chained Pyridine: Two Types of Reusable Base Catalysts

New anionic rhodium complexes as catalysts for the reduction of acetophenone and its derivatives

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