Dinuclear catalysts for the ring opening polymerization of lactide

Kremer, Alexandre B.; Mehrkhodavandi, Parisa

doi:10.1016/j.ccr.2018.09.008

Cited by 130 publications

(90 citation statements)

References 180 publications

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“…In particular, strontium salts can prevent osteoporosis . Moreover, a range of magnesium, zinc, and calcium complexes are known to represent efficient ROP catalysts . Although extensive ligand design enables stereo‐controlled ROP, the utmost majority of these complexes is not commercially available.…”

Section: Methodsmentioning

confidence: 99%

Strontium Isopropoxide: A Highly Active Catalyst for the Ring‐Opening Polymerization of Lactide and Various Lactones

Bandelli

Weber

Schubert

2019

Macromol. Rapid Commun.

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Commercially available strontium isopropoxide represents a suitable catalyst/initiator for the ring‐opening polymerization (ROP) of lactide (LA), ε−caprolactone, δ−valerolactone, δ−caprolactone, and δ−decalactone. Well‐defined polyesters are accessible via the solution polymerization of lactide in toluene with a [LA]:[Sr] ratio of 100:1 at room temperature with or without the addition of dodecanol as coinitiator. Kinetic studies and detailed analysis by means of matrix‐assisted laser desorption ionization mass spectrometry reveal pseudo‐first‐order kinetics of the ROP as well as excellent endgroup fidelity of the polylactide (PLA) with isopropyl and dodecyl α‐endgroups. Both isopropanolate moieties as well as the coinitiator each initiate PLA chains, enabling the synthesis of PLA with tailored molar mass. The polymerization of ε−caprolactone and δ−valerolactone confirms the high catalyst activity, which causes quantitative monomer conversion after 1 min polymerization time but broad molar mass distributions. In contrast, the catalyst is well suited for the ROP of the less reactive δ−caprolactone and δ−decalactone. Although kinetic studies reveal initially bimodal molar mass distributions, polyesters with dispersity values Ð < 1.2 and unimodal molar mass distributions can be obtained at moderate to high monomer conversions.

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Section: Methodsmentioning

confidence: 99%

Strontium Isopropoxide: A Highly Active Catalyst for the Ring‐Opening Polymerization of Lactide and Various Lactones

Bandelli

Weber

Schubert

2019

Macromol. Rapid Commun.

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“…Over the past three decades, many metal catalysts [26][27][28][29][30][31][32] used for the ROP of related cyclic esters have been developed. [33][34][35] In 2006, a series of zinc complexes [36] supported by NNO-tridentate Schiff base ligands ( Figure 1a) were prepared, and these complexes revealed high catalytic activity and great controllability in lactide polymerization. It implied that NNO-tridentate Schiff base ligands could not only enhance the catalytic activity of Zn complexes but also protect the active center from the transesterification.…”

Section: Introductionmentioning

confidence: 99%

Dual zinc catalysts for L‐lactide polymerization and reaction of CO₂ with cyclohexene oxide

Wang

Hsu

et al. 2019

J Chinese Chemical Soc

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A series of zinc complexes, [L XZnEt] (1–5) and [L XZn 2(OAc) 3] (6–9), associated with NNO‐tridentate Schiff base ligands (2‐(((2‐((cyclohexyl[methyl]amino)methyl)phenyl)imino)methyl)phenolate (CAP) derivatives), were synthesized, and their activity toward ring‐opening polymerization (ROP) of L‐lactide (LA) and the reaction of CO2 with cyclohexene oxide were also investigated. All of [L XZnEt] revealed excellent catalytic activity to ring‐opening polymerization (ROP) of LA in the presence of benzyl alcohol. Among them, [L HZnEt] (1) showed the highest activity with 82% conversation within 45 s. In contrast, [L XZn 2(OAc) 3] (6–9) were inactive in ROP of L‐lactide. In addition, all of these Zn complexes demonstrated moderate activity in the reaction of CO2 with cyclohexene oxide in the presence of Bu4NCl.

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“…Complexes of hafnium have been predominantly used as Lewis acid catalysts in various organic transformations, such as the polymerization of cyclic esters, and as catalysts for the homo‐ and copolymerization of α‐olefins . Recently, Hf‐MOF compounds have been used as active catalysts for the activation of small molecules .…”

Section: Introductionmentioning

confidence: 99%

Hydroboration of Aldehydes, Ketones, and Carbodiimides Promoted by Mono(imidazolin‐2‐iminato) Hafnium Complexes

et al. 2020

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Imidazolin‐2‐iminato hafnium complexes of the type [(ImRN)Hf(CH2Ph)3] were synthesized (ImtBuN = 1,3‐di‐tert‐butylimidazolin‐2‐iminato); ImDippN = 1,3‐bis(2,6‐diisopropylphenyl)‐imidazolin‐2‐iminato. The complexes were crystallized and structurally characterized. Despite the oxophilicity of the hafnium center, both hafnium complexes were catalytically active in the hydroboration of aldehydes, ketones, and carbodiimides. Herein, we present the influence of different substrates bearing electron‐withdrawing or electron‐donating groups on the catalytic reactions. Based on stoichiometric reaction in each process, plausible mechanistic scenarios are presented.

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Dinuclear catalysts for the ring opening polymerization of lactide

Cited by 130 publications

References 180 publications

Strontium Isopropoxide: A Highly Active Catalyst for the Ring‐Opening Polymerization of Lactide and Various Lactones

Strontium Isopropoxide: A Highly Active Catalyst for the Ring‐Opening Polymerization of Lactide and Various Lactones

Dual zinc catalysts for L‐lactide polymerization and reaction of CO₂ with cyclohexene oxide

Hydroboration of Aldehydes, Ketones, and Carbodiimides Promoted by Mono(imidazolin‐2‐iminato) Hafnium Complexes

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Dinuclear catalysts for the ring opening polymerization of lactide

Cited by 130 publications

References 180 publications

Strontium Isopropoxide: A Highly Active Catalyst for the Ring‐Opening Polymerization of Lactide and Various Lactones

Strontium Isopropoxide: A Highly Active Catalyst for the Ring‐Opening Polymerization of Lactide and Various Lactones

Dual zinc catalysts for L‐lactide polymerization and reaction of CO2 with cyclohexene oxide

Hydroboration of Aldehydes, Ketones, and Carbodiimides Promoted by Mono(imidazolin‐2‐iminato) Hafnium Complexes

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Dual zinc catalysts for L‐lactide polymerization and reaction of CO₂ with cyclohexene oxide