Making the cut: Monopyrrolidine-based complexes for the ROP of lactide

Shere, Henry; McKeown, Paul; Mahon, Mary F.; Jones, Matthew D.

doi:10.1016/j.eurpolymj.2019.02.046

Cited by 18 publications

(13 citation statements)

References 74 publications

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Section: Resultsmentioning

confidence: 53%

“…Both zinc and magnesium compounds are isostructural and reveal the expected monomeric nature. The metal centers in the magnesium and zinc compounds adopt distorted tetrahedral geometries with typical bond lengths for Zn-O, Mg-O, Zn-N, and Mg-N that are similar in characteristic ranges for the related compounds described previously [39,40,[45][46][47][48][49][50] (see ESI, Table S3). The aminophenol and metal compounds were obtained in high yields-L dmp -H (85%), (L dmp ) 2 Zn (87%), and (L dmp ) 2 Mg (83%), respectively-and characterized by standard elemental analysis and NMR spectroscopy (for details see, the Experimental Section and Supplementary Materials-Figures S1-S16.…”

Section: Resultsmentioning

confidence: 60%

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Lastingly Colored Polylactide Synthesized by Dye-Initiated Polymerization

et al. 2020

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An efficient synthesis strategy of a well-defined polylactide–dye conjugate in a controlled fashion is presented. The introduction of coloring species as end groups of polylactide (PLA) has been performed by using new homoleptic aminophenolate magnesium or zinc coordination compounds. The molecular structure of metal complexes has been determined in solution by NMR spectroscopy, and in the solid state by X-ray analysis. Lastingly colored polymers were obtained with 2-[4-(Nitrophenylazo)-N-ethylphenylamino]ethanol (Disperse Red 1) and 2-[4-(2-Chloro-4-nitrophenylazo)-N-ethylphenylamino]ethanol (Disperse Red 13) at very high lactide conversions, based on MALDI-ToF measurement, and the macromolecules were nearly fully chain end dye-functionalized. Based on 1H NMR, the DPn of conjugates was in the range of 10–300, which was consistent with the reaction setup. Various methods of gel-permeation chromatography (GPC) analysis were applied, and they demonstrated that the number-average molar mass (Mn) values (polystyrene (PS) standards) were a bit higher than calculated, the molar mass distribution index (ƉM) values were moderate to high, the TDA (triple detection array) system was inappropriate for analysis, measurements with PDA (photo diode array) detection at 470 nm gave nearly the same molar mass distributions such as the refractometer, and the relative absorbance of conjugates at 470 nm increased linearly versus (DPn)−1. The presented approach connects the gap between the current strategy of obtaining colored polymer fibers and the design of tailor-made initiators with eco polyesters designed for the targeted applications.

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Section: Resultsmentioning

confidence: 53%

Section: Resultsmentioning

confidence: 60%

Lastingly Colored Polylactide Synthesized by Dye-Initiated Polymerization

et al. 2020

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“…in complex 4 , but this value increases to 78.65% in aryloxide complex 7 (see Figures S9, S10, and S17 and Table S2 in the Supporting Information). The reported range of Zr(IV)–O–C Ar bond angles is very broad for monodentate aryloxide groups: 133.6(10)–179.2(2)°. , …”

Section: Resultsmentioning

confidence: 98%

“…The reported range of Zr(IV)−O−C Ar bond angles is very broad for monodentate aryloxide groups: 133.6(10)−179.2(2)°. 55,56 Preliminary Olefin Polymerization Studies. Complexes 2, 4, 5, and 7 were investigated as precatalysts for slurry-phase ethylene polymerization studies, in order to make comparisons with the previously reported, highly active Pn*Zr(C P R )Cl system and between the different (form)amidinate ligands.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Zirconium Permethylpentalene Amidinate Complexes: Characterization, Bonding, and Olefin Polymerization Catalysis

et al. 2022

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The synthesis and characterization of new zirconium permethylpentalene (form)amidinate complexes are described: Pn*Zr{N(Dipp)2CH}Cl (1), Pn* = η8-C8Me6 and Dipp = 2,6- i Pr-C6H3; [Pn*Zr{N(p-tol)2CH}Cl]2 (2), p-tol = 4-Me-C6H4; [Pn*Zr{N( i Pr)2CMe}Cl]2 (3); Pn*Zr{N( i Pr)2CPh}Cl (4); Pn*Zr{N(4-Me-C6H4)2CH}2 (5); [Pn*Zr{N( i Pr)2CCH2}]2 (6); and Pn*Zr{N( i Pr)2CPh}(O-2,6,-Me-C6H3) (7). The monohalide derivatives 1–4 demonstrate considerable structural diversity as the nature of the (form)amidinate-supporting ligand is changed. While complexes with acidic backbone protons proved susceptible to deprotonation using mild bases, those without underwent straightforward salt metathesis reactions with alkali metal salts, leading to complexes [Pn*Zr{N( i Pr)2CCH2}]2 (6) and Pn*Zr{N( i Pr)2CPh}(O-2,6-Me-C6H3) (7). Preliminary slurry-phase ethylene polymerization studies are also reported using complexes 2, 4, 5, and 7 to gain a direct comparison to the highly active, yet electronically saturated, Pn*Zr(CpR)Cl catalyst family.

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“…The continuous search for novel, more specific heterogeneous and homogenous catalytic systems that better manage polymerization necessarily involves preparing tailored catalysts. Consequently, the reported ROP catalysis literature have grown to include a wide range of metallic complexes with different type of ligands and substituent groups, binuclear complexes, ionic complexes, symmetrical or asymmetrical, etc …”

Section: Introductionmentioning

confidence: 99%

Bis‐β‐(diketonates) Zn(II) complexes substituted with thiophene: Electropolymerization, homogeneous and heterogeneous catalysis for ring opening polymerization of lactide

González

Cruz

Hernández

et al. 2020

Journal of Polymer Science

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Two Bis‐β‐diketonate zinc (II) complexes were synthesized using 1‐(thiophen‐2‐yl)butane‐1,3‐dione and 1‐(thiophen‐2‐yl)‐3‐(thiophen‐3‐yl)propane‐1,3‐dione as ligands. By electropolymerization of their thiophenyl groups, the metallopolymers deposited on FTO electrodes were obtained. The main objective was to study the reactivity of these compounds as ROP catalysts for PLA synthesis, using directly the zinc complexes (homogeneous catalysis) and also the modified electrodes with metallopolymers (heterogeneous catalysis). The homogeneous catalysis studies allowed the optimization of the polymerization conditions, such as reaction time, catalyst concentration, and the use of benzyl alcohol as cocatalyst, as well as their influence on the conversion rate, average molecular weight and polydispersity of PLA, using rac‐LA and L‐LA as monomers. Also, the effect on tacticity and thermal properties were discussed. Finally, the ROP studies using immersed modified electrodes in the polymerization medium were carried out under optimized experimental conditions. These tests were positive for one of the studied compounds, reaching conversions of up to 67%. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 557–567

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Making the cut: Monopyrrolidine-based complexes for the ROP of lactide

Cited by 18 publications

References 74 publications

Lastingly Colored Polylactide Synthesized by Dye-Initiated Polymerization

Lastingly Colored Polylactide Synthesized by Dye-Initiated Polymerization

Zirconium Permethylpentalene Amidinate Complexes: Characterization, Bonding, and Olefin Polymerization Catalysis

Bis‐β‐(diketonates) Zn(II) complexes substituted with thiophene: Electropolymerization, homogeneous and heterogeneous catalysis for ring opening polymerization of lactide

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