Syntheses of Biodegradable and Biocompatible Polymers by Means of Bismuth Catalysts

Kricheldorf, Hans R.

doi:10.1021/cr900029e

Cited by 105 publications

(76 citation statements)

References 120 publications

(217 reference statements)

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“…Moreover, Bi-based catalysts were successfully applied to copolymerizations, e.g., ε-caprolactone and diglycolide. [ 11 ] Reports on the use of alternate catalysts for homopolymerizations of diglycolide are scarce. Thus, it appeared rewarding to apply a Bi-catalyst to homopolymerizations of diglycolide.…”

Section: Introductionmentioning

confidence: 99%

Fast Synthesis of High‐Molecular‐Weight Polyglycolide Using Diphenyl Bismuth Bromide as Catalyst

Schmidt

Beuermann

2014

Macro Chemistry & Physics

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Biodegradable polymers are frequently obtained from ring-opening polymerizations (ROPs). Applications in the biomedical sector require medical-grade materials free of any toxic residues, as well as polymers with well-defi ned properties. Thus, the selection of nontoxic catalysts for ROP, which allow for well-controlled molecular weights, is very important. In this contribution, ROPs of diglycolide are reported by using diphenyl bismuth bromide as catalyst. The reactions are carried out in bulk at temperatures ranging from 130 to 150 °C. The number-average molecular weights are in the range of 20-250 kg mol −1 depending on the reaction temperature and time, as well as the catalyst concentration. The reaction times required to yield diglycolide conversions exceeding 95% are in the range of minutes. The thermal properties such as melting and crystallization temperatures are independent of polymer molecular weight.

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Section: Introductionmentioning

confidence: 99%

Fast Synthesis of High‐Molecular‐Weight Polyglycolide Using Diphenyl Bismuth Bromide as Catalyst

Schmidt

Beuermann

2014

Macro Chemistry & Physics

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“…[1][2][3][4][5] Although biomethylation in the human body has been reported to occur to a low extent after oral uptake of bismuth subsalicylate (BSS, Pepto Bismol), [6,7] strongly adverse side effects were neither reported for BSS nor for bismuth subcitrate (CBS, DeNol). [8][9][10] It is well known that both compounds are products of partial hydrolysis of the respective bismuth carboxylates, [11] but their composition and medicinal effect are still poorly understood.…”

Section: Introductionmentioning

confidence: 99%

From {Bi₂₂O₂₆} to Chiral Ligand‐Protected {Bi₃₈O₄₅}‐Based Bismuth Oxido Clusters

Mansfeld

Miersch

Rüffer

et al. 2011

Chemistry A European J

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The reaction of [Bi(22)O(26)(OSiMe(2)tBu)(14)] (1) in THF with salicylic acid gave [Bi(22)O(24)(HSal)(14)] (2) first, which was converted into [Bi(38)O(45)(HSal)(22)(OH)(2)(DMSO)(16.5)]·DMSO·H(2)O (3·DMSO·H(2)O) after dissolution and crystallization from DMSO. Single-crystal X-ray diffraction analysis and ESI mass spectrometry associated with infrared multi-photon dissociation (IRMPD) tandem MS experiments confirm the formation of the large and quite stable bismuth oxido cluster 3. The reaction of compound 2 with the butoxycarbonyl(BOC)-protected amino acids phenylalanine and valine (BOC-PheOH and BOC-ValOH), respectively, resulted in the formation of chiral [Bi(38)O(45)(BOC-AA)(22)(OH)(2)] (AA=deprotonated amino acid), as shown by a combination of different analytical techniques such as elemental analysis, dynamic light scattering, circular dichroism spectroscopy, and ESI mass spectrometry.

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“…Secondly, bismuth halide and bismuth triflate were found to be efficient catalysts of the ring-opening polymerization of oxazolies [32] and e-caprolactone. [33][34][35] Therefore, the present work should expand our systematic studies of bismuth-based catalysts.…”

Section: Introductionmentioning

confidence: 99%

Polymerization of Cyclosiloxanes by Means of Triflic Acid and Metal Triflates

Yashiro

Kricheldorf

Schwarz

2010

Macro Chemistry & Physics

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Hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5) were equilibrated with potassium tert‐butoxide or triflic acid in bulk at 100 °C to elaborate the 1H NMR and 13C NMR spectra, SEC elution curve, and MALDI‐TOF (MT) mass spectrum of a fully equilibrated poly(dimethylsiloxane). Surprisingly, triflic acid did not effect complete equilibration (even after 360 h), seemingly because cleavage of Si–C bonds eliminates the acidic proton. Large amounts of D4 and D5 together with small amount of D6 were formed in the early stage of the polymerization in contrast to potassium alkoxide‐catalyzed polymerizations. The usefulness of numerous metal triflates as polymerization catalysts of D3 was explored, and only the most acidic ones were active. Bismuth and hafnium triflate catalyzed a polymerization mechanism similar to that of triflic acid but were more active despite their poor solubility. BiCl3 and HfCl4 were considerably less reactive and the polymerization kinetics were quite different from those of the metal triflate catalyzed polymerizations. The decisive role of acidic protons was revealed by addition of a proton scavenger. Bismuth triflate proved to be an interesting and useful catalyst because it combines the highest activity with poor solubility and low toxicity.magnified image

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Syntheses of Biodegradable and Biocompatible Polymers by Means of Bismuth Catalysts

Cited by 105 publications

References 120 publications

Fast Synthesis of High‐Molecular‐Weight Polyglycolide Using Diphenyl Bismuth Bromide as Catalyst

Fast Synthesis of High‐Molecular‐Weight Polyglycolide Using Diphenyl Bismuth Bromide as Catalyst

From {Bi₂₂O₂₆} to Chiral Ligand‐Protected {Bi₃₈O₄₅}‐Based Bismuth Oxido Clusters

Polymerization of Cyclosiloxanes by Means of Triflic Acid and Metal Triflates

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Syntheses of Biodegradable and Biocompatible Polymers by Means of Bismuth Catalysts

Cited by 105 publications

References 120 publications

Fast Synthesis of High‐Molecular‐Weight Polyglycolide Using Diphenyl Bismuth Bromide as Catalyst

Fast Synthesis of High‐Molecular‐Weight Polyglycolide Using Diphenyl Bismuth Bromide as Catalyst

From {Bi22O26} to Chiral Ligand‐Protected {Bi38O45}‐Based Bismuth Oxido Clusters

Polymerization of Cyclosiloxanes by Means of Triflic Acid and Metal Triflates

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From {Bi₂₂O₂₆} to Chiral Ligand‐Protected {Bi₃₈O₄₅}‐Based Bismuth Oxido Clusters