Macrocycles, 1. Macrocyclic polymerizations of (thio)lactones – stepwise ring expansion and ring contraction

Kricheldorf, Hans R.; Lee, Soo‐Ran; Schittenhelm, Nicole

doi:10.1002/macp.1998.021990215

Cited by 6 publications

(5 citation statements)

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“…Sporadic entries to the literature concerning the ROP of tCL have appeared since the initial report in 1968. , Many reports feature late metal alkoxide (Sn, Cd, Mn, etc.) catalyzed ROP of tCL from alcohol or thiol initiators in solvent or bulk, , and a ring-expansion polymerization technique has also been demonstrated . A recent report of the ROP of ε-thiocaprolactone, tCL, used a lipase typically employed in esterification , to yield poly(ε-thionocaprolactone) (PtCL) with higher M w / M n than poly(ε-caprolactone) (PCL) generated under identical conditions.…”

Section: Introductionmentioning

confidence: 99%

Poly(thioester) by Organocatalytic Ring-Opening Polymerization

Bannin

Kiesewetter

2015

Macromolecules

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Organocatalysts typically used for the ring-opening polymerization (ROP) of cyclic ester monomers are applied to a thiolactone, ε-thiocaprolactone (tCL). In the absence of an H-bond donor, a nucleophilic polymerization mechanism is proposed. Despite the decreased ability of thioesters and thiols (versus esters and alcohols) to H-bond, H-bonding organocatalysts—a thiourea in combination with an H-bond accepting base—are also effective for the ROP of tCL. The increased nucleophilicity of thiols (versus alcohols) is implicated in the increased Mw/Mn of the poly(thiocaprolactone) versus poly(caprolactone), but deleterious transesterification is suppressed in the presence of a thiourea. The thioester monomer, tCL, is shown to be thermodynamically similar to ε-caprolactam but kinetically similar to ε-caprolactone.

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Section: Introductionmentioning

confidence: 99%

Poly(thioester) by Organocatalytic Ring-Opening Polymerization

Bannin

Kiesewetter

2015

Macromolecules

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“…A few research groups have reported cyclic tin(IV) alkoxides as initiators for the ring-expan-sion polymerization of lactone and lactide monomers. [12][13][14][15][16][17][18][19][20] Because of the reported absence of termination and transfer reactions, the synthesis of ABA triblock copolymers is theoretically possible, and in one report, 13 low molecular weight block copolymers were synthesized from CL and ␤-D,Lbutyrolactone with the method of ring-expansion polymerization from macrocyclic initiators. Recently, it was demonstrated by Kricheldorf and Hauser 20 that telechelic oligo(esters) of CL could be synthesized from 2,2-dibutyl-2-stanna-1,3-dioxacylcoalkanes.…”

Section: Introductionmentioning

confidence: 99%

“…The most widely used catalysts and initiators for the ROP of lactones and cyclic carbonates are tin(II) alkoxides [Sn(OR) 2 or OctOSnOOR] created in situ from the reaction of tin(II) 2-ethylhexanoate (SnOct 2 ) and an intentionally added alcohol or other active-hydrogen-containing compound. [1][2][3] Monoalkoxides and polyalkoxides based on other metals such as Al(III), 4 -8 Ti(IV), 9 Sn(IV), 9,[12][13][14][15][16][17][18][19][20] and oxodialkoxides 10,11 have been used as initiators for the ROP of ⑀-caprolactone (CL) and lactides. For most of these catalysts, the highest attainable number-average molecular weight (M n ) for polyesters is about 10 5 g/mol.…”

Section: Introductionmentioning

confidence: 99%

Soluble tin(II) macroinitiator adducts for the controlled ring‐opening polymerization of lactones and cyclic carbonates

Storey

Mullen

Desai

et al. 2002

J. Polym. Sci. A Polym. Chem.

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Polyesters and poly(ester carbonates) were synthesized via ring‐opening polymerization with new tin(II) macroinitiator adducts containing oligomeric L‐lactide (LLA), rac‐lactide (rac‐LA), and ϵ‐caprolactone (CL). The novel initiating species were synthesized by the reaction of LLA, rac‐LA, or CL with Sn(OEt)2 (monomer concentration/initiator concentration ≤20) and then were dissolved in methylene chloride or toluene and stored in a stoppered flask for the subsequent ring‐opening polymerization of cyclic esters and carbonates. The soluble tin alkoxide macroinitiators yielded predictable and quantitative initiation of polymerization for up to 1 month of storage time at room temperature. The resulting polymers displayed low polydispersity (≤1.5), and a high monomer conversion (>95%) was obtained within relatively short polymerization times (≤2 h). Adjusting the monomer/macroinitiator ratio effectively controlled the molecular weights of the polymers. NMR was used to characterize the initiating species and polymer microstructure, and size exclusion chromatography was used to determine the molecular weight properties of the polymers. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3434–3442, 2002

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“…Furthermore, ring-expansion polymerizations have been performed by the insertion reaction of various cyclic compounds such as lactone, − cyclic olefin, − N -carboxy anhydride, and thiirane − as monomers. With these strategies, only cyclic polymers can be synthesized, but their ring sizes cannot be controlled.…”

Section: Introductionmentioning

confidence: 99%

Living Ring-Expansion Polymerization of Thiirane with Cyclic Monocarbamothioates

et al. 2020

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We synthesized two kinds of monocarbamothioates TZO(R) containing a thiazolidin-2-one (TZO) skeleton and TZD(R) containing a thiazolidine-2,4-dione (TZD) skeleton. In the reaction of TZO(R) and phenoxypropyrenesulfide (PPS) using tetrabutylammonium chloride (TBAC) as a catalyst in 1-methyl-2-pyrrolidinone at 60 °C, anionic ring-opening polymerization of PPS proceeded to give the corresponding linear polysulfides, polyPPS, with M n = 75 860–206 700 (M w/M n = 1.54–1.73) in high yield. In contrast, in the reaction of TZD(R) and PPS, the continuous insertion reaction of PPS into TZD(R), i.e., living ring-expansion polymerization, occurred to afford cyclic polysulfides TZD(R)-c-poly(PPS) n with M n = 1870–33 420 (M w/M n = 1.07–1.26) in high yield. The ring size could be controlled by the feed ratio of TZD(R)/PPS in the range of 1/5–1/100.

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Macrocycles, 1. Macrocyclic polymerizations of (thio)lactones – stepwise ring expansion and ring contraction

Cited by 6 publications

References 0 publications

Poly(thioester) by Organocatalytic Ring-Opening Polymerization

Poly(thioester) by Organocatalytic Ring-Opening Polymerization

Soluble tin(II) macroinitiator adducts for the controlled ring‐opening polymerization of lactones and cyclic carbonates

Living Ring-Expansion Polymerization of Thiirane with Cyclic Monocarbamothioates

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