Anionic polymerization of methyl methacrylate using tetrakis[tris(dimethylamino)phosphoranylidenamino] phosphonium (P5+) as counterion in tetrahydrofuran

Baskaran, Durairaj; Müller, Axel H. E.

doi:10.1002/(sici)1521-3927(20000401)21:7<390::aid-marc390>3.0.co;2-b

Cited by 23 publications

(15 citation statements)

References 30 publications

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“…In the recent surge for metal-free polymerization techniques, − a family of organic superbases, the phosphazenes, have shown their remarkable potential as promoter/catalyst for the anionic polymerization of various types of monomers, including epoxides, − cyclosiloxanes, − lactams, , cyclopropane derivatives, − (meth)acrylates, − cyclic esters, − and cyclic carbonates. − Generally, phosphazene bases improve the nucleophilicity of the initiator/chain-end significantly by complexation with the counterion (e.g., proton or lithium cation), resulting in a rapid and usually controlled anionic polymerization. Phosphazene-promoted polymerization techniques appeal to us not only for its metal-free feature or the enhanced polymerization rate but also for the powerful synthetic toolbox they provide for sophisticated macromolecular engineering .…”

Section: Introductionmentioning

confidence: 99%

Phosphazene-Promoted Metal-Free Ring-Opening Polymerization of Ethylene Oxide Initiated by Carboxylic Acid

et al. 2014

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The effectiveness of carboxylic acid as initiator for the anionic ring-opening polymerization of ethylene oxide was investigated with a strong phosphazene base (t-BuP 4 ) used as promoter. Kinetic study showed an induction period, i.e., transformation of carboxylic acid to hydroxyl ester, followed by slow chain growth together with simultaneous and fast end-group transesterification, which led to poly(ethylene oxide) (PEO) consisting of monoester (monohydroxyl), diester, and dihydroxyl species. An appropriate t-BuP 4 /acid ratio was proven to be essential to achieve better control over the polymerization and low dispersity of PEO. This work provides important information and enriches the toolbox for macromolecular and biomolecular engineering with protic initiating sites.

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Section: Introductionmentioning

confidence: 99%

Phosphazene-Promoted Metal-Free Ring-Opening Polymerization of Ethylene Oxide Initiated by Carboxylic Acid

et al. 2014

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“…NMR studies 10b showed that the TPP + ion pairs are in a dynamic equilibrium with dormant ylide species (Scheme ). When the ester enolate of methyl isobutyrate was used as an initiator with the same counterion, distinct induction periods were observed which was not the case for the triphenylmethanide anions 10a 1 Equilibrium between Ylides and Ion Pairs …”

Section: Introductionmentioning

confidence: 99%

“…Later it was shown that the structure of the phosphorus-containing cation has a tremendous effect on the apparent reactivity of the chain end. Thus, (1-naphthyl)triphenylphosphonium (NPP + ) counterions lead to an extremely slow polymerization (half-lives of hours in boiling THF), 9b,c whereas the bis(triphenylphosphoranylidene)ammonium (PNP + ) gives faster polymerizations than TPP + 10c. This was explained by the higher stability of the NPP ylide and the lower one of the PNP ylide, as compared to the TPP ylide.…”

Section: Introductionmentioning

confidence: 99%

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Quantum-Chemical Study of Structure and Activity of Chain Ends in Metal-Free Anionic Polymerization of Methacrylates

Weiß¹,

Steiger²,

Jüngling³

et al. 2003

Macromolecules

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Kinetic and NMR studies of the anionic polymerization of methyl methacrylate using tetraphenylphosphonium and other phosphorus-containing, metal-free counterions indicated an equilibrium between an active ion pair and a corresponding ylide as a dormant species. We present density functional theory (DFT) calculations of the energy difference between the ion pair and the ylide for the ester enolate of methyl isobutyrate with various counterions which support this view. It is possible to establish a correlation based on the calculated energy difference between the ylide and the ion pair and the apparent activity of the chain end. The ylide formed after the first polymerization step is extremely stable compared to the ion pair, whereas after addition of one molecule of methyl methacrylate, the ylide of the dimer is destabilized through steric interactions and the polymerization can proceed much faster. This explains the observation of a pronounced induction period when using the ester enolate of methyl isobutyrate as an initiator.

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“…Recently, Baskaran and Müller 13) presented the results of the polymerization of MMA with tetrakis[(N,N-dimethylamino)phosphoranylidenamine] phosphonium (P 5 + ) as counterion. The polymerization with this stable initiator is extremely fast, producing PMMA with narrow MWD but low initiator efficiency.…”

Section: Introductionmentioning

confidence: 99%

Metal-free anionic polymerization of methyl methacrylate in tetrahydrofuran using bis(triphenylphosphoranilydene)ammonium (PNP+) as counterion

Königsmann

Jüngling²,

Müller³

2000

Macromol. Rapid Commun.

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Bis(triphenylphosphoranilydene)ammonium (PNP+) triphenylmethanide (Ph3C–) is a new metal‐free initiator for the living polymerization of methyl methacrylate (MMA). The kinetics of the polymerization strongly depend on the metal counterion of the initiator precursor. When the initiator is made from the metathesis reaction of Ph3CK and PNPCl, the polymerization follows first‐order kinetics up to 0°C with half‐lives below 0.1 s. The propagation rate constants are much higher than those obtained with tetraphenylphosphonium (TPP+) cations, indicating a smaller fraction of dormant ylides. When the initiator is synthesized from Ph3CLi, polymerization proceeds much slower and molecular weight distributions of the obtained polymers are broadened indicating that the active species are mostly lithium enolates in this case.

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Anionic polymerization of methyl methacrylate using tetrakis[tris(dimethylamino)phosphoranylidenamino] phosphonium (P5+) as counterion in tetrahydrofuran

Cited by 23 publications

References 30 publications

Phosphazene-Promoted Metal-Free Ring-Opening Polymerization of Ethylene Oxide Initiated by Carboxylic Acid

Phosphazene-Promoted Metal-Free Ring-Opening Polymerization of Ethylene Oxide Initiated by Carboxylic Acid

Quantum-Chemical Study of Structure and Activity of Chain Ends in Metal-Free Anionic Polymerization of Methacrylates

Metal-free anionic polymerization of methyl methacrylate in tetrahydrofuran using bis(triphenylphosphoranilydene)ammonium (PNP+) as counterion

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