Anionic ring‐opening polymerization of small phosphorus heterocycles and their borane adducts: An ab initio investigation

Coote, Michelle L.; Hodgson, Jennifer L.; Krenske, Elizabeth H.; Wild, S. Bruce

doi:10.1002/hc.20323

Cited by 11 publications

(9 citation statements)

References 36 publications

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“…Several ab initio studies have been reported that evaluate the feasibility of the radical ring-opening polymerization of several phosphorus-containing heterocycles. 82,83 Novel copper halide coordination polymers were prepared using a P 4 S 3 ligand. 84 Phosphonate-capped dendrimers have been prepared and were shown to promote the multiplication of human natural killer cells.…”

Section: ð15þmentioning

confidence: 99%

Inorganic and organometallic polymers

Noonan

Gates

2008

Annu. Rep. Prog. Chem., Sect. A: Inorg. Chem.

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Polymers composed partially or entirely of inorganic elements in the main chain possess unique structures, properties and applications. This report summarizes the developments in the synthesis and study of macromolecules which incorporate main group and transition elements in the polymer backbone. HighlightsMajor accomplishments in the synthesis of inorganic polymers reported in 2007 include: the use of self-assembly to chemically micropattern polysiloxanes, the synthesis of p-conjugated oligomeric models for poly(phenylenedisilene), the preparation of novel polythiophenes bearing borane substituents, the isolation of cyclic ferrocenophane macromolecules, the ''living'' growth of micelles from ferrocenylsilane block copolymers, and the observation of novel electron transfer and conductive properties of zinc-porphyrin polymers.

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Section: ð15þmentioning

confidence: 99%

Inorganic and organometallic polymers

Noonan

Gates

2008

Annu. Rep. Prog. Chem., Sect. A: Inorg. Chem.

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“…The large difference in rate constants for the two pathways suggests that, although the propagation step of the desired anionic polymerization of free phosphiranes is facile [3], the polymerization is likely to be hampered by attack at phosphorus. We have found this to be borne out by experiment.…”

Section: Resultsmentioning

confidence: 95%

“…• C) to enable a practical synthesis of polyphosphines 3 [3]. The borane adduct of 1 (R = Me) had a similar rate constant (k = 6.8 × 10 4 L mol…”

Section: Introductionmentioning

confidence: 99%

Reactivity of phosphiranes toward nucleophiles: Theoretical and experimental investigations

Coote

Krenske

Maulana

et al. 2008

Heteroatom Chemistry

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“…Since the borane adduct exists in equilibrium with the free phosphetane, it is possible that some polymerization will occur, depending upon the stability of the complex. However, for the parent compound (1-methylphosphetane) at least, the calculated equilibrium constant for complex formation (1.2 × 10 20 L mol −1 ) [17] is so large that this possibility is excluded. For the oxide, the propagation rate coefficient is a further 10 orders of magnitude lower than for the borane adduct, and radical ring-opening polymerization will be negligible.…”

Section: Oxides and Borane Adductsmentioning

confidence: 99%

“…five orders of magnitude, despite the fact that there was an increase in strain energy in the borane adduct that rendered ring-opening more thermodynamically favourable. [17] This contra-thermodynamic effect appears to arise partly from the reduced electron density at phosphorus in the attacking Me 2 (H 3 B)P − ion (relative to Me 2 P − ) and partly from the increased HOMO-LUMO gap of the breaking bond in the phosphetane-borane adduct. For the radical ring-opening reactions studied here, the attacking species is the same for each substrate, but the HOMO-LUMO gap remains an important consideration.…”

Section: Oxides and Borane Adductsmentioning

confidence: 99%

Radical Ring-Opening Polymerization of Phosphorus Heterocycles: Computational Design of Suitable Phosphetane Monomers

et al. 2007

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High-level ab initio calculations have been used to determine the propensities of various phosphetanes towards radical ring-opening polymerization. At the G3(MP2)-RAD level of theory, the propagation rate constants of 1-methylphosphetane (7.5 × 10 4 L mol −1 s −1 ), 1-phenylphosphetane (4.6 × 10 5 L mol −1 s −1 ), cis,cis-2,4-dichloro-1-phenylphosphetane (3.8 × 10 7 L mol −1 s −1 ), cis,cis-2,4-difluoro-1-phenylphosphetane (3.0 × 10 7 L mol −1 s −1 ), and 1-phenyl-3-oxaphosphetane (4.0 × 10 6 L mol −1 s −1 ) are very high, rendering them unsuitable for copolymerization with common alkenes. In contrast, the propagation rate constants of 1-tert-butylphosphetane (1.7 × 10 3 L mol −1 s −1 ) and cis,cis-2,4-dimethyl-1-phenylphosphetane (9.2 × 10 2 L mol −1 s −1 ) indicate that either incorporation of a t-butyl substituent at phosphorus or alkylation at the 2-and/or 4-positions will produce monomers with more compatible reactivities for copolymerization with alkenes. In the case of 1-tert-butylphosphetane, however, homolytic substitution of the propagating radical with the t-butyl substituent at P will be competitive with the propagation step and could affect the microstructure of the polymer. The borane adduct and the oxide of 1-phenylphosphetane were both found to be unreactive towards radical ring-opening. The calculations suggest that, for chiral phosphetanes, the ring-opening reaction is enantioselective at phosphorus and the resulting polymer will be isotactic.

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Anionic ring‐opening polymerization of small phosphorus heterocycles and their borane adducts: An ab initio investigation

Cited by 11 publications

References 36 publications

Inorganic and organometallic polymers

Inorganic and organometallic polymers

Reactivity of phosphiranes toward nucleophiles: Theoretical and experimental investigations

Radical Ring-Opening Polymerization of Phosphorus Heterocycles: Computational Design of Suitable Phosphetane Monomers

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