Strain-Induced Ring-Opening Polymerization of Ferrocenylorganocyclotriphosphazenes: A New Synthetic Route to Poly(organophosphazenes)

Harry R. Allcock; Jeffrey A. Dodge; Ian Manners; Geoffrey H. Riding

doi:10.1021/ja00025a026

Strain-Induced Ring-Opening Polymerization of Ferrocenylorganocyclotriphosphazenes: A New Synthetic Route to Poly(organophosphazenes)

Harry R. Allcock
, Jeffrey A. Dodge
, Ian Manners
, Geoffrey H. Riding

Research output: Contribution to journal › Article › peer-review

64 Scopus citations

Abstract

The strained transannular ferrocenylcyclotriphosphazenes N₃P₃(OCH₂CF₃)₄(η-C_sH₄)₂Fe, N₃P₃R(0CH₂CF₃)₃(η-C₅H₄)₂Fe [R = OPh, R = Me, R = Ph (R geminal to Cp), and R = Ph (nongeminal to Cp)], and N₃P₃R₂(OCH₂CF₃)₂(η-C₅H₄)₂Fe [R = Ph (geminal to Cp) and R = Ph (nongeminal to Cp)] undergo ring-opening polymerization when heated at 250 °C in the presence of a small amount (1%) of (NPC1₂)₃, which functions as a polymerization initiator. The cyclic trimers N₃P₃-(OPh)(OCH₂CF₃)₃(η-C₅H₄)₂Fe, N₃P₃Me(OCH₂CF₃)₃(η-C₅H₄)₂Fe, and N₃P₃Ph₂(OCH₂CF₃)₂(η-C₅H₄)₂Fe (Ph groups nongeminal to Cp) also polymerize at 250 °C but in the absence of (NPC1₂)₃. These transformations are the first examples of uncatalyzed ring-opening polymerization of cyclic phosphazenes that lack phosphorus-halogen bonds. By contrast, the sterically crowded cyclotriphosphazene N₃P₃(OPh)₄(η-C₅H₄)₂Fe undergoes ring expansion to the corresponding cyclic hexamer when heated at 250 °C in the presence or absence of (NPC1₂)₃, but it does not polymerize. When heated in the absence of (NPC1₂)₃, N₃P₃(OCH₂CF₃)₄(η-C₅H₄)₂Fe, N₃P₃(OPh)(OCH₂CF₃)₃(η-C₅H₄)₂Fe, and N₃P₃Ph(OCH₂CF₃)₃(η-C₅H₄)₂Fe (Ph nongeminal to Cp) also undergo ring expansion to form the corresponding cyclic hexamers. The Lewis acid BC1₃ initiates the ring-opening polymerization of N₃P₃(OCH₂CF₃)₄(η-C₅H₄)₂Fe and catalyzes the ring expansion of N₃P₃(OPh)₄(η-C₅H₄)₂Fe. Possible explanations for the differences in thermal behavior are given. The implications of these results for the mechanisms of phosphazene ring-opening polymerization and ring-ring equilibration are also discussed.

Original language	English (US)
Pages (from-to)	9596-9603
Number of pages	8
Journal	Journal of the American Chemical Society
Volume	113
Issue number	25
DOIs	https://doi.org/10.1021/ja00025a026
State	Published - Dec 1 1991

All Science Journal Classification (ASJC) codes

Catalysis
General Chemistry
Biochemistry
Colloid and Surface Chemistry

Access to Document

10.1021/ja00025a026

Cite this

@article{7e022a53890445c4b36f96f2adbd111e,

title = "Strain-Induced Ring-Opening Polymerization of Ferrocenylorganocyclotriphosphazenes: A New Synthetic Route to Poly(organophosphazenes)",

abstract = "The strained transannular ferrocenylcyclotriphosphazenes N3P3(OCH2CF3)4(η-CsH4)2Fe, N3P3R(0CH2CF3)3(η-C5H4)2Fe [R = OPh, R = Me, R = Ph (R geminal to Cp), and R = Ph (nongeminal to Cp)], and N3P3R2(OCH2CF3)2(η-C5H4)2Fe [R = Ph (geminal to Cp) and R = Ph (nongeminal to Cp)] undergo ring-opening polymerization when heated at 250 °C in the presence of a small amount (1\%) of (NPC12)3, which functions as a polymerization initiator. The cyclic trimers N3P3-(OPh)(OCH2CF3)3(η-C5H4)2Fe, N3P3Me(OCH2CF3)3(η-C5H4)2Fe, and N3P3Ph2(OCH2CF3)2(η-C5H4)2Fe (Ph groups nongeminal to Cp) also polymerize at 250 °C but in the absence of (NPC12)3. These transformations are the first examples of uncatalyzed ring-opening polymerization of cyclic phosphazenes that lack phosphorus-halogen bonds. By contrast, the sterically crowded cyclotriphosphazene N3P3(OPh)4(η-C5H4)2Fe undergoes ring expansion to the corresponding cyclic hexamer when heated at 250 °C in the presence or absence of (NPC12)3, but it does not polymerize. When heated in the absence of (NPC12)3, N3P3(OCH2CF3)4(η-C5H4)2Fe, N3P3(OPh)(OCH2CF3)3(η-C5H4)2Fe, and N3P3Ph(OCH2CF3)3(η-C5H4)2Fe (Ph nongeminal to Cp) also undergo ring expansion to form the corresponding cyclic hexamers. The Lewis acid BC13 initiates the ring-opening polymerization of N3P3(OCH2CF3)4(η-C5H4)2Fe and catalyzes the ring expansion of N3P3(OPh)4(η-C5H4)2Fe. Possible explanations for the differences in thermal behavior are given. The implications of these results for the mechanisms of phosphazene ring-opening polymerization and ring-ring equilibration are also discussed.",

author = "Allcock, \{Harry R.\} and Dodge, \{Jeffrey A.\} and Ian Manners and Riding, \{Geoffrey H.\}",

year = "1991",

month = dec,

day = "1",

doi = "10.1021/ja00025a026",

language = "English (US)",

volume = "113",

pages = "9596--9603",

journal = "Journal of the American Chemical Society",

issn = "0002-7863",

publisher = "American Chemical Society",

number = "25",

}

TY - JOUR

T1 - Strain-Induced Ring-Opening Polymerization of Ferrocenylorganocyclotriphosphazenes

T2 - A New Synthetic Route to Poly(organophosphazenes)

AU - Allcock, Harry R.

AU - Dodge, Jeffrey A.

AU - Manners, Ian

AU - Riding, Geoffrey H.

PY - 1991/12/1

Y1 - 1991/12/1

N2 - The strained transannular ferrocenylcyclotriphosphazenes N3P3(OCH2CF3)4(η-CsH4)2Fe, N3P3R(0CH2CF3)3(η-C5H4)2Fe [R = OPh, R = Me, R = Ph (R geminal to Cp), and R = Ph (nongeminal to Cp)], and N3P3R2(OCH2CF3)2(η-C5H4)2Fe [R = Ph (geminal to Cp) and R = Ph (nongeminal to Cp)] undergo ring-opening polymerization when heated at 250 °C in the presence of a small amount (1%) of (NPC12)3, which functions as a polymerization initiator. The cyclic trimers N3P3-(OPh)(OCH2CF3)3(η-C5H4)2Fe, N3P3Me(OCH2CF3)3(η-C5H4)2Fe, and N3P3Ph2(OCH2CF3)2(η-C5H4)2Fe (Ph groups nongeminal to Cp) also polymerize at 250 °C but in the absence of (NPC12)3. These transformations are the first examples of uncatalyzed ring-opening polymerization of cyclic phosphazenes that lack phosphorus-halogen bonds. By contrast, the sterically crowded cyclotriphosphazene N3P3(OPh)4(η-C5H4)2Fe undergoes ring expansion to the corresponding cyclic hexamer when heated at 250 °C in the presence or absence of (NPC12)3, but it does not polymerize. When heated in the absence of (NPC12)3, N3P3(OCH2CF3)4(η-C5H4)2Fe, N3P3(OPh)(OCH2CF3)3(η-C5H4)2Fe, and N3P3Ph(OCH2CF3)3(η-C5H4)2Fe (Ph nongeminal to Cp) also undergo ring expansion to form the corresponding cyclic hexamers. The Lewis acid BC13 initiates the ring-opening polymerization of N3P3(OCH2CF3)4(η-C5H4)2Fe and catalyzes the ring expansion of N3P3(OPh)4(η-C5H4)2Fe. Possible explanations for the differences in thermal behavior are given. The implications of these results for the mechanisms of phosphazene ring-opening polymerization and ring-ring equilibration are also discussed.

AB - The strained transannular ferrocenylcyclotriphosphazenes N3P3(OCH2CF3)4(η-CsH4)2Fe, N3P3R(0CH2CF3)3(η-C5H4)2Fe [R = OPh, R = Me, R = Ph (R geminal to Cp), and R = Ph (nongeminal to Cp)], and N3P3R2(OCH2CF3)2(η-C5H4)2Fe [R = Ph (geminal to Cp) and R = Ph (nongeminal to Cp)] undergo ring-opening polymerization when heated at 250 °C in the presence of a small amount (1%) of (NPC12)3, which functions as a polymerization initiator. The cyclic trimers N3P3-(OPh)(OCH2CF3)3(η-C5H4)2Fe, N3P3Me(OCH2CF3)3(η-C5H4)2Fe, and N3P3Ph2(OCH2CF3)2(η-C5H4)2Fe (Ph groups nongeminal to Cp) also polymerize at 250 °C but in the absence of (NPC12)3. These transformations are the first examples of uncatalyzed ring-opening polymerization of cyclic phosphazenes that lack phosphorus-halogen bonds. By contrast, the sterically crowded cyclotriphosphazene N3P3(OPh)4(η-C5H4)2Fe undergoes ring expansion to the corresponding cyclic hexamer when heated at 250 °C in the presence or absence of (NPC12)3, but it does not polymerize. When heated in the absence of (NPC12)3, N3P3(OCH2CF3)4(η-C5H4)2Fe, N3P3(OPh)(OCH2CF3)3(η-C5H4)2Fe, and N3P3Ph(OCH2CF3)3(η-C5H4)2Fe (Ph nongeminal to Cp) also undergo ring expansion to form the corresponding cyclic hexamers. The Lewis acid BC13 initiates the ring-opening polymerization of N3P3(OCH2CF3)4(η-C5H4)2Fe and catalyzes the ring expansion of N3P3(OPh)4(η-C5H4)2Fe. Possible explanations for the differences in thermal behavior are given. The implications of these results for the mechanisms of phosphazene ring-opening polymerization and ring-ring equilibration are also discussed.

UR - https://www.scopus.com/pages/publications/0007150239

UR - https://www.scopus.com/pages/publications/0007150239#tab=citedBy

U2 - 10.1021/ja00025a026

DO - 10.1021/ja00025a026

M3 - Article

AN - SCOPUS:0007150239

SN - 0002-7863

VL - 113

SP - 9596

EP - 9603

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

IS - 25

ER -

Strain-Induced Ring-Opening Polymerization of Ferrocenylorganocyclotriphosphazenes: A New Synthetic Route to Poly(organophosphazenes)

Abstract

All Science Journal Classification (ASJC) codes

Access to Document

Other files and links

Fingerprint

Cite this