Conformation, Bonding, and Flexibility in Short-Chain Linear Phosphazenes

Harry R. Allcock, Norris M. Tollefson, Robert A. Arcus, Robert R. Whittle

Research output: Contribution to journalArticle

99 Citations (Scopus)

Abstract

A number of linear, short-chain phosphazenes have been prepared as structural models for three classes of phosphazene linear high polymers. X-ray diffraction results from studies of OP(C12)NPC13(7), OP(C12)NP(Cl2)NPCl3(10), [C13PNP-(C12)NP(Cl2)NPCl3]+PC16 -(14), OP(OPh)2NP(OPh)3 (8), OP(NHPh)2NP(NHPh)3 (9), and OP(NHPh)2NP(NHPh)2NP(NHPh)3(12) suggest different values for the bond angles and bond lengths than have been used in the past in structural studies of the high polymers. The P—N bond lengths in the short-chain species differ by 0.07 Å or less within each molecule, and planar skeletal conformations are preferred, especially cis—trans planar. The evidence suggests that, although the molecules are stabilized by electron delocalization, the conformations originate from intramolecular nonbonding interactions. The short phosphazene chains stack in the crystal lattice in a parallel arrangement analogous to that expected in polymer microcrystallites. Comparisons between the 31P NMR shifts of the short chain species and the corresponding high polymers revealed a close similarity between the electronic and structural environments of the middle units in the short chain species and in the repeating units of the high polymers.

Original languageEnglish (US)
Pages (from-to)5166-5177
Number of pages12
JournalJournal of the American Chemical Society
Volume107
Issue number18
DOIs
StatePublished - Jan 1 1985

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Conformations
Polymers
Bond length
Molecules
Structural Models
X-Ray Diffraction
Crystal lattices
Nuclear magnetic resonance
Electrons
X ray diffraction

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Allcock, Harry R. ; Tollefson, Norris M. ; Arcus, Robert A. ; Whittle, Robert R. / Conformation, Bonding, and Flexibility in Short-Chain Linear Phosphazenes. In: Journal of the American Chemical Society. 1985 ; Vol. 107, No. 18. pp. 5166-5177.
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abstract = "A number of linear, short-chain phosphazenes have been prepared as structural models for three classes of phosphazene linear high polymers. X-ray diffraction results from studies of OP(C12)NPC13(7), OP(C12)NP(Cl2)NPCl3(10), [C13PNP-(C12)NP(Cl2)NPCl3]+PC16 -(14), OP(OPh)2NP(OPh)3 (8), OP(NHPh)2NP(NHPh)3 (9), and OP(NHPh)2NP(NHPh)2NP(NHPh)3(12) suggest different values for the bond angles and bond lengths than have been used in the past in structural studies of the high polymers. The P—N bond lengths in the short-chain species differ by 0.07 {\AA} or less within each molecule, and planar skeletal conformations are preferred, especially cis—trans planar. The evidence suggests that, although the molecules are stabilized by electron delocalization, the conformations originate from intramolecular nonbonding interactions. The short phosphazene chains stack in the crystal lattice in a parallel arrangement analogous to that expected in polymer microcrystallites. Comparisons between the 31P NMR shifts of the short chain species and the corresponding high polymers revealed a close similarity between the electronic and structural environments of the middle units in the short chain species and in the repeating units of the high polymers.",
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Conformation, Bonding, and Flexibility in Short-Chain Linear Phosphazenes. / Allcock, Harry R.; Tollefson, Norris M.; Arcus, Robert A.; Whittle, Robert R.

In: Journal of the American Chemical Society, Vol. 107, No. 18, 01.01.1985, p. 5166-5177.

Research output: Contribution to journalArticle

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