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Updated: Jul 16, 2026

Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level
Published on: September 26, 2016
The origin of endocyclic bond length variations in disubstituted cyclotriphosphazenes
Michael Calichman1, Agnes Derecskei-Kovacs, Christopher W Allen
1Department of Chemistry, University of Vermont, Burlington, Vermont 05405-0125, USA.
Abstract:
Intraannular ring alternation in heterogeneously substituted cyclotriphosphazenes is investigated using both ab initio and density functional methods. Comparisons of the calculated geometries for N3P3X6 (X = H, F, Cl, Me, Ph) and N3P3X4Y2 (X = F, Cl; Y = Me, Ph, X, Cl) with experimental X-ray data establish the utility of the 6-31G* basis for use with both Hartree-Fock and the B3LYP and B3PW91 functionals. Analysis of orbitals and charges shows that the bonding is best described using a polarized bond model rather than the previous explanation of asymmetric nitrogen-lone-pair donation into the phosphorus-nitrogen bond.
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