title: Structure and conformation of the medium-sized chlorophosphazene rings.
abstract: Medium-sized cyclic oligomeric phosphazenes [PCl2N]m (where m = 5-9) that were prepared from the reaction of PCl5 and NH4Cl in refluxing chlorobenzene have been isolated by a combination of sublimation/extraction and column chromatography from the predominant products [PCl2N]3 and [PCl2N]4. The medium-sized rings [PCl2N]m have been characterized by electrospray ionization-mass spectroscopy (ESI-MS), their (31)P chemical shifts have been reassigned, and their T1 relaxation times have been obtained. Crystallographic data has been recollected for [PCl2N]5, and the crystal structures of [PCl2N]6, and [PCl2N]8 are reported. Halogen-bonding interactions were observed in all the crystal structures of cyclic [PCl2N]m (m = 3-5, 6, 8). The crystal structures of [P(OPh)2N]7 and [P(OPh)2N]8, which are derivatives of the respective [PCl2N]m, are also reported. Comparisons of the intermolecular forces and torsion angles of [PCl2N]8 and [P(OPh)2N]8 with those of three other octameric rings are described. The comparisons show that chlorophosphazenes should not be considered prototypical, in terms of solid-state structure, because of the strong influence of halogen bonding.
authors.affiliation: University of Akron , Department of Chemistry, Akron, Ohio 44325-3601, United States.
authors.forename: David J
authors.initials: DJ
authors.lastname: Bowers
authors.forename: Brian D
authors.initials: BD
authors.lastname: Wright
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Scionti
authors.forename: Anthony
authors.initials: A
authors.lastname: Schultz
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Panzner
authors.forename: Eric B
authors.initials: EB
authors.lastname: Twum
authors.forename: Lin-Lin
authors.initials: LL
authors.lastname: Li
authors.forename: Bryan C
authors.initials: BC
authors.lastname: Katzenmeyer
authors.forename: Benjamin S
authors.initials: BS
authors.lastname: Thome
authors.forename: Peter L
authors.initials: PL
authors.lastname: Rinaldi
authors.forename: Chrys
authors.initials: C
authors.lastname: Wesdemiotis
authors.forename: Wiley J
authors.initials: WJ
authors.lastname: Youngs
authors.forename: Claire A
authors.initials: CA
authors.lastname: Tessier