title: Arrays of dipolar molecular rotors in Tris(o-phenylenedioxy) cyclotriphosphazene.
abstract: Regular two-dimensional or three-dimensional arrays of mutually interacting dipolar molecular rotors represent a worthy synthetic objective. Their dielectric properties, including possible collective behavior, will be a sensitive function of the location of the rotors, the orientation of their axes, and the size of their dipoles. Host-guest chemistry is one possible approach to gaining fine control over these factors. We describe the progress that has been achieved in recent years using tris (o-phenylenedioxy)cyclotriphosphazene as a host and a series of rod-shaped dipolar molecular rotors as guests. Structures of both surface and bulk inclusion compounds have been established primarily by solid-state nuclear magnetic resonance (NMR) and powder X-ray diffraction (XRD) techniques. Low-temperature dielectric spectroscopy revealed rotational barriers as low as 1.5 kcal/mol, but no definitive evidence for collective behavior has been obtained so far.
authors.affiliation: Department of Physics, University of Colorado, Boulder, CO, 80309, USA.
authors.forename: Ke
authors.initials: K
authors.lastname: Zhao
authors.forename: Paul I
authors.initials: PI
authors.lastname: Dron
authors.forename: Jiří
authors.initials: J
authors.lastname: Kaleta
authors.forename: Charles T
authors.initials: CT
authors.lastname: Rogers
authors.forename: Josef
authors.initials: J
authors.lastname: Michl