Arrays of Dipolar Molecular Rotors in Tris (<i>o</i>-phenylenedioxy) cyclotriphosphazene

Zhao K., Dron P. I., Kaleta J., Rogers C. T., Michl J.

MOLECULAR MACHINES AND MOTORS: RECENT ADVANCES AND PERSPECTIVES, cilt.354, ss.163-211, 2014 (SCI-Expanded, Scopus)

Özet

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.