Arrays of Molecular Rotors with Triptycene Stoppers: Surface Inclusion in Hexagonal Tris(o-phenylenedioxy)cyclotriphosphazene

0445865 - ÚOCHB 2016 RIV US eng J - Journal Article
Kaleta, Jiří - Dron, P. I. - Zhao, K. - Shen, Y. - Císařová, I. - Rogers, C. T. - Michl, Josef
Arrays of Molecular Rotors with Triptycene Stoppers: Surface Inclusion in Hexagonal Tris(o-phenylenedioxy)cyclotriphosphazene.
Journal of Organic Chemistry. Roč. 80, č. 12 (2015), s. 6173-6192. ISSN 0022-3263. E-ISSN 1520-6904
EU Projects: European Commission(XE) 227756 - DIPOLAR ROTOR ARRAY
Institutional support: RVO:61388963
Keywords : compound based approach * phosphonitrilic compounds * polysilanes
Subject RIV: CC - Organic Chemistry
Impact factor: 4.785, year: 2015

A new generation of rod-shaped dipolar molecular rotors designed for controlled insertion into channel arrays in the surface of hexagonal tris(o-phenylenedioxy)cyclotriphosphazene (TPP) has been designed and synthesized. Triptycene is used as a stopper intended to prevent complete insertion, forcing the formation of a surface inclusion. Two widely separated C-13 NMR markers are present in the shaft for monitoring the degree of insertion. The structure of the two-dimensional rotor arrays contained in these surface inclusions was examined by solid-state NMR and X-ray powder diffraction. The NMR markers and the triptycene stopper functioned as designed, but half of the guest molecules were not inserted as deeply into the TPP channels as the other half. As a result, the dipolar rotators were distributed equally in two planes parallel to the crystal surface instead of being located in a single plane as would be required for ferroelectricity. Dielectric spectroscopy revealed rotational barriers of similar to 4 kcal/mol but no ferroelectric behavior.
Permanent Link: http://hdl.handle.net/11104/0247940