Tris-o-phenylenedioxycyclotriphosphazene (TPP) Inclusion Compounds Containing a Dipolar Molecular Rotor

0427671 - ÚOCHB 2015 RIV US eng J - Journal Article
Kobr, L. - Zhao, K. - Shen, Y. - Shoemaker, R. K. - Rogers, C. T. - Michl, Josef
Tris-o-phenylenedioxycyclotriphosphazene (TPP) Inclusion Compounds Containing a Dipolar Molecular Rotor.
Crystal Growth & Design. Roč. 14, č. 2 (2014), s. 559-568. ISSN 1528-7483. E-ISSN 1528-7505
EU Projects: European Commission(XE) 227756 - DIPOLAR ROTOR ARRAY
Institutional support: RVO:61388963
Keywords : aromatic nanochannels * single-molecule * dynamics
Subject RIV: CC - Organic Chemistry
Impact factor: 4.891, year: 2014

A rod-shaped molecular rotor consisting of a p-terphenyl shaft attached to p-carborane whose antipodal position carries a dipolar 2,3-dichlorophenyl rotator forms an inclusion compound with hexagonal tris-o-phenylenedioxycyclotriphosphazene (TPP). Results of solid-state NMR spectroscopy, X-ray powder diffraction, dielectric loss spectroscopy, and density functional theory calculations lead us to propose that the whole molecule inserts into the TPP channels, with the rotator located in the outermost surface layer. Although the placement and alignment of the dipoles at the surface appear favorable, the sample does not exhibit collective behavior even at 7 K, presumably due to the relatively large barrier to rotation (similar to 8.6 kcal/mol). In incompletely annealed samples of the inclusion compound, some of the rotators protrude outside the surface and have a rotational barrier of similar to 3.4 kcal/mol. In the inclusion compound of an analog in which the rotator is replaced with a methyl group, some of the methyl substituents are located inside the surface layer of TPP and others protrude above it.
Permanent Link: http://hdl.handle.net/11104/0233199