Inclusion Compound Based Approach to Arrays of Artificial Dipolar Molecular Rotors: Bulk Inclusions

0392508 - ÚOCHB 2014 RIV US eng J - Článek v odborném periodiku
Kobr, L. - Zhao, K. - Shen, Y. - Polívková, Kateřina - Shoemaker, R. K. - Clark, N.A. - Price, J. C. - Rogers, C. T. - Michl, Josef
Inclusion Compound Based Approach to Arrays of Artificial Dipolar Molecular Rotors: Bulk Inclusions.
Journal of Organic Chemistry. Roč. 78, č. 5 (2013), s. 1768-1777. ISSN 0022-3263. E-ISSN 1520-6904
GRANT EU: European Commission(XE) 227756 - DIPOLAR ROTOR ARRAY
Institucionální podpora: RVO:61388963
Klíčová slova: solid-state dynamics * phosphonitrilic compounds * aromatic nanochannels * triethylamine
Kód oboru RIV: CC - Organická chemie
Impakt faktor: 4.638, rok: 2013

We examine the insertion of two dipolar molecular rotors as guests into a host, tris(o-phenylenedioxy)cyclotriphosphazine (TPP, 1), using differential scanning calorimetry, solid-state NMR, powder X-ray diffraction, and dielectric spectroscopy. The rotors are 1-(4'-n-pentylbiphenyl-4-yl)-12-(2,3-dichlorophenyl)-p-dicarba-closo-dodecaborane and 1,12-bis-(2,3-dichlorophenyl) -p-dicarba-closo-dodecaborane. Both enter the bulk even though their nominal diameter exceeds the nominal channel diameter and although a closely related rotor, 1-n-hexadecyl-12-(2,3-dichlorophenyl)-p-dicarba-closo-dodecaborane, is known to produce a surface inclusion compound. Rotational barriers of 5.4-9.3 kcal/mol were found for the dichlorophenyl rotator contained within the TPP channel. Clearly, van der Waals diameters in themselves do not suffice to predict TPP channel entry. It is suggested that the efficacy of the p-carborane stopper is reduced by the presence of the two relatively bulky adjacent benzene rings, which help to stretch the channel, and by the axial direction of its axis, which prevents the attached rotator from contributing to the stopping action.
Trvalý link: http://hdl.handle.net/11104/0221360