Pana, AmaliaAmaliaPanaBadea, Florentina LauraFlorentina LauraBadeaIlis, MonicaMonicaIlisStaicu, TeodoraTeodoraStaicuMicutz, MarinMarinMicutzPasuk, IulianaIulianaPasukCircu, ViorelViorelCircu2019-10-312019-10-3120150022-2860DOI: 10.1016/j.molstruc.2014.11.059http://hdl.handle.net/123456789/1549Journal of Molecular Structure, 2015, 1083, pp. 245-251A series of 3,4,5-tridodecyloxybenzyl pyridinium salts derived from 4-hydroxypyridine has been designed and prepared. The liquid crystalline properties of these compounds were investigated by polarized optical microscopy, differential scanning calorimetry and powder X-ray diffraction while their thermal stability was studied by thermogravimetric analysis. The N-3,4,5-tridodecyloxybenzyl-4-pyridone intermediate shows a monotropic columnar hexagonal mesophase ranging from 56 C down to room temperature while the corresponding bromide dodecyl O-alkylated pyridinium salt shows one enantiotropic columnar mesophase and one additional monotropic columnar phase at lower temperatures. Replacing bromide ion (Br ) with other counterions (NO 3 ; BF 4 and PF 6 ) resulted in mesophase suppression. These luminescent pyridinium salts show weak emission in dichloromethane solutions at room temperature and a pronounced red-shifted emission in solid state. Photoluminescent properties of the pyridinium salts do not depend significantly on the nature of counterion employed.en-USIonic liquid crystals4-HydroxypyridinePyridinium salts4-PyridoneColumnar mesophaseArticle