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Full-Text Articles in Physical Sciences and Mathematics
Thermotropic Liquid-Crystalline And Light-Emitting Properties Of Bis(4-Aalkoxyphenyl) Viologen Bis(Triflimide) Salts, Pradip K. Bhowmik, Muhammed Kareem M. Al-Karawi, Shane T. Killarney, Erenz J. Dizon, Anthony Chang, Jongin Kim, Si L. Chen, Ronald Carlo G. Principe, Andy Ho, Haesook Han
Thermotropic Liquid-Crystalline And Light-Emitting Properties Of Bis(4-Aalkoxyphenyl) Viologen Bis(Triflimide) Salts, Pradip K. Bhowmik, Muhammed Kareem M. Al-Karawi, Shane T. Killarney, Erenz J. Dizon, Anthony Chang, Jongin Kim, Si L. Chen, Ronald Carlo G. Principe, Andy Ho, Haesook Han
Chemistry and Biochemistry Faculty Research
A series of bis(4-alkoxyphenyl) viologen bis(triflimide) salts with alkoxy chains of different lengths were synthesized by the metathesis reaction of respective bis(4-alkoxyphenyl) viologen dichloride salts, which were in turn prepared from the reaction of Zincke salt with the corresponding 4-n-alkoxyanilines, with lithium triflimide in methanol. Their chemical structures were characterized by 1H and 13C nuclear magnetic resonance spectra and elemental analysis. Their thermotropic liquid-crystalline (LC) properties were examined by differential scanning calorimetry, polarizing optical microscopy, and variable temperature X-ray diffraction. Salts with short length alkoxy chains had crystal-to-liquid transitions. Salts of intermediate length alkoxy chains showed both crystal-to-smectic A (SmA) …
Thermotropic Liquid-Crystalline Properties Of Viologens Containing 4-N-Alkylbenzenesulfonates†, Pradip K. Bhowmik, Anthony Chang, Jongin Kim, Erenz J. Dizon, Ronald Carlo G. Principe, Haesook Han
Thermotropic Liquid-Crystalline Properties Of Viologens Containing 4-N-Alkylbenzenesulfonates†, Pradip K. Bhowmik, Anthony Chang, Jongin Kim, Erenz J. Dizon, Ronald Carlo G. Principe, Haesook Han
Chemistry and Biochemistry Faculty Research
A series of viologens containing 4-n-alkylbenzenesulfonates were synthesized by the metathesis reaction of 4-n-alkylbenzenesulfonic acids or sodium 4-n-alkylbezenesulfonates with the respective viologen dibromide in alcohols. Their chemical structures were characterized by Fourier Transform Infrared, 1H and 13C Nuclear Magnetic Resonance spectra and elemental analysis. Their thermotropic liquid-crystalline (LC) properties were examined by differential scanning calorimetry and polarizing optical microscopy. They formed LC phases above their melting transitions and showed isotropic transitions. As expected, all the viologen salts had excellent stabilities in the temperature range of 278–295 °C as determined by thermogravimetric analysis.
Thermotropic Liquid-Crystalline Properties Of Extended Viologen Bis(Triflimide) Salts, Pradip K. Bhowmik, Shane T. Killarney, Jessa Rose A. Li, Jung Jae Koh, Haesook Han, Lewis Sharpnack, Deña M. Agra-Kooijman, Michael R. Fisch, Satyendra Kumar
Thermotropic Liquid-Crystalline Properties Of Extended Viologen Bis(Triflimide) Salts, Pradip K. Bhowmik, Shane T. Killarney, Jessa Rose A. Li, Jung Jae Koh, Haesook Han, Lewis Sharpnack, Deña M. Agra-Kooijman, Michael R. Fisch, Satyendra Kumar
Chemistry and Biochemistry Faculty Research
A series of extended, symmetric viologen triflimides were synthesised by the metathesis reaction of lithium triflimide with the respective viologen tosyalates in methanol. Their chemical structures were characterised by Fourier Transform Infrared, 1H and 13C Nuclear Magnetic Resonance spectroscopy and elemental analysis. Their thermotropic liquid-crystalline (LC) properties were examined by a number of experimental techniques including differential scanning calorimetry, thermogravimetric analysis, polarising optical microscopy and variable temperature X-ray diffraction. The viologen salts containing alkyl chain of two carbon and three carbon atoms were relatively low melting salts. Those of alkyl chains of four carbon and five carbon atoms formed ionic …