Naslov
Photoinduced Gelation by Stilbene Oxalyl Amide Compounds

Autori
Miljanić, Snežana ; Frkanec, Leo ; Meić, Zlatko ; Žinić, Mladen

Izvornik
Langmuir (0743-7463) 21 (2005), 7; 2754-2760

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Cis-Trans Photoisomerization; Stilbene; Gel formation; Gelators; Organogelators; Recognition; Amphiphiles

Sažetak
Oxalyl amide derivatives bearing 4-dodecyloxy-stilbene as a cis-trans photoisomerizing unit were synthesized. The trans derivative acted as a versatile gelator of various organic solvents, whereas the corresponding cis derivative showed a poor gelation ability or none at all. In diluted solution (c = 2.0 x 10(-5) mol dm(-3), ethanol), the cis isomer was photochemically converted into the trans isomer within 4 min. Depending on the radiation wavelength, the trans isomer was stable or liable to photodecomposition. When exposed to irradiation, a concentrated solution of the cis isomer (c = 2.0 x 10(-2) mol dm-3, ethanol) turned into a gel. The FT-Raman, FT-IR, and H-1 NMR spectra demonstrated that the gelation process occurred because of a rapid cis -> trans photoisomerization followed by a self-assembly of the trans molecules. Apart from the formation of hydrogen bonding between the oxalyl amide parts of the molecules, confirmed by FT-IR spectroscopy, it was assumed that the pi-pi stacking between the trans-stilbene units of the molecule and a lipophilic interaction between long alkyl chains were the interactions responsible for gelation.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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