ORGN 578 |
| Sehoon Kim1, Seung Yeul Ryu1, Jangwon Seo1, Soo Young Park1, Young-Woon Kim1, Oh-Hoon Kwon2, and Du-Jeon Jang2. (1) School of Materials Science and Engineering, Seoul National University, San 56-1, Shillim-dong, Kwanak-ku, Seoul, 151-744, South Korea, (2) School of Chemistry, Seoul National University, Seoul, 151-742, South Korea |
| We synthesized a novel tripod organic gelator (TOBA) that is constructed with benzene-1,3,5-tricarboxamide as a self-assembly core motif and three photoactive 2,5-diphenyl-[1,3,4]oxadiazole arms with a long alkyl chain end. TOBA showed robust physical gelation ability in organic media: immobile, transparent-translucent gels were formed in various organic solvents even below a concentration of 0.1 wt%. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) studies gave a picture of supramolecular structure of TOBA: 3-dimensional network of single strand fibrils formed by hydrogen (H)-bonded columnar stacking of TOBA molecules. Moreover, TOBA showed an interesting fluorescing behavior depending on the assembly state, that is, isolated monomer is nonfluorescent while H-bonded sol-gel state is highly fluorescent. Thereby we could observe thermoreversibility of the assembly state (gel-sol-monomer) by optical method. The origin of fluorescence generation in TOBA by H bond was investigated by static and picosecond kinetic studies on state-dependent fluorescence. |
|
Bioorganic, Molecular Recognition, Asymmetric Reactions and Syntheses
11:00 AM-1:00 PM, Wednesday, September 10, 2003 Javits Convention Center -- Hall 1B/1C, Poster
Division of Organic Chemistry |