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| Type |
Poster Presentation |
| Area |
Organic Chemistry |
| Room No. |
Event Hall |
| Time |
4월 19일 (목요일) 11:00~12:30 |
| Code |
ORGN.P-413 |
| Subject |
CD-response of achiral bisporphyrin derivative through supramolecular self-assembly |
| Authors |
Hosoowi Lee, Woo-Dong Jang*
Department of Chemistry, Yonsei University, Korea
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| Abstract |
Recently, the control of supramolecular polymerization process has attracted attention to many researchers. We designed bisporphyrin derivative (C2-(A)-TPP), which composed of two zinc porphyrin units bridged by amide groups and diacetylene moiety with long alkyl side chains. C2-(A)-TPP exhibited distinct transition of aggregation mode upon the condition of self-assembly process. When the C2-(A)-TPP was dissolved in hot methylcyclohexane (MCH), above 368 K, the bisporphyrin exhibited sharp absorption band, indicating molecularly dissolved monomeric state. Upon the cooling of the hot solution, C2-(A)-TPP was formed J-aggregates (Jagg) or H-aggregates (Hagg) and we can control the aggregation mode at 293 K through changing the cooling rate of the hot solution. After fast cooling process,C2-(A)-TPP exhibits Jagg mode which is clearly represented in UV/Vis absorption spectra. Meanwhile, when the hot solution cooled slowly, absorption band was blue-shifted, indicating Hagg of porphyrin. The kinetic product, Jagg, was transformed to thermodynamic stable Hagg upon mechanical agitations, such as shaking, stirring, or sonication. The transformation from Jagg to Hagg was monitored through change of absorption spectra upon stirring and the each state was visualized by AFM: Jagg was obtained as nanoparticles and Hagg was shown as nanofiber, The freshly transformed Hagg from Jagg was CD-silent, but surprisingly after a period of time, the aged Hagg exhibit optical activity in CD measurement. A further study to find out the origin of unexpected CD-signal from achiral bisporphryin assembly is still in progress. |
| E-mail |
hswlee@yonsei.ac.kr |
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121st General Meeting of the KCS