Article

Remarkable Reinforcement of a Supramolecular Gel Constructed by Heteroditopic [18]Crown‐6‐Based Molecular Recognition

Eunyoung NohDepartment of Chemistry and Research Institute of Natural Science, Gyeongsang National University, Jinju 660-701, KoreaSunhong ParkDepartment of Chemistry and Research Institute of Natural Science, Gyeongsang National University, Jinju 660-701 (Korea), Fax: (+82) 55-758-6027Sunwoo KangDepartment of Chemistry and Institute of Basic Science, Sungkyunkwan University,Suwon 440-746,KoreaJin Yong LeeDepartment of Chemistry and Institute of Basic Science, Sungkyunkwan University,Suwon 440-746,KoreaJong Hwa JungDepartment of Chemistry and Research Institute of Natural Science, Gyeongsang National University, Jinju 660-701 (Korea), Fax: (+82) 55-758-6027

2013en

ABI

Abstract

The heteroditopic crown ether-based ligand 1 containing the diazafluorenylimino group as a binding site for the Zn(2+) and Cs(+) was synthesized. The ligand 1 can be gelated in DMSO/water with and without Cs(+) in the presence of the Zn(2+) ion. Interestingly, the remarkable gelation reinforcement of gel 1 occurred with Cs(+) in the presence of Zn(2+), which is due to the formation of a sandwich complex. According to DFT calculations, one Zn(2+) is bound to two diazafluorenylimino moieties in a tetrahedral structure. In addition, one Cs(+) ion is bound to two crown-rings. The Zn(2+)-diazafluorenylimino ligand gel without Cs(+) shows a spherical structure with 250-800 nm diameter, whereas the Zn(2+)-diazafluorenylimino-based ligand gel with Cs(+) shows a fiber structure with 60-70 nm diameter and several micrometers of lengths. The rheological properties of the Zn(2+)-diazafluorenylimino-based ligand gel were strongly dependent on the presence of Cs(+).

Identifiers

DOI: 10.1002/chem.201202710

Citations and references

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