Self-Assembly of Supramolecualr Metallogelator Containing 2-(2′-Hydroxyphenyl) benzoxazole/Zn(II) Chelate

Abstract

A low molar mass organogelator 1 containing 2-(2'-hydroxyphenyl)benzoxazole (HPB) unit with long alkyl chain was synthesized by the reaction with HPB and octyl isocyanate in THF at room temperature. A new chelate-based organogelator 1-Zn(II) was prepared with the reaction of 1 and zinc(II) acetate in methanol and dichloromethane at mild condition. The gelation ability of organogelator was tested by heating-cooling method in various organic solvents, and the opaque gel was formed from DMF. Well-developed self-assembled structure of organogel was confirmed with field emission-scanning electron microscope (FE-SEM) and transmission electron microscope (TEM), and the optical properties of organogel upon aggregation were monitored by UV-Vis and fluorescence spectroscopy, 1-Zn(II) was self-assembled to the sheet-like structure with the thickness of fully extended length of molecules.