Fluorescence enhancement of a tetrazole-based pyridine coordination polymer hydrogel.

Hydrogelation of a pyridine derivative (1) possessing tetrazole moieties as end groups, without long alkyl chain groups, results in the formation of a Mg(NO3)2coordination polymer gel. The polymer exhibits a strong fluorescence enhancement upon gel formation. 1can also be gelated with a variety of magnesium anions such as SO42−, NO3−, Cl−, Br−and I−, indicating that the coordination polymer gel formation of 1does not strongly depend on anions. The SEM and AFM images of Mg2+coordination polymer gel 1display a fibrillar network several micrometres long, with widths in the range of 60–70 nm and thicknesses of about 3 nm. In addition, photophysical studies show that the hydrogel exhibits a typical π–π* transition and gives rise to high fluorescence behavior. The coordination polymer hydrogel exhibits viscoelastic behavior as evidenced from the rheological studies. [ABSTRACT FROM AUTHOR]