Pyrimidinylhydrazide based organogels as colorimetric sensor for I and adsorbent for organic dyes

Abstract

Three pyrimidinylhydrazide based gelators J1, J2, and J3 were synthesized and characterized. In the gelling test, it was found that the position of the nitrogen atom in pyrimidine moieties remarkably affected the gelation properties of gelators for solvents, J2 formed stable organogels with 12 out of the 22 tested solvents, and the lowest critical gelling concentration (cgc) of J2-ethanol gel was as low as 14.8 mg·mL−1. Interestingly, the J2-ethanol gel can act as colorimetric sensor for I- with high selectivity and sensitivity, which can be attributed to the formation of the I--J2 complex via the hydrogen bonds of I- with the hydrazide moieties, the detection limit of J2 for I- is 9.199 × 10−6 M. Also, the J2-toluene gel can quickly adsorb brilliant green and rhodamine B, the dye removal efficiencies from their aqueous solutions by J2-toluene gel reach 94.13% and 92.24% in 6 hours, and the maximum adsorption capacity at adsorption equilibrium were 54 mg·g−1 and 72 mg·g−1 for brilliant green and rhodamine B.