Coordination-induced gelation of an l-glutamic acid Schiff base derivative: the anion effect and cyanide-specific selectivity.

By rational assembly of Zn2+ and Cu2+ with G, three metallogels (ZnG, CuG and Zn-CuG) were prepared. The gelation was controlled by the presence of specific anions, with their efficacy linked to the Hofmeister series. Zn-CuG could fluorescently detect CN- with specific selectivity over S2- and Cys through the competitive coordination of CN- and G with Cu2+.