1,3,5-Triaryl-2-penten-1,5-dione anchored to insoluble supports as heterogeneous chromogenic chemosensor

N-Allyl substituted 1,5-diphenyl-3-(4-N-methylaminophenyl)-2-penten-1,5-dione ( 1a ) has been immobilized on a polystyrene backbone, on the surface of mercaptopropyl-functionalized silica or inside the cavities of zeolite NaY. These solids either in suspension or in films act as chemosensors of Fe3+ and other strong Lewis acid metal ions such as Cu2+ and Pb2+ in buffered water or ethanol. Brönsted acids in low pH aqueous solutions also produce the response of the sensor. For sensing of Fe3+, depending on the loading of 1a (typically from 2.5 to 0.5wt%) the solids can test from 10−2 to 10−4 M aqueous solutions. The time response can vary from tens of minutes to below a minute depending on hydrophilic/hydrophobic nature of the support and also on the 1a loading. The solid sensor was reused up to 10 times by regenerating after every use the initial form with NaAcO treatment.