Selective fluoride sensing using colorimetric reagents containing anthraquinone and urea or thiourea binding sites

Novel colorimetric reagents for fluoride sensing containing anthraquinone as chromogenic signalling subunit and thiourea (L1) and urea (L2) binding sites have been characterised. A selective colour change from orange to brown was observed upon addition of fluoride to CH3CN solutions of L1 and to DMSO solutions of L1 or L2.