A novel cyanide chemodosimeter based on trifluoroacetamide benzhydrol-2 as binding motif: importance of substituent positioning on intra-molecular charge transfer

The nucleophilic nature of cyanide is used to develop a simple, sensitive, and highly effective sensor. Azo dye 6a based on 2-(trifluoroacetamide) benzhydrol-2 (2-TFAB) as anions receptor, presents a new way to build molecular color sensors for cyanide in water. The 2-TFAB moiety of the dye 6a is used as receptor group for cyanides and linked directly by dominant reversible covalent bonding over hydrogen bonding, confirmed by the inactivity of the derivative 6b toward cyanides.