A novel indolium salt as a rapid colorimetric probe for cyanide detection in aqueous solution

In this study, a new chemosensor IDTTH for rapid detection of cyanide (CN) based on 6,6,12,12-Tetrakis(4-hexylphenyl)-6,12-dihydrodithieno[2,3-d:2 ',3 '-d ']-s-indaceno[1,2-b:5,6-b ']di- thiophene-2,8-dicarboxaldehyde-hemicyanine conjugate has been developed. The 6,6,12,12-tetrakis(4-hexylphenyl)-6,12-dihydrodithi-eno[2,3-d:2 ',3 '-d ']-s-indaceno[1,2-b:5,6-b ']dithiophene was served as a signal unit and hemicyanine as a recognition unit. This probe shows high selectivity towards CNions among tested anions. Addition of CNions to probe IDTTH in semi-aqueous solution (acetonitrile/H2O = 1/1, V/V) could lead to a 195 nm blue shift of absorption band, together with colour changes from blue to yellow. The sensing mechanism is attributed to the nucleophilic addition between CNand the C=N bond of indolium group, which could be clearly clarified through the(1)H NMR titration and MS spectral. Moreover, probe IDTTH could be used as the test strips with low cost to detect CNions conveniently by naked eyes.