A new colorimetric sensor based on semithiocarbazone for some anions: 2-(1,3-dioxo-1,3-dihydro-2H-inden-2-ylidene)-N-phenylhydrazine-1-carbothioamide

Carbazones are molecules containing important functional groups in designing anion chemosensors due to proton donor and acceptor sites in their structures. In this paper, we synthesize a novel colorimetric receptor with 1,3-dioxo-indene and thiosemicarbazone moieties by the reaction of ninhydrin and 4-phenyl-thiosemicarbazide in quantitative yield. We then identify its structure by means of FT-IR, $^{1}$H-NMR, $^{13}$C-NMR, and MS spectroscopic techniques. Moreover, we observe the reaction of the title compound with biologically important F$^¯$, OAc$^¯$, CN$^¯$, H2PO4$^¯$, and OH$^¯$ anions in the presence of other anions, such as Cl$^¯$, Br$^¯$, I$^¯$, SCN$^¯$, and OCl$^¯$ in dimethylsulfoxide solution through a color change from yellow to orange-red that can easily be distinguished even by the naked eye under ambient light. Finally, we evaluate the anion-sensing ability of the title compound via UV-vis spectroscopic studies.