A new mechanism for selective recognition of cyanide in organic and aqueous solution

A simple colorimetric and fluorimetric chemosensor 3,5-dinitro-(N-phenyl)benzamide (DNBA), was synthesized for selective determination of cyanide anion in organic and aqueous solutions via novel chemodosimeter approach. The chemosensorDNBAshowed a chromogenic and fluorogenic selective response to CN(-)against competing anions such as F-, AcO-, and H(2)PO(4)(-)in organic (DMSO and ACN) and in aqueous solutions (in DMSO/H2O: 8:2, v/v). The intensive colorimetric and fluorimetric color changes were observed in ambient light and UV-light (lambda(ex). 365 nm) after cyanide interacted withDNBA. A method that can be used in the synthesis of new biologically active benzisoxazole compound was described by the reaction ofDNBAwith TBACN and KCN in DMSO or DMSO/H2O, respectively. All interaction mechanisms betweenDNBAand cyanide and fluoride anions were demonstrated by experimental studies using various spectroscopic methods such as UV/Vis, fluorescence,H-1/C-13 NMR, and mass spectrometry as well as X-ray diffraction method. In addition, the experimental results were also explained with theoretical data. The spectroscopic results showed that cyanide interacts with three different mechanisms; deprotonation, nucleophilic aromatic substitution, and formation of benzisoxazole ring.