The benzil-cyanide reaction and its application to the development of a selective cyanide anion indicator.
The benzil-cyanide reaction is a cyanide-specific reaction that has been exploited to produce a colorimetric indicator for this toxic anion. This was done by producing a pi-extended analogue of benzil, 7, which is soluble in a 70:30 (v/v) mixture of methanol-water. In this medium, dilute solutions of 7 are yellow but produce colorless products when exposed to low concentrations of cyanide anion (> or = 1.7 microM; added as an aqueous NaCN solution), but no other common anions (e.g., OH(-), F(-), N3(-), benzoate(-), and H2PO4(-)). On the basis of these observations and supporting mechanistic analyses, it is concluded that the modified benzil system 7 is a promising cyanide anion indicator that is attractive in terms of its selectivity, ease-of-use, water compatibility, and the low, naked-eye discernible cyanide detection limit it provides.
Cho
Dong-Gyu
DG
Department of Chemistry and Biochemistry and Institute for Cellular and Molecular Biology, 1 University Station A5300, The University of Texas at Austin, Austin, Texas 78712-0165, USA.
Kim
Jong Hoon
JH
Sessler
Jonathan L
JL
D000838:Anions; D003124:Colorimetry / Q000379:methods; D003486:Cyanides / Q000737:chemistry*; D007202:Indicators and Reagents / Q000737:chemistry; D010658:Phenylglyoxal / Q000031:analogs & derivatives* / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet
D000838:Anions; D003486:Cyanides; D007202:Indicators and Reagents; D000644:Quaternary Ammonium Compounds; C009405:tetrabutylammonium; D010658:Phenylglyoxal; C006697:benzil