title: Highly selective colorimetric sensing of cyanide based on formation of dipyrrin adducts.
abstract: Cyanide sensing has attracted increasing interest due to its toxicity and wide use in industrial activities. Herein, we developed three colorimetric cyanide sensors by the modification of the α-position of a dipyrrin chromophore with various carbonyl groups, namely, C(6)F(5)CO, C(6)H(5)CO and CHO for 1, 2 and 3, respectively. In dichloromethane, these sensors respond to both CN(-) and F(-) with distinct colour changes. UV-Vis, (1)H NMR and HRMS measurements imply a two-process interaction between the sensors and CN(-). Initially, CN(-) forms a hydrogen bond with the NH moiety, and then it attacks the carbonyl group of the sensors via a nucleophilic addition reaction. In contrast, in aqueous systems, only cyanide induced vivid solution colour changes from light yellow to pink via nucleophilic addition reactions. The CN(-) detection limits reach a micromolar level of 3.6 × 10(-6) M, 4.2 × 10(-6) M and 7.1 × 10(-6) M for 1, 2 and 3, respectively. In view of the easy synthesis and the highly selective recognition of CN(-) with vivid colour changes, 1-3 may be developed as a novel and promising prototype of selective and sensitive colorimetric cyanide sensors.
authors.affiliation: Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai, PR China.
authors.forename: Yubin
authors.initials: Y
authors.lastname: Ding
authors.forename: Tong
authors.initials: T
authors.lastname: Li
authors.forename: Weihong
authors.initials: W
authors.lastname: Zhu
authors.forename: Yongshu
authors.initials: Y
authors.lastname: Xie
mesh_terms: D016227:Benzoquinones / Q000737:chemistry; D003116:Color; D003124:Colorimetry / Q000379:methods*; D003486:Cyanides / Q000032:analysis* / Q000737:chemistry; D006860:Hydrogen Bonding; D057230:Limit of Detection; D009682:Magnetic Resonance Spectroscopy; D008752:Methylene Chloride / Q000737:chemistry; D011758:Pyrroles / Q000737:chemistry*; D012996:Solutions; D014867:Water / Q000737:chemistry
chemical_list: D016227:Benzoquinones; D003486:Cyanides; D011758:Pyrroles; D012996:Solutions; D014867:Water; C000928:dichlorodicyanobenzoquinone; D008752:Methylene Chloride