title: Benzoindolium-triarylborane conjugates: a ratiometric fluorescent chemodosimeter for the detection of cyanide ions in aqueous medium.
abstract: Based on benzo[e]indolium and dimesitylborylbenzaldehyde a new ratiometric fluorescent chemodosimeter, C41H43BIN (3) has been synthesized and characterized by (1)H, (13)C NMR spectroscopy, mass spectrometry and single crystal X-ray crystallography. Probe 3 was found to be highly selective and sensitive toward cyanide (CN(-)) ions in aqueous medium even in the presence of other competing anions like F(-), Cl(-), Br(-), I(-), H2PO4(-), HCO3(-) and AcO(-). The detection limit was calculated to be 7.1 × 10(-9) M, which is much lower than the maximum permissable concentration in drinking water (1.9 μM) set by the World Health Organization (WHO). In addition, the response time of the probe for CN(-) is less than 5 seconds. The mechanism is based on a nucleophilic addition reaction of cyanide ions at the polarized [>C[double bond, length as m-dash]N<](+) bond of the benzoindolium group thereby blocking the pi-conjugation between the benzoindolium and triarylborane moiety. This was further confirmed by (1)H NMR titration, ESI-MS studies and DFT calculations.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India. sghosh@iitm.ac.in.
authors.forename: C
authors.initials: C
authors.lastname: Arivazhagan
authors.affiliation: Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India. sghosh@iitm.ac.in.
authors.forename: Rosmita
authors.initials: R
authors.lastname: Borthakur
authors.affiliation: Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India. sghosh@iitm.ac.in.
authors.forename: R
authors.initials: R
authors.lastname: Jagan
authors.affiliation: Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India. sghosh@iitm.ac.in.
authors.forename: Sundargopal
authors.initials: S
authors.lastname: Ghosh
mesh_terms: D000838:Anions / Q000737:chemistry; D018360:Crystallography, X-Ray; D003486:Cyanides / Q000032:analysis*; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D011789:Quantum Theory; D013050:Spectrometry, Fluorescence; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000838:Anions; D003486:Cyanides; D005456:Fluorescent Dyes; D007211:Indoles; C000591732:benzo(e)indolium