951. Bifunctional colorimetric chemosensing of fluoride and cyanide ions by nickel-POCOP pincer receptors.
- Author
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Salomón-Flores MK, Bazany-Rodríguez IJ, Martínez-Otero D, García-Eleno MA, Guerra-García JJ, Morales-Morales D, and Dorazco-González A
- Abstract
Three Ni(ii)-POCOP pincer complexes [NiCl{C
6 H2 -4-OH-2,6-(OPPh2 )2 }], 1; [NiCl{C6 H2 -4-OH-2,6-(OPtBu2 )2 }], 2 and [NiCl{C6 H2 -4-OH-2,6-(OPiPr2 )2 }], 3 were studied as bifunctional molecular sensors for inorganic anions and acetate. In CH3 CN, fluoride generates a bathochromic shift with a colorimetric change for 1-3 with a simultaneous fluorescence turn on, this optical effect is based on deprotonation of the para-hydroxy group of the POCOP ligand. On the other hand, in a neutral aqueous solution of 80 vol% CH3 CN, additions of cyanide produce a distinct change of color by forming very stable complexes with the nickel-based receptors 1-3 with log Ka in the range of 4.38-5.03 M-1 and pronounced selectivity over other common anions such as iodide, phosphate, and acetate. Additionally, bromide shows a modest spectral change and affinity, but lower than those observed for cyanide. On the basis of1 H NMR experiments, UV-vis titrations, ESI-MS experiments, and the crystal structure of the neutral bromo complex of 1, it is proposed that the colorimetric change involves an exchange of chloride by CN- on the Ni(ii) atom. The Ni(ii)-based sensor 1 allows the fluorescent selective detection of fluoride with a limit of 5.66 μmol L-1 and colorimetric sensing of cyanide in aqueous medium in the micromolar concentration range.- Published
- 2017
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