Issue 15, 2017

Bifunctional colorimetric chemosensing of fluoride and cyanide ions by nickel-POCOP pincer receptors

Abstract

Three Ni(II)-POCOP pincer complexes [NiCl{C6H2-4-OH-2,6-(OPPh2)2}], 1; [NiCl{C6H2-4-OH-2,6-(OPtBu2)2}], 2 and [NiCl{C6H2-4-OH-2,6-(OPiPr2)2}], 3 were studied as bifunctional molecular sensors for inorganic anions and acetate. In CH3CN, 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% CH3CN, 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 of 1H 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.

Graphical abstract: Bifunctional colorimetric chemosensing of fluoride and cyanide ions by nickel-POCOP pincer receptors

Supplementary files

Article information

Article type
Paper
Submitted
29 Dec 2016
Accepted
22 Feb 2017
First published
23 Feb 2017

Dalton Trans., 2017,46, 4950-4959

Bifunctional colorimetric chemosensing of fluoride and cyanide ions by nickel-POCOP pincer receptors

M. K. Salomón-Flores, I. J. Bazany-Rodríguez, D. Martínez-Otero, M. A. García-Eleno, J. J. Guerra-García, D. Morales-Morales and A. Dorazco-González, Dalton Trans., 2017, 46, 4950 DOI: 10.1039/C6DT04897H

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements