Side Chains of Cobalt Corrinoids Control the Sensitivity and Selectivity in the Colorimetric Detection of Cyanide

Abstract

Substitution of Co(III)-bound water by cyanide allows the rapid colorimetric detection of micromolar amounts of cyanide with cobalt corrinoids. Negatively charged side chains at the periphery of these metal-based sensors increase the selectivity of cyanide versus thiocyanate, the most disturbing anion, by a factor of 30 through additional supramolecular interactions in water.

Identification of Diastereomeric Cyano–Aqua Cobinamides with a Backbone‐Modified Vitamin B12 Derivative and with 1H NMR Spectroscopy

“…[16] This behavior seems disadvantageous for the unequivocal assignment of the isolated isomers. For applications such as cyanide detection, only diastereomeric mixtures of "incomplete" cyano-aqua corrinoids have been employed, [17][18][19][20] whereas initial kinetic studies suggest differences in cyanide coordination. [20] The identification and evaluation of well-defined isomers are important with regard to future improvements of corrin-based chemosensors.…”

Chromogenic and fluorogenic chemosensors and reagents for anions. A comprehensive review of the year 2009

“…The aquocyanocobyrinic acid 64 ( Figure 21) was used as a colorimetric sensor for CN -anion. 96 The first example is a merocyanine derivative functionalized with a dinitrobenzenesulfonyl moiety (66) (Figure 22) that has been successfully employed for the chromogenic and fluorogenic sensing of cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) in methanol-water 3:7 v/v (PBS buffer, pH 7.4) via a modulation in colour from yellow to magenta. 105 The bathochromic shift of the absorption band was explained by a thiol-mediated cleavage of the electron-withdrawing sulfonyl group of The second example uses a chromene derivative (67) (Figure 23).…”

Sulfonium Boranes for the Selective Capture of Cyanide Ions in Water

“…Thus, [2] + is one of the rare molecular systems competent for cyanide sensing at the sub-parts per million level in water. [17] In conclusion, we report the synthesis of a sulfonium borane ( [2] + ) which can be used in pure water for the fluorescence detection of cyanide near the EU maximum allowable concentration. The high affinity of this borane arises from favorable Coulombic effects which serve to stabilize the cyanoborate complex against dissociation.…”