Colorimetric detection of fluoride ions in aqueous medium using thiourea derivatives: a transition metal ion assisted approach

Das, Rituraj; Talukdar, Dhrubajyoti; Sarma, Plaban Jyoti; Kuilya, Hemrupa; Thakuria, Ranjit; Choudhury, Diganta; Mahanta, Sanjeev P.

doi:10.1039/d1dt02173g

Cited by 5 publications

(2 citation statements)

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“…Several anion binding organic receptors having amide, urea, thiourea, pyrrole, indole, and guanidium functionalities capable of forming H-bonds and sometimes followed by deprotonation with the fluoride ion have been studied in the attempt to develop a chemosensor for the recognition of the fluoride ion. Furthermore, to improve the fluoride ion selectivity, the concept of preorganization along with the size of the binding cavity has also been explored with structures like macrocycles, clefts, etc. − As these receptors are mostly organic, they show good selectivity and sensitivity toward tetra alkyl salts of the fluoride ion in organic medium. However, their sensitivity drops abruptly even in the presence of a small amount of water, and hence, recognition of fluoride in aqueous medium by the same receptors is still a challenge.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, to improve the fluoride ion selectivity, the concept of preorganization along with the size of the binding cavity has also been explored with structures like macrocycles, clefts, etc. 34 − 41 As these receptors are mostly organic, they show good selectivity and sensitivity toward tetra alkyl salts of the fluoride ion in organic medium. However, their sensitivity drops abruptly even in the presence of a small amount of water, and hence, recognition of fluoride in aqueous medium by the same receptors is still a challenge.…”

Section: Introductionmentioning

confidence: 99%

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In Situ Ni(II) Complexation Induced Deprotonation of Bis-Thiourea-Based Tweezers in DMSO–Water Medium: An Approach toward Recognition of Fluoride Ions in Water with Organic Probe Molecules

Mushahary,

Biswakarma,

Thakuria

et al. 2024

ACS Omega

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Recognition of fluoride in water through the fluoride-induced Bronsted acid−base deprotonation reaction of an organic probe molecule is still a challenging task owing to the lower basicity of fluoride ions and the instability of the conjugate base of the probe molecules in aqueous medium. Herein, we report a complementary strategy in which the conjugate base of the studied bis-thiourea molecule in dimethyl sulfoxide (DMSO) medium is simultaneously stabilized through chelation of the Ni(II) ion, which eventually facilitates the recognition of the fluoride ion in water samples. The recognition methodology is validated colorimetrically and electrochemically, and finally, the applicability of the approach is explored with water samples collected from fluoride-affected areas. The limit of detection value for the fluoride ion in water medium was found to be 0.2 and 0.3 ppm with UV−visible spectroscopy and differential pulse voltammetry measurements, respectively. The methodology is also demonstrated on a paper strip for the detection of the fluoride ion with the naked eye and a smartphone-based RGB sensor. The scheme has been shown to be effective in enhancing the aqueous fluoride recognition ability of the organic probe molecules with acidic hydrogen prone to deprotonation by the fluoride ion.

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