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Colorimetric Cyanide Chemosensor Based on 1',3,3',4-Tetrahydrospiro[chromene-2,2'-indole].

Dagilienė M, Martynaitis V, Kriščiūnienė V, Krikštolaitytė S, Šačkus A - ChemistryOpen (2015)

Bottom Line: These chemosensors show a distinct color change when treated with cyanide in acetonitrile solution buffered with sodium phosphate, and this procedure is not affected by the presence of other common anions.The mechanism for detection is rationalized by the nucleophilic substitution of the phenolic oxygen atom at the indoline C-2 atom by the cyanide anion to form a stable indolylnitrile adduct and to generate the colored 4-nitrophenolate chromophore.These chemosensors can be synthesized by a simple procedure from commercially available starting materials.

View Article: PubMed Central - PubMed

Affiliation: Institute of Synthetic Chemistry, Kaunas University of Technology Radvilėnų pl. 19, 50254, Kaunas, Lithuania ; Department of Organic Chemistry, Kaunas University of Technology Radvilėnų pl. 19, 50254, Kaunas, Lithuania.

ABSTRACT
A new class of chemosensors based on the 1',3,3',4-tetrahydrospiro[chromene-2,2'-indole] ring system, which detects cyanide with high specificity, is described. These chemosensors show a distinct color change when treated with cyanide in acetonitrile solution buffered with sodium phosphate, and this procedure is not affected by the presence of other common anions. The chemisensors exhibit high sensitivity to low concentrations of cyanide, meeting the European Union water quality control criterion of sensitivity below 0.05 mg L(-1), and show a very fast response within tens of seconds. The mechanism for detection is rationalized by the nucleophilic substitution of the phenolic oxygen atom at the indoline C-2 atom by the cyanide anion to form a stable indolylnitrile adduct and to generate the colored 4-nitrophenolate chromophore. These chemosensors can be synthesized by a simple procedure from commercially available starting materials.

No MeSH data available.


Related in: MedlinePlus

Formation of 4-nitrophenolate chromophore 9.
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sch04: Formation of 4-nitrophenolate chromophore 9.

Mentions: The appearance of this band in the visible region can be rationalized by spirochromene ring opening and formation of 4-nitrophenolate chromophores 9 a–h due to the nucleophilic substitution of the phenolic oxygen by a cyanide group. In this case, the limiting step of the reaction is the C(spiro)−O covalent bond cleavage and the formation of intermediates B, which are in an equilibrated mixture with the starting 1′,3,3′,4-tetrahydrospiro[chromene-2,2′-indoles] (8 a–h). However, intermediates A are quickly consumed when the nucleophilic addition of the cyanide anion to the C-2 carbon occurs to form stable nitriles 9 a–h. In such cases, the ring-opening reaction of 8 a–h becomes irreversible (Scheme 4).


Colorimetric Cyanide Chemosensor Based on 1',3,3',4-Tetrahydrospiro[chromene-2,2'-indole].

Dagilienė M, Martynaitis V, Kriščiūnienė V, Krikštolaitytė S, Šačkus A - ChemistryOpen (2015)

Formation of 4-nitrophenolate chromophore 9.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4522186&req=5

sch04: Formation of 4-nitrophenolate chromophore 9.
Mentions: The appearance of this band in the visible region can be rationalized by spirochromene ring opening and formation of 4-nitrophenolate chromophores 9 a–h due to the nucleophilic substitution of the phenolic oxygen by a cyanide group. In this case, the limiting step of the reaction is the C(spiro)−O covalent bond cleavage and the formation of intermediates B, which are in an equilibrated mixture with the starting 1′,3,3′,4-tetrahydrospiro[chromene-2,2′-indoles] (8 a–h). However, intermediates A are quickly consumed when the nucleophilic addition of the cyanide anion to the C-2 carbon occurs to form stable nitriles 9 a–h. In such cases, the ring-opening reaction of 8 a–h becomes irreversible (Scheme 4).

Bottom Line: These chemosensors show a distinct color change when treated with cyanide in acetonitrile solution buffered with sodium phosphate, and this procedure is not affected by the presence of other common anions.The mechanism for detection is rationalized by the nucleophilic substitution of the phenolic oxygen atom at the indoline C-2 atom by the cyanide anion to form a stable indolylnitrile adduct and to generate the colored 4-nitrophenolate chromophore.These chemosensors can be synthesized by a simple procedure from commercially available starting materials.

View Article: PubMed Central - PubMed

Affiliation: Institute of Synthetic Chemistry, Kaunas University of Technology Radvilėnų pl. 19, 50254, Kaunas, Lithuania ; Department of Organic Chemistry, Kaunas University of Technology Radvilėnų pl. 19, 50254, Kaunas, Lithuania.

ABSTRACT
A new class of chemosensors based on the 1',3,3',4-tetrahydrospiro[chromene-2,2'-indole] ring system, which detects cyanide with high specificity, is described. These chemosensors show a distinct color change when treated with cyanide in acetonitrile solution buffered with sodium phosphate, and this procedure is not affected by the presence of other common anions. The chemisensors exhibit high sensitivity to low concentrations of cyanide, meeting the European Union water quality control criterion of sensitivity below 0.05 mg L(-1), and show a very fast response within tens of seconds. The mechanism for detection is rationalized by the nucleophilic substitution of the phenolic oxygen atom at the indoline C-2 atom by the cyanide anion to form a stable indolylnitrile adduct and to generate the colored 4-nitrophenolate chromophore. These chemosensors can be synthesized by a simple procedure from commercially available starting materials.

No MeSH data available.


Related in: MedlinePlus