Spectrochimica Acta Part A: Molecular and Biomolecular
Spontaneous optical response towards cyanide ion in water by a reactive
binding site probe
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Jong Ho Park , Ramalingam Manivannan , Palanisamy Jayasudha, Young-A Son ⁎
Department of Advanced Organic Materials Engineering, Chungnam National University, 220 Gung-dong, Yuseong-gu, Daejeon 305-764, South Korea
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 15 January 2020
Received in revised form 22 February 2020
Accepted 22 February 2020
Available online 24 February 2020
Indolium derivatives bearing diphenyl amine (R1) and dibenzylamine (R2) linked through benzene was de-
signed, synthesized, characterized and its cyanide recognizing abilities are studied in 100% water. The probes
were exhibited dual channel properties i.e. both colorimetric and fluorimetric changes for the effective sensing
of cyanide ion. The discrete color variation of probes with cyanide ion makes possible as colorimetric sensor
and which was seen easily through naked eye. The recognition of cyanide ion is accomplished via the attachment
of cyanide ion at the C atom of indolium C_N group through nucleophilic addition. Also, the found detection
limits of probes (nM range) were much lower than the WHO limit. Besides, the probes were effectively applied
to determine cyanide ion in real water samples and thus was confirmed with HPLC method.
© 2018 Elsevier B.V. All rights reserved.
Keywords:
Spontaneous responses
Water base sensor
Nucleophilic addition
Real sample
Colorimetric sensor
Cyanide
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. Introduction
There are some materials are of major concern due to lethal toxicity
in the cyanide recognizing field, numerous chemosensors have been
established, where the detecting mechanism is based on metal complex
ensemble displacement, hydrogen bonding interaction, nucleophilic ad-
dition reaction, and anion induced deprotonation etc. [23–26]. In spite
of having various cyanide sensors, some boundaries still are existent,
such as low sensitivity, requirement of short UV light excitation, long re-
sponse time and complicated synthesis procedure etc. but the
chemodosimeter has an advantage of high sensitivity, high detection
limit and sometimes easy detection with turn on fluorescence. How-
ever, many of the reported probes has lack of solubility in water
[27–30] while the small numbers of probes achieve the solubility in
water [31–34]. If the probe soluble in 100% water the detection of any
ion is meaningful and will be effective in the field of environment and
biology. In that way, the development of such probe is challenging for
the recognition of cyanide ion.
in the scientific society since they play a terrifying role as toxins in bio-
logical and environmental domain. Amongst such constituents, cyanide
ion is identified to be an awfully toxic anion and can directly binds with
cytochrome-c which disturbing the mitochondrial electron-transport
chain and leading to a reduced oxidative digestion and oxygen con-
sumption which leads to death [1–9]. Though there are many natural
sources of cyanide known, the problems sue to cyanide is mainly related
to the use of this in large scale industries like gold mining, herbicides,
resin manufacture, metallurgy, plastic and dye production and cyanide
fishing [10–14]. In agreement with the World Health Organization
(
WHO), the tolerable limit of cyanide in drinking water is to be 1.9 μM
[15]. Hence, in detail of an operational sensing system, recognition of cy-
anide is mandatory to be executed from environment and biology.
At present, the colorimetric and fluorimetric techniques are of great
interest and efficient for recognizing cyanide ion instead of many avail-
able techniques such as titrimetric, chromatography and electrochemi-
cal due to its own advantages over these methods like inexpensive,
simple, rapid recognition in real time circumstances [16–22]. Till now,
With this respect, we have planned and synthesized an indolium
based probes R1 and R2 for the recognition of cyanide ion in water.
The probes are designed in such a way that they have an electron
donor and acceptor moieties to have an intramolecular charge transfer
(ICT) transition. In this molecule, dipheyl amine in R1 and dibenzyl
amine in R2 acts as an electron donor moiety and carboxylated indole
as an electron acceptor part. Since the probes highly soluble in water,
the sensing of cyanide ion is in 100% water and will be useful for real
time analysis. The probes sense cyanide ion through nucleophilic addi-
tion reaction mechanism which interrupts the conjugation within the
molecules by disturbing ICT transition. Thereby the small change can
be detected by naked eye and the detection of cyanide is efficient.
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These authors contributed equally to this work.
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386-1425/© 2018 Elsevier B.V. All rights reserved.
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