Recognition of Hg²⁺ Using Diametrically Disubstituted Cyclam Unit

Abstract

A newly synthesized 1,4,8,11-tetraazacyclotetradecane derivative (L), functionalized with a diazo moiety as the reporter functionality, is found to bind specifically to Hg(2+) with an associated change in color that could be visually detected. With biologically benign β-CD, it forms an inclusion complex (L·2β-CD), which shows a much higher solubility in water, and this helps in developing a more intense color on binding to Hg(2+) in a CH(3)CN-HEPES buffer medium. The nontoxic nature of L was checked with the living cells of a Gram negative bacterium, Pseudomonas putida . Further, experiments revealed that these two reagents could be used as staining agents for the detection of Hg(2+) present in this microorganism.

An overview of the recent developments on Hg2+ recognition

“…HEPES buffer (2 : 3, v/v; pH 7.2) medium. 19 However, solubility of the reagent 16 could be further improved simply by allowing this to form an inclusion complex ([3]pseudo rotaxane; 16$2b-CD) with b-cyclodextrin (b-CD). This inclusion complex (L$2b-CD) could be used for developing a more intense colour on binding to Hg 2+ in CH 3 CN-HEPES buffer medium.…”

Synthesis of gold nanoparticles and nanoclusters in a supramolecular gel and their applications in catalytic reduction of p-nitrophenol to p-aminophenol and Hg(ii) sensing

“…A number of probes and sensors have been reported for detection of Hg(II). [81][82][83][84][85][86] Among them are notably promising uorescent Au nanoclusters (AuNCs) which act as sensors for Hg(II) through quenching of their uorescence intensity. [87][88][89][90][91] Recently some theoretical studies indicate that, dispersion forces, which are quite strong and specic for closed-shell heavy metal ions like Hg +2 (4f 14 5d 10 ) and Au + (4f 14 5d 10 ), are further enhanced by relativistic effects.…”

A Mercuric Ion Selective Fluorescent Sensor Based on Rhodamine B with an Ethylene Unit

“…According to the 1:1 complex, the association constant ( K a ) of Rh2 with Hg 2+ was estimated to be 5.2 × 10 7 M −1 by using the Benesi‐Hildebrand equation . It is ~10 2 –10 4 fold larger, compared to other Hg 2+ sensor molecules . Therefore, the binding of Hg 2+ to Rh2 is fairly strong.…”