A Combinatorial Approach To Discover New Chelators for Optical Metal Ion Sensing

Abstract

This paper reports the synthesis and characterization of metal-binding indicators with diverse optical responses on exposure to various heavy metal ions. A combinatorial approach, based on azo coupling of diazonium salts with either phenolic compounds or aromatic amines, generated a library of azo dyes. Each reaction mixture, containing the product(s) of azo coupling, was incubated with a series of solutions, each containing a different heavy metal ion. The absorbance and, in some cases, fluorescence spectra of the resulting complexes were recorded. The metal chelates showed extensive diversity in their UV-visible absorbance spectra upon binding to selected metal ions. Of the azo dyes prepared, the terdentate dyes were particularly useful, providing distinct spectral responses to three or more metal ions in a panel of seven.

A new window towards multidimensional sensing of transition metal cations through dual mode sensing ability of N-benzyl-(3-hydoxy-2-naphthalene): Emission enhancement coupled remarkable spectral shift

“…This will result in reduction of rotational/vibrational degrees of freedom of the system, a direct consequence of which is retardation of nonradiative deactivation channels with consequent opening up of radiative decay routes leading to emission intensity enhancement. However, this explanation, in analogy to literature reports [1][2][3][4][8][9][10][11][12][30][31][32][33][34][60][61][62][63][64][65][66][67][68][69][70][71], does not seem to suffice for the magnitude of emission intensity enhancement observed in the present study. This eventually guided us to account for the findings on the basis of photoinduced electron transfer (PET) mechanism, which is a commonly exploited strategy for fluorosensors for metal ions employing an amine as the receptor [9,[31][32][33][34]72,73].…”

“…Fluorescence signaling systems can be designed for signal transduction upon analyte binding [1][2][3][4][5][6][7][8][9][10][11][12][13] and this opens up new windows to use them as chemical sensors in a variety of immensely significant areas such as biomedical research, preparation of chemical logics for molecular information processing and so forth [14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Also the high degree of sensitivity, noninvasive nature, specificity and real-time monitoring with fast response time are the advantages that add additional edge to fluorescent chemosensors over other techniques.…”

Fluorescence Array-Based Sensing of Metal Ions Using Conjugated Polyelectrolytes

“…Choosing water-soluble CPEs over other organic molecules as a sensing material for metal ions has an advantage because CPEs do not require the addition of cosolvents to the system. 44 The molecular weights of the four polymers were determined using matrix-assisted laser desorption ionization (MALDI) mass spectrometry, as shown in Table 1. By using mass spectrometry as a direct molecular weight determination method, this avoids overestimation of average molecular weight (Mn).…”

Design of fluorescent materials for chemical sensing

“…284 Libraries of fluorescent polymers have been also generated by combinatorial methods by the group of Dordick. 274 They developed a sensor array for divalent and trivalent metal ions consisting of fifteen phenolic homopolymers and copolymers generated from five phenolic monomers. The sensing process is based on the change of the intrinsic polyphenol fluorescence upon addition of a metal ion mixture to an aqueous suspension of the polyphenol.…”