Carbohydrate-Based Switch-On Molecular Sensor for Cu(II) in Buffer:  Absorption and Fluorescence Study of the Selective Recognition of Cu(II) Ions by Galactosyl Derivatives in HEPES Buffer

Abstract

[graph: see text] 1-(Beta-D-galactopyranosyl-1'-deoxy-1'-iminomethyl)-2-hydroxynaphthalene (L1), possessing an ONO binding core, was found to be selective for Cu2+ ions in N-[2-hydroxyethyl]piperazine-N'-[2-ethanesulfonic acid] buffer, at concentrations < or = 580 ppb, at physiological pH by eliciting switch-on behavior, whereas the other ions, viz., Mg2+, Ca2+, Mn2+, Fe2+, Co2+, Ni2+, Zn2+, and Cd2+, caused no significant change in the fluorescence. Whereas the binding characteristics were ascertained by absorption spectroscopy, the species formed were shown by Q-TOF ES MS.

The benzo[b]quinolizinium ion as a water-soluble platform for the fluorimetric detection of biologically relevant analytes

“…-sensitive probes that are not soluble in water. [122][123][124][125][126][127] The detection limit of this probe is 0.2 μM, and we have shown that the fluorimetric detection of Cu , not even when these ions are present in large excess (100 molar equiv.). Although these features may appear promising for fluorimetric detection of Cu 2+ ion with chemosensor 10, this probe is far from being ideal, because it does not exhibit the anticipated shift of the emission maximum on metal-ion binding.…”

“…128 To overcome the above mentioned shortcomings of probe 10 we turned our attention to crown-ether functionalities as receptor units, because it has been demonstrated already with numerous examples that the direct attachment of azacrown ether units to a fluorophore is a general design principle for the development of donor-acceptor based fluorescent probes that change emission wavelength upon complexation of a metal ion (Scheme 1c). [3][4][5][6][7][8][9][10][11][12][122][123][124][125][126][127] Nevertheless, most crown ether host molecules do not bind the analyte to significant extent in water, 129 so that the majority of probes can only operate in non-competitive organic solvents. Therefore, we focused our studies on the 1,4-dioxa-7,13-dithia-10-azacyclopentadecane receptor unit, that is known to bind Hg 2+ ions in water with high affinity.…”

Optical sensor: a promising strategy for environmental and biomedical monitoring of ionic species

“…Similarly in case of fluorescence emission spectral recording, there was sharp decrease in the emission signal at 496 nm up to 5 μM Cu 2+ addition when it was excited at 328 nm. 19 Chemical structure of the receptor 22 and proposed ligand-metal complexation mechanism Singhal et al 100 described the synthesis and copper binding affinity of the ligands 23 ( Fig. With further increase in the copper ion concentration up to 10 μM, a large red shift was observed from 496 to 616 nm with the isoemissive point at 550 nm attributed to the host-guest complex formation via coordination of the free pyrrolidinium nitrogen with Cu 2+ .…”

Coumarine–imino–C2-glucosyl conjugate as receptor for Cu2+ in blood serum milieu, on silica gel sheet and in Hep G2 cells and the characterization of the species of recognition

“…Hence a gluco-based molecular receptor has been designed and synthesized and was explored as a new fluorescent probe for Cu 2+ . Though there are a few glyco-based receptors reported in the literature for Cu 2+ sensing, these were not shown for their suitability to use in blood serum milieu or any other biologically relevant medium [30][31][32][33].…”