Interactions of transition-metal ions with photoexcited states of flavines. Fluorescence quenching studies

Synthesis, spectral characterization and in vitro biological studies of Co(II), Ni(II) and Cu(II) complexes with 1,2,4-triazole Schiff bases

“…There was decrease in intensity of fluorescence of Co(II), Ni(II) and Cu(II) complexes in all prepared solutions. In all other previous studies, it has been reported that, transition metal ions decrease the fluorescence quite effectively [47,48]. Magnetic perturbation, redox activity, etc., has been invoked [48] in the past to rationalize fluorescence quenching by transition metal ions.…”

“…In all other previous studies, it has been reported that, transition metal ions decrease the fluorescence quite effectively [47,48]. Magnetic perturbation, redox activity, etc., has been invoked [48] in the past to rationalize fluorescence quenching by transition metal ions. But, in case of Ni(II) complexes we could observed the enhancement of fluorescence in MeCN solution.…”

“…Moreover, coordination reduces the polarity [29] of the metal ion mainly because of the partial sharing of its positive charge with the donor groups [49 -53] with in the chelate ring system formed during coordination. This process, in turn, increases the lipophilic nature of the central metal atom, which favors its permeation more efficiently through the lipid layer of the micro-organism [48] thus destroying them more aggressively. The minimum inhibitory concentration 10 mg/mL was shown by compound 4 against S. aureus, A. Niger and compound 10 against A. Flavus.…”

Organically Structured Carbon Nanotubes for Fluorescence

“…Thus, SWNTs can be perceived as behaving in a manner similar to that of other fluorescent organic molecules [51] . Metal ions have been used in emission studies to quench the fluorescence of various organic molecules including pyrenes, anthracenes, flavins, bipyridines, and acridinium ions [52][53][54][55] . However, no work before has focused on the interactions between SWNTs and metal ions.…”

A Highly Selective Fluorescent Sensor for Cu2+ Based on a Covalently Immobilized Naphthalimide Derivative

“…Cu 2+ is one of paramagnetic ions and can strongly quench the fluorescence of a fluorophore near it via an electron or energy transfer mechanism. 9 Thus, several fluorescent indicators based on fluorescence quenching have been reported to determine the trace amount of copper ions. [10][11][12] However, most of them only work well in a pure organic solvent media or in an aqueous solution containing an organic co-solvent.…”