Exploration of ruthenium complex of (E)-2-((pyridine-2-yl)methyleneamino) benzoic acid as chemosensor for simultaneous recognition of acetate and HSO4- ions in cell bio-imaging: Experimental and theoretical studies

A ruthenium complex [(RuLCl2)-Cl-1(PPh3)]Cl (L-1=(E)-2-((pyridine-2-yl)methyleneamino)benzoic(E) acid) was synthesized, characterized by analytical techniques, and then it has been employed as chemo-sensor for the recognition of acetate in H2O: CH3 CN (80:20) medium. With fluorescence study, it has been shown that [RuL1 Cl-2(PPh3)](+) efficiently detects acetate ion without interference from other anions (F-, Cl-, Br, I-, NO3-, HSO4-, H2PO4-) except HSO4-,for which the intensity of fluorescence is significantly enhanced. The stoichiometry determined by Job's plot for the interaction of Ru-complex with acetate was found to be 1:2. With DFT study, the energy of HOMO orbitals of the complex was calculated in order to address why the fluorescence intensity was enhanced for the addition of HSO4- ion, it establishes that the energy of HOMO for [RuL1 (AcO)HSO4](-) is being lowered when compared to that for [RuL1 Cl-2(PPh3)](+), inhibiting the excited electron transfer, and thus it increases the fluorescence intensity due to Photo induced Electron Transfer (PET). The recognition of acetate/or HSO4- has been successfully applied into real bio-sample such as Saccharomyces cerevisiae cells by performing confocal fluorescence with using the ruthenium complex. (C) 2018 Elsevier B.V. All rights reserved.