New insights on the picosecond time-resolved fluorescence signatures of metal cation-Morin complexes

Abstract

This article is the second in the sequence of our investigations on morin and metallic cations:morin spectroscopic characterization, completing our first article centred on morin’s photophysical behavior. We explore, here, for the first time metallic cations:morin complexes with Ca(II), Zn(II) and Al(III) in MeOH by steady-state and picosecond time-resolved fluorescence techniques. We evidenced that the metallic cations:morin complexes could exhibit typical pico- and nanosecond time-resolved signatures. We observed that for the metallic cations, with the lowest complexation efficiency, we still see traces of the emission of the morin:solvent complex that we evidenced in our former article. Therefore, supported by steady-state and time-resolved spectroscopies, we present an argued assignment of the time-components extracted from the fluorescence decays to the main species present in solution. We investigated with more accuracy and sensitivity (by time-resolved fluorescence) the presence of cation in aqueous solutions than it was already performed in literature before. We hope that this work will stimulate the development of new methods for the detection of metallic cations in water including time-resolved fluorescence techniques.