Ruthenium(II)‐Polypyridyl‐Based Sensor Bearing a DPA Unit for Selective Detection of Cu(II) Ion in Aqueous Medium

Abstract

Abstract Ruthenium(II) polypyridyl linked di‐(2‐picolyl)amine (DPA) based chemosensor [Ru(bpy) 2 (bpmpip)](PF 6 ) 2 ( Ru‐L ) has been developed for the selective detection of Cu(II) ion in purely aqueous medium. The change in absorbance and emission spectra of chemosensor Ru‐L was observable upon addition of Cu 2+ ion. Competitive binding studies, detection limit (18.9 nM) and binding constants illustrate significant sensing ability of chemosensor Ru‐L . Spectral behaviour of chemosensor Ru‐L at different pH was also investigated in absence and presence of Cu 2+ ion. Binding of Cu 2+ to Ru‐L occurs in 1:1 stoichiometry, in good agreement with the results obatined from ESI‐mass spectrometry, Job's plot experiment and spectroscopic titrations. The emission intensity of Ru‐L was selectively quenched by Cu 2+ ion and an obvious color change from red orange to yellow in aqueous solution as well as on paper strips was observed under UV light. The reversibility cycles for the detection of Cu 2+ ion were achieved by EDTA and corresponding logic gate was also developed. The water solubility, reversibility and optical visualization of the present chemosensor make it ideal for practical applications on real samples.