Abstract
Two ligands H2L1 and HL2 containing imidazole rings and piperazine or morpholine units have been prepared by the reaction of 1,10-phenanthroline-5,6-dione with 4,4´- (1,4-piperazinediyl)bisbenzaldehyde and 4-morpholinobenzaldehyde, respectively. The Ru(II) polypyridyl complexes [(bpy)2Ru(H2L1)Ru(bpy)2]4+ and [(bpy)2Ru(HL2)]2+ have been synthesized by the reaction of Ru(bpy)2Cl2·2H2O with ligands H2L1 and HL2, respectively. The pH effects on the UV=Vis absorption and fluorescence spectra of both complexes have been studied. The ground-state and excited-state ionization constants of the acid-base equilibria have been calculated according to the absorbance and emission data. The photophysical properties of both complexes are strongly dependent on the solution pH. They act as proton-induced “off-on-off” fluorescence pH sensors through protonation and deprotonation of the imidazole, piperazine or morpholine groups, with a maximum on-off ratio of 6 in buffer solution at room temperature.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
