Improved synthesis and naked-eye Ag+ chemosensing properties of 2,9-dichloro-1,10-phenanthroline

Abstract

We have successfully developed a "turn-on" naked-eye chemosensor for Ag+ based on 2,9-dichloro- 1,10-phenanthroline. Phen-Cl2 5 was obtained from dione 4 with good yield and less side products in SOCl2 compared to the literature solvent POCl3. Novel compound N-monodealkylated 9-chloro-1-(3-chloropropyl)-1,10-phenanthrolin-2(1H)-one 6 was obtained when reaction was performed in SOCl2 for 8 h, but increasing reaction time to 16 h resulted full N-dealkylation. Naked-eye and spectroscopic Ag+ selective recognition was observed when 5 was mixed with nitrates of Co2+, Cr3+, Cu2+, Mn2+, Ni2+, Ag+, Fe3+, and Zn2+. Addition of 5 into a colorless solution of Ag+ resulted a light yellow color. Chemosensor successfully detected Ag+ at concentration range 15-210 ?M by UV-visible spectroscopy. Copyright © 2015 American Scientific Publishers.