Rapid and selective detection of biothiols by novel ruthenium(II) complex-based phosphorescence probes

Abstract Considering the excellent photochemical properties of ruthenium(II) complexes, two new ruthenium(II) complexes, RuL 1 -DNBS and RuL 2 -DNBS , have been developed as phosphorescence probes for detection of biothiols in 100:1 (v/v) Hepes buffer (20 mM, pH = 7.2)/CH 3 CN solution. The response rate was highly improved of these two probes toward biothiols because the steric interactions between 1 H -imidazo [4, 5- f ] [ 1 , 10 ] phenanthroline group and ortho-2, 4-dinitrobenzensulfonate resulted in a relatively rapid thiol-induced S N Ar substitution reaction. RuL 1 -DNBS and RuL 2 -DNBS were weakly phosphorescent owing to the effectual photoinduced electron transfer from ruthenium(II) luminophore to the sensing group, 2,4-dinitrobenzenesulfonyl. After reacting with biothiols, the 2,4-dinitrobenzenesulfonyl group of RuL 1 -DNBS and RuL 2 -DNBS were cleavaged and the RuL 1 and RuL 2 were obtained. Meanwhile, the phosphorescence were “turn-on”. Both of these two probes can detect biothiols sensitively and selectively under physiological conditions with submicromolar detection limits. Furthermore, application of RuL 2 -DNBS for detecting of intracellular biothiols has been successfully performed in living Glioma cells.