Self-Enhanced Chemiluminescence of Tris(bipyridine) Ruthenium(II) Derivative Nanohybrids: Mechanism Insight and Application for Sensitive Silver Ions Detection.

In recent years, self-enhanced tris(bipyridine) ruthenium(II)-based luminescence systems have achieved great development in electrochemiluminescence (ECL), but is seldom mentioned in chemiluminescence (CL). Herein, a self-enhanced CL luminophore with excellent CL behavior was synthesized by covalently crosslinking tris(4,4-dicarboxylic acid-2,2-bipyridyl) ruthenium(II) dichloride (Ru(dcbpy)32+) with branched polyethyleneimine (BPEI) in one molecule (BPEI-Ru(II)), which then self-assembled into nanoparticles (BRuNPs). The nanoparticles exhibited stable and strong CL emission with potassium persulfate (K2S2O8) as oxidant. After the redox reaction between K2S2O8 and BRuNPs, and the subsequent intramolecular electron-transfer reaction, excited state luminophores were generated to emit light. This self-enhanced CL system shortened the electron transfer distance and reduced energy loss, thus improving the luminous efficiency. In addition, the CL lifetime of K2S2O8-BRuNPs was longer than classical luminophore such as N-(4-Aminobutyl)-N-ethylisoluminol (ABEI), indicating the potential application of this system in CL imaging. Surprisingly, Ag+ was found to greatly improve the CL efficiency of BRuNPs/K2S2O8 by catalyzing the decomposition of K2S2O8 to generate SO4*. Based on the enhancement effect of Ag+, a simple and rapid CL method was proposed for Ag+ detection. The chemosensor showed wide linger range from 25 nM to 3000 nM, low detection limit of 9.03 nM, as well as good stability and excellent selectivity. More importantly, this result indicated that Ag+ can be used as coreaction accelerator to develop a ternary self-enhanced CL system, BRuNPs/K2S2O8/Ag+.