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 are seldom mentioned in chemiluminescence (CL). Herein, a self-enhanced CL luminophore with excellent CL behavior was synthesized by covalently cross-linking tris(4,4'-dicarboxylic acid-2,2'-bipyridyl) ruthenium(II) dichloride ([Ru(dcbpy)]Cl) with branched polyethylenimine (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 (KSO) as the oxidant. After the redox reaction between KSO 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 BRuNPs/KSO was longer than classical luminophores 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/KSO by catalyzing the decomposition of KSO to generate SO. On the basis of the enhancement effect of Ag, a simple and rapid CL method was proposed for Ag detection. The chemosensor showed a wide linear range from 25 to 3000 nM and 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 a coreaction accelerator to develop a ternary self-enhanced CL system, BRuNPs/KSO/Ag.