Aggregation-induced electrochemiluminescence-active ruthenium(II) complex for selective detection of dopamine

In this paper, we systematically investigated the aggregation-induced electrochemiluminescence (AIECL) of the ruthenium(II) complex ([Ru(phen) 2 (phen-O 2 )](PF 6 ) 2 , phen-O 2 : 5,6-diketone-1,10-phenanthroline), which was dissolved in solvents with different water/acetonitrile volume ratios. The fluorescence intensity of the system increased 11.5-fold when the proportion of water (a poor solvent) in the solvent mixture was increased to 90%, and the electrochemiluminescence intensity increased 16-fold when the proportion of water in the solvent was increased to 80%. Transmission electron microscopy and dynamic light scattering confirmed the aggregation of [Ru(phen) 2 (phen-O 2 )](PF 6 ) 2 molecules into nanoclusters. Aggregation-induced electrochemiluminescence properties were observed to increase with an increase in the proportion of water in H 2 O/CH 3 CN. Due to the excellent aggregation-induced luminescence performance of [Ru(phen) 2 (phen-O 2 )](PF 6 ) 2 , the quantitative detection of dopamine was achieved with a good linear range of 100 pM–1uM and a limitation of detection of 33.3 pM. This simple and sensitive method based on the AIECL effect can be widely applied to the detection and analysis of other small biological molecules.