Electrogenerated chemiluminescence from the monomer of a tetradentate chelate Pt(II) compound

Dual-mode electrochemical and electrochemiluminescence detection of dopamine based on perylene diimide self-assembly material

The self-assembly material N,N-bis-(3-dimethyl aminopropyl)-3,4,9,10-perylene tetracarboxylic acid diimide (PDI) is reported to show electrochemical (EC)/electrochemiluminescence (ECL) property for designing new dual-mode dopamine (DA) sensors. K2S2O8 significantly improved the EC reduction current at -0.346 V and ECL intensity at -0.25 V of the PDI self-assembly material. DA largely decreased the EC reduction current and ECL intensity of this homogeneous EC/ECL material due to the competitive consumption of K2S2O8 in the oxidization process of DA and the low electron conductivity of polyDA formed through the oxidization of DA by K2S2O8. In addition, the ECL quenching mechanism involved an energy-transfer process resulting from the collision between the produced o-benzoquinone species (oxidization of DA) and the excited state of PDI, which decreased the ECL intensity. This homogeneous EC/ECL material showed linear EC current response for DA from 5.0 nM to 50.0 µM with a detection of limit of 2.7 nM and linear ECL response for DA from 1.0 nM to 100.0 µM with a detection of limit of 0.41 nM. The proposed dual-mode EC/ECL sensors also showed good feasibility in urine sample analysis.

Enhanced Electrochemiluminescence of A Macrocyclic Tetradentate Chelate Pt(II) Molecule via Its Collisional Interactions with the Electrode

A macrocyclic tetradentate chelate Pt(II) molecule (Pt1) served as an excellent luminophore in electrochemiluminescence (ECL) processes. The blue ECL of Pt1/S2O82- coreactant system in N,N'-dimethylformamide was found to be 46 times higher than that of the Ru(bpy)2+/S2O82- system or 30 times higher than that of the 9,10-diphenylanthracene/S2O82- system. The unprecedented high ECL quantum efficiencies were caused by the cyclic generation of monomer excited states through collisional interactions of Pt1 molecules with the electrode at an elevated frequency. The ECL is tunable from bright blue to pure white by simply changing the solvent from N,N'-dimethylformamide to dichloromethane. The white ECL of Pt(II) molecule was reported for the first time and the mechanism was proposed to be the simultaneous emissions from the monomer excited state (blue) and excimer (red).