Control of Excitation and Quenching in Multi‐colour Electrogenerated Chemiluminescence Systems through Choice of Co‐reactant

Abstract

We demonstrate a new approach to manipulate the selective emission in mixed electrogenerated chemiluminescence (ECL) systems, where subtle changes in co-reactant properties are exploited to control the relative electron-transfer processes of excitation and quenching. Two closely related tertiary-amine co-reactants, tri-n-propylamine and N,N-diisopropylethylamine, generate remarkably different emission profiles: one provides distinct green and red ECL from [Ir(ppy)3] (ppy=2-phenylpyridinato-C2,N) and a [Ru(bpy)3](2+) (bpy=2,2'-bipyridine) derivative at different applied potentials, whereas the other generates both emissions simultaneously across a wide potential range. These phenomena can be rationalized through the relative exergonicities of electron-transfer quenching of the excited states, in conjunction with the change in concentration of the quenchers over the applied potential range.

Supramolecular iridium(III) assemblies

“…[58] This observation is rather unusual considering that for the vast majority of multichromophoric species, the ECL signals could be addressed at different potentials and thus produce multiple emissive readouts. [59][60][61] The ECL efficiency of S5 was determined to be 2.51%, which is intermediate between the ECL efficiencies of the ionic components 3a (2.83%) and 5b (2.14%). The higher ECL efficiency for S5 compared to 5b is Godbert and co-workers [62] synthetized green-emitting anionic Ir complexes bearing an unsual bidentate orotate dianion as the ancillary ligand (NBu 4 4a and NBu 4 4b in Figure 4a).…”

Efficient green electrogenerated chemiluminescence from cyclometalated iridium(III) complex

“…The larger separation of ECL emissions could be identified two species in a single sample solution containing both compounds [52]. The possibility of the identification of (dfppy) 2 Ir(PyBiz) and Ru(bpy) 3 2+ in a single sample solution is examined.…”

Essential Role of Electrode Materials in Electrochemiluminescence Applications

“…As a matter of fact, GCE shows 10 times and 100 times higher ECL intensity compared to gold and platinum, respectively . Furthermore, GCE are used also in organic solvents, such as acetonitrile, for the characterization of inorganic complexes such as Ru or Ir, and with tertiary amines as coreactant …”

“…[22] Furthermore, GCE are used also in organic solvents, such as acetonitrile, for the characterization of inorganic complexes such as Ru or Ir, [39] and with tertiary amines as coreactant. [40] Figure 2. Cyclic voltammogram and ECL curve at a) platinum and b) gold electrodes in 0.15 m phosphate buffer solutions (pH 7.5)containing1 00 mm TPrA and 1 mMR u(bpy) 3 2 + .T he dotted line represents data in the absence of both Ru(bpy) 3 2 + and TPrA.…”