Intense near-infrared electrochemiluminescence facilitated by energy transfer in bimetallic Ir-Ru metallopolymers

The facile synthesis of a bimetallic polymer is demonstrated by a single-step modification of [Ru(bpy)(2)PVP10](2+) (bpy = bipyridine, PVP = poly-4-vinylpyridine), which has been partially photolyzed, with an iridium precursor. This bimetallic polymer possesses three emissive centres: Ir, Ru(N)(6), and Ru(N)(5). The photophysical, electrochemical and electrochemiluminescent properties of this bimetallic and corresponding monometallic polymers in solution-phase, and when immobilised as a thin layer, are reported. The perceived emission colour can be readily tuned from near-infrared through to green, by varying the ratio of iridium to ruthenium centres in the polymer. Energy transfer from the iridium centre to the Ru(N)(5) and Ru(N)(6) centres is observed on photoexcitation of the polymers in solution-phase. When the materials are immobilised as a thin layer, energy transfer can be observed following excitation via electrochemiluminescent (ECL) pathways. Mechanistic studies were performed and further investigated through 3D ECL. Dexter-type energy transfer enhances the electrochemiluminescence properties of the bimetallic polymer versus the monometallic polymer, improving the limit of detection of the co-reactant oxalate from 20 to 5 mu M. Crown Copyright (C) 2021 Published by Elsevier Ltd. All rights reserved.

Automated summary

A facile synthesis method of a bimetallic polymer with multiple emissive centers was demonstrated by modifying a partially photolyzed [Ru(bpy)(2)PVP10](2+) with an iridium precursor. The tunable emission color from near-infrared to green by adjusting the ratio of iridium to ruthenium centers was achieved. Transfer of energy between the iridium center and ruthenium centers was observed both in solution-phase and when immobilized as a thin layer, enhancing the electrochemiluminescence properties of the bimetallic polymer.