Green and Blue Electrochemically Generated Chemiluminescence from Click Chemistry—Customizable Iridium Complexes

Abstract

Cationic cyclometalated iridium complexes containing two anionic phenylpyridine (ppy) ligands and the neutral bidentate triazole-pyridine ligand, 2-(1-substituted-1H-1,2,3-triazol-4-yl)pyridine (pytl), were investigated. The complexes display a rich and reversible electrochemical behavior, upon investigations by cyclic voltammetry in strictly aprotic conditions, that couples with excellent emission quantum yields and long lifetimes of the excited states. Therefore, in organic media, all complexes have generated intense green electrochemiluminescence (ECL) through the so-called annihilation procedure and, importantly, a modulation of the emission energy (to blue) has been easily obtained by simple fluorination of the ppy ligand. Finally, taking advantage of their remarkable solubility in water, intense ECL was also obtained from aqueous buffer solutions using the co-reactant method, thus making all the investigated complexes highly promising for their effective use as ECL labels in bioanalytical applications.

Strongly Blue Luminescent Cationic Iridium(III) Complexes with an Electron‐Rich Ancillary Ligand: Evaluation of Their Optoelectronic and Electrochemiluminescence Properties

“…The ECL spectra are generally redshifted with respect to the photoluminescent spectra due to the higher concentrations required during ECL acquisition and are broad and unstructured (Table 3). 23 Although a slight redshift of 337 cm –1 is observed in the unstructured ECL spectrum of 1b compared with 1a , 2b exhibits a maximum at λ ECL = 510 nm, which makes it, to the best of our knowledge, amongst the bluest ECL‐active phosphors known (see Figure S10 in the Supporting Information) 5c…”

Towards Water Soluble Mitochondria-Targeting Theranostic Osmium(II) Triazole-Based Complexes

“…We, and others, have paid particular attention to the use of copper-catalysed coupling of alkynes and azides to form 1,2,3-triazole-based ligands [7][8][9][10] and have investigated the photophysical properties of their resultant complexes. A significant number of reports have appeared detailing the photophysical and photochemical properties of triazole-based complexes of Re(I), Ru(II) and Ir(III) [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. Examples of triazole-containing complexes of osmium(II)…”

Synthesis, Photophysics, Electrochemistry and Electrogenerated Chemiluminescence of PEG-Modified BODIPY Dyes in Organic and Aqueous Solutions

“…18-23 A suite of ECL probes with output signals that vary in energy would permit for imaging of multiple labeled biological species simultaneously. Accordingly, current efforts are aimed at the development of new ECL probes, which display emission responses that span the visible region and include various nanostructures, 24-26 metal polypyrridyl complexes, 27 porphyrins 28 and other organic fluorophores. 29-32 BODIPY derivatives are promising candidates in this regard, since their emission output can be synthetically tuned by varying the substituents about the fluorophore and often display higher solubilities than many other polycyclic hydrocarbons of similar size.…”