Cyclometalated Iridium(III) Imidazole Phenanthroline Complexes as Luminescent and Electrochemiluminescent G-Quadruplex DNA Binders

Abstract

Six cyclometalated iridium(III) phenanthroimidazole complexes with different modifications to the imidazole phenanthroline ligand exhibit enhanced luminescence when bound to guanine (G-) quadruplex DNA sequences. The complexes bind with low micromolar affinity to human telomeric and c-myc sequences in a 1:1 complex:quadruplex stoichiometry. Due to the luminescence enhancement upon binding to G-quadruplex DNA, the complexes can be used as selective quadruplex indicators. In addition, the electrogenerated chemiluminescence of all complexes increases in the presence of specific G-quadruplex sequences, demonstrating potential for the development of an ECL-based G-quadruplex assay.

Towards the Development of Photo‐Reactive Ruthenium(II) Complexes Targeting Telomeric G‐Quadruplex DNA

“…The planar ligand CPIP (X=CH) was synthesized by condensation of 4‐chlorobenzaldehyde with 1,10‐phenanthroline‐5,6‐dione in an ammonium‐containing medium as previously reported in the literature . The ligand CPITAP (X=N) was obtained according to a new protocol developed in our laboratory, using 4‐chlorobenzaldehyde and 9,10‐diamino‐1,4,5,8‐tetraazaphenanthrene.…”

“…In the present study, three new photo‐oxidizing ruthenium(II) complexes (Scheme ) that selectively target G‐quadruplex DNA over duplex DNA have been synthesized. They are based on the 2‐(4‐chlorophenyl)‐1 H ‐imidazo[4,5‐ f ][1,10]phenanthroline (CPIP) ligand, some ruthenium(II), platinum(II), or iridium(III) complexes of which have previously been reported for selective DNA switch. However, none of these complexes has shown an ability to induce photo‐electron transfer (PET) with guanine units.…”

The use of organolithium reagents for the synthesis of 4-aryl-2-phenylpyridines and their corresponding iridium(iii) complexes

“…Significantly, this allows for the harvesting of both singlet and triplet excitons within an OLED, theoretically allowing 100% internal quantum, and since their first deployment in these devices by Forrest et al, they have been the subject of numerous patents and papers. [12][13][14][15][16][17][18][19][20][21] Their emission spectra can be readily tuned by altering either the ancillary or 2-phenylpyridine ( ppy) ligand. [12][13][14][15][16][17][18][19][20][21] Their emission spectra can be readily tuned by altering either the ancillary or 2-phenylpyridine ( ppy) ligand.…”

Thiourea and Guanidine Compounds and Their Iridium Complexes in Drug‐Resistant Cancer Cell Lines: Structure‐Activity Relationships and Direct Luminescent Imaging

“…[29,30] Iridium complexes themselves are of great interest as potential cancer therapeutics because they generate a 3D scaffold, enabling structural diversity beyond the 'flatter' organic molecules or platinum complexes used in cancer therapy; they offer an opportunity for simultaneous imaging due to their rich and tunable luminescence properties; [31] and they offer an opportunity for photogeneration of singlet oxygen within cells. [32] Furthermore, cyclometallated iridium complexes similar to those we investigate for organic LEDs have been shown to interfere with protein-protein interactions, [33] bind Gquadruplexes in oncogene promoters, [34] and can be used to target either the mitochondria [35] or endoplasmic reticulum. [36] Mechanisms of action for cell death caused by iridium complexes include generation of reactive oxygen species (ROS) [32] and interference with NF-kB.…”