The synthesis and characterisation of three novel iridium(III) bis-cyclometallated complexes is reported. Their photophysics have been fully characterised by classical methods and revealed charge-transfer (CT) and ligand-centred (LC) transitions. Their ability to selectively interact with G-quadruplex telomeric DNA over duplex DNA has been studied by circular dichroism (CD), bio-layer interferometry (BLI) and surface plasmon resonance (SPR) analyses. Interestingly, one of the complexes was able to promote photoinduced electron transfer (PET) with the guanine DNA base, which in turn led to oxidative damage (such as the formation of 8-oxoguanine) to the telomeric sequence. To the best of our knowledge, this is the first study of highly photo-oxidising bis-cyclometallated iridium(III) complexes with G-quadruplex telomeric DNA.
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http://dx.doi.org/10.1002/chem.201902183 | DOI Listing |
Dalton Trans
August 2020
Department of Chemistry, Durham University, Durham, DH1 3LE, UK.
The synthesis and photophysical properties of a set of iridium(iii) complexes featuring tridentate N^N^O-coordinating ligands are described, of generic structure [Ir(N^C^N-dpyx)(N^N^O-L)] (n = 1 to 4) (dpyx = 1,3-dipyridyl-4,6-dimethylbenzene). The proligands HL are Schiff bases synthesised by condensation of salicylaldehydes with N-methyl-hydrazinopyridines: they are able to coordinate to the Ir(iii) via lateral pyridine-N and phenolate-O atoms and a central hydrazone-N atom; the four examples differ in the substitution pattern within the phenolate ring. The bis-tridentate coordination is confirmed by X-ray diffraction.
View Article and Find Full Text PDFChemistry
October 2019
Institut de la Matière Condensée et des Nanosciences (IMCN), Molecular Chemistry, Materials and Catalysis (MOST), Université catholique de Louvain (UCLouvain), Place Louis Pasteur 1, bte L4.01.02, 1348, Louvain-la-Neuve, Belgium.
The synthesis and characterisation of three novel iridium(III) bis-cyclometallated complexes is reported. Their photophysics have been fully characterised by classical methods and revealed charge-transfer (CT) and ligand-centred (LC) transitions. Their ability to selectively interact with G-quadruplex telomeric DNA over duplex DNA has been studied by circular dichroism (CD), bio-layer interferometry (BLI) and surface plasmon resonance (SPR) analyses.
View Article and Find Full Text PDFChemistry
June 2019
IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20145, Milan, Italy.
Curcumin has chemopreventative properties against a variety of tumours, but has poor bioavailability. Here, two new bis-cyclometallated iridium(III) complexes have been prepared, featuring the natural product curcumin (CUR) or its reduced form, tetrahydrocurcumin (THC), as bidentate, anionic O O-binding ligands. The iridium THC complex is highly luminescent in deoxygenated solution and efficiently generates singlet oxygen under aerated conditions, whereas in the CUR analogue, other non-radiative decay pathways are competitive.
View Article and Find Full Text PDFDalton Trans
July 2019
Instituto de Ciencia Molecular, Universidad de Valencia, Catedrático José Beltrán 2, 46980 Paterna, Spain.
Using a density functional theory approach, we explore the emission properties of a family of bis-cyclometallated cationic iridium(iii) complexes of general formula [Ir(C^N)2(CN-tert-Bu)2]+ that have tert-butyl isocyanides as neutral auxiliary ligands. Taking the [Ir(ppy)2(CN-tert-Bu)2]+ complex (Hppy = 2-phenylpyridine) as a reference, the effect of replacing the pyridine ring in the cyclometallating ppy ligand by a five-membered azole ring has been examined. To this end, two series of complexes differing by the nature of the atom (either nitrogen or carbon) linking the azole to the phenyl ring of the cyclometallating ligand have been designed.
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July 2017
School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK.
Mononuclear and trinuclear bis-cyclometallated Ir complexes of the host ligands tris(4-[4'-methyl-2,2'-bipyridyl]methyl)cyclotriguaiacylene (L1) and tris(4-(4'-methyl-2,2'- bipyridyl)carboxy)cyclotriguaiacylene (L2) have been prepared. Complexes [{Ir(ppy) } (L1)](PF ) (1.1), [{Ir(ppy) }(L1)](PF ) (1.
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