Water-soluble Ir(<scp>iii</scp>) complexes of deprotonated N-methylbipyridinium ligands: fluorine-free blue emitters

Coe, Benjamin J.; Helliwell, Madeleine; Sánchez, Sergio; Peers, Martyn K.; Scrutton, Nigel S.

doi:10.1039/c5dt02591e

Cited by 23 publications

(26 citation statements)

References 30 publications

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“…All of the complexes have emission lifetimes in the microsecond region, ranging from 1.79–2.08 μs (in acetonitrile) with mono‐exponential decay kinetics (Figure S17), suggesting that emission originates from a triplet excited state. The quantum yield, Φ (in acetonitrile) of the iridium(III) complexes increases in the following order; 1 (11.5 %) < 2 (13.9 %) < 3 (17.3 %) < 4 (22.5 %), and is consistent with those reported for similar complexes (Figure S18) …”

Section: Figuresupporting

confidence: 89%

Highly Charged, Cytotoxic, Cyclometalated Iridium(III) Complexes as Cancer Stem Cell Mitochondriotropics

Laws

Eskandari

Lü

et al. 2018

Chemistry A European J

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The cancer stem cell (CSC) toxicity and mechanism of action of a series of iridium(III) complexes bearing polypridyl and charged 1-methyl-2-(2-pyridyl)pyridinium ligands, 1-4 is reported. The most effective complex (containing 1,10-phenanthroline), 3, kills CSCs and bulk cancer cells with equal potency (in the micromolar range), indicating that it could potentially remove heterogenous tumour populations with a single dose. Encouragingly, 3 also inhibits mammopshere formation to a similar extent as salinomycin, a well-established anti-CSC agent. This complex induces CSC apoptosis by mitochondrial membrane depolarization, inhibition of mitochondrial metabolism, and intracellular reactive oxygen species (ROS) generation. To the best of our knowledge, this is the first study to investigate the anti-CSC properties of iridium complexes.

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Section: Figuresupporting

confidence: 89%

Highly Charged, Cytotoxic, Cyclometalated Iridium(III) Complexes as Cancer Stem Cell Mitochondriotropics

Laws

Eskandari

Lü

et al. 2018

Chemistry A European J

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“…The compound 1-methyl-3-(2′-pyridyl)pyridinium hexafluorophosphate and the complex salts 4P-6P and 4Cl-6Cl were synthesised as described previously. 45 All other reagents were obtained commercially and used as supplied. Products were dried overnight in a vacuum desiccator (silica gel) prior to characterisation.…”

Section: Materials and Proceduresmentioning

confidence: 99%

“…1) were synthesised by following the procedure used previously for 4-6. 45 The cyclometalated chloride-bridged dimeric intermediates were isolated in crude form only, but identified by 1 In order to further characterise the system, 13 C NMR experiments were carried out for selected compounds 1P, 4P and 7P in CD 3 CN (see the ESI, Table S1 †). The signals were assigned via HMQC and HMBC spectroscopy.…”

Section: Synthesis and Characterisationmentioning

confidence: 99%

“…In the context of luminescence, Ir III complexes with C^N ligands derived from pyridinium species were apparently unknown until we reported those of deprotonated 1-methyl-3-(2′-pyridyl)pyridinium (3,2′-C^N). 45 The only previous account of structurally related species concerns catalytic studies with hydride complexes that are unsuitable for luminescence. 46 A number of reports of cyclometalated complexes of N-methylbipyridinium species with Pd/Pt 47 or Ru 48 have appeared.…”

Section: Introductionmentioning

confidence: 99%

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Cyclometalated Ir(iii) complexes of deprotonated N-methylbipyridinium ligands: effects of quaternised N centre position on luminescence

et al. 2015

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Six new tricationic Ir(III) complexes of cyclometalating ligands derived from 1-methyl-2-(2'-pyridyl)pyridinium or 1-methyl-4-(2'-pyridyl)pyridinium are described. These complexes of the form [Ir(III)(C^N)2(N^N)](3+) (C^N = cyclometalating ligand; N^N = α-diimine) have been isolated and characterised as their PF6(-) and Cl(-) salts. Four of the PF6(-) salts have been studied by X-ray crystallography, and structures have been obtained also for two complex salts containing MeCN and Cl(-) or two Cl(-) ligands instead of N^N. The influence of the position of the quaternised N atom in C^N and the substituents on N^N on the electronic/optical properties are compared with those of the analogous complexes where C^N derives from 1-methyl-3-(2'-pyridyl)pyridinium (B. J. Coe, et al., Dalton Trans., 2015, 44, 15420). Voltammetric studies reveal one irreversible oxidation and multiple reduction processes which are mostly reversible. The new complexes show intramolecular charge-transfer absorptions between 350 and 450 nm, and exhibit bright green luminescence, with λmax values in the range 508-530 nm in both aqueous and acetonitrile solutions. In order to gain insights into the factors that govern the emission properties, density functional theory (DFT) and time-dependent DFT calculations have been carried out. The results confirm that the emission arises largely from triplet excited states of the C^N ligand ((3)LC), with some triplet metal-to-ligand charge-transfer ((3)MLCT) contributions.

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“…3,4 This has led to the development of a number of circularly polarized luminescent molecules including organic dyes, 5-10 helicenes, 7,[11][12][13][14] and transition metal complexes. [15][16][17] However, chiral complexes of luminescent lanthanide ions have been exploited for their circularly polarized luminescence properties for decades [18][19][20] and that continues with many recent studies. [21][22][23][24][25] Circularly polarized luminescence (CPL) is the differential emission of left vs right circularly polarized light.…”

Section: Introductionmentioning

confidence: 99%

Circularly polarized luminescence of Sm (III) and Eu (III) complexes with chiral ligand (R/S)‐BINAPO

et al. 2019

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Luminescent lanthanide (III) ions have been exploited for circularly polarized luminescence (CPL) for decades. However, very few of these studies have involved chiral samarium (III) complexes. Complexes are prepared by mixing axial chiral ligands (R/S))-2,2'-bis(diphenylphosphoryl)-1,1′-binaphthyl (BINAPO) with europium and samarium Tris (trifluoromethane sulfonate) (Eu (OTf) 3 and Sm (OTf) 3 ). Luminescence-based titration shows that the complex formed is Ln((R/S)-BINAPO) 2 (OTf) 3 , where Ln = Eu or Sm. The CPL spectra are reported for Eu((R/S)-BINAPO) 2 (OTf) 3 and Sm((R/S)-BINAPO) 2 (OTf) 3 .The sign of the dissymmetry factors, g em , was dependent upon the chirality of the BINAPO ligand, and the magnitudes were relatively large. Of all of the complexes in this study, Sm((S)-BINAPO) 2 (OTf) 3 has the largest g em = 0.272, which is one of the largest recorded for a chiral Sm 3+ complex. A theoretical three-dimensional structural model of the complex that is consistent with the experimental observations is developed and refined. This report also shows that (R/S)-BINAPO are the only reported ligands where g em (Sm 3+ ) > g em (Eu 3+ ).

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Water-soluble Ir(iii) complexes of deprotonated N-methylbipyridinium ligands: fluorine-free blue emitters

Cited by 23 publications

References 30 publications

Highly Charged, Cytotoxic, Cyclometalated Iridium(III) Complexes as Cancer Stem Cell Mitochondriotropics

Highly Charged, Cytotoxic, Cyclometalated Iridium(III) Complexes as Cancer Stem Cell Mitochondriotropics

Cyclometalated Ir(iii) complexes of deprotonated N-methylbipyridinium ligands: effects of quaternised N centre position on luminescence

Circularly polarized luminescence of Sm (III) and Eu (III) complexes with chiral ligand (R/S)‐BINAPO

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