Ruthenium(ii) and osmium(ii) polypyridyl complexes of an asymmetric pyrazinyl- and pyridinyl-containing 1,2,4-triazole based ligand. Connectivity and physical properties of mononuclear complexesElectronic supplementary information (ESI) available: 1H NMR spectra of 1a and 1b. See http://www.rsc.org/suppdata/dt/b2/b206667j/

Browne, Wesley R.; O’Connor, Christine; Hughes, Helen; Hage, Ronald; Walter, Olaf; Doering, Manfred; Gallagher, John F.; Vos, Johannes G.

doi:10.1039/b206667j

Cited by 54 publications

(13 citation statements)

References 32 publications

(16 reference statements)

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“…On the one hand, recent years have seen a large number of reports concerning luminescent complexes of rhenium(I) and iridium(III) bearing 1,2,3-triazole-derived ligands , with applications in light-emitting electrochemical cells and light-emitting diodes , and biological imaging. − Osmium(II) complexes incorporating 1,2,3-triazole-based ligands are, on the other hand, rather rare . There are only a few reported examples of luminescent dicationic osmium(II) complexes bearing neutral ligands incorporating a five-membered heterocycle such as 1,2,4-triazoles. , More commonly reported are charge-neutral complexes with anionic 1,2,4-triazolate or pyrazolate ligand systems, which are frequently combined with phosphine, arsine, or carbonyl donors. − We have recently reported a series of tris-bidentate triazole-based osmium(II) complexes and their application in light-emitting electrochemical cell devices , and the bis-tridentate complex [Os(btzpy) 2 ] 2+ (btzpy = 2,6-bis(1-phenyl-1,2,3-triazol-4-yl)pyridine), which exhibits phosphorescence at 595 nm. This latter complex was shown to be readily taken up by cervical cancer (HeLa) and U2OS cancer cell lines and displays a high degree of mitochondrial localization …”

Section: Introductionmentioning

confidence: 99%

Photophysical and Cellular Imaging Studies of Brightly Luminescent Osmium(II) Pyridyltriazole Complexes

Omar¹,

Scattergood²,

McKenzie

et al. 2018

Inorg. Chem.

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The series of complexes [Os(bpy) 3-n (pytz) n ][PF 6 ] 2 (bpy = 2,2'-bipyridyl, pytz = 1-benzyl-4-(pyrid-2yl)-1,2,3-triazole, 1 n = 0, 2 n = 1, 3 n = 2, 4 n = 3) have been prepared and characterised and are rare examples of luminescent 1,2,3-triazole-based osmium(II) complexes. For 3 we present an attractive and particularly mild preparative route via an osmium(II)  6-arene precursor circumventing the harsh conditions that are usually required. Due to the high spin-orbit coupling constant associated with the Os(II) centre the absorption spectra of the complexes all display absorption bands of appreciable intensity in the range 500-700 nm corresponding to spin-forbidden ground-state-to-3 MLCT transitions, which occur at significantly lower energies than the corresponding spin-allowed 1 MLCT transitions. The homoleptic complex 4 is a bright emitter ( max em = 614 nm) with a relatively high quantum yield of emission of ~ 40 % in deoxygenated acetonitrile solutions at RT. Water soluble chloride salts of 1-4 were also prepared, all of which remain emissive in aerated aqueous solutions at room temperature. The complexes were investigated for their potential as phosphorescent cellular imaging agents whereby efficient excitation into the 3 MLCT absorption bands at the red side of the visible range circumvents 2 autofluorescence from biological specimens which do not absorb in this region of the spectrum. Confocal microscopy reveals 4 to be readily taken up by cancer cell lines (HeLa and EJ) with apparent lysosomal and endosomal localisation, whilst toxicity assays reveal that the compounds have low dark and light toxicity. These complexes therefore provide an excellent platform for the development of efficient luminescent cellular imaging agents with advantageous photophysical properties which enable excitation and emission in the biologically transparent region of the optical spectrum. Optimised ground state geometry atomic coordinates and TDDFT data for complexes 1-4. X-ray crystallographic data for 2 and mer-4. Confocal microscopy images and cellular viability data for cells incubated with 1-4. Crystallographic Data Crystallographic information files are available for complexes 2 (CCDC 1826209) and mer-4 (CCDC 1850035).

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Section: Introductionmentioning

confidence: 99%

Photophysical and Cellular Imaging Studies of Brightly Luminescent Osmium(II) Pyridyltriazole Complexes

Omar¹,

Scattergood²,

McKenzie

et al. 2018

Inorg. Chem.

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“…Many literature reports of excited state acid–base chemistry in transition metal compounds have appeared since the first reports by Demas and Peterson in 1976. ,,− All known ruthenium polypyridine compounds with pendant carboxylates − or amines − were found to be photobases. Photoacidic ruthenium compounds are relatively rare and until now appear to be limited to phenol-type or ambidentate cyanide ligands .…”

Section: Introductionmentioning

confidence: 99%

Photoacidic and Photobasic Behavior of Transition Metal Compounds with Carboxylic Acid Group(s)

O’Donnell

Sampaio

et al. 2016

J. Am. Chem. Soc.

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Excited state proton transfer studies of six Ru polypyridyl compounds with carboxylic acid/carboxylate group(s) revealed that some were photoacids and some were photobases. The compounds [Ru(II)(btfmb)2(LL)](2+), [Ru(II)(dtb)2(LL)](2+), and [Ru(II)(bpy)2(LL)](2+), where bpy is 2,2'-bipyridine, btfmb is 4,4'-(CF3)2-bpy, and dtb is 4,4'-((CH3)3C)2-bpy, and LL is either dcb = 4,4'-(CO2H)2-bpy or mcb = 4-(CO2H),4'-(CO2Et)-2,2'-bpy, were synthesized and characterized. The compounds exhibited intense metal-to-ligand charge-transfer (MLCT) absorption bands in the visible region and room temperature photoluminescence (PL) with long τ > 100 ns excited state lifetimes. The mcb compounds had very similar ground state pKa's of 2.31 ± 0.07, and their characterization enabled accurate determination of the two pKa values for the commonly utilized dcb ligand, pKa1 = 2.1 ± 0.1 and pKa2 = 3.0 ± 0.2. Compounds with the btfmb ligand were photoacidic, and the other compounds were photobasic. Transient absorption spectra indicated that btfmb compounds displayed a [Ru(III)(btfmb(-))L2](2+)* localized excited state and a [Ru(III)(dcb(-))L2](2+)* formulation for all the other excited states. Time dependent PL spectral shifts provided the first kinetic data for excited state proton transfer in a transition metal compound. PL titrations, thermochemical cycles, and kinetic analysis (for the mcb compounds) provided self-consistent pKa* values. The ability to make a single ionizable group photobasic or photoacidic through ligand design was unprecedented and was understood based on the orientation of the lowest-lying MLCT excited state dipole relative to the ligand that contained the carboxylic acid group(s).

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“…On the other hand, 2phenylpyridine is known for its capability of undergoing a cyclometalation reaction, by supplying the anionic bonding character with respect to the central metal atom. [9] In sharp contrast, C-linked 2-pyridyl azoles, such as pyrazoles, are known to serve as both neutral chelating ligands [10] or anionic chelates by deprotonation of the pyrazolyl-NH bond. [11] The latter process is conceptually related to the cyclometalation.…”

Section: Introductionmentioning

confidence: 99%

Pt^II Complexes with 6‐(5‐Trifluoromethyl‐Pyrazol‐3‐yl)‐2,2′‐Bipyridine Terdentate Chelating Ligands: Synthesis, Characterization, and Luminescent Properties

Chen¹,

Chang²,

Chi³

et al. 2008

Chemistry An Asian Journal

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A series of Pt(II) complexes Pt(fpbpy)Cl (1), Pt(fpbpy)(OAc) (2), Pt(fpbpy)(NHCOMe) (3), Pt(fpbpy)(NHCOEt) (4), and [Pt(fpbpy)(NCMe)](BF(4)) (5) with deprotonated 6-(5-trifluoromethyl-pyrazol-3-yl)-2,2'-bipyridine terdentate ligand are prepared, among which 1 is converted to complexes 2-5 by a simple ligand substitution. Alternatively, acetamide complex 3 is prepared by hydrolysis of acetonitrile complex 5, while the back conversion from 3 to 1 is regulated by the addition of HCl solution, showing the reaction sequence 1-->5-->3-->1. Multilayer OLED devices are successfully fabricated by using triphenyl-(4-(9-phenyl-9H-fluoren-9-yl)phenyl) silane (TPSi-F) as host material and with doping concentrations of 1 varying from 7 to 100 %. The electroluminescence showed a substantial red-shifting versus the normal photoluminescence detected in solution. Moreover, at a doping concentration of 28 %, the device showed a saturated red luminescence with a maximum external quantum yield of 8.5 % at 20 mA cm(-2) and a peak luminescence of 47,543 cd m(-2) at 18.5 V.

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Cited by 54 publications

References 32 publications

Photophysical and Cellular Imaging Studies of Brightly Luminescent Osmium(II) Pyridyltriazole Complexes

Photophysical and Cellular Imaging Studies of Brightly Luminescent Osmium(II) Pyridyltriazole Complexes

Photoacidic and Photobasic Behavior of Transition Metal Compounds with Carboxylic Acid Group(s)

Pt^II Complexes with 6‐(5‐Trifluoromethyl‐Pyrazol‐3‐yl)‐2,2′‐Bipyridine Terdentate Chelating Ligands: Synthesis, Characterization, and Luminescent Properties

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Cited by 54 publications

References 32 publications

Photophysical and Cellular Imaging Studies of Brightly Luminescent Osmium(II) Pyridyltriazole Complexes

Photophysical and Cellular Imaging Studies of Brightly Luminescent Osmium(II) Pyridyltriazole Complexes

Photoacidic and Photobasic Behavior of Transition Metal Compounds with Carboxylic Acid Group(s)

PtII Complexes with 6‐(5‐Trifluoromethyl‐Pyrazol‐3‐yl)‐2,2′‐Bipyridine Terdentate Chelating Ligands: Synthesis, Characterization, and Luminescent Properties

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Pt^II Complexes with 6‐(5‐Trifluoromethyl‐Pyrazol‐3‐yl)‐2,2′‐Bipyridine Terdentate Chelating Ligands: Synthesis, Characterization, and Luminescent Properties