A Synthetic, Structural, Spectroscopic and DFT study of ReI, CuI, RuII and IrIII Complexes Containing Functionalised Dipyrido[3,2‐a:2′,3′‐c]phenazine (dppz)

Lundin, Natasha J.; Walsh, Penny J.; Howell, Sarah L.; Blackman, Allan G.; Gordon, Keith C.

doi:10.1002/chem.200801369

Cited by 49 publications

(65 citation statements)

References 75 publications

(175 reference statements)

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“…Representative cyclic voltammograms of these complexes are shown in Figure . These complexes show an irreversible oxidation wave with E pa in the range +0.74 V to +1.27 V versus Cp 2 Fe +/0 , which is assigned to metal‐centered Ru 3+/2+ oxidation commonly observed in Ru II diimine complexes . Such an assignment is supported by the higher oxidation potential observed for complexes with electron‐withdrawing substituents and π‐conjugating diimine ligands.…”

Section: Resultsmentioning

confidence: 65%

Luminescent Carbonyl Hydrido Ruthenium(II) Diimine Coordination Compounds: Structural, Photophysical, and Electrochemical Properties

Chu

Shen

et al. 2016

Eur J Inorg Chem

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A series of luminescent carbonyl hydrido ruthenium(II) complexes with various diimine ligands with diverse electronic properties, including Me2bpy (bpy = bipyridine), Me2phen (phen = phenanthroline), PhenCOOH, PhenCN, Me2Ph2phen, Ph2phen, and π‐conjugating dipyrido[3,2‐d:2′,3′‐f]quinoxaline (dpq), dipyrido[3,2‐a:2′,3′‐c](6,7,8,9‐tetrahydro)phenazine (dpqc), and dipyridophenazine (dppz) have been synthesized and characterized. Four of these complexes have been structurally characterized by X‐ray crystallography. The photophysical and electrochemical properties of these complexes have been studied. The effects of the electronic features and π‐conjugation of the diimine ligand on the electronic and photophysical properties of these complexes have also been discussed. Our study revealed that the luminescence performance of these complexes could be significantly enhanced by increasing the rigidity and π‐conjugation of the diimine ligand.

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Section: Resultsmentioning

confidence: 65%

Luminescent Carbonyl Hydrido Ruthenium(II) Diimine Coordination Compounds: Structural, Photophysical, and Electrochemical Properties

Chu

Shen

et al. 2016

Eur J Inorg Chem

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“…All commercial chemicals were used without further purification. 1 H and 13 C NMR measurements were carried out on Bruker 500 spectrometers and referenced to residual solvent peaks.ESI-MS and R.P. UPLC-MS were performed using a Bruker Daltonics HCT 6000 mass spectrometer.…”

Section: Instruments and Methodsmentioning

confidence: 99%

Biological evaluation of nitrile containing Ru(II) polypyridyl complexes as potential photodynamic therapy agents

Mari

Rubbiani

Gasser

2017

Inorganica Chimica Acta

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The use of Ru complexes in light-mediated treatment of cancer (i.e. Photodynamic Therapy-PDT) has recently become extremely relevant with the entry into clinical trials of the first complexof this class against bladder cancer. Herein, we report on the potential application as PDT agents of two inertRu(II) polypyridyl complexes bearing a nitrile containing dppz ligand and two bipy or phenancillary ligands for 1 and 2, respectively (dppz = dipyrido[3,2-a:2′,3′-c]phenazine,bipy = 2,2'-bipyridine, phen = 1,10phenathroline).More specifically, a full characterization of the novel compound 2 was first performed. The distribution coefficients (logD) and 1 O 2 quantum yields in two solvent systems and at two irradiation wavelengths were then determined for both compounds. The phototoxicity of complexes 1 and 2was evaluated on cervical cancer HeLa cells and on non tumorigenic retinal pigment epithelial (RPE1-hTERT) cells. None of the complexes was found to be phototoxic.In vitro fluorescence microscopy indicated a scarce cellular uptake for 2. The lack of biological activity for complexes1 and 2 highlightsthat more investigations are required in order to understand the relationship between structure and biological activity for this class of compounds. 1 Introduction The application of ruthenium complexes as biologically active compounds was thoroughlyinvestigatedin the last decades. Two Ru(III) complexes are currently undergoing Phase II clinical trials as anticancer agents(i.e. NAMI-A and KP-1339) and a Ru(II) organometallic complex is under clinical optimization (i.e. RAPTA-C). [1-4] The complexes which are under evaluation are characterized by a mechanism of cytotoxicity based on ligand exchange. Another class of Ru compounds, namely substitutionally inert Ru(II) polypyridyl complexes, is characterized by favourable photophysicalproperties that make these complexesattractive for applicationssuch as photosensitizers (PSs) in Photodynamic Therapy (PDT) and Photoactivated Chemotherapy (PACT). [5] The use of such complexes for light-mediated treatment of cancer has thoroughly been investigated in the last years. [5] As a highlight of this research, a Ru(II) polypyridyl compound will be soon tested as a PDT agent in the clinics against non-muscle invasive bladder cancer (TLD-1433, Figure 1). [6] Several reasons make this type of compounds usefulin this field of research. For example, they display a strong absorbance in the visible region of the electromagnetic spectrum. Moreover, they are characterized by a reasonably long-lived triplet excited state. This allows for energy transfer to triplet oxygen (3 O 2) to form the toxic singlet oxygen (1 O 2).However, in this recent and promising research area, there is still a great room for optimization. For example, it would be highly desirable to have novel PSs with enhanced biological activity and/or activation wavelengthsin the PDT window (650-900 nm) and/orpossibly O 2-independent mechanisms of action.Our group has investigated the potential of Ru(II) polypyridyl compounds as dr...

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“…All ligands showed μs lifetimes of the transient absorbing states, see 10,20,34 Lifetimes can vary considerably with solvent and temperature, due to the environmental sensitivity of dppz, 8 and also depend on the nature of the probed state. 15 For example, Kuimova et al measured a 10 μs lifetime for [Re(CO) 3 ( py)(dppz-(CO 2 Et) 2 )] + in MeCN, while Dyer et al measured 3.5 μs for [Re(CO) 3 ( py)(dppz)] + in MeCN; in both cases this state is assigned as π,π* in nature.…”

Section: Transient Absorption Spectroscopymentioning

confidence: 99%

Stretching the phenazine MO in dppz: the effect of phenyl and phenyl–ethynyl groups on the photophysics of Re(i) dppz complexes

et al. 2014

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A series of dipyrido[3,2-a:2',3'-c]phenazine (dppz)-based ligands have been synthesised in which phenyl or phenyl-ethynyl linkers are terminated by (t)Bu or CN units. The corresponding [ReCl(CO)3(L)] complexes are also prepared. Electrochemistry shows the ligand which contains a phenyl-ethynyl linker and CN substituent is most easily reduced (by 15 mV relative to the other ligands). All complexes are reduced and oxidised at similar potentials. Electronic absorption spectra are consistent with stabilisation of the LUMO by the binding of the metal centre, as complex spectra are red-shifted relative to their ligand. In addition, those containing phenyl-ethynyl linkers show spectra red-shifted (by 650 cm(-1)) relative to their phenyl-linked analogues. Raman and resonance Raman spectroscopy combined with DFT and TD-DFT calculations are consistent with ligands showing π,π* transitions, and complexes showing metal-to-ligand charge-transfer (MLCT) transitions as the lowest energy absorption. Ligands emit from the π,π* excited state (λem ranging from 450 to 470 nm in CH2Cl2). The complexes show emission from both π,π* and MLCT states; the λem(MLCT) lies at 650-666 nm. Transient lifetimes in CH2Cl2 are decreased by the CN substituent, as this increases knr. Transient resonance Raman spectra (TR(2)) of ligands show spectral features associated with the LC state, and the strong similarities between these and complex spectra support an LC excited state at 355 nm for the complexes. Two-colour TR(3) spectra show only small differences to ground state spectra, the most obvious being a decrease in intensity of C[triple bond, length as m-dash]C bands. For [ReCl(CO)3()] and [ReCl(CO)3()] an increase in intensity of a 1575 cm(-1) band attributed to the dppz˙(-) species suggests that these complexes have significant MLCT state population between 20-60 ns after photoexcitation.

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A Synthetic, Structural, Spectroscopic and DFT study of Re^I, Cu^I, Ru^II and Ir^III Complexes Containing Functionalised Dipyrido[3,2‐a:2′,3′‐c]phenazine (dppz)

Cited by 49 publications

References 75 publications

Luminescent Carbonyl Hydrido Ruthenium(II) Diimine Coordination Compounds: Structural, Photophysical, and Electrochemical Properties

Luminescent Carbonyl Hydrido Ruthenium(II) Diimine Coordination Compounds: Structural, Photophysical, and Electrochemical Properties

Biological evaluation of nitrile containing Ru(II) polypyridyl complexes as potential photodynamic therapy agents

Stretching the phenazine MO in dppz: the effect of phenyl and phenyl–ethynyl groups on the photophysics of Re(i) dppz complexes

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