Sticking and patching: tuning and anchoring cyclometallated ruthenium(<scp>ii</scp>) complexes

Ertl, Cathrin D.; Ris, Daniel P.; Meier, Stefan; Constable, Edwin C.; Housecroft, Catherine E.; Neuburger, Markus; Zampese, Jennifer A.

doi:10.1039/c4dt02797c

Cited by 27 publications

(33 citation statements)

References 54 publications

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“…127,128 Castellano and coworkers estimated the phosphorescence quantum yields to be ϕ < 0.005, 127 Table 1). The lifetimes are in the nanosecond range for all complexes and correlate nicely with the emission energy: the excited state lifetimes become smaller with decreasing emission energy.…”

Section: Tris(bidentate) Ruthenium Complexesmentioning

confidence: 97%

Excited state decay of cyclometalated polypyridine ruthenium complexes: insight from theory and experiment

Kreitner

Heinze

2016

Dalton Trans.

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Deactivation pathways of the triplet metal-to-ligand charge transfer ((3)MLCT) excited state of cyclometalated polypyridine ruthenium complexes with [RuN5C](+) coordination are discussed on the basis of the available experimental data and a series of density functional theory calculations. Three different complex classes are considered, namely with [Ru(N^N)2(N^C)](+), [Ru(N^N^N)(N^C^N)](+) and [Ru(N^N^N)(N^N^C)](+) coordination modes. Excited state deactivation in these complex types proceeds via five distinct decay channels. Vibronic coupling of the (3)MLCT state to high-energy oscillators of the singlet ground state ((1)GS) allows tunneling to the ground state followed by vibrational relaxation (path A). A ligand field excited state ((3)MC) is thermally accessible via a (3)MLCT →(3)MC transition state with the (3)MC state being strongly coupled to the (1)GS surface via a low-energy minimum energy crossing point (path B). Furthermore, a (3)MLCT →(1)GS surface crossing point directly couples the triplet and singlet potential energy surfaces (path C). Charge transfer states either with higher singlet character or with different orbital parentage and intrinsic symmetry restrictions are thermally populated which promote non-radiative decay via tunneling to the (1)GS state (path D). Finally, the excited state can decay via phosphorescence (path E). The dominant deactivation pathways differ for the three individual complex classes. The implications of these findings for isoelectronic iridium(iii) or iron(ii) complexes are discussed. Ultimately, strategies for optimizing the emission efficiencies of cyclometalated polypyridine complexes of d(6)-metal ions, especially Ru(II), are suggested.

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Section: Tris(bidentate) Ruthenium Complexesmentioning

confidence: 97%

Excited state decay of cyclometalated polypyridine ruthenium complexes: insight from theory and experiment

Kreitner

Heinze

2016

Dalton Trans.

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“…2) which is characteristic of proton H F6 of the cyclometallated phenyl ring. 16 We recently commented on the paucity of structural data for [Ru(N^N) 2 (C^N)] + complexes. 16 Fig.…”

Section: Synthesis and Characterization Of The [Ru(bpy) 2 (C^n)] + Bumentioning

confidence: 99%

“…16 We recently commented on the paucity of structural data for [Ru(N^N) 2 (C^N)] + complexes. 16 Fig. 3 shows the structure of the L-[Ru(bpy) 2 (1)] + cation and selected bond distances and angles are given in the figure caption.…”

Section: Synthesis and Characterization Of The [Ru(bpy) 2 (C^n)] + Bumentioning

confidence: 99%

“…It has been demonstrated that tris(bpy)ruthenium(II)-or (bpy)tricarbonylchlororhenium(I)-dyes bearing alkylphosphonate or phosphonic acid anchors bind to NiO, 14,15 but, to the best of our knowledge, [Ru(N^N) 2 (C^N)] + complexes with phosphonic acid anchoring units have not been reported as sensitizers in p-type DSCs. In an initial investigation, 16 we used the strategy shown in Scheme 1 to access a [Ru(bpy) 2 (C^N)] + complex bearing a peripheral phosphonate ester. Although the cyclometallated complex shown in Scheme 1 can be isolated in good yield, its deprotection to yield the corresponding phosphonic acid was, in our hands, unsuccessful.…”

Section: Introductionmentioning

confidence: 99%

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Modular synthesis of simple cycloruthenated complexes with state-of-the-art performance in p-type DSCs

et al. 2016

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“…The X-ray crystal structures of 1 and 2 have been reported previously. [29][30][31] Indisputable structural assignment of 3 would arise from the crystallographic analysis of single-crystal; however, it far was not possible to obtain single-crystals suitable for X-ray crystallographic analysis of any of the newly synthesized com-plexes. To conclude, although the structures of 1-3 were not proven beyond any doubt, the structures are consistent with 1 H-NMR data described.…”

Section: Resultsmentioning

confidence: 99%

DNA Interaction and Cytotoxicity of Cyclometalated Ruthenium(II) Complexes as Potential Anticancer Drugs

Matsui

Sugiyama

Nakai

et al. 2016

CHEMICAL & PHARMACEUTICAL BULLETIN

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To evaluate the anticancer activity of the cyclometalated ruthenium(II) complexes [Ru(bpy) 2 (C^N)]Cl, we have studied the interaction of these complexes using calf thymus DNA (CT-DNA) and cytotoxicity assays with two tumor (L1210 and HeLa) and a non-tumor (BALB/3T3 clone A31) cell lines. It is suggested that the complexes act as intercalators and/or DNA minor groove binders. Moreover, the complexes display favorable cytotoxicity activities with L1210 and HeLa, which in all cases were significantly more favorable than cisplatin. In contrast, the complexes exhibit appreciably lower cytotoxicity toward BALB/3T3 clone A31.Key words cyclometalated ruthenium(II) complex; anticancer drug; cytotoxicity; oxidative DNA cleavage; lipophilicityThe discovery of cisplatin (cis-diamminedichloridoplatinum(II)) by Rosenberg was one of the most significant events for cancer chemotherapy.1) However, the use of cisplatin is restricted by its high toxicity, which leads to undesirable side effects and incidents of drug resistance. With the aim of overcoming these limitations, new platinum-based and non-platinum anticancer drugs are under development. A relatively new line of investigation focuses on ruthenium chemistry in an alternative metallopharmaceutical approach to platinum.2,3) The higher coordination number of ruthenium compared with platinum provides additional coordination sites, which can potentially be used to fine-tune the properties of the complex, for example, by influencing the way the complex interacts with DNA. 4)It is well accepted that ruthenium complexes can display anticancer effects with a fairly high selectivity, the lethality of the tumor cells being higher than that of the normal cells.5-10) Several ruthenium complexes that display an activity comparable to that of cisplatin have been described, and in some cases activities are even better.11-16) Pfeffer and colleagues 17,18) and Chao and colleagues 19,20) have found that some cyclometalated ruthenium(II) complexes are good candidates for becoming anticancer drugs. A cyclometalated ruthenium fragment with a metal-carbon σ bond is a crucial element for a potential anticancer drug. The ruthenium-carbon bond is known to lower the redox potential of ruthenium(III/II) couple dramatically, so that cyclometalated ruthenium(II) complexes may serve as good catalysts for the generation of hydroxyl radicals by virtue of the Fenton-like reaction. In addition, they have good lipophilicity that allows their entries into the cells. 18,20) From two features these cyclometalated ruthenium(II) complexes may lead to excellent anticancer drugs because many cancer cells possess low levels of catalase activity. 21)In the present study, we have synthesized the cyclometalated ruthenium(II) complexes as shown in Fig. 1, [Ru(bpy) 2 (C^N)] Cl, where bpy is 2,2′-bipyridine and C^N is the deprotonated cyclometalating ligand (2-phenylpyridine (phpy), 2-(4-methylphenyl) pyridine (mphpy), or diphenyldiazene (dphdaz)). To evaluate the anticancer activity of these complexes physicochemical p...

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Sticking and patching: tuning and anchoring cyclometallated ruthenium(ii) complexes

Abstract: ARTICLE This journal is © The Royal Society of Chemistry 2013J. Name., 2013, 00, 1-3 | 1 to a semiconductor surface; this complex also exhibits the most favourable absorption properties among the complexes studied.

Cited by 27 publications

References 54 publications

Excited state decay of cyclometalated polypyridine ruthenium complexes: insight from theory and experiment

Excited state decay of cyclometalated polypyridine ruthenium complexes: insight from theory and experiment

Modular synthesis of simple cycloruthenated complexes with state-of-the-art performance in p-type DSCs

DNA Interaction and Cytotoxicity of Cyclometalated Ruthenium(II) Complexes as Potential Anticancer Drugs

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