Polypyridine OsII complexes electrochemical data.
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ABSTRACT:
SUBMITTER: van der Westhuizen D
PROVIDER: S-EPMC7642827 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The data presented in this article is related to the research article entitled "Electrochemical and electronic properties of a series of substituted polypyridine ligands and their Co(II) complexes" (Ferreira et al., 2019). This data article presents electrochemical data of five polypyridine ligands, as well as of the three redox couples of each of their corresponding five polypyridine-containing Co(II) complexes. All complexes exhibit two Co-based redox couples (CoIII/II and CoII/I), as well as a ligand-based reduction of the Co(I) complex.
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Project description:Data in this article is associated with our research article, Electronic Properties of Fe Charge Transfer Complexes - a Combined Experimental and Theoretical Approach [1]. The oxidation and reduction potentials of fourteen FeII complexes are presented here, as extracted from the redox data obtained from its associated cyclic voltammograms, which were measured at scan rates varying from 0.05 V.s-1 to 5.00 V.s-1, under similar experimental conditions. Acetonitrile was used as solvent, and tetrabutylammonium hexafluorophosphate as supporting electrolyte. All data are reported versus the FeII redox couple in ferrocene.
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Project description:The data presented in this paper are related to the research article entitled "Electrochemical properties of a series of Co(II) complexes, containing substituted phenanthrolines" (Ferreira et al., 2018) [1]. This paper presents detailed electrochemical data of eight octahedral Co(II) complexes containing functionalized phenanthrolines-ligands. The data illustrate the shift in the CoIII/II and CoII/I redox couples due to different substituents on the phenanthrolines. Polypyridine Co(II) and Co(III) complexes exhibit properties as potential mediators in dye-sensitized solar cells (DSSCs) (Gajardo and Loeb, 2011; Yu et al., 2011) [2], [3]. The ability of a compound to act as a redox mediator to be used in DSSC, depends on the redox potential of the compound (Grätzel, 2005) [4]. Accurate data of the CoIII/II redox couple is presented here.
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Project description:Three complexes based on an Ir-M (M = FeII, CoII, and NiII) heterobimetallic core and 2-(diphenylphosphino)pyridine (Ph2PPy) ligand were synthesized via the reaction of trans-[IrCl(CO)(Ph2PPy)2] and the corresponding metal chloride. Their structures were established by single-crystal X-ray diffraction as [Ir(CO)(μ-Cl)(μ-Ph2PPy)2FeCl2]·2CH2Cl2 (2), [IrCl(CO)(μ-Ph2PPy)2CoCl2]·2CH2Cl2 (3), and [Ir(CO)(μ-Cl)(μ-Ph2PPy)2NiCl2]·2CH2Cl2 (4). Time-dependent DFT computations suggest a donor-acceptor interaction between a filled 5dz2 orbital on iridium and an empty orbital on the first-row metal atom, which is supported by UV-vis studies. Magnetic moment measurements show that the first-row metals are in their high-spin electronic configurations. Cyclic voltammetry data show that all the complexes undergo irreversible decomposition upon either reduction or oxidation. Reduction of 4 proceeds through an ECE mechanism. While these complexes are not stable to electrocatalysis conditions, the data presented here refine our understanding of the bonding synergies of the first-row and third-row metals.
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Project description:We report on the preparation and thorough characterization of cytotoxic half-sandwich complexes [Ru(??-pcym)(bphen)(dca)]PF? (Ru-dca) and [Os(??-pcym)(bphen)(dca)]PF? (Os-dca) containing dichloroacetate(1-) (dca) as the releasable O-donor ligand bearing its own cytotoxicity; pcym = 1-methyl-4-(propan-2-yl)benzene (p-cymene), bphen = 4,7-diphenyl-1,10-phenanthroline (bathophenanthroline). Complexes Ru-dca and Os-dca hydrolyzed in the water-containing media, which led to the dca ligand release (supported by ¹H NMR and electrospray ionization mass spectra). Mass spectrometry studies revealed that complexes Ru-dca and Os-dca do not interact covalently with the model proteins cytochrome c and lysozyme. Both complexes exhibited slightly higher in vitro cytotoxicity (IC50 = 3.5 ?M for Ru-dca, and 2.6 ?M for Os-dca) against the A2780 human ovarian carcinoma cells than cisplatin (IC50 = 5.9 ?M), while their toxicity on the healthy human hepatocytes was found to be IC50 = 19.1 ?M for Ru-dca and IC50 = 19.7 ?M for Os-dca. Despite comparable cytotoxicity of complexes Ru-dca and Os-dca, both the complexes modified the cell cycle, mitochondrial membrane potential, and mitochondrial cytochrome c release by a different way, as revealed by flow cytometry experiments. The obtained results point out the different mechanisms of action between the complexes.
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Project description:Hypoxia presents a challenge to anticancer therapy, reducing the efficacy of many available treatments. Photodynamic therapy is particularly susceptible to hypoxia, given that its mechanism relies on oxygen. Herein, we introduce two new osmium-based polypyridyl photosensitizers that are active in hypoxia. The lead compounds emerged from a systematic study of two Os(II) polypyridyl families derived from 2,2'-bipyridine (bpy) or 4,4'-dimethyl-2,2'-bipyridine (dmb) as coligands combined with imidazo[4,5-f][1,10]phenanthroline ligands tethered to n = 0-4 thiophenes (IP-nT). The compounds were characterized and investigated for their spectroscopic and (photo)biological activities. The two hypoxia-active Os(II) photosensitizers had n = 4 thiophenes, with the bpy analogue 1-4T being the most potent. In normoxia, 1-4T had low nanomolar activity (half-maximal effective concentration (EC50) = 1-13 nM) with phototherapeutic indices (PI) ranging from 5500 to 55 000 with red and visible light, respectively. A sub-micromolar potency was maintained even in hypoxia (1% O2), with light EC50 and PI values of 732-812 nM and 68-76, respectively -currently among the largest PIs for hypoxic photoactivity. This high degree of activity coincided with a low-energy, long-lived (0.98-3.6 μs) mixed-character intraligand charge-transfer (3ILCT)/ligand-to-ligand charge-transfer (3LLCT) state only accessible in quaterthiophene complexes 1-4T and 2-4T. The coligand identity strongly influenced the photophysical and photobiological results in this study, whereby the bpy coligand led to longer lifetimes (3.6 μs) and more potent photo-cytotoxicity relative to those of dmb. The unactivated compounds were relatively nontoxic both in vitro and in vivo. The maximum tolerated dose for 1-4T and 2-4T in mice was greater than or equal to 200 mg kg-1, an excellent starting point for future in vivo validation.
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Project description:Two bis-tridentate Os(II) compounds based on a heteroditopic terpyridine-bipyridine-type ligand were synthesized, and their photophysical properties were thoroughly studied. The compounds exhibit strong spin-allowed 1MLCT bands in the visible domain (489-521 nm) as well as weak 1GS to 3MLCT bands within the 668-815 nm domain. The compounds display strong luminescence from the 3MLCT state in the near-infrared domain (728-780 nm) at room temperature having lifetimes in the range of 20.0-171.0 ns. After coordination of [Os(tpy-PhCH3/H2pbbzim)2]2+ unit to the terpyridine site of tpy-Hbzim-dipy, the complexes offer vacant pyridine-imidazole motifs for interacting with cationic and anionic guests. Consequently, photophysical properties of the compounds were tuned to a great extent upon interaction with selected cations, anions, pH, as well as protons. Anion-induced alteration of the ground- and excited-state properties of the compound lead to recognition of specific anions in solution. Significant change in the optical spectral behaviors as well as switching of emission spectral properties of the compounds was done in the NIR region upon treating with anions, cations, protons, and solvents (dichloromethane, acetonitrile, methanol, dimethylsulfoxide, and water). Moreover, the optical outputs in response to external stimuli were used to demonstrate binary functions of two-input IMPLICATION, NOR, and XNOR logic gates.
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