Theoretical Investigation of Structural and Electronic Properties of Ruthenium Azopyridine Complexes Dyes for Photovoltaic Applications by Using DFT and TD-DFT Methods

In this work, a series of ruthenium azopyridine complexes was studied theoretically as a sensitizer in Dye Sensitized Solar Cells (DSSCs) using density functional theory (DFT) and time-dependent DFT (TD-DFT). These dyes derive from ruthenium azopyridine complex RuCl2(Azpy)2 considered as the reference by grafting an anchoring group (-COOH). Hens, 4-Hmazpy, 5-Hmazpy and O-Hazpy ligands as well as Azpy were studied. For the four ligands, 20 isomers expected are studied. In order to explore their photoelectrical properties, the ground state and excited state properties of the isolated dyes have been calculated at B3LYP/LANL2DZ level. And the same work was done with the dye RuCl2(5Hmazpy)2 in interaction with titanium dioxide. Comparing to N3, the key parameters including the light harvesting efficiency (LHE), the electron injection driving force ΔGinject , the regeneration driving force ΔGregen , the open circuit voltage VOC, the life time τ and adsorption energy were all scrutinized in detail. It results from this calculation that the ruthenium azopyridine complexes can be used as sensitizer in DSSCs. This work has highlighted the predictive and the guiding role of the theoretical approach in the design and the conception of new dyes for solar cells

Structure of Complexes of 2-Phenylazopyridine with Perchlorate Halides of Ni(II) & with Ferrous Iodide

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The contrasting chemical reactivity of potent isoelectronic iminopyridine and azopyridine osmium(ii) arene anticancer complexes

A wide variety of steric and electronic features can be incorporated into transition metal coordination complexes, offering the prospect of rationally-designed therapeutic agents with novel mechanisms of action. Here we compare the chemical reactivity and anticancer activity of organometallic OsII complexes [Os(η6-arene)(XY)Z]PF6 where arene = p-cymene or biphenyl, XY = N,N′-chelated phenyliminopyridine or phenylazopyridine derivatives, and Z = Cl or I. The X-ray crystal structure of [Os(η6-p-cym)(Impy-OH)I]PF6·0.5CH2Cl2·H2O (Impy-OH = 4-[(2-pyridinylmethylene)amino]-phenol) is reported. Like the azopyridine complexes we reported recently (Dalton Trans., 2011, 40, 10553–10562), some iminopyridine complexes are also potently active towards cancer cells (nanomolar IC50 values). However we show that, unlike the azopyridine complexes, the iminopyridine complexes can undergo aquation, bind to the nucleobase guanine, and oxidize coenzyme nicotine adenine dinucleotide (NADH). We report the first detection of an Os-hydride adduct in aqueous solution by 1H NMR (−4.2 ppm). Active iminopyridine complexes induced a dramatic increase in the levels of reactive oxygen species (ROS) in A549 lung cancer cells. The anticancer activity may therefore involve interference in the redox signalling pathways in cancer cells by a novel mechanism

Ruthenium polypyridyl complexes and their modes of interaction with DNA : is there a correlation between these interactions and the antitumor activity of the compounds?

Various interaction modes between a group of six ruthenium polypyridyl complexes and DNA have been studied using a number of spectroscopic techniques. Five mononuclear species were selected with formula [Ru(tpy) L1L2](2-n)?, and one closely related dinuclear cation of formula [{Ru(apy)(tpy)}2{l-H2N(CH2)6NH2}]4?. The ligand tpy is 2,20:60,200-terpyridine and the ligand L1 is a bidentate ligand, namely, apy (2,20-azobispyridine), 2-phenylazopyridine, or 2-phenylpyridinylmethylene amine. The ligand L2 is a labile monodentate ligand, being Cl-, H2O, or CH3CN. All six species containing a labile L2 were found to be able to coordinate to the DNA model base 9-ethylguanine by 1H NMR and mass spectrometry. The dinuclear cationic species, which has no positions available for coordination to a DNA base, was studied for comparison purposes. The interactions between a selection of four representative complexes and calf-thymus DNA were studied by circular and linear dichroism. To explore a possible relation between DNA-binding ability and toxicity, all compounds were screened for anticancer activity in a variety of cancer cell lines, showing in some cases an activity which is comparable to that of cisplatin. Comparison of the details of the compound structures, their DNA binding, and their toxicity allows the exploration of structure–activity relationships that might be used to guide optimization of the activity of agents of this class of compounds

Current applications and future potential for bioinorganic chemistry in the development of anticancer drugs

This review illustrates notable recent progress in the field of medicinal bioinorganic chemistry as many new approaches to the design of innovative metal-based anticancer drugs are emerging. Current research addressing the problems associated with platinum drugs has focused on other metal-based therapeutics that have different modes of action and on prodrug and targeting strategies in an effort to diminish the side-effects of cisplatin chemotherapy

Illuminating phenylazopyridines to photoswitch metabotropic glutamate receptors: from the flask to the animals

Phenylazopyridines are photoisomerizable compounds with high potential to control biological functions with light. We have obtained a series of phenylazopyridines with light dependent activity as negative allosteric modulators (NAM) of metabotropic glutamate receptor subtype 5 (mGlu5). Here we describe the factors needed to achieve an operational molecular photoisomerization and its effective translation into in vitro and in vivo receptor photoswitching, which includes zebrafish larva motility and the regulation of the antinociceptive effects in mice. The combination of light and some specific phenylazopyridine ligands displays atypical pharmacological profiles, including light-dependent receptor overactivation, which can be observed both in vitro and in vivo. Remarkably, the localized administration of light and a photoswitchable compound in the peripheral tissues of rodents or in the brain amygdalae results in an illumination-dependent analgesic effect. The results reveal a robust translation of the phenylazopyridine photoisomerization to a precise photoregulation of biological activity

การสังเคราะห์และยืนยันโครงสร้างของสารประกอบเชิงซ้อนของโลหะรูทีเนียม โดยมีลิแกนด์ 5-Methy1-2-(phenylazo)pyridine

Thesis (Ph.D., Chemistry)--Prince of Songkla University, 200