- New Ru(ii) photocages operative with near-IR light: New platform for drug delivery in the PDT window
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A series of Ru(ii) complexes bearing the tridentate 2,6-di(quinolin-2-yl)pyridine (dqpy) ligand were designed to undergo photoinduced ligand dissociation with red/near-IR light. The complexes [Ru(dqpy)(L)(CH3CN)]2+, where L = 2,2′-bipyridine (bpy, 1), 4,4′dimethyl-2,2′-bipyridine (Me2bpy, 2), and 1,10-phenanthroline (phen, 3). Complexes 1-3 exhibit red-shifted lowest energy metal-to-ligand charge transfer (MLCT) absorption maxima at ~600 nm, as compared to the corresponding tpy (2,2′;6′,2′′-terpyridine) complexes with MLCT bands at ~565 nm which appear as shoulders to the MLCT bands at ~455 nm. This shift is attributed to the lower energy LUMO afforded by the dqpy ligand when compared to tpy, as evidenced by the shift of the first reduction wave to ~0.3 V more positive potentials in the former. In addition, the lowest MLCT maximum of [Ru(dqpy)(acac)(CH3CN)]+ (4; acac- = acetylacetonate) is observed at 770 nm, attributed to the additional increase in energy of the HOMO afforded by the presence of the π-donating acac- ligand and supported by calculations. Complexes 1-3 undergo ligand substitution upon irradiation with red light, λirr ≥ 610 nm, and the ligand substitution photochemistry of 4 is accessible with near-IR light, λirr ≥ 715 nm and λirr = 735 nm. Complexes 1-4 exhibit similar quantum yields of ligand exchange, ΦL, with 450 and 600 nm irradiation, however, that of 4 is 2-3 times greater than those measured for 1-3. This enhancement is explained by the difference in ligand contributions to the HOMO. Density functional theory calculations predict partial dqpy ππ? character in the MLCT states of 1-3 and a mixed Ru/acac- → dqpy metal/ligand-to-ligand charge transfer (ML-LCT) state in 4. The photoreactivity of 1-4 with tissue-penetrating red and near-IR light, together with their exceptional dark stability (>48 h), makes the new Ru(ii)-dqpy platform ideal for the development of new complexes for photoinduced drug release and for other applications that require broad absorption from the ultraviolet and visible ranges into the near-IR, such as solar energy conversion.
- Al-Afyouni, Malik H.,Rohrabaugh, Thomas N.,Al-Afyouni, Kathlyn F.,Turro, Claudia
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- Novel 11,12h-dihydronaphthalene[1,2-b]quinoline as atypical antipsychotic
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Background: Neurodegenerative, neurological and mental disorders, as well as substance abuse have a worldwide high incidence rate, becoming relevant factors that contribute to premature morbidity and mortality. Dopamine is well known to be involved in these pathologies. The key focus in the search for new drugs, that alleviate or cure these diseases, is pursuing the design of compounds with both efficacy and fewer adverse effects in order to obtain novel agents capable of restoring the homeostasis in the CNS of dopaminergic neurotransmission and counteracting some of neurodegenerative and neuropsychiatric diseases, such as Parkinson's disease, schizophrenia, Huntington's chorea and drug addictions. Methods: the compounds 11,12H-dihydronaphthalene[1,2-b] quinoline 2a and 9-methoxy-11,12H-dihydronaphthalene [1,2-b] quinoline 2b were designed and synthesized. The organic synthesis was performed according to the outlined synthesis strategies, together with a pharmacological evaluation of the male Sprague-Dawley rats. Results: Compound structures were confirmed by1H,13C, DEPT and HETCOR NMR. Pharmacological testing and computational studies validated the asserted medicinal-chemical approach for their design, showing compound 2a acting as an atypical dopamine antagonist. Conclusion: The study showed that compound 2a has an atypical antagonistic action on the central dopaminergic system. These pharmacological and computational-theoretical results support the suitability of the medicinal chemical approach in the design of this compound.
- Moran, María Matilde Ramirez,Angel Guio, Jorge Eduardo,Cano, Natividad Herrera,del Carmen Migliore, Biagina,Izquierdo, Rodolfo,Charris, Jaime,López, Simón,Israel, Anita,Santiago, Ana,Rossi, Roberto,Perdomo, Luis,Dabian, Akram Samear,Sosa, Mariagracia Vera,Villalba, Alejandra,Migliore, Ligia Biagina Angel
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p. 294 - 303
(2018/03/21)
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- Asymmetric transfer hydrogenation of quinolines using tethered Ru(II) catalysts
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The first report of an asymmetric transfer hydrogenation, in formic acid/triethylamine, of quinolines is described. Using a Ru(II) catalyst containing a 4-carbon tether, products of up to 73% ee were formed, whilst a Rh(III)-tethered catalyst gave products of up to 94% ee.
- Parekh, Vimal,Ramsden, James A.,Wills, Martin
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experimental part
p. 1549 - 1556
(2010/11/02)
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