1,720,989 research outputs found
Conversion of Phthalimides to Isoindolines by Diborane
Get PDFReduction of N-alkylsubstituted phthalimides to the corresponding isoindolines by means of diborane is herein described.Fil: Strassert, Cristian A.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Orgánica; ArgentinaFil: Awruch, Josefina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentin
A synthetic approach towards novel octa-substituted zinc(II) phthalocyanines with different solubility and photophysical properties
Get PDFThe synthesis and behavior in homogeneous solutions of 2,3,9,10,16,17,23, 24-octakis(3-phthalimidopropyloxy)phthalocyaninatozinc(II) (5) and 2,3,9,10,16,17,23,24-octakis(3-aminopropyloxy)phthalocyaninatozinc(II) (6) are reported.Fil: Strassert, Cristian A.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Rodriguez, Myriam E.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Dicelio, Lelia Elina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Awruch, Josefina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentin
Photofunctional surfaces for quantitative fluorescence microscopy: monitoring the effects of photogenerated reactive oxygen species at single cell level with spatiotemporal resolution
Get PDFHerein, we report on the implementation of photofunctional surfaces for the investigation of cellular responses by means of quantitative fluorescence microscopy. The developed substrates are able to produce reactive oxygen species under the fluorescence microscope upon irradiation with visible light, and the behavior of cells grown on these surfaces can be consequently investigated in situ and in real time. Moreover, a suitable methodology is presented to simultaneously monitor phototriggered morphological changes and the associated molecular pathways with spatiotemporal resolution employing time-resolved fluorescence anisotropy at the single cell level. The results showed that morphological changes can be complemented with a quantitative evaluation of the associated molecular signaling cascades for the unambiguous assignment of reactive oxygen species-related photoinduced apoptosis. Indeed, similar phenotypes are associated with different cellular processes. Our methodology facilitates the in vitro design and evaluation of photosensitizers for the treatment of cancer and infectious diseases with the aid of functional fluorescence microscopy.Fil: Stegemann, Linda. Westfalische Wilhelms Universitat; AlemaniaFil: Schuermann, Klaus C.. Institut Max Planck Fur Molekulare Physiologie; AlemaniaFil: Strassert, Cristian A.. Westfalische Wilhelms Universitat; AlemaniaFil: Grecco, Hernan Edgardo. Institut Max Planck Fur Molekulare Physiologie; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentin
Functional Pt(II) and Re(I) Complexes with CO- and β-Carboline-Based Coligands: From Time-Resolved Photoluminescence Spectroscopy and Evaluation of 1O2 Photosensitization Efficiency toward in vitro (Photo)cytotoxicity
Get PDFIn this study, the synthesis, photophysical characterization, and (photo)biological assessment of functional rhenium(I)- and platinum(II)-based complexes are presented. These compounds feature anionic 1,2,4-triazolylpyridine-based chromophores and neutral βC-based monodentate coligands, specifically 9H-pyrido[3,4-b]indole (nHo) or 9-methyl-9H-pyrido[3,4-b]indole (MenHo), which have been chosen to promote their biological activity. The impact of transition metal cations, coordination geometries, substitution patterns of the luminophore and coligands on the properties of these complexes was thoroughly assessed, encompassing photoluminescence and singlet dioxygen (1O2) quantum yields, excited state lifetimes, and (non)radiative rate constants, across various temperatures and phases. Superior photophysical characteristics were attained by the Pt(II)-based complexes, while effective capabilities as photosensitizers of 1O2 were observed for all coordination compounds. Incorporation of these complexes into a polymeric matrix (PMMA) significantly enhanced their luminescence efficiencies by preventing diffusional quenching arising from triplet dioxygen (3O2). Furthermore, a comprehensive (photo)cytotoxicity study on human telomerase reverse transcriptase (hTERT)-immortalized cells was conducted to assess the potential applications of these complexes in photodynamic therapy. In summary, a versatile platform for designing photofunctional materials with photosensitizing properties is offered by this coordination chemical approach. Precise control of photophysical and (photo)biological attributes is achievable through the careful selection of metal centers, substitution patterns, and ancillary ligands.Fil: Kirse, Thomas M.. Universität Münster; AlemaniaFil: Maisuls, Iván. Universität Münster; AlemaniaFil: Denofrio, Maria Paula. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; ArgentinaFil: Hepp, Alexander. Universität Münster; AlemaniaFil: Cabrerizo, Franco Martín. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; ArgentinaFil: Strassert, Cristian A.. Universität Münster; Alemani
Energy Transfer between CNT Surface and -Re(CO)3(phen)+∗ Pendants Grafted to P4VP in Nanohybrid Shish-Kebob-like Structures
No full textThe adsorption of a Re(CO)3(phen)-poly(4-vinylpyridine) polymer, RePVP, on multiwall carbon nanotubes surfaces is studied by transmission electron microscopy and absorption spectroscopy in combination with chemometric techniques in MeOH/H2O solvent mixture. Nanohybrid structures like a shish-kebab (NHSK) are observed by TEM when RePVP is wrapped around carbon nanotubes (CNTs) surfaces. The association between RePVP and CNTs studied by absorption spectroscopy suggests the coexistence of CNTs with a high or low content of adsorbed RePVP on their surface. In the absence of CNTs, the photophysical properties of RePVP (i.e., luminescence quantum yield, ΦL, and amplitude-weighted average lifetimes, ⟨τ⟩) are strongly dependent on the morphology of the polymer as witnessed by the dependence of ΦL on the concentration of RePVP (CRePVP) and the fact that in CH3CN ΦL and ⟨τ⟩ are sensitive to O2 while in a MeOH/H2O solvent mixture they are not. In the NHSK, an energy-transfer process between excited −[Re(CO)3(phen)]+* pendent chromophores and the CNTs surface, with static and dynamic components, is responsible for the quenching of the RePVP luminescence by CNTs.Fil: Maisuls, Iván. Westfälische Wilhelms Universität; AlemaniaFil: Ostendorp, Stefan. Westfälische Wilhelms Universität; AlemaniaFil: Wilde, Gerhard. Westfälische Wilhelms Universität; AlemaniaFil: Parola, A. Jorge. Universidade Nova de Lisboa; PortugalFil: Strassert, Cristian A.. Westfälische Wilhelms Universität; AlemaniaFil: Wolcan, Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentin
1.3 Rare earth resources and processing
No full textThis work introduces into the chemistry, materials science and technology of Rare Earth Elements. The chapters by experienced lecturers describe comprehensively the recent studies of their characteristics, properties and applications in functional materials. Due to the broad range of covered topics as hydrogen storage materials, LEDs or permanent magnets this work gives an up-to-date presentation of this fascinating research
1.2 Rare-earth minerals and rare-earth mining
No full textThis work introduces into the chemistry, materials science and technology of Rare Earth Elements. The chapters by experienced lecturers describe comprehensively the recent studies of their characteristics, properties and applications in functional materials. Due to the broad range of covered topics as hydrogen storage materials, LEDs or permanent magnets this work gives an up-to-date presentation of this fascinating research
1.4 Rare earth metal production and refinement
No full textThis work introduces into the chemistry, materials science and technology of Rare Earth Elements. The chapters by experienced lecturers describe comprehensively the recent studies of their characteristics, properties and applications in functional materials. Due to the broad range of covered topics as hydrogen storage materials, LEDs or permanent magnets this work gives an up-to-date presentation of this fascinating research
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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