Síntesis, caracterización y estudios fotofísicos y fotoquímicos de complejos tricarbonílicos de Re(I) en estructuras poliméricas

El interés que ha dado lugar a este trabajo de tesis se ha centrado sobre polímeros derivados de la poli-4-vinilpiridina (P4VP) coordinados a complejos tricarbonílicos de Renio(I) α-diimina. Estos sistemas muestran, además de las propiedades relacionadas a cada componente basado en el metal, las propiedades relacionadas con la estructura y la composición de todo el arreglo polimérico. Mediante variaciones externas (cambio en la polaridad del solvente, protonación de las piridinas libres), es posible lograr la agregación de cientos de cadenas de polímero en arreglos supramoleculares de tamaño nanométrico, y estudiar el efecto que tienen estos cambios morfológicos sobre las propiedades fotoquímicas y fotofísicas de estas supramoleculas.Facultad de Ciencias Exacta

Photochemical properties of a Re(I) polymer containing dppz in its structure : An interplay between dark and bright states of dppz

A new polymer, P4VP-Re(dppz), based on the poly-4-vinylpyridine structure containing Re(CO)3(dppz)⁺ pendants was synthesized. Multiple morphologies of P4VP-Re(dppz), such as vesicles, spherical nanoaggregates, large vesicle compounds, rings and pyramidal structures were observed by AFM and TEM in cast films of P4VP-Re(dppz) in solvents of different polarity and solvent/acid mixtures. Several conformations of a model monomer of P4VP-Re(dppz) were studied by TD-DFT to ascertain the effect of protonation over the molecular structure as well as over the absorption spectroscopy of P4VP-Re(dppz). P4VP-Re(dppz) excited states and their redox reactivity towards the sacrificial reductant TEOA were studied by flash photolysis experiments either in DMF and in DMF/HClO4. Those experiments were compared to the ones derived from thermal reactions of P4VP-Re(dppz) with solvated electrons in pulse radiolysis experiments. All the photophysical and photochemical properties studied were rationalized in terms of an interplay between 3IL(ππ*), 3MLCT(phz) and the 3MLCT(phen) states.Facultad de Ciencias ExactasInstituto de Investigaciones Fisicoquímicas Teóricas y AplicadasFacultad de Ingenierí

Photochemical properties of a Re(I) polymer containing dppz in its structure. An interplay between dark and bright states of dppz

A new polymer, P4VP-Re(dppz), based on the poly-4-vinylpyridine structure containing Re(CO)3(dppz)+ pendants was synthesized. Multiple morphologies of P4VP-Re(dppz), such as vesicles, spherical nanoaggregates, large vesicle compounds, rings and pyramidal structures were observed by AFM and TEM in cast films of P4VP-Re(dppz) in solvents of different polarity and solvent/acid mixtures. Several conformations of a model monomer of P4VP-Re(dppz) were studied by TD-DFT to ascertain the effect of protonation over the molecular structure as well as over the absorption spectroscopy of P4VP-Re(dppz). P4VP-Re(dppz) excited states and their redox reactivity towards the sacrificial reductant TEOA were studied by flash photolysis experiments either in DMF and in DMF/HClO4. Those experiments were compared to the ones derived from thermal reactions of P4VP-Re(dppz) with solvated electrons in pulse radiolysis experiments. All the photophysical and photochemical properties studied were rationalized in terms of an interplay between 3IL(ππ*), 3MLCT(phz) and the 3MLCT(phen) states.Fil: Saavedra Moncada, Alejandra. 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; ArgentinaFil: Gutiérrez Pineda, Eduart Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Maisuls, Iván. 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; ArgentinaFil: Ruiz, Gustavo Teodosio. 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; ArgentinaFil: Lappin, Alexander G.. University of Notre Dame; Estados UnidosFil: Ferraudi, Guillermo J.. University of Notre Dame; Estados UnidosFil: 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

Proceso incorporación del sistema KoboToolbox en el contexto del trabajo comunitario de salud en terreno(Chubut, Argentina)

La llegada de la Covid-19 a la escena laboral fue en todos los casos impactantes. Las transformaciones estresaron tanto el tiempo y el uso de espacio, como las dinámicas de producción; las jerarquías atravesadas por espacios físicos. Entre los grandes cambios, se impone lo que Bifo (2017) denomina como cybertiempo, que implica la habilidad de la atención social para procesar información y aplicar labores a tiempo de modo orgánico, cultural y emocional. En contraposición a la noción infinita de cyberespacio; el cybertiempo muy limitado.Fil: Diez Tetamanti, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Humanidades y Ciencias Sociales Sede Comodoro. Instituto de Investigaciones Geográficas de la Patagonia; ArgentinaFil: Saavedra Moncada, Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Rational Design of Mono- and Bi-Nuclear Cyclometalated Ir(III) Complexes Containing Di-Pyridylamine Motifs: Synthesis, Structure, and Luminescent Properties

Heteroleptic cyclometalated iridium (III) complexes (1–3) containing di-pyridylamine motifs were prepared in a stepwise fashion. The presence of the di-pyridylamine ligands tunes their electronic and optical properties, generating blue phosphorescent emitters at room temperature. Herein we describe the synthesis of the mononuclear iridium complexes [Ir(ppy)2(DPA)][OTf] (1), (ppy = phenylpyridine; DPA = Dipyridylamine) and [Ir(ppy)2(DPA-PhI)][OTf] (2), (DPA-PhI = Dipyridylamino-phenyliodide). Moreover, the dinuclear iridium complex [Ir(ppy)2(L)Ir(ppy)2][OTf]2 (3) containing a rigid angular ligand “L = 3,5-bis[4-(2,2′-dipyridylamino)phenylacetylenyl]toluene” and displaying two di-pyridylamino groups was also prepared. For comparison purposes, the related dinuclear rhodium complex [Rh (ppy)2(L)Rh(ppy)2][OTf]2 (4) was also synthesized. The x-ray molecular structure of complex 2 was reported and confirmed the formation of the target molecule. The rhodium complex 4 was found to be emissive only at low temperature; in contrast, all iridium complexes 1–3 were found to be phosphorescent in solution at 77 K and room temperature, displaying blue emissions in the range of 478–481 nm

Stable Luminescent [Cu(NN)(PP)] + Complexes Incorporating a β‐Cyclodextrin‐Based Diphosphane Ligand with Metal‐Confining Properties

A β-cyclodextrin-based diphosphane with metal-confining properties was efficiently synthesized thanks to an unprecedented Smiles-like rearrangement of diphenyl-(2-phosphanylphenyl)phosphane in the presence of excess n-BuLi. The cis-chelating bidentate ligand is capable of forming very stable heteroleptic [Cu(NN)(PP)]+ complexes in which a metal-bound diimine ligand (bpy, phen, or mmp) is located within the cyclodextrin cavity. As a result of ligand encapsulation, flattening of the metal tetrahedral geometry in the excited state is disfavored, thereby resulting in enhanced luminescent properties

Efecto de las propiedades morfológicas sobre las propiedades fotofísicas del Grupo Colgante –Re(CO)3(PHEN) unido al esqueleto de la Poli-4-Vinilpiridina

Las propiedades fotoquímicas y fotofísicas del polímero Re-P4VP, donde los cromóforos de -Re(I)(CO)3(phen) están unidos a la cadena de la poli-4-vinilpiridina, fueron interpretadas en base a las transformaciones morfológicas del mismo. La morfología del Re-P4VP se estudió bajo diferentes medios y condiciones de concentración por las técnicas de TEM y AFM. Los resultados de estos estudios en Re-P4VP y Re-P4VP en presencia de HClO4, Re-P4VPHnn+, revelaron que sus morfologías son dependientes de la concentración del polímero de Re(I). Estos cambios morfológicos tienen una influencia directa en las propiedades fotofísicas del polímero de Re-P4VP, siendo responsables de un incremento significativo del tiempo de vida del estado excitado MLCTRe(I) ? phen con la concentración del polímero y de un aumento de casi 8 veces en el rendimiento cuántico de luminiscencia después de la protonación del Re-P4VP

Photophysical properties of Re(I)(CO)3(phen) pendants grafted to a poly-4-vinylpyridine backbone: A correlation between photophysical properties and morphological changes of the backbone

Photochemical and photophysical properties of a polymer, Re-P4VP, consisting of single bondRe(I)(CO)3(phen) pendants grafted to a poly-4-vinylpyridine backbone, P4VP, were interpreted on the bases of morphological transformations. These transformations are responsible of a significant increase of the MLCTRe(I)→phen excited state luminescence lifetime when the polymer concentration is increased. Also a nearly 8-fold increase in the luminescence quantum yield resulted from the protonation of Re-P4VP with consequent changes of the excited state decay kinetics. Results of TEM and AFM morphological studies on P4VP and Re-P4VP in the presence of HClO4 acid, i.e., to form Re-P4VPHnn+, revealed that they have concentration dependent morphologies. From low to large concentrations of the Re-P4VP polymer, the morphology of Re-P4VP varies from a nonhomogeneous distribution of spherical nanoaggregates coexisting with micrometer size fibers to an homogeneous distribution of spherical nanoaggregates with diameters around 25 nm. The Re-P4VP morphology is also altered when the polymer pyridines are protonated. Protonation of diluted solutions of Re-P4VP polymers decrease the sizes of the nanoaggregates and small objects with diameters smaller than 10 nm appear.Fil: Saavedra Moncada, Alejandra. 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; ArgentinaFil: Garcia Einschlag, Fernando Sebastian. 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; ArgentinaFil: Prieto, Eduardo Daniel. 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; ArgentinaFil: Ruiz, Gustavo Teodosio. 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; ArgentinaFil: Lappin, Alexander G.. University of Notre Dame; Estados UnidosFil: Ferraudi, Guillermo J.. University of Notre Dame; Estados UnidosFil: 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

Stabilization of Luminescent Mononuclear Three‐Coordinate CuI Complexes by Two Distinct Cavity‐Shaped Diphosphanes Obtained from a Single α‐Cyclodextrin Precursor

International audienceSlightly different reaction conditions afforded two distinct cavity‐shaped cis‐chelating diphosphanes from the same starting materials, namely diphenyl(2‐phosphanylphenyl)phosphane and an α‐cyclodextrin‐derived dimesylate. Thanks to their metal confining properties, the two diphosphanes form only mononuclear [CuX(PP)] complexes (X = Cl, Br, or I) with the tricoordinated metal ion located just above the center of the cavity. The two series of CuI complexes display markedly different luminescence properties that are both influenced by the electronic properties of the ligand and the unique steric environment provided by the cyclodextrin (CD) cavity. The excited state lifetimes of all complexes are significantly longer than those of cavity‐free analogues suggesting peculiar electronic effects that affect radiative deactivation constants. The overall picture stemming from absorption and emission data suggests close lying charge‐transfer (MLCT, XLCT) and triplet ligand‐centered (LC) excited states

Enantiopure, luminescent, cyclometalated Ir( iii ) complexes with N-heterocyclic carbene-naphthalimide chromophore: design, vibrational circular dichroism and TD-DFT calculations

International audienceA series of chiral cyclometalated iridium complexes of the type [Ir(C^N)2(C^C:)], {(C^N) = ppy (2); dfppy (3)} featuring a naphthalimide N-heterocyclic carbene ligand (C^C:) = (Naphthalimide-NHC) are described and fully characterized. The racemic complexes rac-2 and rac-3 were resolved via chiral column chromatography techniques into their corresponding enantiopure species Δ-2, Λ-2, Δ-3, Λ-3 as confirmed by their CD curves. This unique class of molecules containing organic and inorganic chromophores might be used as a platform to probe the stereochemical effect on the photophysical properties. Vibrational circular dichroism (VCD) was used as an important tool to assign successfully the stereochemistry of the enantiomers. TD-DFT calculations are also advanced to support the experimental studies and to rationalize the observed results