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Four silane-containing Schiff base oligomers (o-SBNs and o-SBBs) were synthesized by high-temperature polycondensation reactions using silicon-based dialdehydes with naphthalene and 1,1’-binaphthalene diamine derivates. The samples showed a moderate solubility in common organic solvents, where the incorporation of TPS cores into o-SBN2 allows the formation of highly soluble material in non-polar solvents with higher molecular weights (11.58 kDa) and polydispersity. All oligo-SBs displayed high thermal resistance (above 450 °C), showing enhanced thermal stability for TPS-containing oligomers, with the degradation temperature exceeding 530 °C (o-SBB2) and high Tg values due to the higher aromatic content granted by TPS and 1,1’-binaphthalene moieties. Optical results of the oligo-SBs showed broad absorption and emission behavior in the visible spectrum, ranging from deep blue (o-SBN1 and o-SBB1) to blue (o-SBN2 and o-SBB2). The structure promotes a clear bathochromic shift for TPS-based oligomers, attributed to an extended π-conjugation across the backbone. In addition, the π-π overlap effect highlights larger Stokes shifts for the DMS core oligomers o-SN2 (133 nm) and o-SBB1 (195 nm). The oligo-SBs were found to be wide-bandgap materials, with Egopt values in the range of 2.60 eV to 3.67 eV. The higher molecular weight of o-SBN2, which provided an extended π-conjugation, allows the lowest value of Egopt (2.60 eV) to be achieved. In addition, DFT, TDDFT and EDDM calculations were performed on trimeric oligo-SBs, revealing that HOMOs are localized in the amine-terminal fraction, while LUMOs are localized over the terminal aldehyde groups. These findings highlight the used DMS and TPS cores in Schiff base materials, providing valuable insights into fine-tuning physicochemical properties through the use of suitable building blocks and their potential as optoelectronic materials.

In the search for solution-processable TADF materials as a light emitting layer for OLED devices, polymers have attracted considerable attention due to their better thermal and morphological properties in the film state with respect to small molecules. In this work, a new polymer (p-TPS-DMAC-TRZ) with thermally activated delayed fluorescence (TADF) light-emitting characteristics was prepared from a conjugation-break unit (TPS) and a well-known TADF core (DAMC-TRZ). This material was designed to preserve the photophysical properties of DAMC-TRZ, while improving other properties, such as thermal stability, promoted by its polymerization with a TPS core. Along with excellent solubility in common organic solvents such as toluene, chloroform and THF, the polymer (Mn = 9500; Mw = 15200) showed high thermal stability (TDT5% = 481 °C), and a Tg value of 265 °C, parameters higher than the reference small molecule DMAC-TRZ (TDT5% = 305 °C; Tg = 91 °C). The photoluminescence maximum of the polymer was centered at 508 nm in the solid state, showing a low redshift compared to DMAC-TRZ (500 nm), while also showing a redshift in solution with solvents of increasing polarity. Time-resolved photoluminescence of p-TPS-DMAC-TRZ at 298 K, showed considerable delayed emission in solid state, with two relatively long lifetimes, 0.290 s (0.14) and 2.06 s (0.50), and a short lifetime of 23.6 ns, while at 77 K, the delayed emission was considerably quenched, and two lifetimes in total were observed, 24.6 ns (0.80) and 180 ns (0.20), which was expected from the slower RISC process at lower temperatures, decreasing the efficiency of the delayed emission and demonstrating that p-TPS-DMAC-TRZ has a TADF emission. This is in agreement with room temperature TRPL measurements in solution, where a decrease in both lifetime and delayed contribution to total photoluminescence was observed when oxygen was present. The PLQY of the mCP blend films with 1% p-TPS-DMAC-DMAC-TRZ as a dopant was determined to be equal to 0.62, while in the pure film, it was equal to 0.29, which is lower than that observed for DMAC-TRZ (0.81). Cyclic voltammetry experiments showed similarities between p-TPS-DMAC-TRZ and DAMC-TRZ with HOMO and LUMO energies of −5.14 eV and −2.76 eV, respectively, establishing an electrochemical bandgap value of 2.38 eV. The thin film morphology of p-TPS-DMAC-TRZ and DMAC-TRZ was compared by AFM and FE-SEM, and the results showed that p-TPS-DMAC-TRZ has a smoother surface with fewer defects, such as aggregations. These results show that the design strategy succeeded in improving the thermal and morphological properties in the polymeric material compared to the reference small molecule, while the photophysical properties were mostly maintained, except for the PLQY determined in the pure films. Still, these results show that p-TPS-DMAC-TRZ is a good candidate for use as a light-emitting layer in OLED devices, especially when used as a host-guest mixture in suitable materials such as mCP.

Three new triphenylamine-based oligomeric Schiff bases (polySB1, polySB2 and polySB3) containing tetraphenylsilane core (TPS-core) in the main chain were obtained from TPS-core-based diamines and bis(4-formylphenyl)phenylamine by a high-temperature polycondensation reaction. These new oligomers were structurally characterized by FT-IR, NMR and elemental analysis. All polySBs were highly soluble in common organic solvents, such as chloroform, tetrahydrofuran and chlorobenzene. Samples showed moderate molecular average molecular weight (Mw) and a high thermal stability above 410 °C. Likewise, polySBs showed absorption near 400 nm in the UV-vis range and photoluminescence. The HOMO levels and band-gap values were found in the ranges of −6.06 to −6.18 eV and 2.65–2.72 eV, respectively. The lowest band-gap value was observed for polySB2, which could be attributed to a more effective π-conjugation across the main chain. The results suggest that silicon-containing polySBs are promising wide-band-gap semiconductors materials for optoelectronic applications.

The aim of this study was to determine the electronic influence of substituent groups and annelated rings such as oxazole-oxazinone on the physicochemical and photoprotection, antioxidant capacity, toxicity and singlet oxygen photosensitization biological properties of isoquinoline alkaloid frameworks. Thus, oxoisoaporphine derivatives 1–5 and 3-azaoxoisoaporphine (6), some of them with phenolic structures, did not present any antioxidant capacity, possibly either by formation of keto-enol tautomerism species or the formation of unstable free radicals. Due to the singlet oxygen quantum yields (FD) near to unity, and greater photostability than phenalenone, oxoisoaporphines 4–6 may be considered as photosensitizers for singlet oxygen production and can be used as new universal study tools. The biological application as antibacterial agents is an important and possible tool in the study of compounds with low cytotoxicity and high reactivity in antineoplastic chemotherapy. On the other hand, when boldine and its annelated derivatives B1–4 are irradiated, a photoprotector effect is observed (SPF = 2.35), even after 30 minutes of irradiation. They also act as photoprotectors in cell fibroblast cultures. No hemolysis was detected for boldine hydrochloride and its salts without irradiation. In solutions irradiated before incubation (at concentrations over 200 ppm) photoproducts were toxic to the nauplii of Artemia salina.

Residual circulation from nonlinear interaction of the tidal currents with topography in channels, fjords and bays can be important to represent the distance traveled by suspended materials in the water column (e.g. pathogens). Here the role of the semidiurnal tidal excursion was compared with residual currents, during autumn 2011, to evaluate the connectivity among aquaculture production centers in Caucahue Channel (Chiloe Island, southern Chile), which has been widely occupied by the aquaculture industry. During 2015, around 30 000 t of 3 different species of salmon were harvested in this channel, representing 3.7% of the national production. Along- and cross-channel tidal currents explained around 80 and 40–60% of the total variance, respectively. Thus, the major residual circulation came from the cross-channel component (40–60% of the total variance) caused by tidal asymmetry. We hypothesized that this asymmetry is related to the nonlinear interaction of the oscillatory flow with the Quemchi constriction. The residual advective distances (𝐿adv) were compared with tidal excursion (𝐿exc) and biological diffusivity (𝐿diff) scales, considering the distances between centers (𝐿int), the size of the centers (𝐿cen) and the length of the south arm of the Cauchaue Channel (𝐿 = 11 km). For 3 d time scales, the 𝐿adv/𝐿exc ratio fluctuated between 1.3 and 8, approximately, implying that, although the advective scale is greater, the tidal flow is still intense enough to favor the retention of pathogens. For larger time scales that consider longer-lived pathogens (e.g. greater than 15 d), this ratio grows 1 order of magnitude. In this scenario and in the event of an outbreak within the channel, pathogens could be exported.

Dentro de la obra madura de Spinoza, la Ética y el Tratado Teológico-Político (TTP) se han analizado ampliamente. Sin embargo, el Tratado Político (TP) ha sido menormente estudiado por ser una obra inconclusa y con problemas estructurales. Nosotros afirmamos que la teoría política más acabada de Spinoza se encuentra en el TP. En esta obra se sacan todas las consecuencias de guiarse por una noción estrictamente inmanente de la política. En ese sentido, el TP sigue de manera más coherente el programa trazado por la doctrina fundamental de Spinoza expuesta en la Ética, y no el TTP. Esto nos lleva a la consideración de la política como tendencia en dos direcciones opuestas: ampliación de poder y concentración de poder.

Se prepararon nuevas series de oligo(azometino)s (o-AZs) y poli(azometino)s (PAZs) sililados (series o-AZP, o-AZtF, potiAZTh y poliAZPy. respectivamente) conteniendo núcleos tetrafenilsilano y unidades trifenilamina, tiofeno y piridina en la cadena principal, a partir de monómeros diaminas y dialdehídos por medio de reacciones de policondensación en disolución a alta temperatura. Las series de o-AZs y PAZs fueron caracterizados estructuralmente mediante técnicas espectroscópicas (IR-TE y RMN) y para la serie complejada (potiAZPyM) análisis elemental. La solubilidad de los materiales de las series derivadas de los monómeros sililados (o-AZSi, o-AZP y poliAZPy), serie comparativa (o-AZV) y polímeros conteniendo hierro(III) (poliAZPyM) fue reducida bajo las condiciones estudiadas, similar a lo mostrado por materiales con alto contenido aromático. Las series o-AZtF y poliAZTh resultaron solubles en solventes organicos comunes, y en el caso de PAZs derivados de tiofeno se registró alto peso molecular (22,2 kDa). Asimismo, los o-AZs y PAZs mostraron estabilidad sobre 350 ºC, similar a familias de o-AZs y PAZs reportados previamenteLos o-AZs y PAZs mostraron una amplio intervalo de absorcion y emisión en el intervalo UV-vis, además, evidenciaron fotoluminiscencia, moderados corrimientos de Stokes y energías HOMO-LUMO adecuadas para aplicaciones en opto-eletrónica. Los band gaps ópticos de las diferentes series están en el intervalo de 2,36 a 3,61 eV, donde la serie de PAZs derivados de tiofeno (poliAZTh) presentaron características de semiconductores (poliAZThe; 1,98 eV). La serie poliAZPyM conteniendo unidades TPS y bis(imino)piridina como ligando de anclaje tipo “pinza”, fue empleada para anclar hierro y obtener nuevos catalizadores heterogéneos para la cicloadición de CO2 a epóxidos a fin de preparar carbonatos cíclicos. Estos catalizadores fueron eficientes bajo condiciones moderadas (3 bar de CO2), mostrando alta conversión (hasta 95%) y selectividad hacia el carbonato cíclico en relación con sistemas similares, basados en PAZs, previamente reportados.Estos resultados sugieren que las nuevas series de PAZs presentan alta versatilidad, y de acuerdo con su estructura específica, pueden ser potenciales candidatos para aplicaciones en optoelectrónica y catálisis heterogénea