Two new bipyridine ligands containing, respectively, two and four pyrene units were prepared.The obtained compounds were employed to synthesize new pyrene labeled ruthenium (II) trisbipyridine complex as well as a pyrene labeled ruthenium (II) trisbipyridine cored dendrimer.The obtained bipyridine ligands and the ruthenium complexes were characterized by NMR spectroscopy and MALDI-TOF mass spectroscopy. The optical and photophysical properties of the luminescent macromolecules were studied by absorption and fluorescence spectroscopy. It was noticed that the absorption spectra of the obtained complexes correspond to the sum of the absorption spectra of their components, which indicates a lack of interaction in the ground state.Efficient energy transfer was observed from pyrene units to the metal complex core resulting in the observation of the characteristic ruthenium bipyridine emission band upon excitation at the pyrene absorption wavelength. Moreover, efficient protection to oxygen quenching was remarked in the first generation dendrimer.

New cyclen (1,4,7,10-teraazacyclododecane) cored dendrimers up to the second generation, functionalized with 4, 8 and 16 pyrene units, respectively, were synthesized following a convergent procedure. All new compounds were characterized by NMR spectroscopies and ESI or MALDI TOF mass spectrometry. The optical and photophysical properties of the new dendrimers were studied in THF solution. Absorption spectra showed the typical absorption bands of pyrene moieties. In the fluorescence spectra, monomer as well as excimer emission were observed for all compounds. An increased proportion of excimer emission was observed in the dendrimer of the highest generation.

No abstract

Las especies del género Picramnia se encuentran a lo largo de América tropical, evidenciando una amplia distribución. Además, se han descrito los metabolitos secundarios que presentan algunas de ellas. En la provincia de Napo, ubicada en la Amazonía ecuatoriana, se encuentra una de las especies de este género, cuyos metabolitos aún no han sido elucidados. En el presente trabajo se estableció como objetivo extraer y aislar metabolitos secundarios de esta planta, así como caracterizarlos mediante técnicas espectroscópicas. Se recolectaron las partes aéreas de la planta Picramnia sp. en la Reserva Biológica Jatun Sacha. Las hojas secas y molidas fueron maceradas consecutivamente en diferentes solventes, y algunos de los extractos obtenidos fueron particionados y/o purificados por cromatografía en columna flash. Tanto a las hojas secas como a los extractos obtenidos se les realizó pruebas cualitativas para determinar la presencia de los metabolitos de interés. Se comprobó la presencia de antraquinonas, taninos, terpenoides, fenoles y flavonoides. Finalmente, se identificaron β-sitosterol y crisofanol en fracciones purificadas, las cuales fueron elucidadas usando una combinación de espectroscopía de RMN 1H, RMN 13C y espectrometría de masas. Se conoce que ambas moléculas cuentan con diversas actividades farmacológicas, dentro de las cuales destaca su actividad antimicrobiana.