RT info:eu-repo/semantics/article
T1 Porous organic polymers containing active metal centers for Suzuki–Miyaura heterocoupling reactions
A1 Esteban Hernández, Isabel Noelia
A1 Ferrer, Maria Luisa
A1 Ovin Ania, María Concepción
A1 Campa, José G. de la
A1 Lozano, Ángel E.
A1 Álvarez, Cristina
A1 Miguel García, Jesús Ángel
K1 Palladium
K1 Paladio
K1 Monomers
K1 Monómeros
K1 Mixtures
K1 Mezclas
K1 Polymers
K1 Polímeros
K1 Catalysts
K1 Catálisis
K1 23 Química
AB A new generation of confined palladium(II) catalysts covalently attached inside of porous organic polymers (POPs) has been attained. The synthetic approach employed was straightforward, and there was no prerequisite for making any modification of the precursor polymer. First, POP-based catalytic supports were obtained by reacting one symmetric trifunctional aromatic monomer (1,3,5-triphenylbenzene) with two ketones having electron-withdrawing groups (4,5-diazafluoren-9-one, DAFO, and isatin) in superacidic media. The homopolymers and copolymers were made using stoichiometric ratios between the functional groups, and they were obtained with quantitative yields after the optimization of reaction conditions. Moreover, the number of chelating groups (bipyridine moieties) available to bind Pd(II) ions to the catalyst supports was modified using different DAFO/isatin ratios. The resulting amorphous polymers and copolymers showed high thermal stability, above 500 °C, and moderate–high specific surface areas (from 760 to 935 m2 g–1), with high microporosity contribution (from 64 to 77%). Next, POP-supported Pd(II) catalysts were obtained by simple immersion of the catalyst supports in a palladium(II) acetate solution, observing that the metal content was similar to that theoretically expected according to the amount of bipyridine groups present. The catalytic activity of these heterogeneous catalysts was explored for the synthesis of biphenyl and terphenyl compounds, via the Suzuki–Miyaura cross-coupling reaction using a green solvent (ethanol/water), low palladium loads, and aerobic conditions. The findings showed excellent catalytic activity with quantitative product yields. Additionally, the recyclability of the catalysts, by simply washing it with ethanol, was excellent, with a sp2–sp2 coupling yield higher than 95% after five cycles of use. Finally, the feasibility of these catalysts to be employed in tangible organic reactions was assessed. Thus, the synthesis of a bulky compound, 4,4′-dimethoxy-5′-tert-butyl-m-terphenylene, which is a precursor of a thermal rearrangement monomer, was scaled-up to 2 g, with high conversion and 96% yield of the pure product.
PB American Chemical Society
SN 1944-8252
YR 2020
FD 2020
LK https://uvadoc.uva.es/handle/10324/52801
UL https://uvadoc.uva.es/handle/10324/52801
LA eng
NO ACS Applied Materials & Interfaces, 2020, vol. 12, n. 51, p. 56974–56986
NO Producción Científica
DS UVaDOC
RD 22-dic-2024