Porous aromatic frameworks (PAFs) as efficient supports for N-heterocyclic carbene catalysts. Issue 15 (11th May 2016)

• Record Type: Journal Article
• Authors: Rangel-Rangel, Elizabeth; Verde-Sesto, Ester; Rasero-Almansa, Antonia M.; Iglesias, Marta; Sánchez, Félix
• Is Part Of: Catalysis science & technology. Volume 6:Issue 15(2016)
• Page Start: 6037
• Page End: 6045
• Publication Date: 2016-05-11
• Subjects: Catalysis -- Periodicals; 541.395
• DOI: 10.1039/c6cy00597g
• Languages: English
• ISSNs: 2044-4753

Abstract

Abstract : Polymeric aromatic frameworks (PAFs), easily obtained from organic platforms, as excellent supports to yield robust well-defined organometallic heterogenized catalysts. Abstract : Porous polymeric aromatic frameworks (PAFs) have high porosity and surface area, as well as high physicochemical stability; such characteristics are important in the design of heterogeneous catalysts with high catalytic efficiency and recyclability. This paper presents the synthesis, characterization, post-functionalization and catalytic performance of the resulting modified PAFs based on tetraphenyladamantane (PAF Ad ), tetraphenylmethane (PAF C ) and 9, 9′-spirobisfluorene (PAF spf ) nodes. The PAFs were obtained by the Suzuki–Miyaura cross-coupling under microwave heating, and were sequentially reacted with 1-(chloromethoxy)octane and 1-mesityl-1 H -imidazole or 2-(1 H -imidazol-1-yl)pyridine to yield the corresponding imidazolium chloride derivative (PAF-Im ) which readily formed stable N-heterocyclic carbene (NHC) iridium and ruthenium complexes (PAF- (NHC )Ir, PAF- (NHC )Ru ). The materials were characterized by solid-state NMR spectroscopy, FTIR spectroscopy, and textural analysis. ThePAF- (NHC )M materials display excellent catalytic performance in the N -alkylation of amines with alcohols and transfer hydrogenation of ketones over multiple catalytic cycles.