Tailoring the local electronic structure of microporous solids as macroligands to optimize the performance of heterogenized molecular catalysts

Autor: Wisser, F., Mohr, Y., Berruyer, P., Cardenas, L., Quadrelli E., A., Lesage, A., Farrusseng, D., Canivet, J.
Přispěvatelé: IRCELYON-Ingéniérie, du matériau au réacteur (ING), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), IRCELYON-Etudes & analyse de surfaces, XPS, LEIS (XPS), IRCELYON, ProductionsScientifiques
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: 30. Deutsche Zeolith-Tagung
30. Deutsche Zeolith-Tagung, Feb 2018, Kiel, Germany
ISSN: 2069-2080
Popis: +ING+FWI:YMO:LCS:DFA:JEC; International audience; Heterogeneous catalysis allows to circumvent the problem of separation from the products and to simplify the recyclability of the catalyst. The integration of the catalytically active centers into a solid support without loss of performance compared to the homogeneous analog is still a major challenge.[1] In this context, a molecularly defined support as macroligand, i.e. a solid acting like the ligand in the corresponding molecular complex, can be considered as a key to bridge the gap between molecular and heterogeneous catalysis. Metal-organic frameworks and purely organic microporous polymers are promising candidates.[2] In particular, porous frameworks made by the repetition of a coordinating motif, like the bipyridine motif are of a high interest as far as bipyridines are widely used as chelating ligand for molecular catalysts.[3]We present novel bipyridine containing microporous polymers as a promising class of host materials for catalytically active metal complexes for CO2 reduction into value-added C1-molecules and fine chemicals synthesis such as transfer hydrogenation reaction. Their outstanding stability, tunability and swelling properties make these microporous polymers ideal supports for heterogenization of molecular catalysts. The active metal center, for instance organometallic rhodium complexes, can easily be integrated into the host by post-synthetic infiltration with a suitable precursor. For a rhodium loading of 1.6 wt%, a well-balanced equilibrium between number of active centers, remaining porosity, flexibility and thus accessibility of the active centers and catalytic performance was achieved.[4] Using this catalyst in CO2 photoreduction reaction turnover numbers (up to 113) and turnover frequencies (up to 28 h-1) are the highest reported so far for heterogenized catalysts and are very similar to that of the homogeneous analogs. For the transfer hydrogenation reaction of α-aryl ketones TOF of up to 3.3 h-1were achieved.[4]Here, we will demonstrate that the Hammett parameter – well established in molecular chemistry and homogeneous catalysis[5] – is also an appropriate descriptor for heterogenized organometallic catalytic centers within metal-organic frameworks and microporous polymers. In all reactions investigated, the catalytic activity of the heterogenized catalysts is only driven by the local electron density around the isolated active site and thus correlates with the Hammett constant of the bipyridine substituents. We will show how the rational design of active centers can be guided by the Hammett parameter allowing to optimize the performance of the heterogeneous catalysts. In addition, the use of Hammett plots – representing the activity as a function of the host’s Hammett constant – in combination with other characterization techniques allows to identify diffusion limitations within catalysts.References[1]a) M. P. Conley and C. Copéret, Top. Catal., 2014, 57, 843-851; b) L.-N. He, J.-Q. Wang and J.-L. Wang, Pure Appl. Chem., 2009, 81, 2069-2080.[2] a) T. Islamoglu, et al., Acc. Chem. Res. 2017, 50 (4), 805-813; b) N. B. McKeown, P. M. Budd, Chem. Soc. Rev. 2006, 35 (8), 675-683; c) S. M. Rogge, et al., J. Chem. Soc. Rev. 2017, 46, 3134-3184; d) P. Kuhn, M. Antonietti, A. Thomas, Angew. Chem., Int. Ed. 2008, 47, 3450-3453.[3]C. Kaes, A. Katz, M. W. Hosseini, Chem. Rev. 2000, 100 (10), 3553-3590.[4]F. M. Wisser, et al. 2 papers submitted for publication.[5]C. Hansch, A. Leo, R. W. Taft, Chem. Rev. 1991, 91 (2), 165-195.
Databáze: OpenAIRE
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