Elucidation of the Formation Mechanism of Metal-Organic Frameworks via in-Situ Raman and FTIR Spectroscopy under Solvothermal Conditions

Embrechts H, Kriesten M, Hoffmann K, Peukert W, Hartmann M, Distaso M (2018)

Publication Language: English

Publication Status: Published

Publication Type: Journal article, Original article

Publication year: 2018

Journal

Journal of Physical Chemistry C American Chemical Society

Publisher: American Chemical Society

Book Volume: 122

Pages Range: 12267-12278

Journal Issue: 23

DOI: 10.1021/acs.jpcc.8b02484

Abstract

The metal–organic framework MIL-53(Al) serves as a model system in this study. Its formation mechanism in N,N-dimethylformamide (DMF) is elucidated through simultaneous FTIR and Raman spectroscopy and turbidity measurements collected under in-situ synthesis conditions in a custom-designed solvothermal reactor coupled with reaction sampling. Different synthesis steps are followed over synthesis time including a prenucleation building unit (PNBU) consisting of one linker molecule and one aluminum atom, the assembly of the PNBUs to MIL-53 nuclei in solution, the decomposition of DMF to formic acid and dimethylammonium, and finally the precipitation of the crystalline MOF phase. The rearrangement of the PNBU to form MIL-53 is identified as the rate-limiting reaction step responsible for the long induction time at low temperatures (<80 °C). MOF nucleation and particle growth is followed directly in-situ through a novel method—comparison of the temporal evolution of the respective FTIR and Raman bands. Analysis of the particles isolated after various synthesis times indicates that MIL-53(H₂BDC) of low crystalline long-range order is formed initially, which quickly rearranges to form more ordered, crystalline particles with DMF inside of the pores (MIL-53(DMF)). It is to be expected that the synthesis steps elucidated herein can be generalized to the solvothermal synthesis of other metal–organic framework structures from metal salts and organic acid linkers.

Authors with CRIS profile

Heidemarie Embrechts Lehrstuhl für Feststoff- und Grenzflächenverfahrenstechnik Martin Kriesten Interdisziplinäres Zentrum Erlangen Catalysis Resource Center (ECRC) Kilian Hoffmann Lehrstuhl für Feststoff- und Grenzflächenverfahrenstechnik Wolfgang Peukert Lehrstuhl für Feststoff- und Grenzflächenverfahrenstechnik Monica Distaso Lehrstuhl für Feststoff- und Grenzflächenverfahrenstechnik

How to cite

APA:

Embrechts, H., Kriesten, M., Hoffmann, K., Peukert, W., Hartmann, M., & Distaso, M. (2018). Elucidation of the Formation Mechanism of Metal-Organic Frameworks via in-Situ Raman and FTIR Spectroscopy under Solvothermal Conditions. Journal of Physical Chemistry C, 122(23), 12267-12278. https://dx.doi.org/10.1021/acs.jpcc.8b02484

MLA:

Embrechts, Heidemarie, et al. "Elucidation of the Formation Mechanism of Metal-Organic Frameworks via in-Situ Raman and FTIR Spectroscopy under Solvothermal Conditions." Journal of Physical Chemistry C 122.23 (2018): 12267-12278.

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