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In situ electron paramagnetic resonance and X-ray diffraction monitoring of temperature-induced breathing and related structural transformations in activated V-doped MIL-53(Al)

DOI: 10.1021/acs.jpcc.6b04402 DOI Help

Authors: Irena Nevjestic (Ghent University) , Hannes Depauw (Ghent University) , Karen Leus (Ghent University) , Geert Rampelberg (Ghent University) , Claire Murray (Diamond Light Source) , Christophe Detavernier (Ghent University) , Pascal Van Der Voort (Ghent University) , Freddy Callens (Ghent University) , Henk Vrielinck (Ghent University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: The Journal Of Physical Chemistry C

State: Published (Approved)
Published: July 2016
Diamond Proposal Number(s): 12401

Abstract: The Metal-Organic Framework MIL-53(Al) is characterized by a distinct reversible structural transition between a narrow pore (NP) and a large pore (LP) state, resulting in expansion or contraction of this three-dimensional porous framework also called breathing. This transition is studied for vanadium-doped MIL-53(Al), induced by temperature (T) using in situ Electron Paramagnetic Resonance (EPR) and X-ray Diffraction (XRD) in air and in vacuum. The EPR active VIV=O molecular ions are used as local probes to detect the NP to LP transitions. The EPR spectra of VIV=O embedded in the NP and LP MIL-53(Al) states are clearly distinguishable. The temperature dependent EPR and XRD data can consistently be interpreted in terms of T-ranges in the experiments where one of the states is predominantly present and a narrow T-range in which the two states coexist. In addition the XRD data indicate that the NP state undergoes a transition to a metastable state characterized by different lattice parameters than the NP state at room temperature, before the transition to the LP state occurs. The EPR spectra, on the other hand show that only in the LP state the VIV=O ions can exhibit an interaction with paramagnetic O2 molecules from air.

Journal Keywords: Atmospheric chemistry; Physical and chemical processes; Electron paramagnetic resonance spectroscopy; Vacuum; Molecules

Subject Areas: Chemistry

Instruments: I11-High Resolution Powder Diffraction

Added On: 13/07/2016 10:05

Discipline Tags:

Physical Chemistry Chemistry Materials Science Metal-Organic Frameworks Metallurgy Organometallic Chemistry

Technical Tags:

Diffraction X-ray Powder Diffraction