Complexation of molecular oxygen with nitroxide radicals adsorbed on the surface of silica and MCM-41

Straz, Evgenia L.; Chernova, Daria; Vorobiev, Andrey Kh.

doi:10.1016/j.mencom.2008.09.005

Cited by 2 publications

(3 citation statements)

References 11 publications

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“…The above explanation is very reasonable: first, it is known that adsorption of guest molecules in rather small concentrations can suppress breathing of MIL-53(Al) . Second, compared with volatile TEMPO, its 4-substituted derivatives have stronger intermolecular interactions in the solid phase and lower vapor pressure, possibly leading to the lower diffusivity and higher tendency for clusterization in MOF. , …”

Section: Resultsmentioning

confidence: 93%

“…Prior to adsorption of radical, the MOF was evacuated at 10 −5 Torr for 2 h at room temperature; then, it was maintained for 12 h at 150 °C (activation procedure). The adsorption of nitroxide into MOF was performed at room temperature from the gas phase (equilibrium vapor pressure at room temperature is known to be 0.8 Torr for TEMPO and is noticeably smaller for TEMPO derivatives (0.0117 Torr for TEMPONE)); 22 then, the sample was sealed in the quartz tube.…”

Section: Methodsmentioning

confidence: 99%

“…15 Second, compared with volatile TEMPO, its 4-substituted derivatives have stronger intermolecular interactions in the solid phase and lower vapor pressure, possibly leading to the lower diffusivity and higher tendency for clusterization in MOF. 22,27 Therefore, we implemented another approach, namely, the impregnation method using volatile diethyl ether as a solvent (which was later removed from MOF prior to experiments; see the Experimental Section). This approach led to much better results for 4-substituted TEMPO derivatives and also worked perfectly for unsubstituted TEMPO.…”

Section: Incorporation Of Tempo Derivatives In Mil-53(al)mentioning

confidence: 99%

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Mobility and Reactivity of 4-Substituted TEMPO Derivatives in Metal–Organic Framework MIL-53(Al)

et al. 2016

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Postsynthetic adsorption of stable nitroxide radical probes in diamagnetic nano/mesoporous metal−organic frameworks (MOFs) allows application of electron paramagnetic resonance (EPR) for studying structure, functions, and corresponding guest−host interactions in such MOFs. This approach was recently demonstrated using (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) embedded in structurally flexible MIL-53(Al), with the mobility and reactivity of TEMPO reflecting structural dynamics of MOF. In the present work we embed three derivatives of TEMPO (4-oxo-TEMPO, 4-hydroxo-TEMPO, 4acetamido-TEMPO) in MIL-53(Al) and investigate structural "breathing" of this MOF with temperature to gain deeper understanding of underlying guest−host interactions. Different substituents in the piperidine ring lead to different mobility and reactivity of corresponding nitroxides. The obtained EPR data and molecular dynamics calculations show that the efficiency of nitroxide radical reaction with μ 2 -hydroxo group of MIL-53(Al) strongly correlates with the character of its molecular motion, and the reversibility of this reaction upon structural "breathing" is a general phenomenon. On the basis of these findings, practical suggestions on selecting spin probes for in-MOF EPR studies are formulated.

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Section: Resultsmentioning

confidence: 93%

Section: Methodsmentioning

confidence: 99%