Electron Spin Resonance and Electron Spin Echo Modulation Studies of the Incorporation of Macrocyclic-Complexed Cupric Ions into Siliceous MCM-41

Poeppl, Andreas; Baglioni, Piero; Kevan, Larry

doi:10.1021/j100038a057

Cited by 39 publications

(27 citation statements)

References 3 publications

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“…The determined value of A ∥ translates to A Cu,∥ = 140(2) × 10 –4 cm –1 , which is the parallel hf tensor component of a single copper nucleus. Such values of g ∥ and A Cu,∥ indicate a copper ion in a square pyramidal environment . Our EPR findings agree with the XRD study, which shows that the PW unit has a D 4 h point group symmetry and each Cu 2+ ion has a square pyramidal coordination geometry.…”

Section: Results and Discussionsupporting

confidence: 89%

Electron Paramagnetic Resonance Study of Guest Molecule-Influenced Magnetism in Kagome Metal–Organic Framework

et al. 2016

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We present a continuous-wave electron paramagnetic resonance (EPR) study of Cu(ipa)(H 2 O) (ipa stands for isophthalate ligand) metal−organic framework (MOF) that is based on the kagome topology. The main structural unit of this compound is a copper paddle-wheel (PW) consisting of two Cu 2+ ions interconnected via four carboxylate groups in the syn−syn fashion. X-and Q-band EPR measurements of this MOF allow us to probe distinct magnetic interactions of different magnitudes that originate from these dinuclear units. EPR experiments performed at different temperatures reveal that two Cu 2+ ions in a single PW are antiferromagnetically coupled to the total spin S = 0 state with the exchange coupling constant J = −285 cm −1 . The fine structure pattern observed in the spectra indicates the thermal population of the excited triplet S = 1 spin states of the Cu 2+ pairs. Spectral simulations are used to determine the fine and hyperfine structure tensors of the PW units. At higher temperatures a collapse of the fine structure to a single EPR line is observed, indicating the interdinuclear exchange of the S = 1 spin states mediated via the isophthalate linkers. Comparison of the EPR results with the structural X-ray diffraction data reveals that the dehydration of the compound opens an additional spin triplet exchange path joining apical positions of the PWs. We estimated the effective exchange coupling constants in the as-synthesized and dehydrated forms of the compound by simulating the observed powder patterns. It is shown that the additional path is reversibly closed after the dehydrated sample is allowed to interact with air, demonstrating a peculiar relationship between the adsorbed guest molecules and magnetic properties of kagome MOFs even at room temperature.

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Section: Results and Discussionsupporting

confidence: 89%

Electron Paramagnetic Resonance Study of Guest Molecule-Influenced Magnetism in Kagome Metal–Organic Framework

et al. 2016

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“…The use of deuterated molecules, such as D20 and CD3OH, was also useful in determining the location and structure of Cu2+ in zeolites as a function of the co-cation [43][44]. Recently, the technique has been extended to characterize Cu2+ complexes in mesoporous MCM-41 [45][46]. Surprisingly, Cu2+ was found to bind strongly with surface oxygen atoms and only 2 H2O, 2 MeOH or 2 NH3 could enter the coordination sphere, the larger molecules pyridine and benzene being excluded.…”

Section: Cu2+mentioning

confidence: 99%

Electron Spin Resonance Spectroscopy

2013

Encyclopedia of Biophysics

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Abstract. The theoretical principles of the ESR technique and its application in the field of molecular sieve science are reviewed. The first part of this chapter focuses on the basic principles and instrumentation of the ESR, ENDOR, ESE and ESEEM techniques. Special attention will be given to spectral simulation and quantitative analysis of ESR spectra. In the second part, the general features of the ESR spectra of transition metal ions and paramagnetic clusters in molecular sieves are presented and discussed. In addition, some remarks will be made about the use of paramagnetic molecules, such as NO.

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“…12,13 The latter is useful for organic functionalisation of the pore walls with potential ligands which can be later coordinated to metal species. It is also possible to modify the silicas with metals at this stage of synthesis through complexation, 14 where metal species which will form micelles with the template are used, and also through chemical vapour infiltration. 11 These two approaches can be problematic.…”

Section: Introductionmentioning

confidence: 99%

The modification of M41S materials: addition of metal clusters and nanoparticles

et al. 2010

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The incorporation of various molecular metal clusters, with well defined stoichiometry, into M41S materials has been investigated. The grafting of simple metal clusters, such as [Ru 3 (CO) 12 ] and [PPN] 2 [Fe 4 (CO) 13 ], and the larger, and in one instance, bimetallic, clusters [(dppe) 2 Cu][Cu 6 Fe 4 (CO) 16 ] and [PPh 4 ][Ru 10 (m 6 -C)(m-H)(CO) 24 ] has been achieved. Nanoparticles containing iron and platinum were also anchored on silaceous supports. The proportion of iron to platinum in FePt nanoparticles was adjusted by altering the molar ratios of starting materials.

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Electron Spin Resonance and Electron Spin Echo Modulation Studies of the Incorporation of Macrocyclic-Complexed Cupric Ions into Siliceous MCM-41

Cited by 39 publications

References 3 publications

Electron Paramagnetic Resonance Study of Guest Molecule-Influenced Magnetism in Kagome Metal–Organic Framework

Electron Paramagnetic Resonance Study of Guest Molecule-Influenced Magnetism in Kagome Metal–Organic Framework

Electron Spin Resonance Spectroscopy

The modification of M41S materials: addition of metal clusters and nanoparticles

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