Formation and reactivity of Cr<sup>II</sup>carbonyls hosted in polar and non polar supports

Gianolio, Diego; Groppo, Elena; Estephane, Jane; Prestipino, Carmelo; Nikitenko, Sergey I.; Zecchina, Adriano; Bordiga, Silvia; Taoufik, Mostafa; Quadrelli, Elsje Alessandra; Basset, Jean‐Marie; Lamberti, Carlo

doi:10.1088/1742-6596/190/1/012140

Cited by 4 publications

(10 citation statements)

References 23 publications

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“…Reactivity of CO with Cp 2 Cr encapsulated inside Na-Y zeolite. 866,867 An intense n(CO) band immediately appears at 1850 cm À1 (blue circle and blue curve in Fig. 28a), 734,863 which is very similar to that previously reported in the literature in the case of Cp 2 Cr(CO) in toluene solution.…”

Section: 1supporting

confidence: 87%

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Probing zeolites by vibrational spectroscopies

et al. 2015

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This review addresses the most relevant aspects of vibrational spectroscopies (IR, Raman and INS) applied to zeolites and zeotype materials. Surface Brønsted and Lewis acidity and surface basicity are treated in detail. The role of probe molecules and the relevance of tuning both the proton affinity and the steric hindrance of the probe to fully understand and map the complex site population present inside microporous materials are critically discussed. A detailed description of the methods needed to precisely determine the IR absorption coefficients is given, making IR a quantitative technique. The thermodynamic parameters of the adsorption process that can be extracted from a variable-temperature IR study are described. Finally, cutting-edge space- and time-resolved experiments are reviewed. All aspects are discussed by reporting relevant examples. When available, the theoretical literature related to the reviewed experimental results is reported to support the interpretation of the vibrational spectra on an atomic level.

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Section: 1supporting

confidence: 87%

“…[868][869][870] On this basis, reaction (39) was inferred and supported by parallel Cr K-edge EXAFS analysis. 866,867 This reaction requires the presence of two Cp 2 Cr molecules inside the same supercage, as shown in the top-left inset in Fig. 35a. 9.1.2.…”

Section: 1mentioning

confidence: 99%

Probing zeolites by vibrational spectroscopies

et al. 2015

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“…Estephane et al [37,[81][82][83] developed new strategies to obtain spectroscopic information on isolated molecules and on their reactivity, in particular towards CO. Two Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 6/3/15 2:17 PM matrices were adopted as "scaffolds" to encapsulate and isolate molecules in their cavities: -A non-polar nanoporous polystyrene (PS) matrix (average dimensions of pores 100 Å, high surface area ≈ 1000 m 2 g −1 ) that can act as a "solid solvent" molecularly dispersing the chromocene inside its nanopores (Fig. 5.6a).…”

Section: Structure Of Cp 2 Cr Encapsulated In Ps and Na-y Zeolite Matmentioning

confidence: 99%

“…A systematic XAFS and IR study allowed the authors to obtain a complete structural, electronic and vibrational insight into the isolated molecule and its interaction products with CO in the two different environments [37,[81][82][83]. In these experiments CO sent from gas phase was able to easily diffuse in the porous matrices, overcoming the diffusion problems of experiments performed dispersing Cp 2 Cr in toluene [79,80].…”

Section: Structure Of Cp 2 Cr Encapsulated In Ps and Na-y Zeolite Matmentioning

confidence: 99%

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5. Structural and electronic characterization of nanosized inorganic materials by X-ray absorption spectroscopies

Borfecchia¹,

Agostini²,

Bordiga³

et al. 2013

Inorganic Micro- And Nanomaterials

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Starting from the late seventies, the progressively increased availability of synchrotron light sources has allowed the execution of experiments requiring a high X-ray flux in a continuous interval [1][2][3][4]. Among the various techniques developed, X-ray absorption spectroscopy (XAS, also known as X-ray absorption fine-structure, XAFS) [5][6][7][8][9][10][11][12][13] in both near (XANES) and post (EXAFS) edge regions, has become a powerful characterization technique widely employed in many research fields concerning inorganic chemistry, such as catalysis [13][14][15][16][17], organometallic and coordination complexes [18], metal nanoparticles [19, 20], electrochemical processes [21, 22], coordination polymers or metallorganic frameworks [23], bio-inorganic molecules including metalloproteins [24-27], chemistry of actinide elements [28], and solid state chemistry [12,[29][30][31].In this chapter, we will provide a brief introduction to the basic theory of XAS spectroscopy (Section 5.2), followed by selected examples having some didactic perspective (Sections 5.3-5.7). For the sake of brevity, only a fraction of the subjects mentioned above will be discussed; in particular, the chapter will deal with: the reactivity of the CuCl 2 /Al 2 O 3 -based catalysts for ethylene oxychlorination (Section 5.3); the structure, the electronic configuration and the reactivity of Cp 2 Cr molecules encapsulated in porous solids (Section 5.4); the structural characterization of metal complexes in solution (Section 5.5); the structural characterization of the UiO-66 and UiO-67 class of metallorganic frameworks (Section 5.6); and the determination of the local structure of an Alxw Gayw In 1−xw−yw As/Al xb Ga yb In 1−xb −yb As strained heterostructure grown on InP by metallorganic vapor phase epitaxy (Section 5.7) as an example of space-resolved EXAFS applied to a topic pertinent to solid state chemistry. XAS spectroscopy: Basic backgroundThe aim of this section is to provide the reader with a concise review of the basic physical principles on which the interpretation of EXAFS and XANES data is based. For a more detailed description of the theoretical background and the experimental aspects of XAS we refer to the extensive specialized literature (e.g., [5][6][7][8][9][10][11][12][13]).

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Time Resolved in Situ XAFS Study of the Electrochemical Oxygen Intercalation in SrFeO_2.5 Brownmillerite Structure: Comparison with the Homologous SrCoO_2.5 System

et al. 2010

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International audienceLow temperature oxygen ionic conductors are key materials for the development of the next generation solid oxide fuel cells. In this regard, SrMO2.5 (M = Fe,Co) systems with a Brownmillerite-type structure are able to reversibly intercalate oxygen in an electrochemical reaction at room temperature to reach SrMO3 stoichiometry. To understand and characterize this behavior, at the atomic level, in situ X-ray absorption spectroscopy experiments during the electrochemical oxidation reaction were performed for both SrFeO2.5 and SrCoO2.5 compounds at the Fe and Co K-edge, respectively. The comparative analysis of the two experiments allowed us to emphasize the similarities and differences observed during electrochemical oxidation of the two parent compounds. The data were analyzed both in XANES and EXAFS regions to extract both electronic configuration and local order information. To extract as much information as possible from collected data, the standard linear combination of spectra was complemented by the principal component analysis advanced method, which allowed us to clarify some aspects of the reaction process that were otherwise hidden. As for SrCoO2.5+x ordered intermediates (x = 0.25, 0.375) that could have been identified by neutron diffraction and XAFS experiments [J. Am. Chem. Soc. 2006, 128, 13161], no ordered intermediates of the homologous SrFeO2.5+x different from an oxygen deficient perovskite phase have been reported to occur during the oxygen intercalation reaction, except on a very local level. However, a detailed fit of the EXAFS signals for starting and final phases showed that the final fully oxidized compound (with stoichiometry SrCoO3) has been obtained for SrCoO2.5, whereas for SrFeO2.5, the reaction ended before the expected charge transfer. We interpret the formation of SrFeO3 to be accompanied by the parasitic formation of an unknown phase, containing Fe(III). Furthermore we were able to highlight that, at a local level, the most probable space group for SrCoO2.5 at ambient temperature is Imma, as the average local environments extracted from Pnma and I2mb models were not able to reproduce the experimental EXAFS spectrum

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Formation and reactivity of Cr^IIcarbonyls hosted in polar and non polar supports

Cited by 4 publications

References 23 publications

Probing zeolites by vibrational spectroscopies

Probing zeolites by vibrational spectroscopies

5. Structural and electronic characterization of nanosized inorganic materials by X-ray absorption spectroscopies

Time Resolved in Situ XAFS Study of the Electrochemical Oxygen Intercalation in SrFeO_2.5 Brownmillerite Structure: Comparison with the Homologous SrCoO_2.5 System

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Formation and reactivity of CrIIcarbonyls hosted in polar and non polar supports

Cited by 4 publications

References 23 publications

Probing zeolites by vibrational spectroscopies

Probing zeolites by vibrational spectroscopies

5. Structural and electronic characterization of nanosized inorganic materials by X-ray absorption spectroscopies

Time Resolved in Situ XAFS Study of the Electrochemical Oxygen Intercalation in SrFeO2.5 Brownmillerite Structure: Comparison with the Homologous SrCoO2.5 System

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Formation and reactivity of Cr^IIcarbonyls hosted in polar and non polar supports

Time Resolved in Situ XAFS Study of the Electrochemical Oxygen Intercalation in SrFeO_2.5 Brownmillerite Structure: Comparison with the Homologous SrCoO_2.5 System