Coordination of Cu<sup>2+</sup> to Oxygen Six-Rings of Zeolites

Packet, Dirk; Schoonheydt, Robert A.

doi:10.1021/bk-1988-0368.ch013

“…It was suggested that these ESR signals are, within experimental accuracy, independent of the Si/ Al ratio, the SiϪAl ordering and the type of co-exchanged cation. [20,53] As such, they only reflect the type of coordination of Cu II in the structure. However, the relative intensities of the two ESR signals vary with the Si/Al ratio, the type of co-cation and the Cu II loading, and are indicative of the site preference of Cu II .…”

Section: Zeolite Y and Xmentioning

confidence: 99%

“…However, the relative intensities of the two ESR signals vary with the Si/Al ratio, the type of co-cation and the Cu II loading, and are indicative of the site preference of Cu II . [20,53] Interpretations of the two ESR signals of Cu II in zeolite Y in terms of specific coordination environments at cation sites were published only after the first XRD study of Cu II ϪY became available. Almost all groups assign the two ESR signals to Cu II at two different cation sites.…”

Section: Zeolite Y and Xmentioning

confidence: 99%

See 1 more Smart Citation

The Coordination of CuII in Zeolites − Structure and Spectroscopic Properties

Delabie

¹

,

Pierloot

²

,

Groothaert

³

et al. 2002

Eur. J. Inorg. Chem.

View full text Add to dashboard Cite

Keywords: Zeolites / Copper / Ab initio calculations / Density functional calculations / ESR spectroscopy / UV/Vis spectroscopy / Heterogeneous catalysis Zeolites loaded with transition metal ions are promising heterogeneous catalysts. Knowledge about the location and structure of the metal centers is of paramount importance for the understanding of the catalytic potential of these materials. In this work, the spectroscopic studies of the coordination of Cu II in zeolite A, ZK4, X, Y and mordenite are reviewed. Experimentally, diffuse reflectance spectroscopy [a] teaches general chemistry and computational chemistry. Her main research interest is the application of ab initio methods for the study of spectroscopic and magnetic properties of systems containing transition metals. Marijke H. Groothaert (left center) was born in Neerpelt, Belgium in 1975. In 1998 she received her M. S. degree from the . Since 1998 she is a PhD student at the Center for Surface Chemistry and Catalysis under the supervision of Professor Robert A. Schoonheydt. Her research is concentrated on the coordination of transition metal ions in zeolites and combines spectroscopic techniques with computational methods. Robert A. Schoonheydt (left bottom) received his M. S. degree in 1966 and . Hab. in Leuven, where he teaches quantum chemistry, computational chemistry, and inorganic chemistry. His main research interests are in the application of computational methods in different areas of chemistry.MICROREVIEWS: This feature introduces the readers to the authors' research through a concise overview of the selected topic. Reference to important work from others in the field is included. 515(DRS) and electron spin resonance (ESR) spectroscopy have been applied to study the coordination of Cu II in zeolites. Ab initio calculations on model clusters, representing the Cu II sites in zeolites, are used for the interpretation of the experimental data. The combination of experimental spectroscopic information with theoretical results leads to a new and profound insight into the Cu II −zeolite interaction.

show abstract

“…[1] Cu 2 + -zeolites are, for instance, used as active catalysts for a range of reactions, such as the decomposition of nitrogen oxides, [2][3][4][5][6][7][8][9][10][11][12][13] the selective hydroxylation of methane and benzene to methanol [14][15][16][17][18][19][20] and phenol [21][22][23][24][25] respectively, and the oxidative carbonylation of alcohols. [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] Location of TMIs in zeolites and their coordination is thus established for many zeolite topologies and zeolite compositions. Indeed, Cu 2 + -zeolites are excellent probes to study the coordination chemistry of transition metal ions (TMIs), mainly with the combination of UV/Vis-NIR and EPR spectroscopy and theoretical approaches.…”

Section: Introductionmentioning

confidence: 99%

“…[26][27][28][29][30][31][32][33] In addition, a lot of spectroscopic data on Cu 2 + -containing zeolites are available in literature. [1] Often these spectroscopic studies focused on low transition metal contents, [35][36][37][38]51] while the best catalytic results were mainly reported with high Cu 2 + loadings. [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] Location of TMIs in zeolites and their coordination is thus established for many zeolite topologies and zeolite compositions.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopy and Redox Chemistry of Copper in Mordenite

Vanelderen

¹

,

Vancauwenbergh

²

,

Tsai

³

et al. 2014

View full text Add to dashboard Cite

Copper-containing zeolites, such as mordenite (MOR), have recently gained increased attention as a consequence of their catalytic potential. While the preferred copper loadings in these catalytic studies are generally high, the literature lacks appropriate spectroscopic and structural information on such Cu-rich zeolite samples. Higher copper loadings increase the complexity of the copper identity and their location in the zeolite host, but they also provide the opportunity to create novel Cu sites, which are perhaps energetically less favorable, but possibly more reactive and more suitable for catalysis. In order to address the different role of each Cu site in catalysis, we here report a combined electron paramagnetic resonance (EPR), UV/Vis-NIR and temperature-programmed reduction (TPR) study on highly copper-loaded MOR. Highly resolved diffuse reflectance (DR) spectra of the CuMOR samples were obtained due to the increased copper loading, allowing the differentiation of two isolated mononuclear Cu(2+) sites and the unambiguous correlation with extensively reported features in the EPR spectrum. Ligand field theory is applied together with earlier suggested theoretical calculations to determine their coordination chemistry and location within the zeolite matrix, and the theoretical analysis further allowed us to define factors governing their redox behavior. In addition to monomeric species, an EPR-silent, possibly dimeric, copper site is present in accordance with its charge transfer absorption feature at 22200 cm(-1), and quantified with TPR. Its full description and true location in MOR is currently being investigated.

show abstract

The Coordination of CuII in Zeolites − Structure and Spectroscopic Properties

Delabie¹,

Pierloot²,

Groothaert³

et al. 2002

Eur. J. Inorg. Chem.

View full text Add to dashboard Cite

Keywords: Zeolites / Copper / Ab initio calculations / Density functional calculations / ESR spectroscopy / UV/Vis spectroscopy / Heterogeneous catalysis Zeolites loaded with transition metal ions are promising heterogeneous catalysts. Knowledge about the location and structure of the metal centers is of paramount importance for the understanding of the catalytic potential of these materials. In this work, the spectroscopic studies of the coordination of Cu II in zeolite A, ZK4, X, Y and mordenite are reviewed. Experimentally, diffuse reflectance spectroscopy [a] teaches general chemistry and computational chemistry. Her main research interest is the application of ab initio methods for the study of spectroscopic and magnetic properties of systems containing transition metals. Marijke H. Groothaert (left center) was born in Neerpelt, Belgium in 1975. In 1998 she received her M. S. degree from the . Since 1998 she is a PhD student at the Center for Surface Chemistry and Catalysis under the supervision of Professor Robert A. Schoonheydt. Her research is concentrated on the coordination of transition metal ions in zeolites and combines spectroscopic techniques with computational methods. Robert A. Schoonheydt (left bottom) received his M. S. degree in 1966 and . Hab. in Leuven, where he teaches quantum chemistry, computational chemistry, and inorganic chemistry. His main research interests are in the application of computational methods in different areas of chemistry.MICROREVIEWS: This feature introduces the readers to the authors' research through a concise overview of the selected topic. Reference to important work from others in the field is included. 515(DRS) and electron spin resonance (ESR) spectroscopy have been applied to study the coordination of Cu II in zeolites. Ab initio calculations on model clusters, representing the Cu II sites in zeolites, are used for the interpretation of the experimental data. The combination of experimental spectroscopic information with theoretical results leads to a new and profound insight into the Cu II −zeolite interaction.

show abstract

Coordination of Cu²⁺ to Oxygen Six-Rings of Zeolites

Cited by 12 publications

References 0 publications

The Coordination of CuII in Zeolites − Structure and Spectroscopic Properties

The Coordination of CuII in Zeolites − Structure and Spectroscopic Properties

Spectroscopy and Redox Chemistry of Copper in Mordenite

The Coordination of CuII in Zeolites − Structure and Spectroscopic Properties

Contact Info

Product

Resources

About

Coordination of Cu2+ to Oxygen Six-Rings of Zeolites

Cited by 12 publications

References 0 publications

The Coordination of CuII in Zeolites − Structure and Spectroscopic Properties

The Coordination of CuII in Zeolites − Structure and Spectroscopic Properties

Spectroscopy and Redox Chemistry of Copper in Mordenite

The Coordination of CuII in Zeolites − Structure and Spectroscopic Properties

Contact Info

Product

Resources

About

Coordination of Cu²⁺ to Oxygen Six-Rings of Zeolites