Yu, JS Kim, SJ Hong, SB Kevan, L 2024-01-21T19:39:01Z 2024-01-21T19:39:01Z 2022-01-10 1996-03-07 0956-5000 https://pubs.kist.re.kr/handle/201004/144501 The interaction of Cu-II with deuteriated adsorbates in Cu-II-exchanged gallosilicate with the zeolite L channel-type structure has been investigated by EPR and electron spin echo modulation (ESEM) spectroscopies, and compared with that in Cu-II-exchanged K-L aluminosilicate zeolite. Similar results to those for CuK-L aluminosilicate were observed in CuK-L gallosilicate. It was found that, in the fresh hydrated material, Cu-II is octahedrally coordinated to six water molecules. This species is located in the main channels and rotates rapidly at room temperature. A minor Cu-II diaquo species seen in the aluminosilicate is not observed in the gallosilicate. Evacuation at room temperature removes three of these water molecules, leaving the Cu-II coordinated to three water molecules and anchored to the zeolite lattice by coordination to zeolitic oxygens in an eight-ring; the coordinated water is removed more easily in the gallosilicate than in the aluminosilicate. Upon further evacuation at increasing temperature, Cu-II moves from the main channel towards recessed sites. Dehydration at 400 degrees C produces one Cu-II species located in recessed sites, as evidenced by a lack of broadening of its EPR lines by oxygen. Adsorption of polar molecules such as water and alcohols causes changes in the EPR spectrum of the Cu-II indicating migration into the main channels where adsorbate coordination can occur. Ethene also coordinates with Cu-II but causes less migration. Cu-II forms complexes with two molecules of methanol and ethanol, and with one molecule of ethene, as evidenced by ESEM data, which is the same as for Cu-II in CuK-L aluminosilicate zeolite. English ROYAL SOC CHEMISTRY STRUCTURAL CHARACTERIZATION Y-ZEOLITE RESONANCE COPPER(II) CATALYSTS SIMULATION OXIDATION SPECTRA MAZZITE EPR and electron spin echo modulation spectroscopy of Cu-II ion species in Cu-II-exchanged K-L gallosilicate Article 10.1039/ft9969200855 1 JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS, v.92, no.5, pp.855 - 860 JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS 92 5 855 860 scie scopus A1996UA86500021 2-s2.0-33748625743 Chemistry, Physical Physics, Atomic, Molecular & Chemical Chemistry Physics Article STRUCTURAL CHARACTERIZATION Y-ZEOLITE RESONANCE COPPER(II) CATALYSTS SIMULATION OXIDATION SPECTRA MAZZITE