INTRAZEOLITE SEMICONDUCTORS - NA-23 MAS NMR, TL+ LUMINESCENCE QUENCHING, AND FAR-IR STUDIES OF ACID-BASE PRECURSOR CHEMISTRY IN ZEOLITE-Y

Date

1991-11-01

Author

MCMURRAY, L
HOLMES, AJ
KUPERMAN, A
OZIN, GA
Özkar, Saim

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

168
views

0
downloads

Proton-loaded zeolites, prepared from fully dehydrated zeolites and gaseous, anhydrous Bronsted acids, represent an important step in the synthesis of intrazeolite semiconductor quantum supralattices. Adsorption-induced Na-23 MAS NMR chemical shifts, far-IR Na+ and Tl+ translatory mode frequency shifts, and Tl+ luminescence quenching effects were chosen as probes of cation-anion interaction in these materials. Samples of zeolite Y with various loadings of Tl+ were prepared via aqueous ion-exchange techniques. The samples were characterized by powder X-ray diffraction and far-IR spectroscopy. Luminescence measurements revealed Tl+ excitation and emission bands in the UV spectral region. Exposure of thallium Tl(I) zeolite Y to anhydrous HBr quenched the luminescence intensity. The intensity quenching followed Stern-Volmer quenching kinetics. Preliminary luminescence lifetime studies of this system supported a static ion pair quenching model. Compelling additional evidence in favor of cation-anion pair formation comes from the observation of alpha-cage site-specific Na-23 MAS NMR chemical shifts in HBr/Na56Y compared to virgin Na56Y. The relevance of these observations for proton-loaded zeolite Y to the acid-base precursor chemistry involved in the synthesis of semiconductor nanostructures encapsulated in zeolite Y is critically discussed.

Subject Keywords

Physical and Theoretical Chemistry, General Engineering

URI

https://hdl.handle.net/11511/69957

Journal

JOURNAL OF PHYSICAL CHEMISTRY

DOI

https://doi.org/10.1021/j100176a077

Collections

Department of Chemistry, Article

Suggestions

OpenMETU
Core

INTRAZEOLITE TOPOTAXY - NA-23 DOUBLE-ROTATION NMR-STUDY OF TRANSITION-METAL HEXACARBONYLS AND OXIDES ENCAPSULATED IN SODIUM ZEOLITE-Y JELINEK, R; Özkar, Saim; OZIN, GA (American Chemical Society (ACS), 1992-07-01) Na-23 double-rotation NMR (DOR) provides details on site specific adsorption and anchoring interactions in intrazeolite hexacarbonylmetal(0) complexes, M{M(CO)6}-Na56Y, where M = Mo and W, and their molecular photooxidation products, n{MO3-x}-Na56Y, over the full composition range 0 < m less-than-or-equal-to 16, 0 < n less-than-or-equal-to 32 and 0 less-than-or-equal-to x less-than-or-equal-to 1. The shifts, intensities, and line shapes of the Na-23 DOR resonances carry information on the environments of th...
INTRAZEOLITE PHOTOTOPOTAXY - EXAFS ANALYSIS OF PRECURSOR 8(W(CO)6)-NA56Y AND PHOTOOXIDATION PRODUCTS 16(WO3)-NA56Y AND 28(WO3)-NA56Y MOLLER, K; BEIN, T; Özkar, Saim; OZIN, GA (American Chemical Society (ACS), 1991-06-01) The intrazeolite photooxidation chemistry of alpha-cage encapsulated hexacarbonyltungsten(0) in Na56Y with O2, denoted n{W(CO)6}-Na56Y/O2/hv, which has previously been shown to provide a novel synthetic pathway to alpha-cage located tungsten(VI) oxide, denoted n(WO3)-Na56Y, is now the subject of an extended X-ray absorption fine structure (EXAFS) analysis. The EXAFS data of a precursor 8{W(CO)6}Na56Y, which contains on average one W(CO)6 per alpha-cage shows that the W(CO)6 guest maintains its structural in...
Dielectric Properties of Ethanol and Gasoline Mixtures by Terahertz Spectroscopy and an Effective Method for Determination of Ethanol Content of Gasoline ARIK, Enis; Altan, Hakan; Esentürk, Okan (American Chemical Society (ACS), 2014-05-01) Investigation of frequency dependent permittivity of mixture solutions provides information on the role of intermolecular interactions on relaxation processes of solvent and solute molecules. In this study the dielectric properties of ethanol/gasoline mixtures in the terahertz spectral region are investigated. Frequency dependent absorption coefficients, refractive indices, and complex permittivities of pure ethanol and gasoline, and their mixtures at varying ethanol volume percentages (v/v %) are reported....
Electrochemistry of nickel(II) complexes with N,N'-bis(3,5-di-tert-butylsalicylidene)polymethylenediamines Ozalp-Yaman, S; Kasumov, VT; Önal, Ahmet Muhtar (Elsevier BV, 2005-10-03) The electrochemical oxidation of several N,N'-polymethylenebis(3,5-di-tert- butylsalicylaldiminato)nickel(II) complexes, Ni(L-x), has been studied by cyclic voltammetry and in situ UV-Vis spectroscopy in DMF Cyclic voltammograms of Ni(L-x) (x = 1-4) complexes displayed two-step oxidation processes under nitrogen gas atmosphere. The first oxidation peak potentials of all the Ni(II) complexes corresponds to the reversible one-electron oxidation process of the metal center, yielding Ni(III) species. EPR spectr...
Bosonic helium clusters doped by alkali metal cations: interaction forces and analysis of their most stable structures Marinetti, F.; Coccia, E.; Bodo, E.; Gianturco, F. A.; Yurtsever, E.; Yurtsever, M.; Yıldırım, Erol (Springer Science and Business Media LLC, 2007-07-01) Ab initio potentials are computed for alkali metal cationic partners interacting with He-4 and an overall many-body potential is constructed for each of the ionic dopants in helium clusters. The structures are then obtained via a genetic algorithm approach and results compared with Basin-Hopping Monte Carlo simulations. The classical arrangements are analyzed and quantum effects discussed in comparison with what has been found with Diffusion Monte Carlo calculations. Further corrections to the classical pic...

Citation Formats

L. MCMURRAY, A. HOLMES, A. KUPERMAN, G. OZIN, and S. Özkar, “INTRAZEOLITE SEMICONDUCTORS - NA-23 MAS NMR, TL+ LUMINESCENCE QUENCHING, AND FAR-IR STUDIES OF ACID-BASE PRECURSOR CHEMISTRY IN ZEOLITE-Y,” JOURNAL OF PHYSICAL CHEMISTRY, pp. 9448–9456, 1991, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/69957.