Show/Hide Menu
Hide/Show Apps
Logout
Türkçe
Türkçe
Search
Search
Login
Login
OpenMETU
OpenMETU
About
About
Open Science Policy
Open Science Policy
Open Access Guideline
Open Access Guideline
Postgraduate Thesis Guideline
Postgraduate Thesis Guideline
Communities & Collections
Communities & Collections
Help
Help
Frequently Asked Questions
Frequently Asked Questions
Guides
Guides
Thesis submission
Thesis submission
MS without thesis term project submission
MS without thesis term project submission
Publication submission with DOI
Publication submission with DOI
Publication submission
Publication submission
Supporting Information
Supporting Information
General Information
General Information
Copyright, Embargo and License
Copyright, Embargo and License
Contact us
Contact us
INTRAZEOLITE PHOTOTOPOTAXY - EXAFS ANALYSIS OF PRECURSOR 8(W(CO)6)-NA56Y AND PHOTOOXIDATION PRODUCTS 16(WO3)-NA56Y AND 28(WO3)-NA56Y
Date
1991-06-01
Author
MOLLER, K
BEIN, T
Özkar, Saim
OZIN, GA
Metadata
Show full item record
This work is licensed under a
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License
.
Item Usage Stats
170
views
0
downloads
Cite This
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 integrity with only minor observable perturbations of the skeletal WC and ligand CO bonds compared to those found for the same molecule in the free state. The EXAFS analysis results for the photoxidation products 16(WO3)-Na56Y and 28(WO3)-Na56Y are very similar and display the presence of two terminal tungsten-oxygen bonds (1.75-1.77 angstrom) and two bridging tungsten-oxide bonds (1.94-1.95 angstrom), together with a short distance to a second tungsten (3.24-3.30 angstrom). This bond length and coordination number information for n = 16 and 28 samples is best interpreted in terms of the formation of a single kind of tungsten trioxide dimer unit (WO3)2, most likely interacting with extraframework Na+ cations, denoted ZONa...O2W(mu-O)2WO2...NaOZ. In conjunction with earlier chemical and spectroscopic information on this system, the EXAFS data support the contention that 16(WO3)-Na56Y contains a uniform array of single size and shape tungsten (VI) oxide dimers (WO3)2 housed in the 13-angstrom supercages of the zeolite Y host. The sequential addition of WO3 units to the 16(WO3)-Na56Y sample appears to increase the (WO3)2 dimer population, causing a buildup of alpha-cage encapsulated dimers-of-dimers {(WO3)2}2 rather than further cluster growth to trimers (WO3)2 and/or tetramers (WO3)4.
Subject Keywords
Physical and Theoretical Chemistry
,
General Engineering
URI
https://hdl.handle.net/11511/69956
Journal
JOURNAL OF PHYSICAL CHEMISTRY
DOI
https://doi.org/10.1021/j100166a066
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 SEMICONDUCTORS - NA-23 MAS NMR, TL+ LUMINESCENCE QUENCHING, AND FAR-IR STUDIES OF ACID-BASE PRECURSOR CHEMISTRY IN ZEOLITE-Y
MCMURRAY, L; HOLMES, AJ; KUPERMAN, A; OZIN, GA; Özkar, Saim (American Chemical Society (ACS), 1991-11-01)
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 techniq...
Excitation Localization/Delocalization Isomerism in a Strongly Coupled Covalent Dimer of 1,3-Diphenylisobenzofuran
Schrauben, Joel N.; Akdağ, Akın; Wen, Jin; Havlas, Zdenek; Ryerson, Joseph L.; Smith, Millie B.; Michl, Josef; Johnson, Justin C. (American Chemical Society (ACS), 2016-05-26)
Two isomers of both the lowest excited singlet (S-1) and triplet (T-1) states of the directly para, para'-connected covalent dimer of the singlet-fission chromophore 1,3-diphenylisobenzofuran have been observed. In one isomer, excitation is delocalized over both halves of the dimer, and in the other, it is localized on one or the other half. For a covalent dimer in solution, such "excitation isomerism" is extremely rare. The vibrationally relaxed isomers do not interconvert, and their photophysical properti...
Sol-gel Approaches for Elaboration of Polyol Dehydrogenase-Based Bioelectrodes
Urbanova, Veronika; Kohring, Gert-Wieland; Klein, Tobias; Wang, Zhijie; Mert, Olcay; Emrullahoglu, Mustafa; Buran, Kerem; Demir, Ayhan Gürbüz; Etienne, Mathieu; Walcarius, Alain (Walter de Gruyter GmbH, 2013-01-01)
This review describes the input of sol-gel chemistry to the immobilization of polyol dehydrogenases on electrodes, for applications in bioelectrocatalysis. The polyol dehydrogenases are described and their application for biosensing, biofuel cell and electrosynthesis are briefly discussed. The immobilization of proteins via sol-gel approaches is described, including a discussion on the difficulty to maintain the activity of proteins in a silica matrix and the strategies developed to offer a proper environme...
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....
Citation Formats
IEEE
ACM
APA
CHICAGO
MLA
BibTeX
K. MOLLER, T. BEIN, S. Özkar, and G. OZIN, “INTRAZEOLITE PHOTOTOPOTAXY - EXAFS ANALYSIS OF PRECURSOR 8(W(CO)6)-NA56Y AND PHOTOOXIDATION PRODUCTS 16(WO3)-NA56Y AND 28(WO3)-NA56Y,”
JOURNAL OF PHYSICAL CHEMISTRY
, pp. 5276–5281, 1991, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/69956.