Electron spin mapping of coal molecular structure by ENDOR (electron nuclear double resonance): Quarterly technical progress report. [Perylene radicals]
ENDOR and x-band EPR spectra were obtained for solutions of perylene in benzene or d6-benzene onto an activated alumina or silica-alumina surface. The investigators believe that their matrix ENDOR observations show the radical sites for perylene adsorbed on their particular alumina and silica-alumina surfaces to be different. The data indicate that on the alumina the radical has stronger interactions and/or less mobility relative to the frozen solvent than it does on the silica-alumina. Their alumina surface is marked by spectroscopic evidence of the ubiquitous proton while their silica-alumina is not. Finally, the perylene radical on their alumina rests near at least one aluminum atom; the typical detection range of matrix ENDOR is limited to within 5 to 6 angstroms. Conversely, the aluminum-27 resonance is never observed with our Houdry M-46 silica-alumina material. Even considering that their Houdry catalyst contains only 10% of the aluminum in alumina and the inherent lack of matrix intensity on this surface, they would still expect to detect a weak aluminum-27 resonance at liquid helium temperature on purely statistical grounds. Its absence indicates a preference of the perylene radical for a site near an aluminum atom on their alumina, and/or the lack of a preference for an ''alumina-type'' site in the Houdry M-46 silica-alumina. They conclude that observation of matrix ENDOR features has proven to be a valuable complementary tool in the study of radicals adsorbed on metal oxide surfaces. 18 refs., 7 figs., 1 tab.
- Research Organization:
- Illinois Univ., Urbana (USA)
- DOE Contract Number:
- FG22-84PC70782
- OSTI ID:
- 6715605
- Report Number(s):
- DOE/PC/70782-11; ON: DE87008390
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
ADSORPTION
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AROMATICS
BENZENE
CHALCOGENIDES
CONDENSED AROMATICS
DATA
DEUTERIUM COMPOUNDS
ELECTRON SPIN RESONANCE
ENDOR
EXPERIMENTAL DATA
HYDROCARBONS
HYDROGEN COMPOUNDS
HYPERFINE STRUCTURE
INFORMATION
LOW TEMPERATURE
MAGNETIC RESONANCE
MINERALS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PERYLENE
RADICALS
RESONANCE
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES
TEMPERATURE EFFECTS
ULTRALOW TEMPERATURE