@article {375,
	title = {Hyperfine and host-guest interactions of the Mu-cyclohexadienyl radical in NaY zeolite},
	journal = {Journal of Physical Chemistry B},
	volume = {106},
	number = {25},
	year = {2002},
	note = {ISI Document Delivery No.: 565EUTimes Cited: 8Cited Reference Count: 88},
	month = {Jun},
	pages = {6395-6407},
	type = {Article},
	abstract = {The adsorption and dynamical behavior of the muonated cyclohexadienyl radical (C(6)H(6)Mu) in NaY zeolite, formed by muonium (Mu) addition on adsorbed benzene. was investigated by the muon spin resonance (muSR) technique, primarily at loadings of 2-3 C6H6 molecules per supercage of NaY. The dynamics of this radical are expected to be the same as its isotopic analogue, C6H7, for which there are no similar data available. Both TF-muSR and ALC-muSR spectra were recorded, with the most detailed information provided by the positions and line widths of the avoided level crossing resonances. In concert with H-2 NMR, neutron diffraction and molecular dynamics studies of the parent benzene molecule, as well as current theoretical calculations, the dominant adsorption site for the C(6)H(6)Mu radical is believed to be the S-II Na cation, within a supercage, which gives rise to three observed ALC lines, corresponding to two different orientations for the muon (proton) of the CHMu methylene group: pointing toward (endo) and away (exo) from the Na cation. The cation interaction gives rise to unprecedentedly large (approximate to20\%) shifts in hyperfine coupling constants, indicative of a strong bond formed with the T electrons of the C(6)H(6)Mu radical. An additional but weaker resonance line is also seen, which is interpreted as being due to adsorption at the window sites between supercages. The ALC lines associated with the CH,,Mu radical bound to both the Na cation and window sites are all broad, approximate to1 kG, change little with temperature and exhibit mainly static line shapes over the whole temperature range studied, from 3 to 322 K. This indicates a much stronger host-guest interaction for C(6)H(6)Mu, particularly with the Na cation. than is known for benzene, to the extent that this site acts as an effective trap for the free radical, over the critical muSR time scale of 50 ns.},
	keywords = {AROMATIC-MOLECULES, ELASTIC NEUTRON-SCATTERING, GAS-PHASE, H-2 NMR, MAGNETIC-RESONANCE, MOLECULAR-DYNAMICS, RAY-POWDER DIFFRACTION, REORIENTATIONAL DYNAMICS, SODIUM-Y ZEOLITE, SPIN RELAXATION},
	isbn = {1520-6106},
	url = {<Go to ISI>://000176356700007},
	author = {Fleming, Donald G. and Shelley, M. Y. and Arseneau, D. J. and Senba, M. and Pan, J. J. and Roduner, E.}
}
@inbook {3163,
	title = {MUON SPIN RELAXATION STUDIES OF CYCLOHEXADIENYL RADICALS IN NAUSY},
	booktitle = {Zeolites and Related Microporous Materials: State of the Art 1994},
	series = {Studies in Surface Science and Catalysis},
	volume = {84},
	year = {1994},
	note = {ISI Document Delivery No.: BD02ETimes Cited: 3Cited Reference Count: 22Proceedings Paper10th International Zeolite ConferenceJUL 17-22, 1994GARMISCH PARTENKIR, GERMANYSARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS},
	pages = {469-475},
	publisher = {Elsevier Science Publ B V},
	organization = {Elsevier Science Publ B V},
	address = {Amsterdam},
	abstract = {The avoided level crossing muon spin resonance (ALC-mu SR) technique is a promising new tool that can be used as a highly sensitive microscopic probe of radical motions in zeolites. We report a recent experiment in which this technique was used to identify a muonated cyclohexadienyl radical (C(6)H(6)Mu) and explore its reorientational dynamics in NaUSY. The observed evolution of the Delta M=1 ALC resonance lines are interpreted in terms of the site exchange dynamics of the radical.},
	keywords = {benzene, DIFFUSION, LEVEL-CROSSING RESONANCE, LOCALIZATION, MOLECULAR-DYNAMICS, NAX, NMR, NUCLEAR MAGNETIC-RESONANCE, SODIUM-Y ZEOLITE},
	isbn = {0-444-81847-2},
	url = {<Go to ISI>://A1994BD02E00057},
	author = {Shelley, M. and Arseneau, D. J. and Senba, M. and Pan, J. J. and Snooks, R. and Kreitzman, S. R. and Fleming, Donald G. and Roduner, E.},
	editor = {Weitkamp, J. and Karge, H. G. and Pfeifer, H. and Holderich, W.}
}
