@article {335,
	title = {Diamagnetic clusters of paramagnetic endometallofullerenes: A solid-state MAS NMR study},
	journal = {Journal of Physical Chemistry B},
	volume = {108},
	year = {2004},
	note = {J Phys Chem B846BKTimes Cited:10Cited References Count:39},
	month = {Aug 19},
	pages = {12450-12455},
	abstract = {<p>Solid powder samples of complexes of the endometallofullerenes (EMF) La@C-82 and Y@C-82 with hexamethylphosphoramide (HMPA) were studied by magic-angle spinning (MAS) NMR. We have obtained well-resolved P-31 NMR spectra and C-13 NMR spectra for both La-EMF/HMPA and Y-EMF/HMPA and La-139 spectra for the La-EMF/HMPA. The (31)p measurements on La-EMF/HMPA and Y-EMF/HMPA have revealed considerable chemical shifts of (31)p signals relative to pure HMPA. Two-dimensional exchange P-31 experiments revealed that HMPA molecules at different sites in the EMF/HMPA complex do not change positions at a time scale of up to 1 s. Both EMF samples demonstrate a vast chemical shift range for 31p of the bound HMPA molecules. In addition, the La-EMF/HMPA exhibits the enormous spreading of the chemical shifts for La-139. The experimental results suggest that paramagnetic La@C-82 and Y@C-92 in the solid state form clusters (nanoparticles) in which the exchange coupling of the EMF takes place with quenching of the most electron spins.</p>
},
	keywords = {complexes},
	isbn = {1520-6106},
	doi = {Doi 10.1021/Jp048610z},
	url = {<Go to ISI>://WOS:000223289500027},
	author = {Koltover, V. K. and Logan, J. W. and Heise, H. and Bubnov, V. P. and Estrin, Y. I. and Kareev, I. E. and Lodygina, V. P. and Pines, A.}
}
