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Spin-transfer complexes of endohedral metallofullerenes: ENDOR and NMR evidences
Date Issued
01-07-2003
Author(s)
Koltover, Vitaly K.
Bubnov, Vyacheslav P.
Estrin, Yakov I.
Lodygina, Vera P.
Davydov, Roman M.
Subramoni, Mahadevan
Manoharan, Periakaruppan T.
Abstract
The aim of this research was to answer the question whether the area of localization of unpaired electron in a paramagnetic endohedral metallofullerene is restricted by the fullerene shell or a "spin-leakage" beyond the fullerene cage is possible. Herein, we report an ENDOR investigation of La@C82 embedded into the polycarbonate films. The intensive 1H-ENDOR signal has been revealed. Since the La-EMF does not contain hydrogen atoms, this result testifies to the contact hyperfine interaction of the unpaired electron of La-EMF with the matrix hydrogen atoms, i.e. electron spin density on the polymer protons. We also report a NMR investigation of a liquid solution of the same La-EMF in hexamethylphosphoramide (HMPA), molecules of which contain the NMR active nucleus, phosphorus-31. The paramagnetic shift of the 31P NMR signal of bulk HMPA molecules in the presence of La-EMF has been revealed. Thus, much as the charge-transfer complexes, the paramagnetic EMF molecules can form the spin-transfer complexes in which the electron spin density partially localizes beyond the fullerene cage on atoms of the matrix in which the EMF molecules are embedded.
Volume
5