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Formation, Isolation, and Spectroscopic Properties of Some Isomers of C 60 H 38 , C 60 H 40 , C 60 H 42 , and C 60 H 44 − Analysis of the Effect of the Different Shapes of Various Helium‐Containing Hydrogenated Fullerenes on Their 3 He Chemical Shifts
Author(s) -
Peera Asghar,
Saini Rajesh K.,
Alemany Lawrence B.,
Billups W. Edward,
Saunders Martin,
Khong Anthony,
Syamala M. S.,
Cross R. James
Publication year - 2003
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200300350
Subject(s) - chemistry , fullerene , chemical shift , nmr spectra database , spectral line , helium , analytical chemistry (journal) , carbon 13 nmr , stereochemistry , organic chemistry , astronomy , physics
A complex mixture of C 60 H 38 to C 60 H 44 has been prepared by a much milder procedure (Benkeser reduction) than the hydrogenation procedures that have frequently been used to produce such highly hydrogenated derivatives of C 60 . 1 H and 13 C NMR spectra of fractions isolated by HPLC showed that more highly hydrogenated fullerenes exhibited signals that were shifted upfield. The opposite trend appears to hold in 3 He NMR spectra of the corresponding endohedral helium compounds. The changes in the 1 H, 13 C, and 3 He chemical shifts are reasonable for fullerenes hydrogenated to different extents. In particular, previously reported substantial changes in the shapes of the various hydrogenated fullerenes can reasonably account for the interesting trends apparent both in the 3 He chemical shifts of He@C 60 H x ( x = 0−44) and in the HPLC retention times of the corresponding non‐helium‐containing species. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)