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Synthesis, Structure, and Properties of Novel Open‐Cage Fullerenes Having Heteroatom(s) on the Rim of the Orifice
Author(s) -
Murata Yasujiro,
Murata Michihisa,
Komatsu Koichi
Publication year - 2003
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200390184
Subject(s) - fullerene , chemistry , ring (chemistry) , heteroatom , derivative (finance) , fullerene chemistry , singlet oxygen , crystallography , body orifice , photochemistry , oxygen , organic chemistry , ecology , financial economics , economics , biology
A thermal liquid‐phase reaction of fullerene C 60 with 3‐(2‐pyridyl)‐5,6‐diphenyl‐1,2,4‐triazine afforded aza‐open‐cage fullerene derivative 5 having an eight‐membered‐ring orifice on the fullerene cage. Compound 5 was found to undergo oxidative ring‐enlargement reactions with singlet oxygen under photo‐irradiation to give azadioxo‐open‐cage fullerene derivatives 9 and 10 , which have a 12‐membered‐ring orifice, in addition to a small amount of azadioxa‐open‐cage fullerene derivative 11 , which has a 10‐membered‐ring orifice. A thermal reaction of 9 with elemental sulfur in the presence of tetrakis(dimethylamino)ethylene resulted in further ring‐enlargement to give azadioxothia‐open‐cage fullerene derivative 15 , which has a 13‐membered‐ring orifice. The structures of 5 and 15 were determined by X‐ray crystallography, while those of 9, 10 , and 11 were confirmed by the agreement of observed 13 C NMR spectra with those obtained by DFT‐GIAO calculations. These reactions were rationalized based on the results of molecular orbital calculations. Following electrochemical measurements, compounds 9 and 10 , which have two carbonyl groups on the rim of the orifice, were found to be more readily reduced than C 60 itself (the first reduction potential was found to be 0.2 V lower than that of C 60 ), while the first reduction potentials of other open‐cage fullerene derivatives, 5, 11 , and 15 , were nearly the same as that of C 60 .