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Efficient Synthesis of C 2 v ‐Symmetrical Pentakisadducts of C 60 as Versatile Building Blocks for Fullerene Architectures that Involve a Mixed Octahedral Addition Pattern
Author(s) -
Hörmann Frank,
Donaubauer Wolfgang,
Hampel Frank,
Hirsch Andreas
Publication year - 2012
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.201102638
Subject(s) - fullerene , octahedron , moiety , yield (engineering) , mass spectrometry , chemistry , fourier transform infrared spectroscopy , spectroscopy , crystallography , materials science , combinatorial chemistry , stereochemistry , organic chemistry , crystal structure , chemical engineering , physics , chromatography , engineering , quantum mechanics , metallurgy
We report here on the selective synthesis of fullerene pentakisadducts 3 with an incomplete octahedral addition pattern by means of mixed [5:1]hexakisadducts 1 that involve an isoxazoline moiety as a protection group. The isoxazoline addend can be cleanly cleaved by irradiation with light. By using this protection–deprotection strategy, a variety of fullerene pentakisadducts 3 were synthesized in 29–44 % overall yield without the need of HPLC purification. This novel photolytic deprotection of 1 can be explained by an initial electron transfer that leads to a biradical, which can easily eliminate the isoxazoline added. The very efficient and straightforward syntheses of the bisfullerene 4 and the globular hexakisadduct 7 , each of which involves mixed octahedral addition patterns, clearly demonstrate the advantage of fullerene pentakisadducts 3 as suitable precursors for the construction of highly functional and complex [5:1]hexakisadduct architectures. Complete structural characterization of all new compounds was carried out by MALDI mass spectrometry, UV/Vis, FTIR, 1 H NMR and 13 C NMR spectroscopy, as well as X‐ray diffraction.