Flat corannulene has been considered so far only as a transition state of the bowl-to-bowl inversion process. This study was driven by the prediction that substituents with strong steric repulsion could destabilize the bowl-shaped conformation of this molecule to such an extent that the highly unstable planar geometry would become an isolable molecule. To examine the substituents' effect on the corannulene bowl depth, optimized structures for the highly-congested decakis(t-butylsulfido)corannulene were calculated. The computations, performed with both the M06-2X/def2-TZVP and the B3LYP/def2-TZVP methods (the latter with and without Grimme's D3 dispersion correction), predict that this molecule can achieve two minimum structures: a flat carbon framework and a bowl-shaped structure, which are very close in energy. This rather unusual compound was easily synthesized from decachlorocorannulene under mild reaction conditions, and X-ray crystallographic studies gave similar results to the theoretical predictions. This compound crystallized in two different polymorphs, one exhibiting a completely flat corannulene core and the other having a bowl-shaped conformation.
|Number of pages||11|
|State||Published - 28 Dec 2020|
Bibliographical noteFunding Information:
K. is the incumbent of the Benno Gitter & Ilana Ben-Ami Chair of Biotechnology, Technion. E. K. and O. R. acknowledge the nancial support by the Ministry of Science, Technology and Space (MOST, grant no. 3-10855), the Open University of Israel (OUI) and the Institute of Catalysis Science and Technology, Technion. A. S. thanks the Israeli Science Foundation (grant no. 1485/11) for nancial support. E. S. acknowledges nancial support from the Irwin and Joan Jacobs Fellowship and the Fine Scholarship for PhD Students. R. G. P. is grateful for a Schulich Graduate Fellowship.
© The Royal Society of Chemistry.