A. Borchard, K. Hardcastle, P. Gantzel
Jan 8, 1993
Citations
0
Influential Citations
16
Citations
Journal
Tetrahedron Letters
Abstract
The structure and synthesis of the overcrowded polynuclear aromatic 1, 6, 7, 10-tetramethylfluoranthene, 1 , is presented. The structures of 1 and 11 have been determined by X-ray diffraction to be twisted into conformations of approximately C 2 symmetry due to the buttressing of the flanking methyl groups. Semi-empirical calculations (AM1) on 1 find two minima, twist and fold; the twist is of lower energy. The energy for enantiomerization of 1 is set at below 7.0 kcal/mol by variable temperature NMR. Computations predict a likely path to account for the ribbon twist.