Internal dynamics and optical rotations predicted for O(h)- and O-symmetric cubanes.
B3LYP/6-31G(d) calculations find that cubanes, persubstituted with NO2 or BF2 groups, are predicted to undergo near-barrierless, internal disrotations. However, as a consequence of the intrinsically higher energies of eclipsed conformations for threefold than for twofold rotors, the threshold mechanisms for octamethyl-, octakis(trifluoromethyl)-, octakis(trichloromethyl)-, octakis(tribromomethyl)-, octasilylcubane, and octakis(trichlorosilyl)cubane are calculated to be mono- or conrotation. The cubanes with the larger substituents are predicted to be O-symmetric, resolvable, and thus optically active.
Department of Chemistry and the Center for Advanced Scientific Computing and Modeling, Univeristy of North Texas, 1155 Union Circle, #305070, Denton, Texas 76203-5017, USA.
David A
DA
Hrovat
Christine M
CM
Isborn
Bart
B
Kahr
Weston Thatcher
WT
Borden