Cyclooctatetraenophanes: A Computational Study
2015
Bachrach, Steven M. | Tang, Meghan W.
DFT (ωB97X-D, B3LYP-D3, M06-2x, and B3LYP) along with MP2 computations were performed on four cyclophanes composed of two or three cyclooctatetraene (COT) rings connected by two, four, or eight ethylene bridges. Both COT rings in cyclophanes with two ethylene bridges (2) and with four bridges in the 1, 2, 5, and 6 positions (6) are in a tub conformation. However, the cyclophane with the four bridges in the 1, 3, 5, and 7 positions (7) is notable for the near planar geometry of the COT rings. The triple-decker cyclophane 8 has planar top and bottom COT rings, while the central ring is puckered with alternating carbon positions up and down. The nature of the COT rings, especially their antiaromatic character, is assessed using NICS and bond alternation and the distance between the centers of the COT rings.
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