Singly and doubly twisted [36]annulenes: synthesis and calculations.
A cyclophane with a [36]annulene periphery, including four anthrylene and two phenylene units, was synthesized in a four-step sequence using a McMurry cyclization. Upon crystallization from different solvents, four different conformations were determined by X-ray structure analysis. Two conformations exhibit a double twist (Hückel topology) and two structures include a single twist (Möbius topology). By using DFT calculations a conformation with a triple twist (Möbius) was located. However, our calculations and the NMR spectroscopy data do not provide evidence for aromaticity (for Möbius structures) or antiaromaticity (for Hückel structures).
Institut für Organische Chemie, Universität Kiel, Otto-Hahn-Platz 4, 24118 Kiel, Germany.
Ali Reza
AR
Mohebbi
Eva-Katrin
EK
Mucke
Gaston R
GR
Schaller
Felix
F
Köhler
Frank D
FD
Sönnichsen
Ludger
L
Ernst
Christian
C
Näther
Rainer
R
Herges