Structures and electronic states of regular and singly N-confused hexaphyrins(126.96.36.199.1.1) were thoroughly studied with the aid of DFT calculations. To obtain systematic information, all the conceivable structures (450 structures in total) were examined. Unlike the hexaphyrins(188.8.131.52.1.1) reported previously (J. Org. Chem. 2010, 75, 8213-8223), the electronic states of hexaphyrins were highly affected by their conformations. The planar conformers (dumbbell, rectangular, triangular) show Hückel antiaromaticity, while the singly twisted conformers show Möbius aromaticity. Figure-eight structures correspond to the doubly twisted structures and show nonaromaticity. Disruption of annulenic circuits in singly N-confused hexaphyrins caused weakening of both aromatic and antiaromatic characteristics. Relative stabilities among conformers were mainly governed by the intramolecular hydrogen bonds and secondarily affected by the steric factors. In addition, interconversion pathways among conformers were proposed on the basis of calculations on singly N-confused hexaphyrins.
All Science Journal Classification (ASJC) codes
- Organic Chemistry