Yoon Zin Seok, Noh Su Bum, Cho Dong-Gyu, Sessler Jonathan L, Kim Dongho
Department of Chemistry, Yonsei University, Seoul 120-749, Korea.
Chem Commun (Camb). 2007 Jun 21(23):2378-80. doi: 10.1039/b618674b.
Using the bidirectional NICS scan method in conjunction with two-photon absorption (TPA) measurements, it has proved possible to determine the relationship between pi-conjugation and aromaticity in two structurally related expanded porphyrin systems, sapphyrin and inverted sapphyrin, and establish that differences in these defining factors depend on the presence or absence of a key sp3 hybrid molecular orbital within the macrocyclic periphery.
