meso-Aryl substituted rubyrin (hexaphyrin(220.127.116.11.1.0)) 2 and a series of rubyrin-type large expanded porphyrins were obtained from a facile one-pot oxidative coupling reaction of meso-pentafluorophenyl substituted tripyrrane 1. The structures of two of the resulting products were determined by single-crystal X-ray diffraction analysis. Whereas dodecaphyrin-(18.104.22.168.1. 0.1.1.0.1.1.0) 4 takes a symmetric helical conformation, the larger species, pentadecaphyrin-(22.214.171.124.126.96.36.199.0.1.1.0.1.1.0) 5, adopts a nonsymmetric distorted conformation in the solid state that contains an intramolecular helical structure. The ability of rubyrin 2 to act as an anion receptor in its diprotonated form (2.2H+) was demonstrated in methanolic solutions. Oxidation of 2 with MnO2 gave rubyrin 6, a species that displays antiaromatic characteristics. Rubyrin 2 and rubyrin 6 both underwent metallation when reacted with Zn-(OAc)2 to give the corresponding biszinc(II) complexes 7 and 8 quantitatively without engendering a change in the oxidation state of the ligands. As a result, complexes 7 and 8 exhibit aromatic and antiaromatic character, respectively. NICS calculation on these compounds also supported aromaticity of 2 and 7, and antiaromaticity of 6 and 8.
All Science Journal Classification (ASJC) codes
- Organic Chemistry