References

General ChemistryCatalysisOrganic Chemistry
Inglese

meso‐Aryl Substituted Rubyrin and Its Higher Homologues: Structural Characterization and Chemical Properties

Pubblicato in Chemistry – A European Journal
Autori Soji Shimizu, Won‐Seob Cho, Jonathan L. Sessler, Hiroshi Shinokubo, Atsuhiro Osuka

Abstractmeso‐Aryl substituted rubyrin ([26]hexaphyrin(1.1.0.1.1.0)) 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 [52]dodecaphyrin(1.1.0.1.1.0.1.1.0.1.1.0) 4 takes a symmetric helical conformation, the larger species, [62]pentadecaphyrin(1.1.0.1.1.0.1.1.0.1.1.0.1.1.0) 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 [24]rubyrin 6, a species that displays antiaromatic characteristics. [26]Rubyrin 2 and [24]rubyrin 6 both underwent metallation when reacted with Zn(OAc)2 to give the corresponding bis‐zinc(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.

Inglese

Six questions on topology in theoretical chemistry

Pubblicato in Computational and Theoretical Chemistry
Autori Paul L. Ayers, Russell J. Boyd, Patrick Bultinck, Michel Caffarel, Ramon Carbó-Dorca, Mauro Causá, Jerzy Cioslowski, Julia Contreras-Garcia, David L. Cooper, Philip Coppens, Carlo Gatti, Simon Grabowsky, Paolo Lazzeretti, Piero Macchi, Ángel Martín Pendás, Paul L.A. Popelier, Klaus Ruedenberg, Henry Rzepa, Andreas Savin, Alexander Sax, W.H. Eugen Schwarz, Shant Shahbazian, Bernard Silvi, Miquel Solà, Vladimir Tsirelson