Synthesis and characterization of 7, 16-bis(phenylazo)tetraaza[14]annulenes

✍ Scribed by Kazunori Sakata; Junichi Yamashita; Mamoru Hashimoto; Akihiko Tsuge; Yasuhiro Tanoue

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2001
• Tongue: English
• Weight: 50 KB
• Volume: 38
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570380419

✦ Synopsis

Abstract

The diazo coupling reaction between a tetraaza[14]annulene (1) and a series of 4‐substituted phenyl‐diazonium tetrafluoroborates yielded the corresponding 7, 16‐disubstituted products. Mass spectra indicate the presence of molecular ion peaks that substantiate the 7,16‐disubstituted products (4); the lack of olefinic proton signals corresponding to the 7,16‐ position in the ^1^H nmr spectra of 4 also show that diazo coupling has taken place. Analysis of signals corresponding to the methyl groups of 4 in their ^1^H and ^13^C nmr spectra indicate that the imine‐bis‐hydrazone form is present for compounds that do not contain p‐methoxyphenyl groups. However, analysis of methyl signals in the nmr specta of compounds 4 containing p‐methoxyphenyl groups show that the bis‐azo form and the imine‐bis‐hydrazone form are present through tautomerism. Complexation with nickel(II) ion induces the formation of the bis‐ azo structure.