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Synthesis of aminyl biradicals by base-induced Csp³-Csp³ coupling of cationic azo dyes.

ABSTRACT: The synthesis of the industrially important polymer parylene is achieved by polymerization of p-quinodimethane (p-QDM). The polymerization is thought to proceed via a biradical p-QDM dimer, but isolation or characterization of such a biradical has remained elusive. Here, we describe the synthesis of an aza-analogue of this p-QDM dimer. The biradical is formed by base-induced dimerization of an azoimidazolium dye. Due to the presence of sterically shielded aminyl radicals instead of terminal H₂? groups, the stability of this dimer is sufficient for analyses by ESR spectroscopy and X-ray crystallography. A similar Csp³-Csp³ coupling was observed for an azotriazolium dye, suggesting that base-induced C-C coupling reactions can be realized for different types of azo dyes.

SUBMITTER: Liu Y

PROVIDER: S-EPMC6568049 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature

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Synthesis of aminyl biradicals by base-induced Csp3-Csp3 coupling of cationic azo dyes.

Liu Yizhu Y Varava Paul P Fabrizio Alberto A Eymann Léonard Y M LYM Tskhovrebov Alexander G AG Planes Ophélie Marie OM Solari Euro E Fadaei-Tirani Farzaneh F Scopelliti Rosario R Sienkiewicz Andrzej A Corminboeuf Clémence C Severin Kay K

Chemical science 20190509 22

The synthesis of the industrially important polymer parylene is achieved by polymerization of p-quinodimethane (p-QDM). The polymerization is thought to proceed via a biradical p-QDM dimer, but isolation or characterization of such a biradical has remained elusive. Here, we describe the synthesis of an aza-analogue of this p-QDM dimer. The biradical is formed by base-induced dimerization of an azoimidazolium dye. Due to the presence of sterically shielded aminy ...[more]

PMID: 31293757

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