Synthesis and Photophysical Properties of α-(<i>N</i>-Biphenyl)-Substituted 2,2′-Bipyridine-Based Push–Pull Fluorophores

Abstract

A series of new α-(N-biphenyl)-substituted 2,2′-bipyridines were obtained through the combination of the ipso-nucleophilic aromatic substitution of the C5-cyano group, aza-Diels–Alder and Suzuki cross-coupling reactions, starting from 5-cyano-1,2,4-triazines. For the obtained compounds, photophysical and fluorosolvatochromic properties were studied. Fluorophores 3l and 3b demonstrated unexpected AIEE activity, while 3a and 3h showed promising nitroexplosive detection abilities.

Keywords

• α-(<i>N</i>-Biphenyl)-substituted 2,2′-bipyridines
• “push–pull” fluorophores
• fluorescence
• fluorosolvatochromic properties
• Lippert–Mataga equation
• AIEE