Synthesis and Luminescence Spectral Properties of New Cyano-Substituted 2,2′-Bipyridine Derivatives

Previously unknown 2-{4-aryl-5-cyano-[2,2′-bipyridin]-6(1H)-ylidene}malononitriles were synthe­sized by reaction of 3-aryl-1-(pyridin-2-yl)prop-2-en-1-ones (azachalcones) with malononitrile dimer. Their colored solutions showed fluorescence in the yellow–orange region with the emission maxima located at λ 565 to 582 nm, depending on the substituent in position 4 of the pyridine ring bearing cyano groups. The synthesized compounds are promising for further study as chemosensors due to a unique combination of 2,2′-bipyridine and buta-1,3-diene-1,1,3-tricarbonitrile fragments in their molecules.