Functionalized 2-(5-arylpyridin-2-yl)quinolines: synthesis and photophysical properties

Pot, Atom, Step Economic (PASE) Approach towards (Aza)‐2,2′‐Bipyridines: Synthesis and Photophysical Studies

“…The compounds are arranged in order of increasing their emission maxima. Thus, the smallest effect on the bathochromic shift of the emission maxima was observed when one of the pyridine ring was replaced with quinolone one, including 6,7‐difluoroquinoline (Table , entries 2–3), and by the introduction of the ester group in the C5 position of pyridine ring (Table , entry 4). A greater effect was achieved for the present reported 2,2′‐bipyridines, upon the introducing the methoxy group (Table , entry 5) in the C4 position of the pyridine ring: this resulted the bathochromic shift from 357 to 411 nm.…”

“…As for the fluorescence quantum yields, the unsubstituted 5‐phenyl‐2,2′‐bipyridine (Table , entry 1) exhibits a very low quantum yield, which could be explained by the large contribution of n‐π transitions to the excited state . Replacement of the pyridine residue with the quinolone one, including its 6,7‐difluoro analogue, as well as the introduction of the ester group does not significantly affect the quantum yield. In contrast, the introduction of methoxy group (Table , entry 5) or aromatic substituents into the external pyridine ring (Table , entries 6 and 8), as well as the replacement of the pyridine ring with benzo[ h ]quinolone one resulted in a significant increase in quantum yield.…”