Synthesis, spectral and luminescent properties of new alkylamino-beta-ketoenol compounds and metal complexes on their basis for creation of fluorescent probes for biomolecules and optical materials

Vasyl I. Pekhnyo
V.I. Vernadsky Institute of General and Inorganic Chemistry of the National Academy of Sciences of Ukraine, Kyiv, Ukraine

Viktor Y. Chernii
V.I. Vernadsky Institute of General and Inorganic Chemistry of the National Academy of Sciences of Ukraine, Kyiv, Ukraine

Svitlana V. Chernii
V.I. Vernadsky Institute of General and Inorganic Chemistry of the National Academy of Sciences of Ukraine, Kyiv, Ukraine

Iryna M. Tretyakova
V.I. Vernadsky Institute of General and Inorganic Chemistry of the National Academy of Sciences of Ukraine, Kyiv, Ukraine


A series of chalcones and alkylamino-β-ketoenol dyes based on dehydroacetic acid were synthesized in this work. Their individuality is established and physicochemical properties are investigated. A number of phthalocyanine complexes of zirconium and hafnium with these β-ketoenol ligands have been obtained, and their spectral-luminescent properties have been studied. It is established that the obtained complexes absorbs light in a wide spectral range from 300 to 700 nm. Functionalized alkylamino-β-ketoenoles are reported as probes for fluorescent detection of protein aggregates that associated with dangerous diseases, including neurodegenerative disorders. Depending on the nature of the substituents, these dyes can increase the fluorescence intensity tenfold in the presence of fibrillar aggregates, but are practically insensitive to native proteins. The studied dyes have a green-yellow emission in the region of 495–540 nm. For the most effective compound (2E,5Z,7E)-8-(4-(dimethylamino)phenyl)-6-hydroxy-2-(2-methoxyethyl-amino)octa-2,5,7-trien-4-one the fluorescence quantum yield upon binding to insulin fibrils reaches 47.0%, while for the free dye this value is about 0.5%. Due to its sensing properties, this dye exceeds the properties of Thioflavin T, which is the standard for the determination of amyloid fibrils. Alkylamino-β-ketoenol dyes have been shown to be promising as fluorescent probes for the detection of β-pleated protein aggregates.





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