4,5-Diaryl-3-hydroxy-2,2’-bipyridine-6-carbonitriles as Prospective Luminophores

Abstract

The derivatives of 3-hydroxy-2,2'-bipyridines are of interest due to their photophysical properties. They are also efficient and selective probes for Cu2+ and Zn2+ cations. We synthesized a series of 4,5-diaryl-3-hydroxy-2,2'-bipyridine-6-carbonitriles and studied their photophysical properties both in acetonitrile solutions and in powders. The compounds have high fluorescence quantum yield values in powder (up to 92.9%) and low values in acetonitrile solutions. Also, in acetonitrile solutions these compounds exhibit the large Stokes shift values, up to 241 nm, which is important for biovisualization applications. The photophysical properties of several compounds in different solvents were studied. It was demonstrated that the addition of Zn2+ cations to solutions of these compounds in THF results in a significant hypsochromic shift of the emission maximum simultaneously with a significant increase in the emission intensity. This shows that these compounds are potential probes for Zn2+ cations.