Synthesis, Characterization, and Luminescent Property of Amide Functionalized Ruthenium(II) Complexes

Abstract

Amide functionalized bipyridine ligands and their ruthenium(II) complexes of the type [Ru(bipyridine)₂(L)](PF₆)₂ were synthesized and characterized by UV/Visible, emission, FTIR, ¹H NMR spectroscopies and elemental analysis. Thermal properties of the ruthenium(II) polypyridyl complexes have been investigated using thermogravimetric analysis (TGA) and differential thermal analysis (DTA) techniques. These complexes show remarkable thermal stability at high temperatures under nitrogen atmosphere. The ruthenium(II) complexes show increasing fluorescence intensity in the presence of the amide groups. The increase of the emission intensity and quantum yield of the molecules may be attributed to the change of dipole moment of the amide group on electronic excitation. The effects of substituent (‒CH₃, ‒OCH₃, ‒COOC₂H₅, ‒COOH) on photophysical properties of molecules were correlated with the Hammett Substituent Constants. The molecules exhibit linear correlation for absorption and emission maxima.

Keywords:

• Amide group
• bipyridine
• hydrogen bonding
• ruthenium(II) complexes