Synthesis and photophysical characterization of ruthenium(II) and platinum(II) complexes with bis-pyridylethynyl-phenanthroline ligands as a metalloligand

Abstract

Novel ruthenium complexes Ru(L)(bpy)₂(PF₆)₂ and platinum organometallic complexes Pt(L)(−≡−C₆H₅CH₃)₂ with bis-(pyridinyl)ethynyl-phenanthrolines (L = 3,8-bis[2-(3-pyridinyl)ethynyl]-1,10-phenanthroline or 3,8-bis[2-(4-pyridinyl)ethynyl]-1,10-phenanthroline) that function as metalloligands by extra pyridyl units have been prepared using respective synthetic methods. These complexes have broad absorption bands assignable to the MLCT band as the main contributing factor in the 400 to 550 nm wavelength region. Furthermore, these complexes show phosphorescence centered around 680 nm upon excitation at 425 nm. These emissions were assigned to a triplet MLCT-based luminescence for the ruthenium complexes, while a triplet MLCT as the main element, including the interligand charge transfer as the minor element, was assigned for the platinum organometallic complexes. The quantum yields of the emission of the present ruthenium complexes were relatively high, and these complexes are exactly phosphorescent dyes, although the emission intensities of the platinum complexes are poor. These two types of complexes are capable of selective photophysical detection of some metal ions and can serve as metalloligands in the construction of supramolecular metallocycles.