Synthesis, structure, photophysics, electrochemistry, and ion-binding studies of ruthenium(II) 1,10-phenanthroline complexes containing thia-, selena-, and aza-crown pendants

Abstract

A series of ruthenium(II) diimine complexes containing thia-, selena- and aza-crowns derived from 1,10-phenanthroline have been synthesized and characterized, and their photophysics and electrochemistry were studied. Their interaction with metal ions was investigated by UV-vis, luminescence, and 1H NMR spectroscopy. The crystal structures of [Ru(bpy) 2(L1)](PF 6) 2, [Ru(bpy) 2(L2)] (ClO 4) 2, [Ru(bpy) 2(L3)](ClO 4) 2, and [Ru(bpy) 2(L4)](ClO 4) 2 have been determined. The luminescence properties of [Ru(bpy) 2(L1)] (ClO 4) 2 were found to be sensitive and selective toward the presence of Hg 2+ ions in an acetonitrile solution. The addition of alkaline-earth metal ions, Zn 2+, Cd 2+, and Hg 2+ ions, to the solution of [Ru(bpy) 2(L6)](ClO 4) 2 in acetonitrile gave rise to large changes in the UV-vis and emission spectra. The binding of metal ions to [Ru(bpy) 2(L6)](ClO 4) 2 was found to cause a strong enhancement in the emission intensities of the complex, with high specificity toward Hg 2+ ions. © 2007 American Chemical Society.