Luminescent chemosensor for Hg2+ ion based on a dinuclear Ru(II) complex containing open chain azacrown ether

• We synthesized one Ru(II) complex with open chain azacrown ether.
• The complex can serve as a luminescent turn-off sensor toward Hg2+.
• The complex displays selective and sensitive luminescence quenching upon the addition of Hg2+.

One novel dinuclear Ru(II) complex [{Ru(bpy)2}2(μ2-H2L)](PF6)4 based on the flexible open chain azacrown ether was prepared and characterized. Complex [{Ru(bpy)2}2(μ2-H2L)]4+ supplies vacant coordination sites toward the added cations and finally results in a unique selectivity to Hg2+ over other metal ions in H2O-CH3CN solution (1:1, v/v). Upon addition of Hg2+, complex [{Ru(bpy)2}2(μ2-H2L)]4+ shows a remarkable decrease in luminescence intensity. The complex interacts with Hg2+ in a 1:1 stoichiometry with an association constant of 5.02 × 104 M−1. The detection limit for Hg2+ is found to be 2 × 10−7 mol L−1, and all tested background metal ions exhibit no interference with the detection of Hg2+.

A dinuclear Ru(II) polypyridine complex containing open chain azacrown ether has been synthesized. The complex acts as a luminescent on–off sensor with high selectivity toward Hg2+ among 17 metal ions.Figure optionsDownload as PowerPoint slide