Chromogenic mercury ions recognition of a new ruthenium(II) complex with cyclometalated 2-(2-thienyl)pyridine in CH3CN-aqueous system

A new cyclometalated complex [Ru(II)(deeb)2(thpy)]PF6 (1) was synthesized using 4,4′-diethylester-2,2′-bipyridine (deeb) and 2-(2-thienyl)pyridine (thpy) as ligands. Its maximum MLCT absorption is about 575 nm, extending beyond 750 nm. When Hg2 + was added to the CH3CN-aqueous solution of 1, a remarkable color change from dark-red to yellow with a blue-shift of 120 nm occurred, which indicated that the as-prepared complex 1 can serve as a sensitive “naked-eye” indicator for Hg2 +.