Cyclometalated Ir(III) Complex as a Metalloligand and a Selective Cu(II) Sensor: Synthesis and Structural Characterization of a Heterometallic Tetranuclear Ir(III)/Cu(II) Complex

摘要

A cyclometalated Ir(III) complex, [Ir(ppy)_(2)(LH)] (2 ) [LH_(2) = 1,2-bis(pyridine-2-carboxamido)benzene; ppyH = 2-phenylpyridine] was synthesized and structurally characterized. [Ir(ppy)_(2)(LH)] contains free donor sites and functions as a metalloligand. Accordingly, it interacts with a Cu(II) salt to afford the heterometallic tetranuclear complex, [{Ir(ppy)_(2)(L)}_(2){Cu_(2)Cl_(2)}] (3 ). In the latter, a Cu_(2)Cl_(2) dimer bridges the two cyclometalated Ir(III) units, resulting in a Ir~(III)–Cu~(II)–Cu~(II)–Ir~(III) motif. 2 also functions as a selective and reversible sensor for Cu~(2+), as revealed by quenching of its emission and subsequent revival of the luminescence signal upon addition of EDTA.