Syntheses and structural characterization of heterometallic trinuclear {Cu(I), Ag(I)}-Ir(III) hydride complexes bridged by Ir metalloligands

Abstract

The reactions of [Ir(H)2(PPh3)2(tptz)]PF6 (1) (tptz = 2,4,6-tris(2-pyridyl)-s-triazine) with {Cu(I), Ag(I)} salts under Ar afforded heterometallic trinuclear {Cu(I), Ag(I)}-Ir(III)-tptz hydride complexes [CuIr2(H)4(PPh3)4(tptz)2](PF6)3·2Me2CO (2), [AgIr2(H)4(PPh3)4(tptz)2](PF6)3·4Me2CO·H2O (3a) and [AgIr2(H)4(PPh3)4(tptz)2](CF3SO3)2(PF6)·4Me2CO (3b). We have demonstrated that Ir(III)-tptz complex 1 can serve as a potentially bridgeable Ir metalloligand. X-ray analyses showed that meaningful intramolecular π-π stacking interactions exist in {Cu(I), Ag(I)}-Ir(III)-tptz hydride complexes 2, 3a and 3b. These intramolecular π-π stacking interactions could be contributed to the structural stabilization of the distorted boat-shaped structure. 1H and 31P NMR analyses showed that the structures of {Cu(I), Ag(I)}-Ir(III)-tptz hydride complexes 2 and 3a are kept in solution. The significant 1H NMR upfield shifts could be induced by the ring current effect from the phenyl groups of adjacent PPh3 ligands.

Keywords

• Heterometallic complexes
• Copper complexes
• Iridium complexes
• Silver complexes
• Hydride complexes
• Metalloligands