A Stable Iridium(IV) Complex Containing the Kläui Tripodal Ligand [Co(η 5 ‐C 5 H 5 ){P(O)(OEt) 2 } 3 ] –

Iridium and rhodium complexes containing the Kläui oxygen tripodal ligand [Co(η 5 ‐C 5 H 5 ){P(O)(OEt) 2 } 3 ] – (L OEt – ) have been synthesized and their redox chemistry investigated. Treatment of [Ir(COE) 2 Cl] 2 (COE = cyclooctene) with [AgL OEt ] afforded [Ir(L OEt )Cl 2 (COE)] ( 1 ), which reacted with AgNO 3 , 4,4′‐di‐ tert ‐butyl‐2,2′‐bipyridyl (dtbpy), and NH 4 PF 6 to give [Ir(L OEt )(dtbpy)(COE)][PF 6 ] ( 2 ). Ozonolysis of complex 1 in CH 2 Cl 2 afforded the Ir IV complex [Ir(L OEt )Cl 3 ] ( 3 ), which exhibited an EPR signal (CH 2 Cl 2 , 4 K) with g = 1.65 and 1.06. The Ir IV /Ir III reduction potential for complex 3 in acetonitrile was determined to be ca. 0 V vs. ferrocenium/ferrocene. Treatment of [Rh(bpy)Cl 3 (DMF)] (bpy = 2,2′‐bipyridyl; DMF = N , N ‐dimethylformamide) with [AgL OEt ] and Ag(OTf) (OTf – = triflate) afforded [Rh(L OEt )(bpy)Cl][OTf] ( 4 ), which reacted with AgOTf in refluxing acetone to yield [Rh(L OEt )(bpy)(acetone)][OTf] 2 ( 5 ). Reaction of [RhL OEt Cl 2 ] 2 with 1 equiv. or an excess of tert ‐butylamine in refluxing tetrahydrofuran afforded [Rh(L OEt )Cl 2 (NH 2 t Bu)] ( 6 ) or [Rh(L OEt )Cl 2 (NH 2 t Bu) 2 ] ( 7 ). Complex 7 contains one chlorido ligand and one noncoordinated chloride ion that is hydrogen‐bonded to the two tert ‐butylamine ligands. The crystal structures of complexes 1 , 3 , and 7 were determined.