A Stable Iridium(IV) Complex Containing the Kläui Tripodal Ligand [Co(η⁵‐C₅H₅){P(O)(OEt)₂}₃]^–

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