Qualitatively Different Reactivities of Hydride Reagents toward [(α-diimine)(η5-C5Me5)ClIr]+ Cations: Substitution, Electron Transfer (Reduction), or Stepwise Hydrogenation
摘要:
Whereas complex cations [(alpha-diimine)(eta(5)-C-5-Me-5)ClIr](+) with 2,2'-bipyridine and related aromatic ligands show only the expected Cl/H exchange on reaction with borohydrides, the systems [(RN=CHCH=NR)(eta(5)-C5Me5)ClIr](+) undergo reduction to the enediamido(2-)-iridium,(III) species [(RNCH=CHNR)(eta(5)-C-5-Me-5)Ir], even in protic media, if R is an axially shielding 2,6-dialkylphenyl group. In protic media the complex ion with R = cyclohexyl undergoes Cl/H exchange and stepwise hydrogenation of the a-diimine ligand via [(RHNCH2CH=NR)(eta(5)-C5Me5)HIr](PF6) to the structurally characterized compound [(RHNCH2CH2NHR)(eta(5)-C5Me6)HIr][BH3(CN)].