Octametallic Cluster of Cp*Ir(glycinato) Cations

Abstract

Removal of chloride from Cp*Ir(glycinato)Cl in noncoordinating solvents with Ag[PF₆] or Tl[PF₆] leads to the formation of a closed octametallic loop of cations. The same loop also sequesters a number of PF₆⁻ counter anions. This is in contrast with reports that piano-stool complexes with amino acids form only trimetallic [Cp*Ir(aminoacidato)]₃³⁺ moieties upon creating the cation. Cp*Ir(glycinato)Cl also forms a trimetallic compound as well as an octametallic compound, and the octametallic vs trimetallic formation appears to be dependent on the anion. The synthesis and characterization of the octametallic complex, as well as some monometallic and trimetallic compounds, are reported, including the X-ray crystal structures.